namespace: change -> git.grassecon.net/kamikazechaser/vise

.gitignore

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+examples/**/*.bin
+examples/**/*.txt

LICENSE

@@ -0,0 +1,661 @@
+                    GNU AFFERO GENERAL PUBLIC LICENSE
+                       Version 3, 19 November 2007
+
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+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If your software can interact with users remotely through a computer
+network, you should also make sure that it provides a way for users to
+get its source.  For example, if your program is a web application, its
+interface could display a "Source" link that leads users to an archive
+of the code.  There are many ways you could offer source, and different
+solutions will be better for different programs; see section 13 for the
+specific requirements.
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU AGPL, see
+<https://www.gnu.org/licenses/>.

Makefile

@@ -0,0 +1,15 @@
+examples: profile session helloworld validate
+
+.PHONY: examples
+
+profile:
+	bash examples/compile.bash examples/profile
+
+session:
+	bash examples/compile.bash examples/session
+
+helloworld:
+	bash examples/compile.bash examples/helloworld
+
+validate:
+	bash examples/compile.bash examples/validate

README.md

@@ -1,27 +1,63 @@
-# festive: A Constrained Size Output Virtual Machine
+# vise: A Constrained Size Output Virtual Machine
 
 An attempt at defining a small VM to handle menu interaction for size-constrained clients and servers.
 
+
+## Rationale
+
 Original motivation was to create a simple templating renderer for USSD clients, combined with an agnostic data-retrieval reference that may conceal any level of complexity.
 
 
+## Features
+
+### Implemented
+
+* Define and enforce max output size for every individual output.
+* Allow one single data entry to fill remaining available size capacity.
+* An assembly-like mini-language to define:
+    - external code execution.
+    - input validation and routing.
+    - menu definitions.
+    - flow control.
+    - exception handling.
+* templated output from results of external code execution.
+* generate and navigate pages where data symbol contents are too long to display on a single page.
+* pluggable function design for handling external code execution calls.
+
+
+### Pending
+
+* Node Walking Audit Tool (NWAT) to ensure all nodes produce output within constraints.
+* Input generator engine for the NWAT.
+* State error flag debugger representation, builtin as well as user-defined.
+* Stepwise debug view on log/stderr of state mutations.
+* Toolset to assist bootstrapping/recovering (failed) state from spec.
+
+
+### Possibly useful
+
+* Breakpoints.
+* Key/value database reference example.
+* Same-page catch with dedicated error string to prepend to template
+
 
 ## Opcodes
 
-The VM defines the following opcode symbols:
+The VM defines the following opcode symbols, alphabetically:
 
-* `CATCH <symbol> <signal>` - Jump to symbol if signal is set (see `signals` below).
+* `CATCH <symbol> <signal>` - Jump to symbol if signal is set (see `signals` below). If match, has same side-effect as move.
-* `CROAK <signal>` - Clear state and restart execution from top if signal is set (see `signals` below).
+* `CROAK <signal>` - Clear state and restart execution from top if signal is set (see `signals` below). If match, has same side-effect as move.
-* `LOAD <symbol> <size>` - Execute the code symbol `symbol` and cache the data, constrained to the given `size`. Can be exposed with `MAP` within scope, 
-* `RELOAD <symbol>` - Execute a code symbol already loaded by `LOAD` and cache the data, constrained to the previously given `size` for the same symbol. 
-* `MAP <symbol>` - Expose a code symbol previously loaded by `LOAD` to the rendering client. Roughly corresponds to the `global` directive in Python.
-* `MOVE <symbol>` - Create a new execution frame, invalidating all previous `MAP` calls. More detailed: After a `MOVE` call, a `BACK` call will return to the same execution frame, with the same symbols available, but all `MAP` calls will have to be repeated.
 * `HALT` - Stop execution. The remaining bytecode (typically, the routing code for the node) is returned to the invoking function.
 * `INCMP <arg> <symbol>` - Compare registered input to `arg`. If match, it has the same side-effects as `MOVE`. In addition, any consecutive `INCMP` matches will be ignored until `HALT` is called.
-* `MSIZE <max> <min>` - Set min and max display size of menu part to `num` bytes.
+* `LOAD <symbol> <size>` - Execute the code symbol `symbol` and cache the data, constrained to the given `size`. Can be exposed with `MAP` within scope.  See "External code" below.
-* `MOUT <choice> <display>` - Add menu display entry. Each entry should have a matching `INCMP` whose `arg` matches `choice`. `display` is a descriptive text of the menu item.
+* `MAP <symbol>` - Expose a code symbol previously loaded by `LOAD` to the rendering client. Roughly corresponds to the `global` directive in Python.
 * `MNEXT <choice> <display>` - Define how to display the choice for advancing when browsing menu.
+* `MOUT <choice> <display>` - Add menu display entry. Each entry should have a matching `INCMP` whose `arg` matches `choice`. `display` is a descriptive text of the menu item.
+* `MOVE <symbol>` - Create a new execution frame, invalidating all previous `MAP` calls.
 * `MPREV <choice> <display>` - Define how to display the choice for returning when browsing menu.
+* `MSEP` -  **Not yet implemented**. Marker for menu page separation. Incompatible with browseable nodes.
+* `MSIZE <max> <min>` - **Not yet implemented**. Set min and max display size of menu part to `num` bytes.
+* `RELOAD <symbol>` - Execute a code symbol already loaded by `LOAD` and cache the data, constrained to the previously given `size` for the same symbol. See "External code" below.
 
 
 ### External code
@@ -34,6 +70,8 @@ Loaded symbols are not automatically exposed to the rendering client. To expose
 
 The associated content of loaded symbols may be refreshed using the `RELOAD` opcode. `RELOAD` only works within the same constraints as `MAP`. However, updated content must be available even if a `MAP` precedes a `RELOAD` within the same frame.
 
+Methods handling `LOAD` symbols have the client input available to them.
+
 
 ### External symbol optimizations
 
@@ -55,6 +93,8 @@ The signal flag arguments should only set a single flag to be tested. If more th
 
 First 8 flags are reserved and used for internal VM operations.
 
+When a signal is caught, the *bytecode buffer is flushed* before the target symbol code is loaded.
+
 
 ### Avoid duplicate menu items
 
@@ -79,20 +119,19 @@ To assist with menu creation, a few batch operation symbols have been made avail
 
 The fixed-size output is generated using a templating language, and a combination of one or more _max size_ properties, and an optional _sink_ property that will attempt to consume all remaining capacity of the rendered template.
 
-For example, in this example
+In this example
 
 - `maxOutputSize` is 256 bytes long.
 - `template` is 120 bytes long.
 - param `one` has max size 10 but uses 5.
 - param `two` has max size 20 but uses 12.
 - param `three` is a _sink_.
+- rendered menu is 15 bytes long.
 
-The renderer may use up to `256 - 120 - 5 - 12 = 119` bytes from the _sink_ when rendering the output.
+The renderer may use up to `256 - 120 - 5 - 12 - 15 = 104` bytes from the _sink_ when rendering the output.
 
 
-### Menu rendering
+### Menu browsing
-
-The menu is appended to the template output.
 
 A max size can be set for the menu, which will count towards the space available for the _template sink_.
 
@@ -117,6 +156,8 @@ Multipage outputs, like listings, are handled using the _sink_ output constraint
 
 ### Languages support
 
+**Not yet implemented**
+
 Language for rendering is determined at the top-level state.
 
 Lookups dependent on language are prefixed by either `ISO 639-1` or `ISO 639-3` language codes, followed by `:`.
@@ -140,19 +181,19 @@ Currently the following rules apply for encoding in version `0`:
 
 ## Reference implementation
 
-This repository provides a `golang` reference implementation for the `festive` concept.
+This repository provides a `golang` reference implementation for the `vise` concept.
-
-In this reference implementation some constraints apply
 
 
 ### Structure
 
-_TODO_: `state` will be separated into `cache` and `session`.
+- `asm`: Assembly parser and compiler.
-
+- `cache`: Holds and manages all loaded content.
-- `vm`: Defines instructions, and applies transformations according to the instructions.
-- `state`: Holds the code cache, contents cache aswell as error tates from code execution.
-- `resource`: Retrieves data and bytecode from external symbols, and retrieves and renders templates.
 - `engine`: Outermost interface. Orchestrates execution of bytecode against input. 
+- `persist`: Interface and reference implementation of `state` and `cache` persistence across asynchronous vm executions.
+- `render`: Renders menu and templates, and enforces output size constraints.
+- `resource`: Retrieves data and bytecode from external symbols, and retrieves templates.
+- `state`: Holds the bytecode buffer, error states and navigation states.
+- `vm`: Defines instructions, and applies transformations according to the instructions.
 
 
 ### Template rendering
@@ -162,6 +203,28 @@ Template rendering is done using the `text/template` faciilty in the `golang` st
 It expects all replacement symbols to be available at time of rendering, and has no tolerance for missing ones.
 
 
+## Runtime engine
+
+The runtime engine:
+
+* Validates client input
+* Runs VM with client input
+* Renders result
+* Restarts execution from top if the vm has nothing more to do.
+
+There are two flavors of the engine:
+
+* `engine.Loop` - class used for continuous, in-memory interaction with the vm (e.g. terminal).
+* `engine.RunPersisted` - method which combines single vm executions with persisted state (e.g. http).
+
+
+### Client identification
+
+The `engine.Config` struct defines a property `SessionId` which is added to the `context.Context` passed through entire engine vm call roundtrip.
+
+This is used to identify the caller, and thus defines a top-level storage key under which data entries should be retrieved.
+
+
 ## Bytecode examples
 
 (Minimal, WIP)
@@ -180,7 +243,7 @@ It expects all replacement symbols to be available at time of rendering, and has
 
 ## Assembly examples
 
-See `testdata/*.fst`
+See `testdata/*.vis`
 
 
 ## Development tools
@@ -190,14 +253,14 @@ Located in the `dev/` directory.
 
 ### Test data generation
 
-`go run ./dev/testdata/ <directory>`
+`go run ./dev/gendata/ <directory>`
 
 Outputs bytecodes and templates for test data scenarios used in `engine` unit tests.
 
 
 ### Interactive runner
 
-`go run ./dev [-d <data_directory>] [--root <root_symbol>]`
+`go run ./dev/interactive [-d <data_directory>] [--root <root_symbol>] [--session-id <session_id>]`
 
 Creates a new interactive session using `engine.DefaultEngine`, starting execution at symbol `root_symbol`
 
@@ -207,6 +270,8 @@ If `data_directory` is not set, current directory will be used.
 
 if `root_symbol` is not set, the symbol `root` will be used.
 
+if `session_id` is set, mutable data will be stored and retrieved keyed by the given identifer (if implemented).
+
 
 ### Assembler
 
@@ -221,3 +286,20 @@ Will output bytecode on STDOUT generated from a valid assembly file.
 
 Will list all the instructions on STDOUT from a valid binary file.
 
+
+## Interactive case examples
+
+Found in `examples/`.
+
+Be sure to `make examples` before running them.
+
+Can be run with e.g. `go run ./examples/<case> [...]`
+
+The available options are the same as for the `dev/interactive` tool.
+
+Contents of the case directory:
+
+* `*.vis` - assembly code.
+* `*.bin` - bytecode for each node symbol (only available after make).
+* `*.txt.orig` - default contents of a single data entry.
+* `*.txt` - current contents of a single data entry (only available after make).

asm/asm.go

@@ -13,20 +13,21 @@ import (
 	"github.com/alecthomas/participle/v2"
 	"github.com/alecthomas/participle/v2/lexer"
 
-	"git.defalsify.org/festive/vm"
+	"git.grassecon.net/kamikazechaser/vise/vm"
 )
 
-
+// Asm assembles bytecode from the vise assembly mini-language.
 type Asm struct {
 	Instructions []*Instruction `@@*`
 }
 
+// Arg holds all parsed argument elements of a single line of assembly code.
 type Arg struct {
-	Sym *string `(@Sym Whitespace?)?`
+	Sym      *string `(@Sym Whitespace?)?`
-	Size *uint32 `(@Size Whitespace?)?`
+	Size     *uint32 `(@Size Whitespace?)?`
-	Flag *uint8 `(@Size Whitespace?)?`
+	Flag     *uint8  `(@Size Whitespace?)?`
 	Selector *string `(@Sym Whitespace?)?`
-	Desc *string `(Quote ((@Sym | @Size) @Whitespace?)+ Quote Whitespace?)?`
+	Desc     *string `(Quote ((@Sym | @Size) @Whitespace?)+ Quote Whitespace?)?`
 }
 
 func flush(b *bytes.Buffer, w io.Writer) (int, error) {
@@ -91,8 +92,13 @@ func parseTwoSym(b *bytes.Buffer, arg Arg) (int, error) {
 		selector = strconv.FormatUint(uint64(*arg.Size), 10)
 		sym = *arg.Selector
 	} else if arg.Selector != nil {
-		sym = *arg.Sym
+		if *arg.Sym == "*" {
-		selector = *arg.Selector
+			sym = *arg.Selector
+			selector = *arg.Sym
+		} else {
+			sym = *arg.Sym
+			selector = *arg.Selector
+		}
 	}
 
 	n, err := writeSym(b, selector)
@@ -156,12 +162,12 @@ func parseOne(op vm.Opcode, instruction *Instruction, w io.Writer) (int, error)
 	a := instruction.OpArg
 	var n_buf int
 	var n_out int
-	
+
 	b := bytes.NewBuffer(nil)
 
 	n, err := writeOpcode(b, op)
 	n_buf += n
-	if  err != nil {
+	if err != nil {
 		return n_out, err
 	}
 
@@ -214,6 +220,7 @@ func parseOne(op vm.Opcode, instruction *Instruction, w io.Writer) (int, error)
 	return flush(b, w)
 }
 
+// String implements the String interface.
 func (a Arg) String() string {
 	s := "[Arg]"
 	if a.Sym != nil {
@@ -235,12 +242,14 @@ func (a Arg) String() string {
 	return fmt.Sprintf(s)
 }
 
+// Instruction represents one full line of assembly code.
 type Instruction struct {
-	OpCode string `@Ident`
+	OpCode  string `@Ident`
-	OpArg Arg `(Whitespace @@)?`
+	OpArg   Arg    `(Whitespace @@)?`
 	Comment string `Comment? EOL`
 }
 
+// String implement the String interface.
 func (i Instruction) String() string {
 	return fmt.Sprintf("%s %s", i.OpCode, i.OpArg)
 }
@@ -250,7 +259,7 @@ var (
 		{"Comment", `(?:#)[^\n]*`},
 		{"Ident", `^[A-Z]+`},
 		{"Size", `[0-9]+`},
-		{"Sym", `[a-zA-Z_][a-zA-Z0-9_]*`},
+		{"Sym", `[a-zA-Z_\*\.][a-zA-Z0-9_]*`},
 		{"Whitespace", `[ \t]+`},
 		{"EOL", `[\n\r]+`},
 		{"Quote", `["']`},
@@ -263,7 +272,7 @@ var (
 
 func numSize(n uint32) int {
 	v := math.Log2(float64(n))
-	return int((v  / 8) + 1)
+	return int((v / 8) + 1)
 }
 
 func writeOpcode(w *bytes.Buffer, op vm.Opcode) (int, error) {
@@ -292,6 +301,9 @@ func writeDisplay(w *bytes.Buffer, s string) (int, error) {
 	return w.WriteString(s)
 }
 func writeSize(w *bytes.Buffer, n uint32) (int, error) {
+	if n == 0 {
+		return w.Write([]byte{0x01, 0x00})
+	}
 	bn := [4]byte{}
 	sz := numSize(n)
 	if sz > 4 {
@@ -299,22 +311,25 @@ func writeSize(w *bytes.Buffer, n uint32) (int, error) {
 	}
 	w.Write([]byte{byte(sz)})
 	binary.BigEndian.PutUint32(bn[:], n)
-	c := 4-sz
+	c := 4 - sz
 	return w.Write(bn[c:])
 }
 
+// Batcher handles assembly commands that generates multiple instructions, such as menu navigation commands.
 type Batcher struct {
 	menuProcessor MenuProcessor
-	inMenu bool
+	inMenu        bool
 }
 
+// NewBatcher creates a new Batcher objcet.
 func NewBatcher(mp MenuProcessor) Batcher {
 	return Batcher{
 		menuProcessor: NewMenuProcessor(),
 	}
 }
 
-func(bt *Batcher) MenuExit(w io.Writer) (int, error) {
+// MenuExit generates the instructions for the batch and writes them to the given io.Writer.
+func (bt *Batcher) MenuExit(w io.Writer) (int, error) {
 	if !bt.inMenu {
 		return 0, nil
 	}
@@ -323,7 +338,8 @@ func(bt *Batcher) MenuExit(w io.Writer) (int, error) {
 	return w.Write(b)
 }
 
-func(bt *Batcher) MenuAdd(w io.Writer, code string, arg Arg) (int, error) {
+// MenuAdd adds a new menu instruction to the batcher.
+func (bt *Batcher) MenuAdd(w io.Writer, code string, arg Arg) (int, error) {
 	bt.inMenu = true
 	var selector string
 	var sym string
@@ -343,10 +359,12 @@ func(bt *Batcher) MenuAdd(w io.Writer, code string, arg Arg) (int, error) {
 	return 0, err
 }
 
-func(bt *Batcher) Exit(w io.Writer) (int, error) {
+// Exit is a synonym for MenuExit
+func (bt *Batcher) Exit(w io.Writer) (int, error) {
 	return bt.MenuExit(w)
 }
 
+// Parse one or more lines of assembly code, and write assembled bytecode to the provided writer.
 func Parse(s string, w io.Writer) (int, error) {
 	rd := strings.NewReader(s)
 	ast, err := asmParser.Parse("file", rd)
@@ -354,9 +372,7 @@ func Parse(s string, w io.Writer) (int, error) {
 		return 0, err
 	}
 
-	batch := Batcher{
+	batch := Batcher{}
-		
-	}
 
 	var rn int
 	for _, v := range ast.Instructions {

asm/asm_test.go

@@ -7,10 +7,9 @@ import (
 	"log"
 	"testing"
 
-	"git.defalsify.org/festive/vm"
+	"git.grassecon.net/kamikazechaser/vise/vm"
 )
 
-
 func TestParserInit(t *testing.T) {
 	var b []byte
 	b = vm.NewLine(b, vm.HALT, nil, nil, nil)
@@ -236,7 +235,7 @@ func TestParserWriteMultiple(t *testing.T) {
 	if n != n_expect {
 		t.Fatalf("expected total %v bytes output, got %v", n_expect, n)
 	}
-	
+
 	rb := r.Bytes()
 	if !bytes.Equal(rb, r_expect) {
 		t.Fatalf("expected result:\n\t%v, got:\n\t%x", r_expect_hex, rb)

asm/doc.go

@@ -0,0 +1,2 @@
+// Package asm parses and compiles vise assembly code to bytecode.
+package asm

asm/menu.go

@@ -3,45 +3,53 @@ package asm
 import (
 	"fmt"
 
-	"git.defalsify.org/festive/vm"
+	"git.grassecon.net/kamikazechaser/vise/vm"
 )
 
+// BatchCode defines quasi-opcodes that expand to mulitple individual vm instructions.
 type BatchCode uint16
 
 const (
-	_MENU_OFFSET = 256
+	_MENU_OFFSET  = 256
-	MENU_DOWN = _MENU_OFFSET
+	MENU_DOWN     = _MENU_OFFSET
-	MENU_UP = _MENU_OFFSET + 1
+	MENU_UP       = _MENU_OFFSET + 1
-	MENU_NEXT = _MENU_OFFSET + 2
+	MENU_NEXT     = _MENU_OFFSET + 2
 	MENU_PREVIOUS = _MENU_OFFSET + 3
 )
 
 var (
 	batchCode = map[string]BatchCode{
-		"DOWN": MENU_DOWN,
+		"DOWN":     MENU_DOWN,
-		"UP": MENU_UP,
+		"UP":       MENU_UP,
-		"NEXT": MENU_NEXT,
+		"NEXT":     MENU_NEXT,
 		"PREVIOUS": MENU_PREVIOUS,
 	}
 )
 
 type menuItem struct {
-	code BatchCode
+	code    BatchCode
-	choice string
+	choice  string
 	display string
-	target string
+	target  string
 }
 
+// MenuProcessor handles code lines with BatchCode quasi-opcodes that control menu generation.
+//
+// It creates vm instructions for display of menu and handling of input on either size of a vm.HALT instruction.
 type MenuProcessor struct {
 	items []menuItem
-	size uint32
+	size  uint32
 }
 
+// NewMenuProcessor creates a new MenuProcessor object.
 func NewMenuProcessor() MenuProcessor {
 	return MenuProcessor{}
 }
 
-func(mp *MenuProcessor) Add(bop string, choice string, display string, target string) error {
+// Add a menu batch instruction to be processed.
+//
+// Instructions will be rendered in the order in which they have been added.
+func (mp *MenuProcessor) Add(bop string, choice string, display string, target string) error {
 	bopCode := batchCode[bop]
 	if bopCode == 0 {
 		return fmt.Errorf("unknown menu instruction: %v", bop)
@@ -50,15 +58,16 @@ func(mp *MenuProcessor) Add(bop string, choice string, display string, target st
 		return fmt.Errorf("target is only valid for DOWN")
 	}
 	m := menuItem{
-		code: bopCode,
+		code:    bopCode,
-		choice: choice,
+		choice:  choice,
 		display: display,
-		target: target,
+		target:  target,
 	}
 	mp.items = append(mp.items, m)
 	return nil
 }
 
+// ToLines returns the generated bytecode from the added menu batch instructions.
 func (mp *MenuProcessor) ToLines() []byte {
 	preLines := []byte{}
 	postLines := []byte{}

asm/menu_test.go

@@ -3,10 +3,9 @@ package asm
 import (
 	"testing"
 
-	"git.defalsify.org/festive/vm"
+	"git.grassecon.net/kamikazechaser/vise/vm"
 )
 
-
 func TestMenuInterpreter(t *testing.T) {
 	m := NewMenuProcessor()
 	err := m.Add("DOWN", "0", "inky", "foo")

cache/cache.go

@@ -5,23 +5,20 @@ import (
 	"log"
 )
 
+// Cache stores loaded content, enforcing size limits and keeping track of size usage.
 type Cache struct {
 	CacheSize uint32 // Total allowed cumulative size of values (not code) in cache
 	CacheUseSize uint32 // Currently used bytes by all values (not code) in cache
 	Cache []map[string]string // All loaded cache items
-	//CacheMap map[string]string // Mapped
+	Sizes map[string]uint16 // Size limits for all loaded symbols.
-	//outputSize uint32 // Max size of output
-	sizes map[string]uint16 // Size limits for all loaded symbols.
-	//sink *string
 }
 
 // NewCache creates a new ready-to-use cache object
 func NewCache() *Cache {
 	ca := &Cache{
 		Cache: []map[string]string{make(map[string]string)},
-		sizes: make(map[string]uint16),
+		Sizes: make(map[string]uint16),
 	}
-	//ca.resetCurrent()
 	return ca
 }
 
@@ -54,20 +51,23 @@ func(ca *Cache) Add(key string, value string, sizeLimit uint16) error {
 		}
 		return fmt.Errorf("key %v already defined in frame %v", key, checkFrame)
 	}
-	sz := ca.checkCapacity(value)
+	var sz uint32
-	if sz == 0 {
+	if len(value) > 0 {
-		return fmt.Errorf("Cache capacity exceeded %v of %v", ca.CacheUseSize + sz, ca.CacheSize)
+		sz = ca.checkCapacity(value)
+		if sz == 0 {
+			return fmt.Errorf("Cache capacity exceeded %v of %v", ca.CacheUseSize + sz, ca.CacheSize)
+		}
 	}
 	log.Printf("add key %s value size %v limit %v", key, sz, sizeLimit)
 	ca.Cache[len(ca.Cache)-1][key] = value
 	ca.CacheUseSize += sz
-	ca.sizes[key] = sizeLimit
+	ca.Sizes[key] = sizeLimit
 	return nil
 }
 
 // ReservedSize returns the maximum byte size available for the given symbol.
 func(ca *Cache) ReservedSize(key string) (uint16, error) {
-	v, ok := ca.sizes[key]
+	v, ok := ca.Sizes[key]
 	if !ok {
 		return 0, fmt.Errorf("unknown symbol: %s", key)
 	}
@@ -83,8 +83,8 @@ func(ca *Cache) ReservedSize(key string) (uint16, error) {
 // - value is longer than size limit
 // - replacing value exceeds cumulative cache capacity
 func(ca *Cache) Update(key string, value string) error {
-	sizeLimit := ca.sizes[key]
+	sizeLimit := ca.Sizes[key]
-	if ca.sizes[key] > 0 {
+	if ca.Sizes[key] > 0 {
 		l := uint16(len(value))
 		if l > sizeLimit {
 			return fmt.Errorf("update value length %v exceeds value size limit %v", l, sizeLimit)
@@ -97,9 +97,6 @@ func(ca *Cache) Update(key string, value string) error {
 	r := ca.Cache[checkFrame][key]
 	l := uint32(len(r))
 	ca.Cache[checkFrame][key] = ""
-	//if ca.CacheMap[key] != "" {
-	//	ca.CacheMap[key] = value
-	//}
 	ca.CacheUseSize -= l
 	sz := ca.checkCapacity(value)
 	if sz == 0 {
@@ -113,6 +110,9 @@ func(ca *Cache) Update(key string, value string) error {
 	return nil
 }
 
+// Get the content currently loaded for a single key, loaded at any level.
+//
+// Fails if key has not been loaded.
 func(ca *Cache) Get(key string) (string, error) {
 	i := ca.frameOf(key)
 	r, ok := ca.Cache[i][key]
@@ -136,7 +136,6 @@ func(ca *Cache) Reset() {
 func (ca *Cache) Push() error {
 	m := make(map[string]string)
 	ca.Cache = append(ca.Cache, m)
-	//ca.resetCurrent()
 	return nil
 }
 

cache/doc.go

@@ -0,0 +1,2 @@
+// Package cache is a memory store for key-value pairs for all loaded symbols available for output.
+package cache

cache/memory.go

@@ -1,5 +1,6 @@
 package cache
 
+// Memory defines the interface for store of a symbol mapped content store.
 type Memory interface {
 	Add(key string, val string, sizeLimit uint16) error
 	Update(key string, val string) error

dev/asm/doc.go

@@ -0,0 +1,2 @@
+// Executable asm compiles festival assembly code to bytecode instructions.
+package main

dev/asm/main.go

@@ -6,11 +6,11 @@ import (
 	"log"
 	"os"
 
-	"git.defalsify.org/festive/asm"
+	"git.grassecon.net/kamikazechaser/vise/asm"
 )
 
 func main() {
-	if (len(os.Args) < 2) {
+	if len(os.Args) < 2 {
 		os.Exit(1)
 	}
 	fp := os.Args[1]

dev/disasm/doc.go

@@ -0,0 +1,2 @@
+// Executable disasm generates festival assembly code from bytecode instructions.
+package main

dev/disasm/main.go

@@ -2,14 +2,14 @@ package main
 
 import (
 	"fmt"
-	"os"
 	"io/ioutil"
+	"os"
 
-	"git.defalsify.org/festive/vm"
+	"git.grassecon.net/kamikazechaser/vise/vm"
 )
 
 func main() {
-	if (len(os.Args) < 2) {
+	if len(os.Args) < 2 {
 		os.Exit(1)
 	}
 	fp := os.Args[1]

dev/gendata/doc.go

@@ -0,0 +1,2 @@
+// Execution gendata output testdata provisions compatible with resource.FsResource to a filesystem directory.
+package main

dev/gendata/main.go

@@ -4,7 +4,7 @@ import (
 	"fmt"
 	"os"
 
-	"git.defalsify.org/festive/testdata"
+	"git.grassecon.net/kamikazechaser/vise/testdata"
 )
 
 func main() {

dev/interactive/doc.go

@@ -0,0 +1,2 @@
+// Executable interactive runs the Engine execution loop against interactive client input in the terminal.
+package main

dev/interactive/main.go

@@ -0,0 +1,45 @@
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"os"
+
+	"git.grassecon.net/kamikazechaser/vise/engine"
+)
+
+func main() {
+	var dir string
+	var root string
+	var size uint
+	//var sessionId string
+	flag.StringVar(&dir, "d", ".", "resource dir to read from")
+	flag.UintVar(&size, "s", 0, "max size of output")
+	flag.StringVar(&root, "root", "root", "entry point symbol")
+	//flag.StringVar(&sessionId, "session-id", "default", "session id")
+	flag.Parse()
+	fmt.Fprintf(os.Stderr, "starting session at symbol '%s' using resource dir: %s\n", root, dir)
+
+	ctx := context.Background()
+	en := engine.NewSizedEngine(dir, uint32(size))
+	cont, err := en.Init(ctx)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "engine init exited with error: %v\n", err)
+		os.Exit(1)
+	}
+	if !cont {
+		_, err = en.WriteResult(os.Stdout, ctx)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "dead init write error: %v\n", err)
+			os.Exit(1)
+		}
+		os.Stdout.Write([]byte{0x0a})
+		os.Exit(0)
+	}
+	err = engine.Loop(&en, os.Stdin, os.Stdout, ctx)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "loop exited with error: %v\n", err)
+		os.Exit(1)
+	}
+}

engine/default.go

@@ -0,0 +1,34 @@
+package engine
+
+import (
+	"context"
+
+	"git.grassecon.net/kamikazechaser/vise/cache"
+	"git.grassecon.net/kamikazechaser/vise/resource"
+	"git.grassecon.net/kamikazechaser/vise/state"
+)
+
+// NewDefaultEngine is a convenience function to instantiate a filesystem-backed engine with no output constraints.
+func NewDefaultEngine(dir string) Engine {
+	st := state.NewState(0)
+	rs := resource.NewFsResource(dir)
+	ca := cache.NewCache()
+	cfg := Config{
+		Root: "root",
+	}
+	ctx := context.TODO()
+	return NewEngine(cfg, &st, &rs, ca, ctx)
+}
+
+// NewSizedEngine is a convenience function to instantiate a filesystem-backed engine with a specified output constraint.
+func NewSizedEngine(dir string, size uint32) Engine {
+	st := state.NewState(0)
+	rs := resource.NewFsResource(dir)
+	ca := cache.NewCache()
+	cfg := Config{
+		OutputSize: size,
+		Root:       "root",
+	}
+	ctx := context.TODO()
+	return NewEngine(cfg, &st, &rs, ca, ctx)
+}

engine/doc.go

@@ -0,0 +1,2 @@
+// Package engine orchestrates client input with vm execution.
+package engine

engine/engine.go

@@ -0,0 +1,183 @@
+package engine
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"log"
+
+	"git.grassecon.net/kamikazechaser/vise/cache"
+	"git.grassecon.net/kamikazechaser/vise/render"
+	"git.grassecon.net/kamikazechaser/vise/resource"
+	"git.grassecon.net/kamikazechaser/vise/state"
+	"git.grassecon.net/kamikazechaser/vise/vm"
+)
+
+// Config globally defines behavior of all components driven by the engine.
+type Config struct {
+	OutputSize uint32 // Maximum size of output from a single rendered page
+	SessionId  string
+	Root       string
+	FlagCount  uint32
+	CacheSize  uint32
+}
+
+// Engine is an execution engine that handles top-level errors when running client inputs against code in the bytecode buffer.
+type Engine struct {
+	st    *state.State
+	rs    resource.Resource
+	ca    cache.Memory
+	vm    *vm.Vm
+	root  string
+	initd bool
+}
+
+// NewEngine creates a new Engine
+func NewEngine(cfg Config, st *state.State, rs resource.Resource, ca cache.Memory, ctx context.Context) Engine {
+	var szr *render.Sizer
+	if cfg.OutputSize > 0 {
+		szr = render.NewSizer(cfg.OutputSize)
+	}
+	ctx = context.WithValue(ctx, "sessionId", cfg.SessionId)
+	engine := Engine{
+		st: st,
+		rs: rs,
+		ca: ca,
+		vm: vm.NewVm(st, rs, ca, szr),
+	}
+	engine.root = cfg.Root
+
+	return engine
+}
+
+// Init must be explicitly called before using the Engine instance.
+//
+// It loads and executes code for the start node.
+func (en *Engine) Init(ctx context.Context) (bool, error) {
+	if en.initd {
+		log.Printf("already initialized")
+		return true, nil
+	}
+	sym := en.root
+	if sym == "" {
+		return false, fmt.Errorf("start sym empty")
+	}
+	inSave, _ := en.st.GetInput()
+	err := en.st.SetInput([]byte{})
+	if err != nil {
+		return false, err
+	}
+	b := vm.NewLine(nil, vm.MOVE, []string{sym}, nil, nil)
+	log.Printf("start new init VM run with code %x", b)
+	b, err = en.vm.Run(b, ctx)
+	if err != nil {
+		return false, err
+	}
+
+	log.Printf("ended init VM run with code %x", b)
+	en.st.SetCode(b)
+	err = en.st.SetInput(inSave)
+	if err != nil {
+		return false, err
+	}
+	return len(b) > 0, nil
+}
+
+// Exec processes user input against the current state of the virtual machine environment.
+//
+// If successfully executed, output of the last execution is available using the WriteResult call.
+//
+// A bool return valus of false indicates that execution should be terminated. Calling Exec again has undefined effects.
+//
+// Fails if:
+// - input is formally invalid (too long etc)
+// - no current bytecode is available
+// - input processing against bytcode failed
+func (en *Engine) Exec(input []byte, ctx context.Context) (bool, error) {
+	var err error
+	if en.st.Moves == 0 {
+		cont, err := en.Init(ctx)
+		if err != nil {
+			return false, err
+		}
+		return cont, nil
+	}
+	err = vm.ValidInput(input)
+	if err != nil {
+		return true, err
+	}
+	err = en.st.SetInput(input)
+	if err != nil {
+		return false, err
+	}
+
+	log.Printf("new execution with input '%s' (0x%x)", input, input)
+	code, err := en.st.GetCode()
+	if err != nil {
+		return false, err
+	}
+	if len(code) == 0 {
+		return false, fmt.Errorf("no code to execute")
+	}
+
+	log.Printf("start new VM run with code %x", code)
+	code, err = en.vm.Run(code, ctx)
+	if err != nil {
+		return false, err
+	}
+	log.Printf("ended VM run with code %x", code)
+
+	v, err := en.st.MatchFlag(state.FLAG_TERMINATE, false)
+	if err != nil {
+		return false, err
+	}
+	if v {
+		if len(code) > 0 {
+			log.Printf("terminated with code remaining: %x", code)
+		}
+		return false, err
+	}
+
+	en.st.SetCode(code)
+	if len(code) == 0 {
+		log.Printf("runner finished with no remaining code")
+		_, err = en.reset(ctx)
+		return false, err
+	}
+
+	return true, nil
+}
+
+// WriteResult writes the output of the last vm execution to the given writer.
+//
+// Fails if
+// - required data inputs to the template are not available.
+// - the template for the given node point is note available for retrieval using the resource.Resource implementer.
+// - the supplied writer fails to process the writes.
+func (en *Engine) WriteResult(w io.Writer, ctx context.Context) (int, error) {
+	r, err := en.vm.Render(ctx)
+	if err != nil {
+		return 0, err
+	}
+	return io.WriteString(w, r)
+}
+
+// start execution over at top node while keeping current state of client error flags.
+func (en *Engine) reset(ctx context.Context) (bool, error) {
+	var err error
+	var isTop bool
+	for !isTop {
+		isTop, err = en.st.Top()
+		if err != nil {
+			return false, err
+		}
+		_, err = en.st.Up()
+		if err != nil {
+			return false, err
+		}
+		en.ca.Pop()
+	}
+	en.st.Restart()
+	en.initd = false
+	return en.Init(ctx)
+}

engine/engine_test.go

@@ -0,0 +1,187 @@
+package engine
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"io/ioutil"
+	"path"
+	"testing"
+
+	"git.grassecon.net/kamikazechaser/vise/cache"
+	"git.grassecon.net/kamikazechaser/vise/resource"
+	"git.grassecon.net/kamikazechaser/vise/state"
+	"git.grassecon.net/kamikazechaser/vise/testdata"
+)
+
+var (
+	dataGenerated bool   = false
+	dataDir       string = testdata.DataDir
+)
+
+type FsWrapper struct {
+	*resource.FsResource
+	st *state.State
+}
+
+func NewFsWrapper(path string, st *state.State) FsWrapper {
+	rs := resource.NewFsResource(path)
+	wr := FsWrapper{
+		&rs,
+		st,
+	}
+	wr.AddLocalFunc("one", wr.one)
+	wr.AddLocalFunc("inky", wr.inky)
+	wr.AddLocalFunc("pinky", wr.pinky)
+	return wr
+}
+
+func (fs FsWrapper) one(sym string, input []byte, ctx context.Context) (resource.Result, error) {
+	return resource.Result{
+		Content: "one",
+	}, nil
+}
+
+func (fs FsWrapper) inky(sym string, input []byte, ctx context.Context) (resource.Result, error) {
+	return resource.Result{
+		Content: "tinkywinky",
+	}, nil
+}
+
+func (fs FsWrapper) pinky(sym string, input []byte, ctx context.Context) (resource.Result, error) {
+	r := fmt.Sprintf("xyzzy: %x", input)
+	return resource.Result{
+		Content: r,
+	}, nil
+}
+
+func (fs FsWrapper) GetCode(sym string) ([]byte, error) {
+	sym += ".bin"
+	fp := path.Join(fs.Path, sym)
+	r, err := ioutil.ReadFile(fp)
+	return r, err
+}
+
+func generateTestData(t *testing.T) {
+	if dataGenerated {
+		return
+	}
+	var err error
+	dataDir, err = testdata.Generate()
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestEngineInit(t *testing.T) {
+	var err error
+	generateTestData(t)
+	ctx := context.TODO()
+	st := state.NewState(17)
+	rs := NewFsWrapper(dataDir, &st)
+	ca := cache.NewCache().WithCacheSize(1024)
+
+	en := NewEngine(Config{
+		Root: "root",
+	}, &st, &rs, ca, ctx)
+
+	_, err = en.Init(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+	w := bytes.NewBuffer(nil)
+	_, err = en.WriteResult(w, ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+	b := w.Bytes()
+	expect_str := `hello world
+1:do the foo
+2:go to the bar`
+
+	if !bytes.Equal(b, []byte(expect_str)) {
+		t.Fatalf("expected:\n\t%s\ngot:\n\t%s\n", expect_str, b)
+	}
+
+	input := []byte("1")
+	_, err = en.Exec(input, ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+	r, _ := st.Where()
+	if r != "foo" {
+		t.Fatalf("expected where-string 'foo', got %s", r)
+	}
+	w = bytes.NewBuffer(nil)
+	_, err = en.WriteResult(w, ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+	b = w.Bytes()
+	expect := `this is in foo
+
+it has more lines
+0:to foo
+1:go bar
+2:see long`
+
+	if !bytes.Equal(b, []byte(expect)) {
+		t.Fatalf("expected\n\t%s\ngot:\n\t%s\n", expect, b)
+	}
+}
+
+func TestEngineExecInvalidInput(t *testing.T) {
+	generateTestData(t)
+	ctx := context.TODO()
+	st := state.NewState(17)
+	rs := NewFsWrapper(dataDir, &st)
+	ca := cache.NewCache().WithCacheSize(1024)
+
+	en := NewEngine(Config{
+		Root: "root",
+	}, &st, &rs, ca, ctx)
+	var err error
+	_, err = en.Init(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, err = en.Exec([]byte("_foo"), ctx)
+	if err == nil {
+		t.Fatalf("expected fail on invalid input")
+	}
+}
+
+func TestEngineResumeTerminated(t *testing.T) {
+	generateTestData(t)
+	ctx := context.TODO()
+	st := state.NewState(17)
+	rs := NewFsWrapper(dataDir, &st)
+	ca := cache.NewCache().WithCacheSize(1024)
+
+	en := NewEngine(Config{
+		Root: "root",
+	}, &st, &rs, ca, ctx)
+	var err error
+	_, err = en.Init(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	_, err = en.Exec([]byte("1"), ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	_, err = en.Exec([]byte("1"), ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	location, idx := st.Where()
+	if location != "root" {
+		t.Fatalf("expected 'root', got %s", location)
+	}
+	if idx != 0 {
+		t.Fatalf("expected idx '0', got %v", idx)
+	}
+}

engine/loop.go

@@ -2,7 +2,6 @@ package engine
 
 import (
 	"bufio"
-	"bytes"
 	"context"
 	"fmt"
 	"io"
@@ -10,15 +9,22 @@ import (
 	"strings"
 )
 
-func Loop(en *Engine, startSym string, ctx context.Context, reader io.Reader, writer io.Writer) error {
+// Loop starts an engine execution loop with the given symbol as the starting node.
-	err := en.Init(startSym, ctx)
+//
+// The root reads inputs from the provided reader, one line at a time.
+//
+// It will execute until running out of bytecode in the buffer.
+//
+// Any error not handled by the engine will terminate the oop and return an error.
+//
+// Rendered output is written to the provided writer.
+func Loop(en *Engine, reader io.Reader, writer io.Writer, ctx context.Context) error {
+	var err error
+	_, err = en.WriteResult(writer, ctx)
 	if err != nil {
-		return fmt.Errorf("cannot init: %v\n", err)
+		return err
 	}
-
+	writer.Write([]byte{0x0a})
-	b := bytes.NewBuffer(nil)
-	en.WriteResult(b)
-	fmt.Println(b.String())
 
 	running := true
 	bufReader := bufio.NewReader(reader)
@@ -36,12 +42,12 @@ func Loop(en *Engine, startSym string, ctx context.Context, reader io.Reader, wr
 		if err != nil {
 			return fmt.Errorf("unexpected termination: %v\n", err)
 		}
-		//b := bytes.NewBuffer(nil)
+		_, err = en.WriteResult(writer, ctx)
-		err = en.WriteResult(writer)
 		if err != nil {
 			return err
 		}
 		writer.Write([]byte{0x0a})
+
 	}
 	return nil
 }

engine/loop_test.go

@@ -0,0 +1,129 @@
+package engine
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"log"
+	"strings"
+	"testing"
+
+	"git.grassecon.net/kamikazechaser/vise/cache"
+	"git.grassecon.net/kamikazechaser/vise/resource"
+	"git.grassecon.net/kamikazechaser/vise/state"
+)
+
+func TestLoopTop(t *testing.T) {
+	generateTestData(t)
+	ctx := context.TODO()
+	st := state.NewState(0)
+	rs := resource.NewFsResource(dataDir)
+	ca := cache.NewCache().WithCacheSize(1024)
+
+	cfg := Config{
+		Root: "root",
+	}
+	en := NewEngine(cfg, &st, &rs, ca, ctx)
+	var err error
+	_, err = en.Init(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	input := []string{
+		"2",
+		"j",
+		"1",
+	}
+	inputStr := strings.Join(input, "\n")
+	inputBuf := bytes.NewBuffer(append([]byte(inputStr), 0x0a))
+	outputBuf := bytes.NewBuffer(nil)
+	log.Printf("running with input: %s", inputBuf.Bytes())
+
+	err = Loop(&en, inputBuf, outputBuf, ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+	location, _ := st.Where()
+	if location != "foo" {
+		fmt.Errorf("expected location 'foo', got %s", location)
+	}
+}
+
+func TestLoopBackForth(t *testing.T) {
+	generateTestData(t)
+	ctx := context.TODO()
+	st := state.NewState(0)
+	rs := resource.NewFsResource(dataDir)
+	ca := cache.NewCache().WithCacheSize(1024)
+
+	cfg := Config{
+		Root: "root",
+	}
+	en := NewEngine(cfg, &st, &rs, ca, ctx)
+	var err error
+	_, err = en.Init(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	input := []string{
+		"1",
+		"0",
+		"1",
+		"0",
+	}
+	inputStr := strings.Join(input, "\n")
+	inputBuf := bytes.NewBuffer(append([]byte(inputStr), 0x0a))
+	outputBuf := bytes.NewBuffer(nil)
+	log.Printf("running with input: %s", inputBuf.Bytes())
+
+	err = Loop(&en, inputBuf, outputBuf, ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+}
+
+func TestLoopBrowse(t *testing.T) {
+	generateTestData(t)
+	ctx := context.TODO()
+	st := state.NewState(0)
+	rs := resource.NewFsResource(dataDir)
+	ca := cache.NewCache().WithCacheSize(1024)
+
+	cfg := Config{
+		OutputSize: 68,
+		Root:       "root",
+	}
+	en := NewEngine(cfg, &st, &rs, ca, ctx)
+	var err error
+	_, err = en.Init(ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	input := []string{
+		"1",
+		"2",
+		"00",
+		"11",
+		"00",
+	}
+	inputStr := strings.Join(input, "\n")
+	inputBuf := bytes.NewBuffer(append([]byte(inputStr), 0x0a))
+	outputBuf := bytes.NewBuffer(nil)
+	log.Printf("running with input: %s", inputBuf.Bytes())
+
+	err = Loop(&en, inputBuf, outputBuf, ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	location, idx := st.Where()
+	if location != "long" {
+		fmt.Errorf("expected location 'long', got %s", location)
+	}
+	if idx != 1 {
+		fmt.Errorf("expected idx 1, got %v", idx)
+	}
+}

engine/persist.go

@@ -0,0 +1,50 @@
+package engine
+
+import (
+	"context"
+	"io"
+
+	"git.grassecon.net/kamikazechaser/vise/persist"
+	"git.grassecon.net/kamikazechaser/vise/resource"
+)
+
+// RunPersisted performs a single vm execution from client input using a persisted state.
+//
+// State is first loaded from storage. The vm is initialized with the state and executed. The new state is then saved to storage.
+//
+// The resulting output of the execution will be written to the provided writer.
+//
+// The state is identified by the SessionId member of the Config. Before first execution, the caller must ensure that an
+// initialized state actually is available for the identifier, otherwise the method will fail.
+//
+// It will also fail if execution by the underlying Engine fails.
+func RunPersisted(cfg Config, rs resource.Resource, pr persist.Persister, input []byte, w io.Writer, ctx context.Context) error {
+	err := pr.Load(cfg.SessionId)
+	if err != nil {
+		return err
+	}
+
+	en := NewEngine(cfg, pr.GetState(), rs, pr.GetMemory(), ctx)
+
+	c, err := en.WriteResult(w, ctx)
+	if err != nil {
+		return err
+	}
+	err = pr.Save(cfg.SessionId)
+	if err != nil {
+		return err
+	}
+	if c > 0 {
+		return err
+	}
+
+	_, err = en.Exec(input, ctx)
+	if err != nil {
+		return err
+	}
+	_, err = en.WriteResult(w, ctx)
+	if err != nil {
+		return err
+	}
+	return pr.Save(cfg.SessionId)
+}

engine/persist_test.go

@@ -0,0 +1,73 @@
+package engine
+
+import (
+	"context"
+	"io/ioutil"
+	"os"
+	"testing"
+
+	"git.grassecon.net/kamikazechaser/vise/cache"
+	"git.grassecon.net/kamikazechaser/vise/persist"
+	"git.grassecon.net/kamikazechaser/vise/state"
+)
+
+func TestPersist(t *testing.T) {
+	generateTestData(t)
+	cfg := Config{
+		OutputSize: 83,
+		SessionId:  "xyzzy",
+		Root:       "root",
+	}
+	rs := NewFsWrapper(dataDir, nil)
+
+	persistDir, err := ioutil.TempDir("", "vise_engine_persist")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	st := state.NewState(3)
+	ca := cache.NewCache().WithCacheSize(1024)
+	pr := persist.NewFsPersister(persistDir).WithContent(&st, ca)
+
+	w := os.Stdout
+	ctx := context.TODO()
+
+	st = state.NewState(cfg.FlagCount)
+	ca = cache.NewCache()
+	ca = ca.WithCacheSize(cfg.CacheSize)
+	pr = persist.NewFsPersister(persistDir).WithContent(&st, ca)
+	err = pr.Save(cfg.SessionId)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	pr = persist.NewFsPersister(persistDir)
+	inputs := []string{
+		"", // trigger init, will not exec
+		"1",
+		"2",
+		"00",
+	}
+	for _, v := range inputs {
+		err = RunPersisted(cfg, rs, pr, []byte(v), w, ctx)
+		if err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	pr = persist.NewFsPersister(persistDir)
+	err = pr.Load(cfg.SessionId)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	stAfter := pr.GetState()
+	location, idx := stAfter.Where()
+	if location != "long" {
+		t.Fatalf("expected 'long', got %s", location)
+	}
+	if idx != 1 {
+		t.Fatalf("expected '1', got %v", idx)
+	}
+
+}

examples/compile.bash

@@ -0,0 +1,13 @@
+for f in $(ls $1/*.vis); do
+	b=$(basename $f)
+	b=${b%.*}
+	go run ./dev/asm $1/$b.vis > $1/$b.bin
+done
+
+for f in $(ls $1/*.txt.orig); do
+	b=$(basename $f)
+	b=${b%.*}
+	#go run ./dev/asm $1/$b.vis > $1/$b.bin
+	echo $b
+	cp -v $f $1/$b
+done

examples/helloworld/que.txt.orig

@@ -0,0 +1 @@
+world

examples/helloworld/root

@@ -0,0 +1 @@
+hello, {{.que}}!

examples/helloworld/root.vis

@@ -0,0 +1,2 @@
+LOAD que 5
+MAP que

examples/profile/entry_email

@@ -0,0 +1,2 @@
+Your email is now: {{.myemail}}
+Enter new email.

examples/profile/entry_email.vis

@@ -0,0 +1,5 @@
+MAP myemail
+MOUT 0 "abort"
+HALT
+INCMP 0 _
+INCMP * entry_email_save 

examples/profile/entry_email_save.vis

@@ -0,0 +1,3 @@
+LOAD do_email_save 1
+RELOAD myemail
+MOVE _

examples/profile/entry_name

@@ -0,0 +1,2 @@
+Name is currently: {{.myname}}
+Enter new name.

examples/profile/entry_name.vis

@@ -0,0 +1,5 @@
+MAP myname
+MOUT 0 "abort"
+HALT
+INCMP 0 _
+INCMP * entry_name_save 

examples/profile/entry_name_save.vis

@@ -0,0 +1,3 @@
+LOAD do_name_save 1
+RELOAD myname
+MOVE _

examples/profile/identified

@@ -0,0 +1,3 @@
+You are identified as:
+Name: {{.myname}}
+Email: {{.myemail}}

examples/profile/identified.vis

@@ -0,0 +1,2 @@
+MAP myname
+MAP myemail

examples/profile/main.go

@@ -0,0 +1,139 @@
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"os"
+	"path"
+
+	testdataloader "github.com/peteole/testdata-loader"
+
+	"git.grassecon.net/kamikazechaser/vise/cache"
+	"git.grassecon.net/kamikazechaser/vise/engine"
+	"git.grassecon.net/kamikazechaser/vise/resource"
+	"git.grassecon.net/kamikazechaser/vise/state"
+)
+
+const (
+	USERFLAG_IDENTIFIED = iota + state.FLAG_USERSTART
+	USERFLAG_HAVENAME
+	USERFLAG_HAVEEMAIL
+)
+
+var (
+	baseDir     = testdataloader.GetBasePath()
+	scriptDir   = path.Join(baseDir, "examples", "profile")
+	emptyResult = resource.Result{}
+)
+
+type profileResource struct {
+	*resource.FsResource
+	st          *state.State
+	haveEntered bool
+}
+
+func newProfileResource(st *state.State, rs *resource.FsResource) *profileResource {
+	return &profileResource{
+		rs,
+		st,
+		false,
+	}
+}
+
+func (pr *profileResource) checkEntry() error {
+	log.Printf("%v %v", USERFLAG_IDENTIFIED, USERFLAG_HAVENAME)
+	if pr.haveEntered {
+		return nil
+	}
+	one, err := pr.st.GetFlag(USERFLAG_HAVENAME)
+	if err != nil {
+		return err
+	}
+	two, err := pr.st.GetFlag(USERFLAG_HAVEEMAIL)
+	if err != nil {
+		return err
+	}
+	if one && two {
+		_, err = pr.st.SetFlag(USERFLAG_IDENTIFIED)
+		if err != nil {
+			return err
+		}
+		pr.haveEntered = true
+	}
+	return nil
+}
+
+func (pr profileResource) nameSave(sym string, input []byte, ctx context.Context) (resource.Result, error) {
+	log.Printf("writing name to file")
+	fp := path.Join(scriptDir, "myname.txt")
+	err := ioutil.WriteFile(fp, input, 0600)
+	if err != nil {
+		return emptyResult, err
+	}
+	changed, err := pr.st.SetFlag(USERFLAG_HAVENAME)
+	if err != nil {
+		return emptyResult, err
+	}
+	if changed {
+		pr.checkEntry()
+	}
+	return emptyResult, err
+}
+
+func (pr profileResource) emailSave(sym string, input []byte, ctx context.Context) (resource.Result, error) {
+	log.Printf("writing email to file")
+	fp := path.Join(scriptDir, "myemail.txt")
+	err := ioutil.WriteFile(fp, input, 0600)
+	if err != nil {
+		return emptyResult, err
+	}
+	changed, err := pr.st.SetFlag(USERFLAG_HAVEEMAIL)
+	if err != nil {
+		return emptyResult, err
+	}
+	if changed {
+		pr.checkEntry()
+	}
+	return resource.Result{}, err
+}
+
+func main() {
+	var dir string
+	var root string
+	var size uint
+	var sessionId string
+	flag.UintVar(&size, "s", 0, "max size of output")
+	flag.StringVar(&root, "root", "root", "entry point symbol")
+	flag.StringVar(&sessionId, "session-id", "default", "session id")
+	flag.Parse()
+	fmt.Fprintf(os.Stderr, "starting session at symbol '%s' using resource dir: %s\n", root, dir)
+
+	st := state.NewState(3)
+	rsf := resource.NewFsResource(scriptDir)
+	rs := newProfileResource(&st, &rsf)
+	rs.AddLocalFunc("do_name_save", rs.nameSave)
+	rs.AddLocalFunc("do_email_save", rs.emailSave)
+	ca := cache.NewCache()
+	cfg := engine.Config{
+		Root:       "root",
+		SessionId:  sessionId,
+		OutputSize: uint32(size),
+	}
+	ctx := context.Background()
+	en := engine.NewEngine(cfg, &st, rs, ca, ctx)
+	var err error
+	_, err = en.Init(ctx)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "engine init fail: %v\n", err)
+		os.Exit(1)
+	}
+
+	err = engine.Loop(&en, os.Stdin, os.Stdout, ctx)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "loop exited with error: %v\n", err)
+		os.Exit(1)
+	}
+}

examples/profile/myemail.txt.orig

@@ -0,0 +1 @@
+(not set)

examples/profile/myname.txt.orig

@@ -0,0 +1 @@
+(not set)

examples/profile/root

@@ -0,0 +1 @@
+Please input profile data

examples/profile/root.vis

@@ -0,0 +1,5 @@
+LOAD myname 64
+LOAD myemail 64
+CATCH identified 8 0
+DOWN entry_name 0 "name"
+DOWN entry_email 1 "email"

examples/session/input

@@ -0,0 +1,2 @@
+hey hey hey
+your data is {{.do_save}}

examples/session/input.vis

@@ -0,0 +1,4 @@
+MAP do_save
+HALT
+RELOAD do_save
+INCMP * .

examples/session/main.go

@@ -0,0 +1,86 @@
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"io/ioutil"
+	"log"
+	"os"
+	"path"
+
+	testdataloader "github.com/peteole/testdata-loader"
+
+	"git.grassecon.net/kamikazechaser/vise/cache"
+	"git.grassecon.net/kamikazechaser/vise/engine"
+	"git.grassecon.net/kamikazechaser/vise/resource"
+	"git.grassecon.net/kamikazechaser/vise/state"
+)
+
+var (
+	baseDir     = testdataloader.GetBasePath()
+	scriptDir   = path.Join(baseDir, "examples", "session")
+	emptyResult = resource.Result{}
+)
+
+func save(sym string, input []byte, ctx context.Context) (resource.Result, error) {
+	sessionId := ctx.Value("SessionId").(string)
+	sessionDir := path.Join(scriptDir, sessionId)
+	err := os.MkdirAll(sessionDir, 0700)
+	if err != nil {
+		return emptyResult, err
+	}
+	fp := path.Join(sessionDir, "data.txt")
+	if len(input) > 0 {
+		log.Printf("write data %s session %s", input, sessionId)
+		err = ioutil.WriteFile(fp, input, 0600)
+		if err != nil {
+			return emptyResult, err
+		}
+	}
+	r, err := ioutil.ReadFile(fp)
+	if err != nil {
+		err = ioutil.WriteFile(fp, []byte("(not set)"), 0600)
+		if err != nil {
+			return emptyResult, err
+		}
+	}
+	return resource.Result{
+		Content: string(r),
+	}, nil
+}
+
+func main() {
+	var root string
+	var size uint
+	var sessionId string
+	flag.UintVar(&size, "s", 0, "max size of output")
+	flag.StringVar(&root, "root", "root", "entry point symbol")
+	flag.StringVar(&sessionId, "session-id", "default", "session id")
+	flag.Parse()
+	fmt.Fprintf(os.Stderr, "starting session at symbol '%s' using resource dir: %s\n", root, scriptDir)
+
+	st := state.NewState(0)
+	rs := resource.NewFsResource(scriptDir)
+	rs.AddLocalFunc("do_save", save)
+	ca := cache.NewCache()
+	cfg := engine.Config{
+		Root:       "root",
+		SessionId:  sessionId,
+		OutputSize: uint32(size),
+	}
+	ctx := context.Background()
+	ctx = context.WithValue(ctx, "SessionId", sessionId)
+	en := engine.NewEngine(cfg, &st, rs, ca, ctx)
+	var err error
+	_, err = en.Init(ctx)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "engine init fail: %v\n", err)
+		os.Exit(1)
+	}
+	err = engine.Loop(&en, os.Stdin, os.Stdout, ctx)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "loop exited with error: %v\n", err)
+		os.Exit(1)
+	}
+}

examples/session/root.vis

@@ -0,0 +1,2 @@
+LOAD do_save 0
+MOVE input

examples/validate/end

@@ -0,0 +1,2 @@
+You made it.
+Any input to go again.

examples/validate/end.vis

@@ -0,0 +1,3 @@
+HALT
+LOAD again 0
+INCMP * _

examples/validate/main.go

@@ -0,0 +1,84 @@
+package main
+
+import (
+	"context"
+	"flag"
+	"fmt"
+	"os"
+	"path"
+
+	testdataloader "github.com/peteole/testdata-loader"
+
+	"git.grassecon.net/kamikazechaser/vise/cache"
+	"git.grassecon.net/kamikazechaser/vise/engine"
+	"git.grassecon.net/kamikazechaser/vise/resource"
+	"git.grassecon.net/kamikazechaser/vise/state"
+)
+
+var (
+	baseDir     = testdataloader.GetBasePath()
+	scriptDir   = path.Join(baseDir, "examples", "validate")
+	emptyResult = resource.Result{}
+)
+
+const (
+	USERFLAG_HAVESOMETHING = state.FLAG_USERSTART
+)
+
+type verifyResource struct {
+	*resource.FsResource
+	st *state.State
+}
+
+func (vr *verifyResource) verify(sym string, input []byte, ctx context.Context) (resource.Result, error) {
+	var err error
+	if string(input) == "something" {
+		_, err = vr.st.SetFlag(USERFLAG_HAVESOMETHING)
+	}
+	return resource.Result{
+		Content: "",
+	}, err
+}
+
+func (vr *verifyResource) again(sym string, input []byte, ctx context.Context) (resource.Result, error) {
+	var err error
+	_, err = vr.st.ResetFlag(USERFLAG_HAVESOMETHING)
+	return resource.Result{}, err
+}
+
+func main() {
+	var root string
+	var size uint
+	var sessionId string
+	flag.UintVar(&size, "s", 0, "max size of output")
+	flag.StringVar(&root, "root", "root", "entry point symbol")
+	flag.StringVar(&sessionId, "session-id", "default", "session id")
+	flag.Parse()
+	fmt.Fprintf(os.Stderr, "starting session at symbol '%s' using resource dir: %s\n", root, scriptDir)
+
+	st := state.NewState(1)
+	rsf := resource.NewFsResource(scriptDir)
+	rs := verifyResource{&rsf, &st}
+	rs.AddLocalFunc("verifyinput", rs.verify)
+	rs.AddLocalFunc("again", rs.again)
+	ca := cache.NewCache()
+	cfg := engine.Config{
+		Root:       "root",
+		SessionId:  sessionId,
+		OutputSize: uint32(size),
+	}
+	ctx := context.Background()
+	ctx = context.WithValue(ctx, "SessionId", sessionId)
+	en := engine.NewEngine(cfg, &st, rs, ca, ctx)
+	var err error
+	_, err = en.Init(ctx)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "engine init fail: %v\n", err)
+		os.Exit(1)
+	}
+	err = engine.Loop(&en, os.Stdin, os.Stdout, ctx)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "loop exited with error: %v\n", err)
+		os.Exit(1)
+	}
+}

examples/validate/root

@@ -0,0 +1 @@
+Please write "something"

examples/validate/root.vis

@@ -0,0 +1,6 @@
+LOAD verifyinput 0
+MAP verifyinput
+HALT
+RELOAD verifyinput
+CATCH . 8 1
+MOVE end

go.mod

@@ -0,0 +1,11 @@
+module git.grassecon.net/kamikazechaser/vise
+
+go 1.20
+
+require (
+	github.com/alecthomas/participle/v2 v2.0.0
+	github.com/fxamacker/cbor/v2 v2.4.0
+	github.com/peteole/testdata-loader v0.3.0
+)
+
+require github.com/x448/float16 v0.8.4 // indirect

go/dev/interactive.go

@@ -1,27 +0,0 @@
-package main
-
-import (
-	"context"
-	"flag"
-	"fmt"
-	"os"
-
-	"git.defalsify.org/festive/engine"
-)
-
-func main() {
-	var dir string
-	var root string
-	flag.StringVar(&dir, "d", ".", "resource dir to read from")
-	flag.StringVar(&root, "root", "root", "entry point symbol")
-	flag.Parse()
-	fmt.Fprintf(os.Stderr, "starting session at symbol '%s' using resource dir: %s\n", root, dir)
-
-	ctx := context.Background()
-	en := engine.NewDefaultEngine(dir)
-	err := engine.Loop(&en, root, ctx, os.Stdin, os.Stdout)
-	if err != nil {
-		fmt.Fprintf(os.Stderr, "loop exited with error: %v", err)
-		os.Exit(1)
-	}
-}

go/engine/default.go

@@ -1,14 +0,0 @@
-package engine
-
-import (
-	"git.defalsify.org/festive/cache"
-	"git.defalsify.org/festive/resource"
-	"git.defalsify.org/festive/state"
-)
-
-func NewDefaultEngine(dir string) Engine {
-	st := state.NewState(0)
-	rs := resource.NewFsResource(dir)
-	ca := cache.NewCache()
-	return NewEngine(&st, &rs, ca)
-}

go/engine/engine.go

@@ -1,123 +0,0 @@
-package engine
-
-import (
-	"context"
-	"fmt"
-	"io"
-	"log"
-
-	"git.defalsify.org/festive/cache"
-	"git.defalsify.org/festive/resource"
-	"git.defalsify.org/festive/state"
-	"git.defalsify.org/festive/vm"
-)
-
-//type Config struct {
-//	FlagCount uint32
-//	CacheSize uint32
-//}
-
-// Engine is an execution engine that handles top-level errors when running user inputs against currently exposed bytecode.
-type Engine struct {
-	st *state.State
-	rs resource.Resource
-	ca cache.Memory
-	vm *vm.Vm
-}
-
-// NewEngine creates a new Engine
-func NewEngine(st *state.State, rs resource.Resource, ca cache.Memory) Engine {
-	engine := Engine{
-		st: st,
-		rs: rs,
-		ca: ca,
-		vm: vm.NewVm(st, rs, ca, nil),
-	}
-	return engine
-}
-
-// Init must be explicitly called before using the Engine instance.
-//
-// It loads and executes code for the start node.
-func(en *Engine) Init(sym string, ctx context.Context) error {
-	err := en.st.SetInput([]byte{})
-	if err != nil {
-		return err
-	}
-	b := vm.NewLine(nil, vm.MOVE, []string{sym}, nil, nil)
-	b, err = en.vm.Run(b, ctx)
-	if err != nil {
-		return err
-	}
-	en.st.SetCode(b)
-	return nil
-}
-
-// Exec processes user input against the current state of the virtual machine environment.
-//
-// If successfully executed, output of the last execution is available using the WriteResult call.
-// 
-// A bool return valus of false indicates that execution should be terminated. Calling Exec again has undefined effects.
-//
-// Fails if:
-// - input is formally invalid (too long etc)
-// - no current bytecode is available
-// - input processing against bytcode failed
-func (en *Engine) Exec(input []byte, ctx context.Context) (bool, error) {
-	err := vm.ValidInput(input)
-	if err != nil {
-		return true, err
-	}
-	err = en.st.SetInput(input)
-	if err != nil {
-		return false, err
-	}
-
-	log.Printf("new execution with input '%s' (0x%x)", input, input)
-	code, err := en.st.GetCode()
-	if err != nil {
-		return false, err
-	}
-	if len(code) == 0 {
-		return false, fmt.Errorf("no code to execute")
-	}
-	code, err = en.vm.Run(code, ctx)
-	if err != nil {
-		return false, err
-	}
-
-	v, err := en.st.MatchFlag(state.FLAG_TERMINATE, false)
-	if err != nil {
-		return false, err
-	}
-	if v {
-		if len(code) > 0 {
-			log.Printf("terminated with code remaining: %x", code)
-		}
-		return false, nil
-	}
-
-	en.st.SetCode(code)
-	if len(code) == 0 {
-		log.Printf("runner finished with no remaining code")
-		return false, nil
-	}
-
-	return true, nil
-}
-
-// WriteResult writes the output of the last vm execution to the given writer.
-//
-// Fails if
-// - required data inputs to the template are not available.
-// - the template for the given node point is note available for retrieval using the resource.Resource implementer.
-// - the supplied writer fails to process the writes.
-func(en *Engine) WriteResult(w io.Writer) error {
-	//location, idx := en.st.Where()
-	r, err := en.vm.Render()
-	if err != nil {
-		return err
-	}
-	_, err = io.WriteString(w, r)
-	return err
-}

go/engine/engine_test.go

@@ -1,139 +0,0 @@
-package engine
-
-import (
-	"bytes"
-	"context"
-	"fmt"
-	"io/ioutil"
-	"path"
-	"testing"
-
-	"git.defalsify.org/festive/cache"
-	"git.defalsify.org/festive/resource"
-	"git.defalsify.org/festive/state"
-	"git.defalsify.org/festive/testdata"
-)
-
-var (
-	dataGenerated bool = false
-	dataDir string = testdata.DataDir
-)
-
-type FsWrapper struct {
-	*resource.FsResource
-	st *state.State
-}
-
-func NewFsWrapper(path string, st *state.State) FsWrapper {
-	rs := resource.NewFsResource(path)
-	return FsWrapper {
-		&rs, 
-		st,
-	}
-}
-
-func(fs FsWrapper) one(sym string, ctx context.Context) (string, error) {
-	return "one", nil
-}
-
-func(fs FsWrapper) inky(sym string, ctx context.Context) (string, error) {
-	return "tinkywinky", nil
-}
-
-func(fs FsWrapper) FuncFor(sym string) (resource.EntryFunc, error) {
-	switch sym {
-	case "one":
-		return fs.one, nil
-	case "inky":
-		return fs.inky, nil
-	}
-	return nil, fmt.Errorf("function for %v not found", sym)
-}
-
-func(fs FsWrapper) GetCode(sym string) ([]byte, error) {
-	sym += ".bin"
-	fp := path.Join(fs.Path, sym)
-	r, err := ioutil.ReadFile(fp)
-	return r, err
-}
-
-func generateTestData(t *testing.T) {
-	if dataGenerated {
-		return
-	}
-	var err error
-	dataDir, err = testdata.Generate()
-	if err != nil {
-		t.Fatal(err)
-	}
-}
-
-func TestEngineInit(t *testing.T) {
-	generateTestData(t)
-	ctx := context.TODO()
-	st := state.NewState(17)
-	rs := NewFsWrapper(dataDir, &st)
-	ca := cache.NewCache().WithCacheSize(1024)
-	
-	en := NewEngine(&st, &rs, ca)
-	err := en.Init("root", ctx)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	w := bytes.NewBuffer(nil)
-	err = en.WriteResult(w)
-	if err != nil {
-		t.Fatal(err)
-	}
-	b := w.Bytes()
-	expect_str := `hello world
-1:do the foo
-2:go to the bar`
-
-	if !bytes.Equal(b, []byte(expect_str)) {
-		t.Fatalf("expected:\n\t%s\ngot:\n\t%s\n", expect_str, b)
-	}
-
-	input := []byte("1")
-	_, err = en.Exec(input, ctx)
-	if err != nil {
-		t.Fatal(err)
-	}
-	r, _ := st.Where()
-	if r != "foo" {
-		t.Fatalf("expected where-string 'foo', got %s", r)
-	}
-	w = bytes.NewBuffer(nil)
-	err = en.WriteResult(w)
-	if err != nil {
-		t.Fatal(err)
-	}
-	b = w.Bytes()
-	expect := `this is in foo
-
-it has more lines
-0:to foo
-1:go bar`
-	if !bytes.Equal(b, []byte(expect)) {
-		t.Fatalf("expected\n\t%s\ngot:\n\t%s\n", expect, b)
-	}
-}
-
-func TestEngineExecInvalidInput(t *testing.T) {
-	generateTestData(t)
-	ctx := context.TODO()
-	st := state.NewState(17)
-	rs := NewFsWrapper(dataDir, &st)
-	ca := cache.NewCache().WithCacheSize(1024)
-
-	en := NewEngine(&st, &rs, ca)
-	err := en.Init("root", ctx)
-	if err != nil {
-		t.Fatal(err)
-	}
-	_, err = en.Exec([]byte("_foo"), ctx)
-	if err == nil {
-		t.Fatalf("expected fail on invalid input")
-	}
-}

go/engine/loop_test.go

@@ -1,44 +0,0 @@
-package engine
-
-import (
-	"bytes"
-	"context"
-	"log"
-	"strings"
-	"testing"
-
-	"git.defalsify.org/festive/cache"
-	"git.defalsify.org/festive/resource"
-	"git.defalsify.org/festive/state"
-)
-
-func TestLoopCorrect(t *testing.T) {
-	generateTestData(t)
-	ctx := context.TODO()
-	st := state.NewState(0)
-	//rs := NewFsWrapper(dataDir, &st)
-	rs := resource.NewFsResource(dataDir)
-	ca := cache.NewCache().WithCacheSize(1024)
-	
-	en := NewEngine(&st, &rs, ca)
-	err := en.Init("root", ctx)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	input := []string{
-		"1",
-		"0",
-		"1",
-		"0",
-		}		
-	inputStr := strings.Join(input, "\n")
-	inputBuf := bytes.NewBuffer(append([]byte(inputStr), 0x0a))
-	outputBuf := bytes.NewBuffer(nil)
-	log.Printf("running with input: %s", inputBuf.Bytes())
-
-	err = Loop(&en, "root", ctx, inputBuf, outputBuf)
-	if err != nil {
-		t.Fatal(err)
-	}
-}

go/go.mod

@@ -1,8 +0,0 @@
-module git.defalsify.org/festive
-
-go 1.20
-
-require (
-	github.com/alecthomas/participle/v2 v2.0.0
-	github.com/peteole/testdata-loader v0.3.0
-)

go/render/render.go

@@ -1 +0,0 @@
-package render

go/render/size_test.go

@@ -1,169 +0,0 @@
-package render
-
-import (
-	"context"
-	"fmt"
-	"testing"
-
-	"git.defalsify.org/festive/state"
-	"git.defalsify.org/festive/resource"
-	"git.defalsify.org/festive/cache"
-)
-
-type TestSizeResource struct {
-	*resource.MenuResource
-}
-
-func getTemplate(sym string) (string, error) {
-	var tpl string
-	switch sym {
-	case "small":
-		tpl = "one {{.foo}} two {{.bar}} three {{.baz}}"
-	case "toobig":
-		tpl = "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vivamus in mattis lorem. Aliquam erat volutpat. Ut vitae metus."
-	case "pages":
-		tpl = "one {{.foo}} two {{.bar}} three {{.baz}}\n{{.xyzzy}}"
-	}
-	return tpl, nil
-}
-
-func funcFor(sym string) (resource.EntryFunc, error) {
-	switch sym {
-	case "foo":
-		return getFoo, nil
-	case "bar":
-		return getBar, nil
-	case "baz":
-		return getBaz, nil
-	case "xyzzy":
-		return getXyzzy, nil
-	}
-	return nil, fmt.Errorf("unknown func: %s", sym)
-}
-
-func getFoo(sym string, ctx context.Context) (string, error) {
-	return "inky", nil
-}
-
-func getBar(sym string, ctx context.Context) (string, error) {
-	return "pinky", nil
-}
-
-func getBaz(sym string, ctx context.Context) (string, error) {
-	return "blinky", nil
-}
-
-func getXyzzy(sym string, ctx context.Context) (string, error) {
-	return "inky pinky\nblinky clyde sue\ntinkywinky dipsy\nlala poo\none two three four five six seven\neight nine ten\neleven twelve", nil
-}
-
-func TestSizeCheck(t *testing.T) {
-	szr := NewSizer(16)
-	l, ok := szr.Check("foobar")
-	if !ok {
-		t.Fatalf("expected ok")
-	}
-	if l != 10 {
-		t.Fatalf("expected 10, got %v", l)
-	}
-
-	l, ok = szr.Check("inkypinkyblinkyclyde")
-	if ok {
-		t.Fatalf("expected not ok")
-	}
-	if l != 0 {
-		t.Fatalf("expected 0, got %v", l)
-	}
-}
-
-func TestSizeLimit(t *testing.T) {
-	st := state.NewState(0)
-	ca := cache.NewCache()
-	mn := NewMenu().WithOutputSize(32)
-	mrs := resource.NewMenuResource().WithEntryFuncGetter(funcFor).WithTemplateGetter(getTemplate)
-	rs := TestSizeResource{
-		mrs,
-	}
-	szr := NewSizer(128)
-	pg := NewPage(ca, rs).WithMenu(mn).WithSizer(szr)
-	ca.Push()
-	st.Down("test")
-	ca.Add("foo", "inky", 4)
-	ca.Add("bar", "pinky", 10)
-	ca.Add("baz", "blinky", 0)
-	pg.Map("foo")
-	pg.Map("bar")
-	pg.Map("baz")
-
-	mn.Put("1", "foo the foo")
-	mn.Put("2", "go to bar")
-
-	var err error
-	_, err = pg.Render("small", 0)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	_, err = pg.Render("toobig", 0)
-	if err == nil {
-		t.Fatalf("expected size exceeded")
-	}
-}
-
-func TestSizePages(t *testing.T) {
-	st := state.NewState(0)
-	ca := cache.NewCache()
-	mn := NewMenu().WithOutputSize(32)
-	mrs := resource.NewMenuResource().WithEntryFuncGetter(funcFor).WithTemplateGetter(getTemplate)
-	rs := TestSizeResource{
-		mrs,	
-	}
-	szr := NewSizer(128)
-	pg := NewPage(ca, rs).WithSizer(szr).WithMenu(mn)
-	ca.Push()
-	st.Down("test")
-	ca.Add("foo", "inky", 4)
-	ca.Add("bar", "pinky", 10)
-	ca.Add("baz", "blinky", 20)
-	ca.Add("xyzzy", "inky pinky\nblinky clyde sue\ntinkywinky dipsy\nlala poo\none two three four five six seven\neight nine ten\neleven twelve", 0)
-	pg.Map("foo")
-	pg.Map("bar")
-	pg.Map("baz")
-	pg.Map("xyzzy")
-
-	mn.Put("1", "foo the foo")
-	mn.Put("2", "go to bar")
-
-	r, err := pg.Render("pages",  0)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	expect := `one inky two pinky three blinky
-inky pinky
-blinky clyde sue
-tinkywinky dipsy
-lala poo
-1:foo the foo
-2:go to bar`
-
-
-	if r != expect {
-		t.Fatalf("expected:\n\t%s\ngot:\n\t%s\n", expect, r)
-	}
-	r, err = pg.Render("pages", 1)
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	expect = `one inky two pinky three blinky
-one two three four five six seven
-eight nine ten
-eleven twelve
-1:foo the foo
-2:go to bar`
-	if r != expect {
-		t.Fatalf("expected:\n\t%s\ngot:\n\t%s\n", expect, r)
-	}
-
-}

go/state/flag.go

@@ -1,8 +0,0 @@
-package state
-
-const (
-	FLAG_READIN = 1
-	FLAG_INMATCH = 2
-	FLAG_TERMINATE = 3
-	FLAG_DIRTY = 4
-)

persist/doc.go

@@ -0,0 +1,2 @@
+// Package persist enables persistent storage of the execution state.
+package persist

persist/fs.go

@@ -0,0 +1,86 @@
+package persist
+
+import (
+	"io/ioutil"
+	"log"
+	"path"
+	"path/filepath"
+
+	"github.com/fxamacker/cbor/v2"
+
+	"git.grassecon.net/kamikazechaser/vise/cache"
+	"git.grassecon.net/kamikazechaser/vise/state"
+)
+
+// FsPersister is an implementation of Persister that saves state to the file system.
+type FsPersister struct {
+	State  *state.State
+	Memory *cache.Cache
+	dir    string
+}
+
+// NewFsPersister creates a new FsPersister.
+//
+// The filesystem store will be at the given directory. The directory must exist.
+func NewFsPersister(dir string) *FsPersister {
+	fp, err := filepath.Abs(dir)
+	if err != nil {
+		panic(err)
+	}
+	return &FsPersister{
+		dir: fp,
+	}
+}
+
+// WithContent sets a current State and Cache object.
+//
+// This method is normally called before Serialize / Save.
+func (p *FsPersister) WithContent(st *state.State, ca *cache.Cache) *FsPersister {
+	p.State = st
+	p.Memory = ca
+	return p
+}
+
+// GetState implements the Persister interface.
+func (p *FsPersister) GetState() *state.State {
+	return p.State
+}
+
+// GetState implements the Persister interface.
+func (p *FsPersister) GetMemory() cache.Memory {
+	return p.Memory
+}
+
+// GetState implements the Persister interface.
+func (p *FsPersister) Serialize() ([]byte, error) {
+	return cbor.Marshal(p)
+}
+
+// GetState implements the Persister interface.
+func (p *FsPersister) Deserialize(b []byte) error {
+	err := cbor.Unmarshal(b, p)
+	return err
+}
+
+// GetState implements the Persister interface.
+func (p *FsPersister) Save(key string) error {
+	b, err := p.Serialize()
+	if err != nil {
+		return err
+	}
+	fp := path.Join(p.dir, key)
+	log.Printf("saved key %v state %x", key, p.State.Code)
+	return ioutil.WriteFile(fp, b, 0600)
+}
+
+// GetState implements the Persister interface.
+func (p *FsPersister) Load(key string) error {
+	fp := path.Join(p.dir, key)
+	b, err := ioutil.ReadFile(fp)
+	if err != nil {
+		return err
+	}
+	err = p.Deserialize(b)
+	log.Printf("loaded key %v state %x", key, p.State.Code)
+	return err
+}

persist/fs_test.go

@@ -0,0 +1,106 @@
+package persist
+
+import (
+	"bytes"
+	"io/ioutil"
+	"log"
+	"reflect"
+	"testing"
+
+	"git.grassecon.net/kamikazechaser/vise/cache"
+	"git.grassecon.net/kamikazechaser/vise/state"
+	"git.grassecon.net/kamikazechaser/vise/vm"
+)
+
+func TestSerializeState(t *testing.T) {
+	st := state.NewState(12)
+	st.Down("foo")
+	st.Down("bar")
+	st.Down("baz")
+	st.Next()
+	st.Next()
+
+	b := vm.NewLine(nil, vm.LOAD, []string{"foo"}, []byte{42}, nil)
+	b = vm.NewLine(b, vm.HALT, nil, nil, nil)
+	st.SetCode(b)
+
+	ca := cache.NewCache().WithCacheSize(1024)
+	ca.Add("inky", "pinky", 13)
+	ca.Add("blinky", "clyde", 42)
+
+	pr := NewFsPersister(".").WithContent(&st, ca)
+	v, err := pr.Serialize()
+	if err != nil {
+		t.Error(err)
+	}
+	log.Printf("v %b", v)
+
+	prnew := NewFsPersister(".")
+	err = prnew.Deserialize(v)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if !reflect.DeepEqual(prnew.State.ExecPath, pr.State.ExecPath) {
+		t.Fatalf("expected %s, got %s", prnew.State.ExecPath, pr.State.ExecPath)
+	}
+	if !bytes.Equal(prnew.State.Code, pr.State.Code) {
+		t.Fatalf("expected %x, got %x", prnew.State.Code, pr.State.Code)
+	}
+	if prnew.State.BitSize != pr.State.BitSize {
+		t.Fatalf("expected %v, got %v", prnew.State.BitSize, pr.State.BitSize)
+	}
+	if prnew.State.SizeIdx != pr.State.SizeIdx {
+		t.Fatalf("expected %v, got %v", prnew.State.SizeIdx, pr.State.SizeIdx)
+	}
+	if !reflect.DeepEqual(prnew.Memory, pr.Memory) {
+		t.Fatalf("expected %v, got %v", prnew.Memory, pr.Memory)
+	}
+}
+
+func TestSaveLoad(t *testing.T) {
+	st := state.NewState(12)
+	st.Down("foo")
+	st.Down("bar")
+	st.Down("baz")
+	st.Next()
+	st.Next()
+
+	b := vm.NewLine(nil, vm.LOAD, []string{"foo"}, []byte{42}, nil)
+	b = vm.NewLine(b, vm.HALT, nil, nil, nil)
+	st.SetCode(b)
+
+	ca := cache.NewCache().WithCacheSize(1024)
+	ca.Add("inky", "pinky", 13)
+	ca.Add("blinky", "clyde", 42)
+
+	dir, err := ioutil.TempDir("", "vise_persist")
+	if err != nil {
+		t.Error(err)
+	}
+	pr := NewFsPersister(dir).WithContent(&st, ca)
+	err = pr.Save("xyzzy")
+	if err != nil {
+		t.Error(err)
+	}
+
+	prnew := NewFsPersister(dir)
+	err = prnew.Load("xyzzy")
+	if err != nil {
+		t.Error(err)
+	}
+	if !reflect.DeepEqual(prnew.State.ExecPath, pr.State.ExecPath) {
+		t.Fatalf("expected %s, got %s", prnew.State.ExecPath, pr.State.ExecPath)
+	}
+	if !bytes.Equal(prnew.State.Code, pr.State.Code) {
+		t.Fatalf("expected %x, got %x", prnew.State.Code, pr.State.Code)
+	}
+	if prnew.State.BitSize != pr.State.BitSize {
+		t.Fatalf("expected %v, got %v", prnew.State.BitSize, pr.State.BitSize)
+	}
+	if prnew.State.SizeIdx != pr.State.SizeIdx {
+		t.Fatalf("expected %v, got %v", prnew.State.SizeIdx, pr.State.SizeIdx)
+	}
+	if !reflect.DeepEqual(prnew.Memory, pr.Memory) {
+		t.Fatalf("expected %v, got %v", prnew.Memory, pr.Memory)
+	}
+}

persist/persist.go

@@ -0,0 +1,16 @@
+package persist
+
+import (
+	"git.grassecon.net/kamikazechaser/vise/cache"
+	"git.grassecon.net/kamikazechaser/vise/state"
+)
+
+// Persister interface defines the methods needed for a component that can store the execution state to a storage location.
+type Persister interface {
+	Serialize() ([]byte, error) // Output serializes representation of the state.
+	Deserialize(b []byte) error // Restore state from a serialized state.
+	Save(key string) error      // Serialize and commit the state representation to persisted storage.
+	Load(key string) error      // Load the state representation from persisted storage and Deserialize.
+	GetState() *state.State     // Get the currently loaded State object.
+	GetMemory() cache.Memory    // Get the currently loaded Cache object.
+}

render/doc.go

@@ -0,0 +1,2 @@
+// Package render handles output size constraints and paginated rendering of contents and menus against templates.
+package render

render/menu.go

@@ -4,6 +4,17 @@ import (
 	"fmt"
 )
 
+// BrowseError is raised when browsing outside the page range of a rendered node.
+type BrowseError struct {
+	Idx uint16
+	PageCount uint16
+}
+
+// Error implements the Error interface.
+func(err *BrowseError) Error() string {
+	return fmt.Sprintf("index is out of bounds: %v", err.Idx)
+}
+
 // BrowseConfig defines the availability and display parameters for page browsing.
 type BrowseConfig struct {
 	NextAvailable bool
@@ -26,13 +37,14 @@ func DefaultBrowseConfig() BrowseConfig {
 	}
 }
 
+// Menu renders menus. May be included in a Page object to render menus for pages.
 type Menu struct {
-	menu [][2]string
+	menu [][2]string // selector and title for menu items.
-	browse BrowseConfig
+	browse BrowseConfig // browse definitions.
-	pageCount uint16
+	pageCount uint16 // number of pages the menu should represent.
-	canNext bool
+	canNext bool // availability flag for the "next" browse option.
-	canPrevious bool
+	canPrevious bool // availability flag for the "previous" browse option.
-	outputSize uint16
+	outputSize uint16 // maximum size constraint for the menu.
 }
 
 // NewMenu creates a new Menu with an explicit page count.
@@ -52,6 +64,11 @@ func(m *Menu) WithOutputSize(outputSize uint16) *Menu {
 	return m
 }
 
+// GetOutputSize returns the defined heuristic menu size.
+func(m *Menu) GetOutputSize() uint32 {
+	return uint32(m.outputSize)
+}
+
 // WithBrowseConfig defines the criteria for page browsing.
 func(m *Menu) WithBrowseConfig(cfg BrowseConfig) *Menu {
 	m.browse = cfg
@@ -69,6 +86,11 @@ func(m *Menu) Put(selector string, title string) error {
 	return nil
 }
 
+// ReservedSize returns the maximum render byte size of the menu.
+func(m *Menu) ReservedSize() uint16 {
+	return m.outputSize
+}
+
 // Render returns the full current state of the menu as a string.
 //
 // After this has been executed, the state of the menu will be empty.
@@ -107,7 +129,8 @@ func(m *Menu) applyPage(idx uint16) error {
 		}
 		return nil
 	} else if idx >= m.pageCount {
-		return fmt.Errorf("index %v out of bounds (%v)", idx, m.pageCount)
+		return &BrowseError{Idx: idx, PageCount: m.pageCount}
+		//return fmt.Errorf("index %v out of bounds (%v)", idx, m.pageCount)
 	}
 	
 	m.reset()
@@ -145,6 +168,7 @@ func(m *Menu) shiftMenu() (string, string, error) {
 	return r[0], r[1], nil
 }
 
+// prepare menu object for re-use.
 func(m *Menu) reset() {
 	if m.browse.NextAvailable {
 		m.canNext = true
@@ -155,6 +179,3 @@ func(m *Menu) reset() {
 }
 
 
-func(m *Menu) ReservedSize() uint16 {
-	return m.outputSize
-}

render/page.go

@@ -7,29 +7,31 @@ import (
 	"strings"
 	"text/template"
 
-	"git.defalsify.org/festive/cache"
+	"git.grassecon.net/kamikazechaser/vise/cache"
-	"git.defalsify.org/festive/resource"
+	"git.grassecon.net/kamikazechaser/vise/resource"
 )
 
+// Page exectues output rendering into pages constrained by size.
 type Page struct {
-	cacheMap map[string]string // Mapped
+	cacheMap map[string]string // Mapped content symbols
-	cache cache.Memory
+	cache    cache.Memory      // Content store.
-	resource resource.Resource
+	resource resource.Resource // Symbol resolver.
-	menu *Menu
+	menu     *Menu             // Menu rendererer.
-	sink *string
+	sink     *string           // Content symbol rendered by dynamic size.
-	sinkSize uint16
+	sizer    *Sizer            // Process size constraints.
-	sizer *Sizer
 }
 
+// NewPage creates a new Page object.
 func NewPage(cache cache.Memory, rs resource.Resource) *Page {
 	return &Page{
-		cache: cache,
+		cache:    cache,
 		cacheMap: make(map[string]string),
 		resource: rs,
 	}
 }
 
-func(pg *Page) WithMenu(menu *Menu) *Page {
+// WithMenu sets a menu renderer for the page.
+func (pg *Page) WithMenu(menu *Menu) *Page {
 	pg.menu = menu
 	if pg.sizer != nil {
 		pg.sizer = pg.sizer.WithMenuSize(pg.menu.ReservedSize())
@@ -37,7 +39,8 @@ func(pg *Page) WithMenu(menu *Menu) *Page {
 	return pg
 }
 
-func(pg *Page) WithSizer(sizer *Sizer) *Page {
+// WithSizer sets a size constraints definition for the page.
+func (pg *Page) WithSizer(sizer *Sizer) *Page {
 	pg.sizer = sizer
 	if pg.menu != nil {
 		pg.sizer = pg.sizer.WithMenuSize(pg.menu.ReservedSize())
@@ -45,8 +48,8 @@ func(pg *Page) WithSizer(sizer *Sizer) *Page {
 	return pg
 }
 
-// Size returns size used by values and menu, and remaining size available
+// Usage returns size used by values and menu, and remaining size available
-func(pg *Page) Usage() (uint32, uint32, error) {
+func (pg *Page) Usage() (uint32, uint32, error) {
 	var l int
 	var c uint16
 	for k, v := range pg.cacheMap {
@@ -59,12 +62,10 @@ func(pg *Page) Usage() (uint32, uint32, error) {
 		log.Printf("v %x %v %v %v %v", []byte(v), len(v), l, sz, c)
 	}
 	r := uint32(l)
-	rsv := uint32(c)-r
+	rsv := uint32(c) - r
-	log.Printf("size before %v %v", r, c)
 	if pg.menu != nil {
 		r += uint32(pg.menu.ReservedSize())
 	}
-	log.Printf("size after %v %v", r, c)
 	return r, rsv, nil
 }
 
@@ -73,7 +74,7 @@ func(pg *Page) Usage() (uint32, uint32, error) {
 // After this, Val() will return the value for the key, and Size() will include the value size and limitations in its calculations.
 //
 // Only one symbol with no size limitation may be mapped at the current level.
-func(pg *Page) Map(key string) error {
+func (pg *Page) Map(key string) error {
 	v, err := pg.cache.Get(key)
 	if err != nil {
 		return err
@@ -95,12 +96,14 @@ func(pg *Page) Map(key string) error {
 			return err
 		}
 	}
-	log.Printf("page map is now: %v", pg.cacheMap)
+	log.Printf("mapped %s", key)
 	return nil
 }
 
+// Val gets the mapped content for the given symbol.
+//
 // Fails if key is not mapped.
-func(pg *Page) Val(key string) (string, error) {
+func (pg *Page) Val(key string) (string, error) {
 	r := pg.cacheMap[key]
 	if len(r) == 0 {
 		return "", fmt.Errorf("key %v not mapped", key)
@@ -108,8 +111,8 @@ func(pg *Page) Val(key string) (string, error) {
 	return r, nil
 }
 
-// Moved from cache, MAP should hook to this object
+// Sizes returned the actual used bytes by each mapped symbol.
-func(pg *Page) Sizes() (map[string]uint16, error) {
+func (pg *Page) Sizes() (map[string]uint16, error) {
 	sizes := make(map[string]uint16)
 	var haveSink bool
 	for k, _ := range pg.cacheMap {
@@ -123,13 +126,12 @@ func(pg *Page) Sizes() (map[string]uint16, error) {
 			}
 			haveSink = true
 		}
-		pg.sinkSize = l
 	}
 	return sizes, nil
 }
 
-// DefaultRenderTemplate is an adapter to implement the builtin golang text template renderer as resource.RenderTemplate.
+// RenderTemplate is an adapter to implement the builtin golang text template renderer as resource.RenderTemplate.
-func(pg *Page) RenderTemplate(sym string, values map[string]string, idx uint16) (string, error) {
+func (pg *Page) RenderTemplate(sym string, values map[string]string, idx uint16) (string, error) {
 	tpl, err := pg.resource.GetTemplate(sym)
 	if err != nil {
 		return "", err
@@ -143,7 +145,7 @@ func(pg *Page) RenderTemplate(sym string, values map[string]string, idx uint16)
 		return "", fmt.Errorf("sizer needed for indexed render")
 	}
 	log.Printf("render for index: %v", idx)
-	
+
 	tp, err := template.New("tester").Option("missingkey=error").Parse(tpl)
 	if err != nil {
 		return "", err
@@ -157,8 +159,29 @@ func(pg *Page) RenderTemplate(sym string, values map[string]string, idx uint16)
 	return b.String(), err
 }
 
+// Render renders the current mapped content and menu state against the template associated with the symbol.
+func (pg *Page) Render(sym string, idx uint16) (string, error) {
+	var err error
+
+	values, err := pg.prepare(sym, pg.cacheMap, idx)
+	if err != nil {
+		return "", err
+	}
+
+	return pg.render(sym, values, idx)
+}
+
+// Reset prepared the Page object for re-use.
+//
+// It clears mappings and removes the sink definition.
+func (pg *Page) Reset() {
+	pg.sink = nil
+	pg.cacheMap = make(map[string]string)
+}
+
 // render menu and all syms except sink, split sink into display chunks
-func(pg *Page) prepare(sym string, values map[string]string, idx uint16) (map[string]string, error) {
+// TODO: Function too long, split up
+func (pg *Page) prepare(sym string, values map[string]string, idx uint16) (map[string]string, error) {
 	var sink string
 
 	if pg.sizer == nil {
@@ -180,7 +203,7 @@ func(pg *Page) prepare(sym string, values map[string]string, idx uint16) (map[st
 		}
 		noSinkValues[k] = v
 	}
-	
+
 	if sink == "" {
 		log.Printf("no sink found for sym %s", sym)
 		return values, nil
@@ -191,23 +214,51 @@ func(pg *Page) prepare(sym string, values map[string]string, idx uint16) (map[st
 	if err != nil {
 		return nil, err
 	}
-
+	// remaining includes core menu
 	remaining, ok := pg.sizer.Check(s)
 	if !ok {
 		return nil, fmt.Errorf("capacity exceeded")
 	}
 
-	log.Printf("%v bytes available for sink split", remaining)
+	var menuSizes [4]uint32 // mainSize, prevsize, nextsize, nextsize+prevsize
+	if pg.menu != nil {
+		cfg := pg.menu.GetBrowseConfig()
+		tmpm := NewMenu().WithBrowseConfig(cfg)
+		v, err := tmpm.Render(0)
+		if err != nil {
+			return nil, err
+		}
+		menuSizes[0] = uint32(len(v))
+		tmpm = tmpm.WithPageCount(2)
+		v, err = tmpm.Render(0)
+		if err != nil {
+			return nil, err
+		}
+		menuSizes[1] = uint32(len(v)) - menuSizes[0]
+		v, err = tmpm.Render(1)
+		if err != nil {
+			return nil, err
+		}
+		menuSizes[2] = uint32(len(v)) - menuSizes[0]
+		menuSizes[3] = menuSizes[1] + menuSizes[2]
+	}
+
+	log.Printf("%v bytes available for sink split before navigation", remaining)
 
 	l := 0
 	var count uint16
 	tb := strings.Builder{}
 	rb := strings.Builder{}
 
+	netRemaining := remaining - 1
+	if len(sinkValues) > 1 {
+		netRemaining -= menuSizes[1] - 1
+	}
+
 	for i, v := range sinkValues {
-		log.Printf("processing sinkvalue %v: %s", i, v)
 		l += len(v)
-		if uint32(l) > remaining {
+		log.Printf("processing sinkvalue %v: %s", i, v)
+		if uint32(l) > netRemaining-1 {
 			if tb.Len() == 0 {
 				return nil, fmt.Errorf("capacity insufficient for sink field %v", i)
 			}
@@ -217,10 +268,14 @@ func(pg *Page) prepare(sym string, values map[string]string, idx uint16) (map[st
 			pg.sizer.AddCursor(c)
 			tb.Reset()
 			l = 0
+			if count == 0 {
+				netRemaining -= menuSizes[2]
+			}
 			count += 1
 		}
 		if tb.Len() > 0 {
 			tb.WriteByte(byte(0x00))
+			l += 1
 		}
 		tb.WriteString(v)
 	}
@@ -246,7 +301,8 @@ func(pg *Page) prepare(sym string, values map[string]string, idx uint16) (map[st
 	return noSinkValues, nil
 }
 
-func(pg *Page) render(sym string, values map[string]string, idx uint16) (string, error) {
+// render template, menu (if it exists), and audit size constraint (if it exists).
+func (pg *Page) render(sym string, values map[string]string, idx uint16) (string, error) {
 	var ok bool
 	r := ""
 	s, err := pg.RenderTemplate(sym, values, idx)
@@ -255,20 +311,18 @@ func(pg *Page) render(sym string, values map[string]string, idx uint16) (string,
 	}
 	log.Printf("rendered %v bytes for template", len(s))
 	r += s
-	if pg.sizer != nil {
+
-		_, ok = pg.sizer.Check(r)
+	if pg.menu != nil {
-		if !ok {
+		s, err = pg.menu.Render(idx)
-			return "", fmt.Errorf("limit exceeded: %v", pg.sizer)
+		if err != nil {
+			return "", err
+		}
+		log.Printf("rendered %v bytes for menu", len(s))
+		if len(s) > 0 {
+			r += "\n" + s
 		}
 	}
-	s, err = pg.menu.Render(idx)
+
-	if err != nil {
-		return "", err
-	}
-	log.Printf("rendered %v bytes for menu", len(s))
-	if len(s) > 0 {
-		r += "\n" + s
-	}
 	if pg.sizer != nil {
 		_, ok = pg.sizer.Check(r)
 		if !ok {
@@ -277,21 +331,3 @@ func(pg *Page) render(sym string, values map[string]string, idx uint16) (string,
 	}
 	return r, nil
 }
-
-func(pg *Page) Render(sym string, idx uint16) (string, error) {
-	var err error
-
-	values, err := pg.prepare(sym, pg.cacheMap, idx)
-	if err != nil {
-		return "", err
-	}
-
-	log.Printf("nosink %v", values)
-	return pg.render(sym, values, idx)
-}
-
-func(pg *Page) Reset() {
-	pg.sink = nil
-	pg.sinkSize = 0
-	//pg.cacheMap = make(map[string]string)
-}

render/page_test.go

@@ -3,10 +3,9 @@ package render
 import (
 	"testing"
 
-	"git.defalsify.org/festive/cache"
+	"git.grassecon.net/kamikazechaser/vise/cache"
 )
 
-
 func TestPageCurrentSize(t *testing.T) {
 	t.Skip("usage is not in use, and it is unclear how it should be calculated")
 	ca := cache.NewCache()

render/size.go

@@ -7,15 +7,17 @@ import (
 	"strings"
 )
 
+// Sizer splits dynamic contents into individual segments for browseable pages.
 type Sizer struct {
-	outputSize uint32
+	outputSize uint32 // maximum output for a single page.
-	menuSize uint16
+	menuSize uint16 // actual menu size for the dynamic page being sized
-	memberSizes map[string]uint16
+	memberSizes map[string]uint16 // individual byte sizes of all content to be rendered by template.
-	totalMemberSize uint32
+	totalMemberSize uint32 // total byte size of all content to be rendered by template (sum of memberSizes)
-	crsrs []uint32
+	crsrs []uint32 // byte offsets in the sink content for browseable pages indices.
-	sink string
+	sink string // sink symbol.
 }
 
+// NewSizer creates a new Sizer object with the given output size constraint.
 func NewSizer(outputSize uint32) *Sizer {
 	return &Sizer{
 		outputSize: outputSize,
@@ -23,11 +25,13 @@ func NewSizer(outputSize uint32) *Sizer {
 	}
 }
 
+// WithMenuSize sets the size of the menu being used in the rendering context.
 func(szr *Sizer) WithMenuSize(menuSize uint16) *Sizer {
 	szr.menuSize = menuSize
 	return szr
 }
 
+// Set adds a content symbol in the state it will be used by the renderer.
 func(szr *Sizer) Set(key string, size uint16) error {
 	szr.memberSizes[key] = size
 	if size == 0 {
@@ -37,12 +41,13 @@ func(szr *Sizer) Set(key string, size uint16) error {
 	return nil
 }
 
+// Check audits whether the rendered string is within the output size constraint of the sizer.
 func(szr *Sizer) Check(s string) (uint32, bool) {
-	log.Printf("sizercheck %s", s)
 	l := uint32(len(s))
 	if szr.outputSize > 0 {
 		if l > szr.outputSize {
 			log.Printf("sizer check fails with length %v: %s", l, szr)
+			log.Printf("sizer contents:\n%s", s)
 			return 0, false
 		}
 		l = szr.outputSize - l
@@ -50,6 +55,7 @@ func(szr *Sizer) Check(s string) (uint32, bool) {
 	return l, true
 }
 
+// String implements the String interface.
 func(szr *Sizer) String() string {
 	var diff uint32
 	if szr.outputSize > 0 {
@@ -58,6 +64,9 @@ func(szr *Sizer) String() string {
 	return fmt.Sprintf("output: %v, member: %v, menu: %v, diff: %v", szr.outputSize, szr.totalMemberSize, szr.menuSize, diff)
 }
 
+// Size gives the byte size of content for a single symbol.
+//
+// Fails if the symbol has not been registered using Set
 func(szr *Sizer) Size(s string) (uint16, error) {
 	r, ok := szr.memberSizes[s]
 	if !ok {
@@ -66,11 +75,20 @@ func(szr *Sizer) Size(s string) (uint16, error) {
 	return r, nil
 }
 
+// Menusize returns the currently defined menu size.
+func(szr *Sizer) MenuSize() uint16 {
+	return szr.menuSize
+}
+
+// AddCursor adds a pagination cursor for the paged sink content.
 func(szr *Sizer) AddCursor(c uint32) {
 	log.Printf("added cursor: %v", c)
 	szr.crsrs = append(szr.crsrs, c)
 }
 
+// GetAt the paged symbols for the current page index.
+//
+// Fails if index requested is out of range.
 func(szr *Sizer) GetAt(values map[string]string, idx uint16) (map[string]string, error) {
 	if szr.sink == "" {
 		return values, nil
@@ -84,7 +102,6 @@ func(szr *Sizer) GetAt(values map[string]string, idx uint16) (map[string]string,
 			c := szr.crsrs[idx]
 			v = v[c:]
 			nl := strings.Index(v, "\n")
-			log.Printf("k %v v %v c %v nl %v", k, v, c, nl)
 			if nl > 0 {
 				v = v[:nl]
 			}

render/size_test.go

@@ -0,0 +1,251 @@
+package render
+
+import (
+	"context"
+	"fmt"
+	"testing"
+
+	"git.grassecon.net/kamikazechaser/vise/cache"
+	"git.grassecon.net/kamikazechaser/vise/resource"
+	"git.grassecon.net/kamikazechaser/vise/state"
+)
+
+type TestSizeResource struct {
+	*resource.MenuResource
+}
+
+func getTemplate(sym string) (string, error) {
+	var tpl string
+	switch sym {
+	case "small":
+		tpl = "one {{.foo}} two {{.bar}} three {{.baz}}"
+	case "toobig":
+		tpl = "Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vivamus in mattis lorem. Aliquam erat volutpat. Ut vitae metus."
+	case "pages":
+		tpl = "one {{.foo}} two {{.bar}} three {{.baz}}\n{{.xyzzy}}"
+	}
+	return tpl, nil
+}
+
+func funcFor(sym string) (resource.EntryFunc, error) {
+	switch sym {
+	case "foo":
+		return getFoo, nil
+	case "bar":
+		return getBar, nil
+	case "baz":
+		return getBaz, nil
+	case "xyzzy":
+		return getXyzzy, nil
+	}
+	return nil, fmt.Errorf("unknown func: %s", sym)
+}
+
+func getFoo(sym string, input []byte, ctx context.Context) (resource.Result, error) {
+	return resource.Result{
+		Content: "inky",
+	}, nil
+}
+
+func getBar(sym string, input []byte, ctx context.Context) (resource.Result, error) {
+	return resource.Result{
+		Content: "pinky",
+	}, nil
+}
+
+func getBaz(sym string, input []byte, ctx context.Context) (resource.Result, error) {
+	return resource.Result{
+		Content: "blinky",
+	}, nil
+}
+
+func getXyzzy(sym string, input []byte, ctx context.Context) (resource.Result, error) {
+	return resource.Result{
+		Content: "inky pinky\nblinky clyde sue\ntinkywinky dipsy\nlala poo\none two three four five six seven\neight nine ten\neleven twelve",
+	}, nil
+}
+
+func TestSizeCheck(t *testing.T) {
+	szr := NewSizer(16)
+	l, ok := szr.Check("foobar")
+	if !ok {
+		t.Fatalf("expected ok")
+	}
+	if l != 10 {
+		t.Fatalf("expected 10, got %v", l)
+	}
+
+	l, ok = szr.Check("inkypinkyblinkyclyde")
+	if ok {
+		t.Fatalf("expected not ok")
+	}
+	if l != 0 {
+		t.Fatalf("expected 0, got %v", l)
+	}
+}
+
+func TestSizeLimit(t *testing.T) {
+	st := state.NewState(0)
+	ca := cache.NewCache()
+	mn := NewMenu().WithOutputSize(32)
+	mrs := resource.NewMenuResource().WithEntryFuncGetter(funcFor).WithTemplateGetter(getTemplate)
+	rs := TestSizeResource{
+		mrs,
+	}
+	szr := NewSizer(128)
+	pg := NewPage(ca, rs).WithMenu(mn).WithSizer(szr)
+	ca.Push()
+	st.Down("test")
+	err := ca.Add("foo", "inky", 4)
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = ca.Add("bar", "pinky", 10)
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = ca.Add("baz", "blinky", 0)
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = pg.Map("foo")
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = pg.Map("bar")
+	if err != nil {
+		t.Fatal(err)
+	}
+	err = pg.Map("baz")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	mn.Put("1", "foo the foo")
+	mn.Put("2", "go to bar")
+
+	_, err = pg.Render("small", 0)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	_, err = pg.Render("toobig", 0)
+	if err == nil {
+		t.Fatalf("expected size exceeded")
+	}
+}
+
+func TestSizePages(t *testing.T) {
+	st := state.NewState(0)
+	ca := cache.NewCache()
+	mn := NewMenu().WithOutputSize(32)
+	mrs := resource.NewMenuResource().WithEntryFuncGetter(funcFor).WithTemplateGetter(getTemplate)
+	rs := TestSizeResource{
+		mrs,
+	}
+	szr := NewSizer(128)
+	pg := NewPage(ca, rs).WithSizer(szr).WithMenu(mn)
+	ca.Push()
+	st.Down("test")
+	ca.Add("foo", "inky", 4)
+	ca.Add("bar", "pinky", 10)
+	ca.Add("baz", "blinky", 20)
+	ca.Add("xyzzy", "inky pinky\nblinky clyde sue\ntinkywinky dipsy\nlala poo\none two three four five six seven\neight nine ten\neleven twelve", 0)
+	pg.Map("foo")
+	pg.Map("bar")
+	pg.Map("baz")
+	pg.Map("xyzzy")
+
+	mn.Put("1", "foo the foo")
+	mn.Put("2", "go to bar")
+
+	r, err := pg.Render("pages", 0)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	expect := `one inky two pinky three blinky
+inky pinky
+blinky clyde sue
+tinkywinky dipsy
+lala poo
+1:foo the foo
+2:go to bar`
+
+	if r != expect {
+		t.Fatalf("expected:\n\t%x\ngot:\n\t%x\n", expect, r)
+	}
+	r, err = pg.Render("pages", 1)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	expect = `one inky two pinky three blinky
+one two three four five six seven
+eight nine ten
+eleven twelve
+1:foo the foo
+2:go to bar`
+	if r != expect {
+		t.Fatalf("expected:\n\t%s\ngot:\n\t%s\n", expect, r)
+	}
+
+}
+
+func TestManySizes(t *testing.T) {
+	for i := 60; i < 160; i++ {
+		st := state.NewState(0)
+		ca := cache.NewCache()
+		mn := NewMenu().WithOutputSize(32)
+		mrs := resource.NewMenuResource().WithEntryFuncGetter(funcFor).WithTemplateGetter(getTemplate)
+		rs := TestSizeResource{
+			mrs,
+		}
+		szr := NewSizer(uint32(i))
+		pg := NewPage(ca, rs).WithSizer(szr).WithMenu(mn)
+		ca.Push()
+		st.Down("pages")
+		ca.Add("foo", "inky", 10)
+		ca.Add("bar", "pinky", 10)
+		ca.Add("baz", "blinky", 10)
+		ca.Add("xyzzy", "inky pinky\nblinky clyde sue\ntinkywinky dipsy\nlala poo\none two three four five six seven\neight nine ten\neleven twelve", 0)
+		pg.Map("foo")
+		pg.Map("bar")
+		pg.Map("baz")
+		pg.Map("xyzzy")
+		_, err := pg.Render("pages", 0)
+		if err != nil {
+			t.Fatal(err)
+		}
+	}
+}
+
+func TestManySizesMenued(t *testing.T) {
+	for i := 60; i < 160; i++ {
+		st := state.NewState(0)
+		ca := cache.NewCache()
+		mn := NewMenu().WithOutputSize(32)
+		mrs := resource.NewMenuResource().WithEntryFuncGetter(funcFor).WithTemplateGetter(getTemplate)
+		rs := TestSizeResource{
+			mrs,
+		}
+		szr := NewSizer(uint32(i))
+		pg := NewPage(ca, rs).WithSizer(szr).WithMenu(mn)
+		ca.Push()
+		st.Down("pages")
+		ca.Add("foo", "inky", 10)
+		ca.Add("bar", "pinky", 10)
+		ca.Add("baz", "blinky", 10)
+		ca.Add("xyzzy", "inky pinky\nblinky clyde sue\ntinkywinky dipsy\nlala poo\none two three four five six seven\neight nine ten\neleven twelve", 0)
+		pg.Map("foo")
+		pg.Map("bar")
+		pg.Map("baz")
+		pg.Map("xyzzy")
+		mn.Put("0", "yay")
+		mn.Put("12", "nay")
+		_, err := pg.Render("pages", 0)
+		if err != nil {
+			t.Fatal(err)
+		}
+	}
+}

resource/doc.go

@@ -0,0 +1,2 @@
+// Package resource interfaces retrieval of bytecode, output templates and external code execution.
+package resource

resource/fs.go

@@ -39,12 +39,19 @@ func(fs FsResource) GetCode(sym string) ([]byte, error) {
 	return ioutil.ReadFile(fp)
 }
 
+func(fs *FsResource) AddLocalFunc(sym string, fn EntryFunc) {
+	if fs.fns == nil {
+		fs.fns = make(map[string]EntryFunc)
+	}
+	fs.fns[sym] = fn
+}
+
 func(fs FsResource) FuncFor(sym string) (EntryFunc, error) {
 	fn, ok := fs.fns[sym]
 	if ok {
 		return fn, nil
 	}
-	_, err := fs.getFuncNoCtx(sym)
+	_, err := fs.getFuncNoCtx(sym, nil)
 	if err != nil {
 		return nil, fmt.Errorf("unknown sym: %s", sym)
 	}
@@ -55,18 +62,20 @@ func(fs FsResource) String() string {
 	return fmt.Sprintf("fs resource at path: %s", fs.Path)
 }
 
-func(fs FsResource) getFunc(sym string, ctx context.Context) (string, error) {
+func(fs FsResource) getFunc(sym string, input []byte, ctx context.Context) (Result, error) {
-	return fs.getFuncNoCtx(sym)
+	return fs.getFuncNoCtx(sym, input)
 }
 
-func(fs FsResource) getFuncNoCtx(sym string) (string, error) {
+func(fs FsResource) getFuncNoCtx(sym string, input []byte) (Result, error) {
 	fb := sym + ".txt"
 	fp := path.Join(fs.Path, fb)
 	log.Printf("getfunc search dir %s %s for %s", fs.Path, fp, sym)
 	r, err := ioutil.ReadFile(fp)
 	if err != nil {
-		return "", fmt.Errorf("failed getting data for sym '%s': %v", sym, err)
+		return Result{}, fmt.Errorf("failed getting data for sym '%s': %v", sym, err)
 	}
 	s := string(r)
-	return strings.TrimSpace(s), nil
+	return Result{
+		Content: strings.TrimSpace(s),
+	}, nil
 }

resource/resource.go

@@ -4,8 +4,15 @@ import (
 	"context"
 )
 
+// Result contains the results of an external code operation.
+type Result struct {
+	Content string // content value for symbol after execution.
+	FlagSet []uint32 // request caller to set error flags at given indices.
+	FlagReset []uint32 // request caller to reset error flags at given indices.
+}
+
 // EntryFunc is a function signature for retrieving value for a key
-type EntryFunc func(sym string, ctx context.Context) (string, error)
+type EntryFunc func(sym string, input []byte, ctx context.Context) (Result, error)
 type CodeFunc func(sym string) ([]byte, error)
 type TemplateFunc func(sym string) (string, error)
 type FuncForFunc func(sym string) (EntryFunc, error)
@@ -17,6 +24,9 @@ type Resource interface {
 	FuncFor(sym string) (EntryFunc, error) // Resolve symbol content point for.
 }
 
+// MenuResource contains the base definition for building Resource implementations.
+//
+// TODO: Rename to BaseResource
 type MenuResource struct {
 	sinkValues []string
 	codeFunc CodeFunc
@@ -47,14 +57,17 @@ func(m *MenuResource) WithTemplateGetter(templateGetter TemplateFunc) *MenuResou
 	return m
 }
 
+// FuncFor implements Resource interface
 func(m *MenuResource) FuncFor(sym string) (EntryFunc, error) {
 	return m.funcFunc(sym)
 }
 
+// GetCode implements Resource interface
 func(m *MenuResource) GetCode(sym string) ([]byte, error) {
 	return m.codeFunc(sym)
 }
 
+// GetTemplate implements Resource interface
 func(m *MenuResource) GetTemplate(sym string) (string, error) {
 	return m.templateFunc(sym)
 }

resource/resource_test.go

@@ -37,18 +37,27 @@ func funcFor(sym string) (EntryFunc, error) {
 	return nil, fmt.Errorf("unknown func: %s", sym)
 }
 
-func get(sym string, ctx context.Context) (string, error) {
+func get(sym string, input []byte, ctx context.Context) (Result, error) {
 	switch sym {
 	case "foo":
-		return "inky", nil
+		return Result{
+			Content: "inky",
+		}, nil
 	case "bar":
-		return "pinky", nil
+		return Result{
+			Content: "pinky",
+		}, nil
 	case "baz":
-		return "blinky", nil
+		return Result{
+			Content: "blinky",
+		}, nil
 	}
-	return "", fmt.Errorf("unknown sym: %s", sym)
+	return Result{}, fmt.Errorf("unknown sym: %s", sym)
 }
 
-func getXyzzy(sym string, ctx context.Context) (string, error) {
+func getXyzzy(sym string, input []byte, ctx context.Context) (Result, error) {
-	return "inky pinky\nblinky clyde sue\ntinkywinky dipsy\nlala poo\none two three four five six seven\neight nine ten\neleven twelve", nil
+	r := "inky pinky\nblinky clyde sue\ntinkywinky dipsy\nlala poo\none two three four five six seven\neight nine ten\neleven twelve"
+	return Result{
+		Content: r,
+	}, nil
 }

resource/state.go

@@ -1,7 +1,7 @@
 package resource
 
 import (
-	"git.defalsify.org/festive/state"
+	"git.grassecon.net/kamikazechaser/vise/state"
 )
 
 type StateResource struct {
@@ -14,13 +14,13 @@ func ToStateResource(rs Resource) *StateResource {
 }
 
 func NewStateResource(st *state.State) *StateResource {
-	return &StateResource {
+	return &StateResource{
 		NewMenuResource(),
 		st,
 	}
 }
 
-func(sr *StateResource) WithState(st *state.State) *StateResource {
+func (sr *StateResource) WithState(st *state.State) *StateResource {
 	if sr.st != nil {
 		panic("state already set")
 	}

resource/state_test.go

@@ -3,7 +3,7 @@ package resource
 import (
 	"testing"
 
-	"git.defalsify.org/festive/state"
+	"git.grassecon.net/kamikazechaser/vise/state"
 )
 
 func TestStateResourceInit(t *testing.T) {

state/flag.go

@@ -0,0 +1,24 @@
+package state
+
+const (
+	FLAG_READIN = iota
+	FLAG_INMATCH 
+	FLAG_TERMINATE 
+	FLAG_DIRTY
+	FLAG_WAIT
+	FLAG_LOADFAIL
+	FLAG_USERSTART = 8
+)
+
+func IsWriteableFlag(flag uint32) bool {
+	if flag > 7 {
+		return true
+	}
+	//if flag & FLAG_WRITEABLE > 0 {
+	//	return true	
+	//}
+	return false
+}
+
+type FlagDebugger struct {
+}

state/state.go

@@ -6,6 +6,13 @@ import (
 	"strings"
 )
 
+type IndexError struct {
+}
+
+func(err *IndexError) Error() string {
+	return fmt.Sprintf("already at first index")
+}
+
 // State holds the command stack, error condition of a unique execution session.
 //
 // It also holds cached values for all results of executed symbols.
@@ -22,25 +29,25 @@ import (
 //
 // 8 first flags are reserved.
 type State struct {
+	Code []byte // Pending bytecode to execute
+	ExecPath []string // Command symbols stack
+	BitSize uint32 // size of (32-bit capacity) bit flag byte array
+	SizeIdx uint16
 	Flags []byte // Error state
+	Moves uint32 // Number of times navigation has been performed
 	input []byte // Last input
-	code []byte // Pending bytecode to execute
-	execPath []string // Command symbols stack
-	arg *string // Optional argument. Nil if not set.
-	bitSize uint32 // size of (32-bit capacity) bit flag byte array
-	sizeIdx uint16
 }
 
 // number of bytes necessary to represent a bitfield of the given size.
-func toByteSize(bitSize uint32) uint8 {
+func toByteSize(BitSize uint32) uint8 {
-	if bitSize == 0 {
+	if BitSize == 0 {
 		return 0
 	}
-	n := bitSize % 8
+	n := BitSize % 8
 	if n > 0 {
-		bitSize += (8 - n)
+		BitSize += (8 - n)
 	}
-	return uint8(bitSize / 8)
+	return uint8(BitSize / 8)
 }
 
 // Retrieve the state of a state flag
@@ -51,12 +58,12 @@ func getFlag(bitIndex uint32, bitField []byte) bool {
 	return (b & (1 << localBitIndex)) > 0
 }
 
-// NewState creates a new State object with bitSize number of error condition states in ADDITION to the 8 builtin flags.
+// NewState creates a new State object with BitSize number of error condition states in ADDITION to the 8 builtin flags.
-func NewState(bitSize uint32) State {
+func NewState(BitSize uint32) State {
 	st := State{
-		bitSize: bitSize + 8,
+		BitSize: BitSize + 8,
 	}
-	byteSize := toByteSize(bitSize + 8)
+	byteSize := toByteSize(BitSize + 8)
 	if byteSize > 0 {
 		st.Flags = make([]byte, byteSize) 
 	} else {
@@ -71,8 +78,8 @@ func NewState(bitSize uint32) State {
 //
 // Fails if bitindex is out of range.
 func(st *State) SetFlag(bitIndex uint32) (bool, error) {
-	if bitIndex + 1 > st.bitSize {
+	if bitIndex + 1 > st.BitSize {
-		return false, fmt.Errorf("bit index %v is out of range of bitfield size %v", bitIndex, st.bitSize)
+		return false, fmt.Errorf("bit index %v is out of range of bitfield size %v", bitIndex, st.BitSize)
 	}
 	r := getFlag(bitIndex, st.Flags)
 	if r {
@@ -92,8 +99,8 @@ func(st *State) SetFlag(bitIndex uint32) (bool, error) {
 //
 // Fails if bitindex is out of range.
 func(st *State) ResetFlag(bitIndex uint32) (bool, error) {
-	if bitIndex + 1 > st.bitSize {
+	if bitIndex + 1 > st.BitSize {
-		return false, fmt.Errorf("bit index %v is out of range of bitfield size %v", bitIndex, st.bitSize)
+		return false, fmt.Errorf("bit index %v is out of range of bitfield size %v", bitIndex, st.BitSize)
 	}
 	r := getFlag(bitIndex, st.Flags)
 	if !r {
@@ -110,15 +117,15 @@ func(st *State) ResetFlag(bitIndex uint32) (bool, error) {
 //
 // Fails if bit field index is out of range.
 func(st *State) GetFlag(bitIndex uint32) (bool, error) {
-	if bitIndex + 1 > st.bitSize {
+	if bitIndex + 1 > st.BitSize {
-		return false, fmt.Errorf("bit index %v is out of range of bitfield size %v", bitIndex, st.bitSize)
+		return false, fmt.Errorf("bit index %v is out of range of bitfield size %v", bitIndex, st.BitSize)
 	}
 	return getFlag(bitIndex, st.Flags), nil
 }
 
 // FlagBitSize reports the amount of bits available in the bit field index.
 func(st *State) FlagBitSize() uint32 {
-	return st.bitSize
+	return st.BitSize
 }
 
 // FlagBitSize reports the amount of bits available in the bit field index.
@@ -151,7 +158,7 @@ func(st *State) MatchFlag(sig uint32, invertMatch bool) (bool, error) {
 // If the given byte slice is too small for the bit field bitsize, the check will terminate at end-of-data without error.
 func(st *State) GetIndex(flags []byte) bool {
 	var globalIndex uint32
-	if st.bitSize == 0 {
+	if st.BitSize == 0 {
 		return false
 	}
 	if len(flags) == 0 {
@@ -161,7 +168,7 @@ func(st *State) GetIndex(flags []byte) bool {
 	var localIndex uint8
 	l := uint8(len(flags))
 	var i uint32
-	for i = 0; i < st.bitSize; i++ {
+	for i = 0; i < st.BitSize; i++ {
 		testVal := flags[byteIndex] & (1 << localIndex)
 		if (testVal & st.Flags[byteIndex]) > 0 {
 			return true
@@ -182,50 +189,56 @@ func(st *State) GetIndex(flags []byte) bool {
 
 // Where returns the current active rendering symbol.
 func(st *State) Where() (string, uint16) {
-	if len(st.execPath) == 0 {
+	if len(st.ExecPath) == 0 {
 		return "", 0
 	}
-	l := len(st.execPath)
+	l := len(st.ExecPath)
-	return st.execPath[l-1], st.sizeIdx
+	return st.ExecPath[l-1], st.SizeIdx
 }
 
 // Next moves to the next sink page index.
 func(st *State) Next() (uint16, error) {
-	if len(st.execPath) == 0 {
+	if len(st.ExecPath) == 0 {
 		return 0, fmt.Errorf("state root node not yet defined")
 	}
-	st.sizeIdx += 1
+	st.SizeIdx += 1
 	s, idx := st.Where()
 	log.Printf("next page for %s: %v", s, idx)
-	return st.sizeIdx, nil
+	st.Moves += 1
+	return st.SizeIdx, nil
+}
+
+func(st *State) Same() {
+	st.Moves += 1
 }
 
 // Previous moves to the next sink page index.
 //
 // Fails if try to move beyond index 0.
 func(st *State) Previous() (uint16, error) {
-	if len(st.execPath) == 0 {
+	if len(st.ExecPath) == 0 {
 		return 0, fmt.Errorf("state root node not yet defined")
 	}
-	if st.sizeIdx == 0 {
+	if st.SizeIdx == 0 {
-		return 0, fmt.Errorf("already at first index")
+		return 0, &IndexError{} // ("already at first index")
 	}
-	st.sizeIdx -= 1
+	st.SizeIdx -= 1
 	s, idx := st.Where()
 	log.Printf("previous page for %s: %v", s, idx)
-	return st.sizeIdx, nil
+	st.Moves += 1
+	return st.SizeIdx, nil
 }
 
 // Sides informs the caller which index page options will currently succeed.
 //
 // Two values are returned, for the "next" and "previous" options in that order. A false value means the option is not available in the current state.
 func(st *State) Sides() (bool, bool) {
-	if len(st.execPath) == 0 {
+	if len(st.ExecPath) == 0 {
 		return false, false
 	}
 	next := true
-	log.Printf("sides %v", st.sizeIdx)
+	log.Printf("sides %v", st.SizeIdx)
-	if st.sizeIdx == 0 {
+	if st.SizeIdx == 0 {
 		return next, false	
 	}
 	return next, true
@@ -235,18 +248,19 @@ func(st *State) Sides() (bool, bool) {
 //
 // Fails if first Down() was never called.
 func(st *State) Top() (bool, error) {
-	if len(st.execPath) == 0 {
+	if len(st.ExecPath) == 0 {
 		return false, fmt.Errorf("state root node not yet defined")
 	}
-	return len(st.execPath) == 1, nil
+	return len(st.ExecPath) == 1, nil
 }
 
 // Down adds the given symbol to the command stack.
 //
 // Clears mapping and sink.
 func(st *State) Down(input string) error {
-	st.execPath = append(st.execPath, input)
+	st.ExecPath = append(st.ExecPath, input)
-	st.sizeIdx = 0
+	st.SizeIdx = 0
+	st.Moves += 1
 	return nil
 }
 
@@ -258,29 +272,30 @@ func(st *State) Down(input string) error {
 //
 // Fails if called at top frame.
 func(st *State) Up() (string, error) {
-	l := len(st.execPath)
+	l := len(st.ExecPath)
 	if l == 0 {
 		return "", fmt.Errorf("exit called beyond top frame")
 	}
-	log.Printf("execpath before %v", st.execPath)
+	log.Printf("execpath before %v", st.ExecPath)
-	st.execPath = st.execPath[:l-1]
+	st.ExecPath = st.ExecPath[:l-1]
 	sym := ""
-	if len(st.execPath) > 0 {
+	if len(st.ExecPath) > 0 {
-		sym = st.execPath[len(st.execPath)-1]
+		sym = st.ExecPath[len(st.ExecPath)-1]
 	}
-	st.sizeIdx = 0
+	st.SizeIdx = 0
-	log.Printf("execpath after %v", st.execPath)
+	log.Printf("execpath after %v", st.ExecPath)
+	st.Moves += 1
 	return sym, nil
 }
 
 // Depth returns the current call stack depth.
 func(st *State) Depth() uint8 {
-	return uint8(len(st.execPath)-1)
+	return uint8(len(st.ExecPath)-1)
 }
 
 // Appendcode adds the given bytecode to the end of the existing code.
 func(st *State) AppendCode(b []byte) error {
-	st.code = append(st.code, b...)
+	st.Code = append(st.Code, b...)
 	log.Printf("code changed to 0x%x", b)
 	return nil
 }
@@ -288,13 +303,13 @@ func(st *State) AppendCode(b []byte) error {
 // SetCode replaces the current bytecode with the given bytecode.
 func(st *State) SetCode(b []byte) {
 	log.Printf("code set to 0x%x", b)
-	st.code = b
+	st.Code = b
 }
 
 // Get the remaning cached bytecode
 func(st *State) GetCode() ([]byte, error) {
-	b := st.code
+	b := st.Code
-	st.code = []byte{}
+	st.Code = []byte{}
 	return b, nil
 }
 
@@ -316,10 +331,22 @@ func(st *State) SetInput(input []byte) error {
 	return nil
 }
 
-func(st *State) Reset() error {
+// Reset re-initializes the state to run from top node with accumulated client state.
+func(st *State) Restart() error {
+	st.resetBaseFlags()
+	st.Moves = 0
+	st.SizeIdx = 0
+	st.input = []byte{}
 	return nil
 }
 
+// String implements String interface
 func(st State) String() string {
-	return fmt.Sprintf("path: %s", strings.Join(st.execPath, "/"))
+	return fmt.Sprintf("moves %v idx %v flags: 0x%x path: %s", st.Moves, st.SizeIdx, st.Flags, strings.Join(st.ExecPath, "/"))
 }
+
+// initializes all flags not in control of client.
+func(st *State) resetBaseFlags() {
+	st.Flags[0] = 0
+}
+

state/state_test.go

@@ -21,7 +21,7 @@ func TestNewState(t *testing.T) {
 	}
 }
 
-func TestStateFlags(t *testing.T) {
+func TestStateflags(t *testing.T) {
 	st := NewState(9)
 	v, err := st.GetFlag(2)
 	if err != nil {

testdata/testdata.go

@@ -8,7 +8,7 @@ import (
 
 	testdataloader "github.com/peteole/testdata-loader"
 
-	"git.defalsify.org/festive/vm"
+	"git.grassecon.net/kamikazechaser/vise/vm"
 )
 
 type genFunc func() error
@@ -16,7 +16,7 @@ type genFunc func() error
 var (
 	BaseDir = testdataloader.GetBasePath()
 	DataDir = ""
-	dirLock = false	
+	dirLock = false
 )
 
 func out(sym string, b []byte, tpl string, data map[string]string) error {
@@ -66,11 +66,12 @@ func foo() error {
 	b := []byte{}
 	b = vm.NewLine(b, vm.MOUT, []string{"0", "to foo"}, nil, nil)
 	b = vm.NewLine(b, vm.MOUT, []string{"1", "go bar"}, nil, nil)
+	b = vm.NewLine(b, vm.MOUT, []string{"2", "see long"}, nil, nil)
 	b = vm.NewLine(b, vm.LOAD, []string{"inky"}, []byte{20}, nil)
 	b = vm.NewLine(b, vm.HALT, nil, nil, nil)
 	b = vm.NewLine(b, vm.INCMP, []string{"0", "_"}, nil, nil)
 	b = vm.NewLine(b, vm.INCMP, []string{"1", "baz"}, nil, nil)
-	//b = vm.NewLine(b, vm.CATCH, []string{"_catch"}, []byte{1}, []uint8{1})
+	b = vm.NewLine(b, vm.INCMP, []string{"2", "long"}, nil, nil)
 
 	data := make(map[string]string)
 	data["inky"] = "one"
@@ -106,6 +107,35 @@ func baz() error {
 	return out("baz", b, tpl, nil)
 }
 
+func long() error {
+	b := []byte{}
+	b = vm.NewLine(b, vm.MOUT, []string{"0", "back"}, nil, nil)
+	b = vm.NewLine(b, vm.MNEXT, []string{"00", "nexxt"}, nil, nil)
+	b = vm.NewLine(b, vm.MPREV, []string{"11", "prevvv"}, nil, nil)
+	b = vm.NewLine(b, vm.LOAD, []string{"longdata"}, []byte{0x00}, nil)
+	b = vm.NewLine(b, vm.MAP, []string{"longdata"}, nil, nil)
+	b = vm.NewLine(b, vm.HALT, nil, nil, nil)
+	b = vm.NewLine(b, vm.INCMP, []string{"0", "_"}, nil, nil)
+	b = vm.NewLine(b, vm.INCMP, []string{"00", ">"}, nil, nil)
+	b = vm.NewLine(b, vm.INCMP, []string{"11", "<"}, nil, nil)
+
+	tpl := `data
+{{.longdata}}`
+
+	data := make(map[string]string)
+	data["longdata"] = `INKY 12
+PINKY 5555
+BLINKY 3t7
+CLYDE 11
+TINKYWINKY 22
+DIPSY 666
+LALA 111
+POO 222
+`
+
+	return out("long", b, tpl, data)
+}
+
 func defaultCatch() error {
 	b := []byte{}
 	b = vm.NewLine(b, vm.MOUT, []string{"0", "back"}, nil, nil)
@@ -123,7 +153,7 @@ func generate() error {
 		return err
 	}
 
-	fns := []genFunc{root, foo, bar, baz, defaultCatch}
+	fns := []genFunc{root, foo, bar, baz, long, defaultCatch}
 	for _, fn := range fns {
 		err = fn()
 		if err != nil {
@@ -133,8 +163,11 @@ func generate() error {
 	return nil
 }
 
+// Generate outputs bytecode, templates and content symbols to a temporary directory.
+//
+// This directory can in turn be used as data source for the the resource.FsResource object.
 func Generate() (string, error) {
-	dir, err := ioutil.TempDir("", "festive_testdata_")
+	dir, err := ioutil.TempDir("", "vise_testdata_")
 	if err != nil {
 		return "", err
 	}
@@ -144,6 +177,11 @@ func Generate() (string, error) {
 	return dir, err
 }
 
+// Generate outputs bytecode, templates and content symbols to a specified directory.
+//
+// The directory must exist, and must not have been used already in the same code execution.
+//
+// This directory can in turn be used as data source for the the resource.FsResource object.
 func GenerateTo(dir string) error {
 	if dirLock {
 		return fmt.Errorf("directory already overridden")

vm/doc.go

@@ -0,0 +1,2 @@
+// Package vm handles the line-by-line execution of vise bytecode.
+package vm

vm/input.go

@@ -5,18 +5,17 @@ import (
 	"fmt"
 	"regexp"
 
-	"git.defalsify.org/festive/cache"
+	"git.grassecon.net/kamikazechaser/vise/cache"
-	"git.defalsify.org/festive/state"
+	"git.grassecon.net/kamikazechaser/vise/state"
 )
 
 var (
 	inputRegexStr = "^[a-zA-Z0-9].*$"
-	inputRegex = regexp.MustCompile(inputRegexStr)
+	inputRegex    = regexp.MustCompile(inputRegexStr)
-	ctrlRegexStr = "^[><_^]$"
+	ctrlRegexStr  = "^[><_^.]$"
-	ctrlRegex = regexp.MustCompile(ctrlRegexStr)
+	ctrlRegex     = regexp.MustCompile(ctrlRegexStr)
-	symRegexStr = "^[a-zA-Z0-9][a-zA-Z0-9_]+$"
+	symRegexStr   = "^[a-zA-Z0-9][a-zA-Z0-9_]+$"
-	symRegex = regexp.MustCompile(symRegexStr)
+	symRegex      = regexp.MustCompile(symRegexStr)
-
 )
 
 // CheckInput validates the given byte string as client input.
@@ -61,7 +60,7 @@ func valid(target []byte) bool {
 			ok = true
 		}
 	}
-	return ok 
+	return ok
 }
 
 // CheckTarget tests whether the navigation state transition is available in the current state.
@@ -76,7 +75,7 @@ func CheckTarget(target []byte, st *state.State) (bool, error) {
 	switch target[0] {
 	case '_':
 		topOk, err := st.Top()
-		if err!= nil {
+		if err != nil {
 			return false, err
 		}
 		return topOk, nil
@@ -137,6 +136,10 @@ func applyTarget(target []byte, st *state.State, ca cache.Memory, ctx context.Co
 				return sym, idx, err
 			}
 		}
+	case '.':
+		st.Same()
+		location, idx := st.Where()
+		return location, idx, nil
 	default:
 		sym = string(target)
 		err := st.Down(sym)

vm/runner.go

@@ -5,51 +5,52 @@ import (
 	"fmt"
 	"log"
 
-	"git.defalsify.org/festive/cache"
+	"git.grassecon.net/kamikazechaser/vise/cache"
-	"git.defalsify.org/festive/render"
+	"git.grassecon.net/kamikazechaser/vise/render"
-	"git.defalsify.org/festive/resource"
+	"git.grassecon.net/kamikazechaser/vise/resource"
-	"git.defalsify.org/festive/state"
+	"git.grassecon.net/kamikazechaser/vise/state"
 )
 
+// Vm holds sub-components mutated by the vm execution.
 type Vm struct {
-	st *state.State
+	st    *state.State      // Navigation and error states.
-	rs resource.Resource
+	rs    resource.Resource // Retrieves content, code, and templates for symbols.
-	pg *render.Page
+	ca    cache.Memory      // Loaded content.
-	ca cache.Memory
+	mn    *render.Menu      // Menu component of page.
-	mn *render.Menu
+	sizer *render.Sizer     // Apply size constraints to output.
-	sizer *render.Sizer
+	pg    *render.Page      // Render outputs with menues to size constraints.
 }
 
-
+// NewVm creates a new Vm.
 func NewVm(st *state.State, rs resource.Resource, ca cache.Memory, sizer *render.Sizer) *Vm {
 	vmi := &Vm{
-		st: st,
+		st:    st,
-		rs: rs,
+		rs:    rs,
-		ca: ca,
+		ca:    ca,
-		pg: render.NewPage(ca, rs),
+		pg:    render.NewPage(ca, rs),
 		sizer: sizer,
 	}
 	vmi.Reset()
+	log.Printf("vm created with state: %v", st)
 	return vmi
 }
 
-func(vmi *Vm) Reset() {
+// Reset re-initializes sub-components for output rendering.
+func (vmi *Vm) Reset() {
 	vmi.mn = render.NewMenu()
 	vmi.pg.Reset()
-	vmi.pg = vmi.pg.WithMenu(vmi.mn) //render.NewPage(vmi.ca, vmi.rs).WithMenu(vmi.mn)
+	vmi.pg = vmi.pg.WithMenu(vmi.mn)
 	if vmi.sizer != nil {
-		vmi.pg = vmi.pg.WithSizer(vmi.sizer)	
+		vmi.pg = vmi.pg.WithSizer(vmi.sizer)
 	}
 }
 
-//type Runner func(instruction []byte, st state.State, rs resource.Resource, ctx context.Context) (state.State, []byte, error)
-
 // Run extracts individual op codes and arguments and executes them.
 //
 // Each step may update the state.
 //
 // On error, the remaining instructions will be returned. State will not be rolled back.
-func(vm *Vm) Run(b []byte, ctx context.Context) ([]byte, error) {
+func (vm *Vm) Run(b []byte, ctx context.Context) ([]byte, error) {
 	running := true
 	for running {
 		r, err := vm.st.MatchFlag(state.FLAG_TERMINATE, false)
@@ -60,6 +61,24 @@ func(vm *Vm) Run(b []byte, ctx context.Context) ([]byte, error) {
 			log.Printf("terminate set! bailing!")
 			return []byte{}, nil
 		}
+		//vm.st.ResetBaseFlags()
+		_, err = vm.st.ResetFlag(state.FLAG_TERMINATE)
+		if err != nil {
+			panic(err)
+		}
+
+		waitChange, err := vm.st.ResetFlag(state.FLAG_WAIT)
+		if err != nil {
+			panic(err)
+		}
+		if waitChange {
+			log.Printf("waitchange")
+			_, err = vm.st.ResetFlag(state.FLAG_INMATCH)
+			if err != nil {
+				panic(err)
+			}
+		}
+
 		_, err = vm.st.SetFlag(state.FLAG_DIRTY)
 		if err != nil {
 			panic(err)
@@ -121,9 +140,9 @@ func(vm *Vm) Run(b []byte, ctx context.Context) ([]byte, error) {
 // If there is remaining bytecode, this method is a noop.
 //
 // If input has not been matched, a default invalid input page should be generated aswell as a possiblity of return to last screen (or exit).
-// 
+//
 // If the termination flag has been set but not yet handled, execution is allowed to terminate.
-func(vm *Vm) RunDeadCheck(b []byte, ctx context.Context) ([]byte, error) {
+func (vm *Vm) RunDeadCheck(b []byte, ctx context.Context) ([]byte, error) {
 	if len(b) > 0 {
 		return b, nil
 	}
@@ -148,7 +167,6 @@ func(vm *Vm) RunDeadCheck(b []byte, ctx context.Context) ([]byte, error) {
 		return b, nil
 	}
 
-
 	log.Printf("no code remaining but not terminating")
 	location, _ := vm.st.Where()
 	if location == "" {
@@ -159,32 +177,49 @@ func(vm *Vm) RunDeadCheck(b []byte, ctx context.Context) ([]byte, error) {
 }
 
 // RunMap executes the MAP opcode
-func(vm *Vm) RunMap(b []byte, ctx context.Context) ([]byte, error) {
+func (vm *Vm) RunMap(b []byte, ctx context.Context) ([]byte, error) {
 	sym, b, err := ParseMap(b)
 	err = vm.pg.Map(sym)
 	return b, err
 }
 
 // RunMap executes the CATCH opcode
-func(vm *Vm) RunCatch(b []byte, ctx context.Context) ([]byte, error) {
+func (vm *Vm) RunCatch(b []byte, ctx context.Context) ([]byte, error) {
 	sym, sig, mode, b, err := ParseCatch(b)
 	if err != nil {
 		return b, err
 	}
 	r, err := vm.st.MatchFlag(sig, mode)
 	if err != nil {
+		var perr error
+		_, perr = vm.st.SetFlag(state.FLAG_TERMINATE)
+		if perr != nil {
+			panic(perr)
+		}
+		log.Printf("terminate set")
 		return b, err
 	}
 	if r {
-		log.Printf("catch at flag %v, moving to %v", sig, sym) //bitField, d)
+		//b = append(bh, b...)
-		vm.st.Down(sym)
+		//vm.st.Down(sym)
-		b = []byte{}
+		//vm.ca.Push()
-	} 
+		actualSym, _, err := applyTarget([]byte(sym), vm.st, vm.ca, ctx)
+		if err != nil {
+			return b, err
+		}
+		log.Printf("catch at flag %v, moving to '%v' ('%v')", sig, sym, actualSym)
+		sym = actualSym
+		bh, err := vm.rs.GetCode(sym)
+		if err != nil {
+			return b, err
+		}
+		b = bh
+	}
 	return b, nil
 }
 
 // RunMap executes the CROAK opcode
-func(vm *Vm) RunCroak(b []byte, ctx context.Context) ([]byte, error) {
+func (vm *Vm) RunCroak(b []byte, ctx context.Context) ([]byte, error) {
 	sig, mode, b, err := ParseCroak(b)
 	if err != nil {
 		return b, err
@@ -195,7 +230,7 @@ func(vm *Vm) RunCroak(b []byte, ctx context.Context) ([]byte, error) {
 	}
 	if r {
 		log.Printf("croak at flag %v, purging and moving to top", sig)
-		vm.st.Reset()
+		vm.Reset()
 		vm.pg.Reset()
 		vm.ca.Reset()
 		b = []byte{}
@@ -204,13 +239,12 @@ func(vm *Vm) RunCroak(b []byte, ctx context.Context) ([]byte, error) {
 }
 
 // RunLoad executes the LOAD opcode
-func(vm *Vm) RunLoad(b []byte, ctx context.Context) ([]byte, error) {
+func (vm *Vm) RunLoad(b []byte, ctx context.Context) ([]byte, error) {
 	sym, sz, b, err := ParseLoad(b)
 	if err != nil {
 		return b, err
 	}
-
+	r, err := vm.refresh(sym, vm.rs, ctx)
-	r, err := refresh(sym, vm.rs, ctx)
 	if err != nil {
 		return b, err
 	}
@@ -219,13 +253,13 @@ func(vm *Vm) RunLoad(b []byte, ctx context.Context) ([]byte, error) {
 }
 
 // RunLoad executes the RELOAD opcode
-func(vm *Vm) RunReload(b []byte, ctx context.Context) ([]byte, error) {
+func (vm *Vm) RunReload(b []byte, ctx context.Context) ([]byte, error) {
 	sym, b, err := ParseReload(b)
 	if err != nil {
 		return b, err
 	}
 
-	r, err := refresh(sym, vm.rs, ctx)
+	r, err := vm.refresh(sym, vm.rs, ctx)
 	if err != nil {
 		return b, err
 	}
@@ -240,7 +274,7 @@ func(vm *Vm) RunReload(b []byte, ctx context.Context) ([]byte, error) {
 }
 
 // RunLoad executes the MOVE opcode
-func(vm *Vm) RunMove(b []byte, ctx context.Context) ([]byte, error) {
+func (vm *Vm) RunMove(b []byte, ctx context.Context) ([]byte, error) {
 	sym, b, err := ParseMove(b)
 	if err != nil {
 		return b, err
@@ -257,19 +291,21 @@ func(vm *Vm) RunMove(b []byte, ctx context.Context) ([]byte, error) {
 	if err != nil {
 		return b, err
 	}
-	log.Printf("loaded additional code: %x", code)
+	log.Printf("loaded code for %s: %x", sym, code)
 	b = append(b, code...)
+	vm.Reset()
 	return b, nil
 }
 
 // RunIncmp executes the INCMP opcode
-func(vm *Vm) RunInCmp(b []byte, ctx context.Context) ([]byte, error) {
+// TODO: create state transition table and simplify flow
+func (vm *Vm) RunInCmp(b []byte, ctx context.Context) ([]byte, error) {
 	sym, target, b, err := ParseInCmp(b)
 	if err != nil {
 		return b, err
 	}
 
-	change, err := vm.st.SetFlag(state.FLAG_READIN)
+	reading, err := vm.st.GetFlag(state.FLAG_READIN)
 	if err != nil {
 		panic(err)
 	}
@@ -278,29 +314,31 @@ func(vm *Vm) RunInCmp(b []byte, ctx context.Context) ([]byte, error) {
 		panic(err)
 	}
 	if have {
-		if change {
+		if reading {
-			_, err = vm.st.ResetFlag(state.FLAG_INMATCH)
+			log.Printf("ignoring input %s, already have match", sym)
-			if err != nil {
-				panic(err)
-			}
-		} else {
 			return b, nil
 		}
+	} else {
+		_, err = vm.st.SetFlag(state.FLAG_READIN)
+		if err != nil {
+			panic(err)
+		}
 	}
 	input, err := vm.st.GetInput()
 	if err != nil {
 		return b, err
 	}
-	log.Printf("sym is %s", sym)
+	log.Printf("testing sym %s input %s", sym, input)
-	if sym == "*" {
+
+	if !have && sym == "*" {
 		log.Printf("input wildcard match ('%s'), target '%s'", input, target)
 	} else {
 		if sym != string(input) {
+			log.Printf("foo")
 			return b, nil
 		}
 		log.Printf("input match for '%s', target '%s'", input, target)
 	}
-
 	_, err = vm.st.SetFlag(state.FLAG_INMATCH)
 	if err != nil {
 		panic(err)
@@ -310,40 +348,58 @@ func(vm *Vm) RunInCmp(b []byte, ctx context.Context) ([]byte, error) {
 		panic(err)
 	}
 
-	target, _, err = applyTarget([]byte(target), vm.st, vm.ca, ctx)
+	newTarget, _, err := applyTarget([]byte(target), vm.st, vm.ca, ctx)
-	if err != nil {
+
+	_, ok := err.(*state.IndexError)
+	if ok {
+		_, err = vm.st.SetFlag(state.FLAG_READIN)
+		if err != nil {
+			panic(err)
+		}
+		return b, nil
+	} else if err != nil {
 		return b, err
 	}
 
+	target = newTarget
+
+	vm.Reset()
+
 	code, err := vm.rs.GetCode(target)
 	if err != nil {
 		return b, err
 	}
+	log.Printf("bar")
 	log.Printf("loaded additional code for target '%s': %x", target, code)
 	b = append(b, code...)
 	return b, err
 }
 
 // RunHalt executes the HALT opcode
-func(vm *Vm) RunHalt(b []byte, ctx context.Context) ([]byte, error) {
+func (vm *Vm) RunHalt(b []byte, ctx context.Context) ([]byte, error) {
 	var err error
 	b, err = ParseHalt(b)
 	if err != nil {
 		return b, err
 	}
 	log.Printf("found HALT, stopping")
-	return b, err
+
+	_, err = vm.st.SetFlag(state.FLAG_WAIT)
+	if err != nil {
+		panic(err)
+	}
+	return b, nil
 }
 
 // RunMSize executes the MSIZE opcode
-func(vm *Vm) RunMSize(b []byte, ctx context.Context) ([]byte, error) {
+func (vm *Vm) RunMSize(b []byte, ctx context.Context) ([]byte, error) {
 	log.Printf("WARNING MSIZE not yet implemented")
 	_, _, b, err := ParseMSize(b)
 	return b, err
 }
 
 // RunMOut executes the MOUT opcode
-func(vm *Vm) RunMOut(b []byte, ctx context.Context) ([]byte, error) {
+func (vm *Vm) RunMOut(b []byte, ctx context.Context) ([]byte, error) {
 	choice, title, b, err := ParseMOut(b)
 	if err != nil {
 		return b, err
@@ -353,52 +409,61 @@ func(vm *Vm) RunMOut(b []byte, ctx context.Context) ([]byte, error) {
 }
 
 // RunMNext executes the MNEXT opcode
-func(vm *Vm) RunMNext(b []byte, ctx context.Context) ([]byte, error) {
+func (vm *Vm) RunMNext(b []byte, ctx context.Context) ([]byte, error) {
-       selector, display, b, err := ParseMNext(b)
+	selector, display, b, err := ParseMNext(b)
-       if err != nil {
+	if err != nil {
-	       return b, err
+		return b, err
-       }
+	}
-       cfg := vm.mn.GetBrowseConfig()
+	cfg := vm.mn.GetBrowseConfig()
-       cfg.NextSelector = selector
+	cfg.NextSelector = selector
-       cfg.NextTitle = display
+	cfg.NextTitle = display
-       cfg.NextAvailable = true
+	cfg.NextAvailable = true
-       vm.mn = vm.mn.WithBrowseConfig(cfg)
+	vm.mn = vm.mn.WithBrowseConfig(cfg)
-       return b, nil
+	return b, nil
-}
-	
-// RunMPrev executes the MPREV opcode
-func(vm *Vm) RunMPrev(b []byte, ctx context.Context) ([]byte, error) {
-       selector, display, b, err := ParseMPrev(b)
-       if err != nil {
-	       return b, err
-       }
-       cfg := vm.mn.GetBrowseConfig()
-       cfg.PreviousSelector = selector
-       cfg.PreviousTitle = display
-       cfg.PreviousAvailable = true
-       vm.mn = vm.mn.WithBrowseConfig(cfg)
-       return b, nil
 }
 
-func(vm *Vm) Render() (string, error) {
+// RunMPrev executes the MPREV opcode
+func (vm *Vm) RunMPrev(b []byte, ctx context.Context) ([]byte, error) {
+	selector, display, b, err := ParseMPrev(b)
+	if err != nil {
+		return b, err
+	}
+	cfg := vm.mn.GetBrowseConfig()
+	cfg.PreviousSelector = selector
+	cfg.PreviousTitle = display
+	cfg.PreviousAvailable = true
+	vm.mn = vm.mn.WithBrowseConfig(cfg)
+	return b, nil
+}
+
+// Render wraps output rendering, and handles error when attempting to browse beyond the rendered page count.
+func (vm *Vm) Render(ctx context.Context) (string, error) {
 	changed, err := vm.st.ResetFlag(state.FLAG_DIRTY)
 	if err != nil {
-		panic(err)	
+		panic(err)
 	}
 	if !changed {
-		log.Printf("Render called when not dirty, please investigate.")
+		return "", nil
 	}
 	sym, idx := vm.st.Where()
 	r, err := vm.pg.Render(sym, idx)
+	var ok bool
+	_, ok = err.(*render.BrowseError)
+	if ok {
+		vm.Reset()
+		b := NewLine(nil, MOVE, []string{"_catch"}, nil, nil)
+		vm.Run(b, ctx)
+		sym, idx := vm.st.Where()
+		r, err = vm.pg.Render(sym, idx)
+	}
 	if err != nil {
 		return "", err
 	}
-	vm.Reset()
 	return r, nil
 }
 
 // retrieve data for key
-func refresh(key string, rs resource.Resource, ctx context.Context) (string, error) {
+func (vm *Vm) refresh(key string, rs resource.Resource, ctx context.Context) (string, error) {
 	fn, err := rs.FuncFor(key)
 	if err != nil {
 		return "", err
@@ -406,6 +471,35 @@ func refresh(key string, rs resource.Resource, ctx context.Context) (string, err
 	if fn == nil {
 		return "", fmt.Errorf("no retrieve function for external symbol %v", key)
 	}
-	return fn(key, ctx)
+	input, _ := vm.st.GetInput()
-}
+	r, err := fn(key, input, ctx)
+	if err != nil {
+		log.Printf("loadfail %v", err)
+		var perr error
+		_, perr = vm.st.SetFlag(state.FLAG_LOADFAIL)
+		if perr != nil {
+			panic(err)
+		}
+		return "", err
+	}
+	for _, flag := range r.FlagSet {
+		if !state.IsWriteableFlag(flag) {
+			continue
+		}
+		_, err = vm.st.SetFlag(flag)
+		if err != nil {
+			panic(err)
+		}
+	}
+	for _, flag := range r.FlagReset {
+		if !state.IsWriteableFlag(flag) {
+			continue
+		}
+		_, err = vm.st.ResetFlag(flag)
+		if err != nil {
+			panic(err)
+		}
+	}
 
+	return r.Content, err
+}

vm/runner_test.go

@@ -6,30 +6,60 @@ import (
 	"fmt"
 	"log"
 	"testing"
-	
+
-	"git.defalsify.org/festive/cache"
+	"git.grassecon.net/kamikazechaser/vise/cache"
-	"git.defalsify.org/festive/render"
+	"git.grassecon.net/kamikazechaser/vise/render"
-	"git.defalsify.org/festive/resource"
+	"git.grassecon.net/kamikazechaser/vise/resource"
-	"git.defalsify.org/festive/state"
+	"git.grassecon.net/kamikazechaser/vise/state"
 )
 
 var dynVal = "three"
 
 type TestResource struct {
 	resource.MenuResource
-	state *state.State
+	state    *state.State
+	RootCode []byte
 }
 
-func getOne(sym string, ctx context.Context) (string, error) {
+func getOne(sym string, input []byte, ctx context.Context) (resource.Result, error) {
-	return "one", nil
+	return resource.Result{
+		Content: "one",
+	}, nil
 }
 
-func getTwo(sym string, ctx context.Context) (string, error) {
+func getTwo(sym string, input []byte, ctx context.Context) (resource.Result, error) {
-	return "two", nil
+	return resource.Result{
+		Content: "two",
+	}, nil
 }
 
-func getDyn(sym string, ctx context.Context) (string, error) {
+func getDyn(sym string, input []byte, ctx context.Context) (resource.Result, error) {
-	return dynVal, nil
+	return resource.Result{
+		Content: dynVal,
+	}, nil
+}
+
+func getEcho(sym string, input []byte, ctx context.Context) (resource.Result, error) {
+	r := fmt.Sprintf("echo: %s", input)
+	return resource.Result{
+		Content: r,
+	}, nil
+}
+
+func setFlag(sym string, input []byte, ctx context.Context) (resource.Result, error) {
+	s := fmt.Sprintf("ping")
+	r := resource.Result{
+		Content: s,
+	}
+	if len(input) > 0 {
+		r.FlagSet = append(r.FlagSet, uint32(input[0]))
+	}
+	if len(input) > 1 {
+		r.FlagReset = append(r.FlagReset, uint32(input[1]))
+	}
+	log.Printf("setflag %v", r)
+	return r, nil
+
 }
 
 type TestStatefulResolver struct {
@@ -50,6 +80,8 @@ func (r TestResource) GetTemplate(sym string) (string, error) {
 		return "root", nil
 	case "_catch":
 		return "aiee", nil
+	case "flagCatch":
+		return "flagiee", nil
 	}
 	panic(fmt.Sprintf("unknown symbol %s", sym))
 	return "", fmt.Errorf("unknown symbol %s", sym)
@@ -65,21 +97,35 @@ func (r TestResource) FuncFor(sym string) (resource.EntryFunc, error) {
 		return getDyn, nil
 	case "arg":
 		return r.getInput, nil
+	case "echo":
+		return getEcho, nil
+	case "setFlagOne":
+		return setFlag, nil
 	}
 	return nil, fmt.Errorf("invalid function: '%s'", sym)
 }
 
-func(r TestResource) getInput(sym string, ctx context.Context) (string, error) {
+func (r TestResource) getInput(sym string, input []byte, ctx context.Context) (resource.Result, error) {
 	v, err := r.state.GetInput()
-	return string(v), err
+	return resource.Result{
+		Content: string(v),
+	}, err
 }
 
-func(r TestResource) GetCode(sym string) ([]byte, error) {
+func (r TestResource) GetCode(sym string) ([]byte, error) {
 	var b []byte
-	if sym == "_catch" {
+	switch sym {
+	case "_catch":
 		b = NewLine(b, MOUT, []string{"0", "repent"}, nil, nil)
 		b = NewLine(b, HALT, nil, nil, nil)
+	case "flagCatch":
+		b = NewLine(b, MOUT, []string{"0", "repent"}, nil, nil)
+		b = NewLine(b, HALT, nil, nil, nil)
+		b = NewLine(b, MOVE, []string{"_"}, nil, nil)
+	case "root":
+		b = r.RootCode
 	}
+
 	return b, nil
 }
 
@@ -93,13 +139,13 @@ func TestRun(t *testing.T) {
 	b = NewLine(b, HALT, nil, nil, nil)
 	_, err := vm.Run(b, context.TODO())
 	if err != nil {
-		t.Errorf("run error: %v", err)	
+		t.Errorf("run error: %v", err)
 	}
 
 	b = []byte{0x01, 0x02}
 	_, err = vm.Run(b, context.TODO())
 	if err == nil {
-		t.Errorf("no error on invalid opcode")	
+		t.Errorf("no error on invalid opcode")
 	}
 }
 
@@ -112,16 +158,17 @@ func TestRunLoadRender(t *testing.T) {
 	st.Down("bar")
 
 	var err error
+	ctx := context.TODO()
 	b := NewLine(nil, LOAD, []string{"one"}, []byte{0x0a}, nil)
 	b = NewLine(b, MAP, []string{"one"}, nil, nil)
 	b = NewLine(b, LOAD, []string{"two"}, []byte{0x0a}, nil)
 	b = NewLine(b, MAP, []string{"two"}, nil, nil)
 	b = NewLine(b, HALT, nil, nil, nil)
-	b, err = vm.Run(b, context.TODO())
+	b, err = vm.Run(b, ctx)
 	if err != nil {
 		t.Fatal(err)
 	}
-	r, err := vm.Render()
+	r, err := vm.Render(ctx)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -133,17 +180,17 @@ func TestRunLoadRender(t *testing.T) {
 	b = NewLine(nil, LOAD, []string{"two"}, []byte{0x0a}, nil)
 	b = NewLine(b, MAP, []string{"two"}, nil, nil)
 	b = NewLine(b, HALT, nil, nil, nil)
-	b, err = vm.Run(b, context.TODO())
+	b, err = vm.Run(b, ctx)
 	if err != nil {
 		t.Fatal(err)
 	}
 	b = NewLine(nil, MAP, []string{"one"}, nil, nil)
 	b = NewLine(b, HALT, nil, nil, nil)
-	_, err = vm.Run(b, context.TODO())
+	_, err = vm.Run(b, ctx)
 	if err != nil {
 		t.Fatal(err)
 	}
-	r, err = vm.Render()
+	r, err = vm.Render(ctx)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -159,11 +206,12 @@ func TestRunMultiple(t *testing.T) {
 	ca := cache.NewCache()
 	vm := NewVm(&st, &rs, ca, nil)
 
+	ctx := context.TODO()
 	b := NewLine(nil, MOVE, []string{"test"}, nil, nil)
 	b = NewLine(b, LOAD, []string{"one"}, []byte{0x00}, nil)
 	b = NewLine(b, LOAD, []string{"two"}, []byte{42}, nil)
 	b = NewLine(b, HALT, nil, nil, nil)
-	b, err := vm.Run(b, context.TODO())
+	b, err := vm.Run(b, ctx)
 	if err != nil {
 		t.Error(err)
 	}
@@ -179,15 +227,16 @@ func TestRunReload(t *testing.T) {
 	szr := render.NewSizer(128)
 	vm := NewVm(&st, &rs, ca, szr)
 
+	ctx := context.TODO()
 	b := NewLine(nil, MOVE, []string{"root"}, nil, nil)
 	b = NewLine(b, LOAD, []string{"dyn"}, nil, []uint8{0})
 	b = NewLine(b, MAP, []string{"dyn"}, nil, nil)
 	b = NewLine(b, HALT, nil, nil, nil)
-	_, err := vm.Run(b, context.TODO())
+	_, err := vm.Run(b, ctx)
 	if err != nil {
 		t.Fatal(err)
 	}
-	r, err := vm.Render()
+	r, err := vm.Render(ctx)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -197,7 +246,7 @@ func TestRunReload(t *testing.T) {
 	dynVal = "baz"
 	b = NewLine(nil, RELOAD, []string{"dyn"}, nil, nil)
 	b = NewLine(b, HALT, nil, nil, nil)
-	_, err = vm.Run(b, context.TODO())
+	_, err = vm.Run(b, ctx)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -240,7 +289,7 @@ func TestRunArg(t *testing.T) {
 	bi = NewLine(bi, HALT, nil, nil, nil)
 	b, err := vm.Run(bi, context.TODO())
 	if err != nil {
-		t.Error(err)	
+		t.Error(err)
 	}
 	l := len(b)
 	if l != 0 {
@@ -271,7 +320,7 @@ func TestRunInputHandler(t *testing.T) {
 	var err error
 	_, err = vm.Run(bi, context.TODO())
 	if err != nil {
-		t.Fatal(err)	
+		t.Fatal(err)
 	}
 	r, _ := st.Where()
 	if r != "foo" {
@@ -288,13 +337,13 @@ func TestRunArgInvalid(t *testing.T) {
 	_ = st.SetInput([]byte("foo"))
 
 	var err error
-	
+
 	st.Down("root")
 	b := NewLine(nil, INCMP, []string{"bar", "baz"}, nil, nil)
 
 	b, err = vm.Run(b, context.TODO())
 	if err != nil {
-		t.Fatal(err)	
+		t.Fatal(err)
 	}
 	r, _ := st.Where()
 	if r != "_catch" {
@@ -310,21 +359,23 @@ func TestRunMenu(t *testing.T) {
 
 	var err error
 
+	ctx := context.TODO()
+
 	b := NewLine(nil, MOVE, []string{"foo"}, nil, nil)
 	b = NewLine(b, MOUT, []string{"0", "one"}, nil, nil)
 	b = NewLine(b, MOUT, []string{"1", "two"}, nil, nil)
 	b = NewLine(b, HALT, nil, nil, nil)
 
-	b, err = vm.Run(b, context.TODO())
+	b, err = vm.Run(b, ctx)
 	if err != nil {
-		t.Error(err)	
+		t.Error(err)
 	}
 	l := len(b)
 	if l != 0 {
 		t.Errorf("expected empty remainder, got length %v: %v", l, b)
 	}
-	
+
-	r, err := vm.Render()
+	r, err := vm.Render(ctx)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -343,21 +394,23 @@ func TestRunMenuBrowse(t *testing.T) {
 
 	var err error
 
+	ctx := context.TODO()
+
 	b := NewLine(nil, MOVE, []string{"foo"}, nil, nil)
 	b = NewLine(b, MOUT, []string{"0", "one"}, nil, nil)
 	b = NewLine(b, MOUT, []string{"1", "two"}, nil, nil)
 	b = NewLine(b, HALT, nil, nil, nil)
 
-	b, err = vm.Run(b, context.TODO())
+	b, err = vm.Run(b, ctx)
 	if err != nil {
-		t.Error(err)	
+		t.Error(err)
 	}
 	l := len(b)
 	if l != 0 {
 		t.Errorf("expected empty remainder, got length %v: %v", l, b)
 	}
-	
+
-	r, err := vm.Render()
+	r, err := vm.Render(ctx)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -376,7 +429,6 @@ func TestRunReturn(t *testing.T) {
 	var err error
 
 	st.Down("root")
-	st.SetInput([]byte("0"))
 	b := NewLine(nil, INCMP, []string{"0", "bar"}, nil, nil)
 	b = NewLine(b, HALT, nil, nil, nil)
 	b = NewLine(b, INCMP, []string{"1", "_"}, nil, nil)
@@ -384,6 +436,7 @@ func TestRunReturn(t *testing.T) {
 
 	ctx := context.TODO()
 
+	st.SetInput([]byte("0"))
 	b, err = vm.Run(b, ctx)
 	if err != nil {
 		t.Fatal(err)
@@ -402,3 +455,130 @@ func TestRunReturn(t *testing.T) {
 		t.Fatalf("expected location 'root', got '%s'", location)
 	}
 }
+
+func TestRunLoadInput(t *testing.T) {
+	st := state.NewState(5)
+	rs := TestResource{}
+	ca := cache.NewCache()
+	vm := NewVm(&st, &rs, ca, nil)
+
+	var err error
+
+	st.Down("root")
+	st.SetInput([]byte("foobar"))
+
+	b := NewLine(nil, LOAD, []string{"echo"}, []byte{0x00}, nil)
+	b = NewLine(b, HALT, nil, nil, nil)
+
+	ctx := context.TODO()
+
+	b, err = vm.Run(b, ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	r, err := ca.Get("echo")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if r != "echo: foobar" {
+		t.Fatalf("expected 'echo: foobar', got %s", r)
+	}
+}
+
+func TestInputBranch(t *testing.T) {
+	st := state.NewState(5)
+	rs := TestResource{}
+	ca := cache.NewCache()
+	vm := NewVm(&st, &rs, ca, nil)
+
+	var err error
+
+	st.Down("root")
+
+	b := NewLine(nil, LOAD, []string{"setFlagOne"}, []byte{0x00}, nil)
+	b = NewLine(b, RELOAD, []string{"setFlagOne"}, nil, nil)
+	b = NewLine(b, CATCH, []string{"flagCatch"}, []byte{8}, []uint8{0})
+	b = NewLine(b, CATCH, []string{"one"}, []byte{9}, []uint8{0})
+	rs.RootCode = b
+
+	//b = NewLine(b, RELOAD, []string{"setFlagOne"}, nil, nil)
+	//b = NewLine(b, CATCH, []string{"flagCatch"}, []byte{8}, []uint8{0})
+
+	ctx := context.TODO()
+
+	st.SetInput([]byte{0x08})
+	b, err = vm.Run(b, ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+	location, _ := st.Where()
+	if location != "flagCatch" {
+		t.Fatalf("expected 'flagCatch', got %s", location)
+	}
+
+	st.SetInput([]byte{0x09, 0x08})
+	b, err = vm.Run(b, ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+	location, _ = st.Where()
+	if location != "one" {
+		t.Fatalf("expected 'one', got %s", location)
+	}
+}
+
+func TestInputIgnore(t *testing.T) {
+	st := state.NewState(5)
+	rs := TestResource{}
+	ca := cache.NewCache()
+	vm := NewVm(&st, &rs, ca, nil)
+
+	var err error
+
+	st.Down("root")
+
+	b := NewLine(nil, INCMP, []string{"foo", "one"}, nil, nil)
+	b = NewLine(b, INCMP, []string{"bar", "two"}, nil, nil)
+	b = NewLine(b, HALT, nil, nil, nil)
+
+	ctx := context.TODO()
+
+	st.SetInput([]byte("foo"))
+	b, err = vm.Run(b, ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	location, _ := st.Where()
+	if location != "one" {
+		t.Fatalf("expected 'one', got %s", location)
+	}
+}
+
+func TestInputIgnoreWildcard(t *testing.T) {
+	st := state.NewState(5)
+	rs := TestResource{}
+	ca := cache.NewCache()
+	vm := NewVm(&st, &rs, ca, nil)
+
+	var err error
+
+	st.Down("root")
+
+	b := NewLine(nil, INCMP, []string{"foo", "one"}, nil, nil)
+	b = NewLine(b, INCMP, []string{"*", "two"}, nil, nil)
+
+	ctx := context.TODO()
+
+	st.SetInput([]byte("foo"))
+	b, err = vm.Run(b, ctx)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	location, _ := st.Where()
+	if location != "one" {
+		t.Fatalf("expected 'one', got %s", location)
+	}
+}