Instructions and render for menu display

README.md

@@ -17,8 +17,9 @@ The VM defines the following opcode symbols:
 * `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` and and move to `symbol` node on match. Any consecutive matches will be ignored until `HALT` is called.
+* `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 <num>` - Set max display size of menu part to `num` bytes.
+* `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.
 
 ### External code
 
@@ -128,14 +129,15 @@ It expects all replacement symbols to be available at time of rendering, and has
 (Minimal, WIP)
 
 ```
-0008 03666f6f 03626172     # INCMP "foo" "bar" - move to node "bar" if input is "FOO"
+000a 03666f6f 06746f20666f6f  # MOUT "foo" "to foo" - display a menu entry for choice "foo", described by "to foo"
-0001 0461696565 01 01      # CATCH "aiee" 1 1  - move to node "aiee" (and immediately halt) if input match flag (1) is not set (1)
+0008 03666f6f 03626172        # INCMP "foo" "bar"   - move to node "bar" if input is "FOO"
-0003 04616263 020104       # LOAD "abc" 260    - execute code symbol "abc" with a result size limit of 260 (2 byte BE integer, 0x0104)
+0001 0461696565 01 01         # CATCH "aiee" 1 1    - move to node "aiee" (and immediately halt) if input match flag (1) is not set (1)
-0003 04646566 00           # LOAD "def" 0      - execute code symbol "abc" with no size limit (sink)
+0003 04616263 020104          # LOAD "abc" 260      - execute code symbol "abc" with a result size limit of 260 (2 byte BE integer, 0x0104)
-0005 04616263              # MAP "abc"         - make "abc" available for renderer
+0003 04646566 00              # LOAD "def" 0        - execute code symbol "abc" with no size limit (sink)
-0007                       # HALT              - stop execution (require new input to continue)
+0005 04616263                 # MAP "abc"           - make "abc" available for renderer
-0006 03313233              # MOVE "123"        - move to node "123" (regardless of input)
+0007                          # HALT                - stop execution (require new input to continue)
-0007                       # HALT              - stop execution
+0006 03313233                 # MOVE "123"          - move to node "123" (regardless of input)
+0007                          # HALT                - stop execution
 ```
 
 ## Development tools

go/engine/engine.go

@@ -32,21 +32,25 @@ func NewEngine(st *state.State, rs resource.Resource) Engine {
 //
 // It makes sure bootstrapping code has been executed, and that the exposed bytecode is ready for user input.
 func(en *Engine) Init(sym string, ctx context.Context) error {
-	b := vm.NewLine([]byte{}, vm.MOVE, []string{sym}, nil, nil)
+	b := vm.NewLine(nil, vm.MOVE, []string{sym}, nil, nil)
 	var err error
-	_, err = vm.Run(b, en.st, en.rs, ctx)
+	b, err = vm.Run(b, en.st, en.rs, ctx)
 	if err != nil {
 		return err
 	}
-	location := en.st.Where()
+//	location := en.st.Where()
-	code, err := en.rs.GetCode(location)
+//	code, err := en.rs.GetCode(location)
-	if err != nil {
+//	if err != nil {
-		return err
+//		return err
-	}
+//	}
-	if len(code) == 0 {
+//	if len(code) == 0 {
-		return fmt.Errorf("no code found at resource %s", en.rs)
+//		return fmt.Errorf("no code found at resource %s", en.rs)
-	}
+//	}
-	return en.st.AppendCode(code)
+//
+//	code, err = vm.Run(code, en.st, en.rs, ctx)
+//
+	en.st.SetCode(b)
+	return nil
 }
 
 // Exec processes user input against the current state of the virtual machine environment.
@@ -97,6 +101,13 @@ func(en *Engine) WriteResult(w io.Writer) error {
 	if err != nil {
 		return err
 	}
+	m, err := en.rs.RenderMenu()
+	if err != nil {
+		return err
+	}
+	if len(m) > 0 {
+		r += "\n" + m
+	}
 	c, err := io.WriteString(w, r)
 	log.Printf("%v bytes written as result for %v", c, location)
 	return err

go/engine/engine_test.go

@@ -39,10 +39,16 @@ func(fs FsWrapper) one(ctx context.Context) (string, error) {
 	return "one", nil
 }
 
+func(fs FsWrapper) inky(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)
 }
@@ -93,6 +99,20 @@ func TestEngineInit(t *testing.T) {
 	}
 	r := st.Where()
 	if r != "foo" {
-		t.Fatalf("expected where-string 'foo', got %v", r)
+		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)
 	}
 }

go/resource/fs.go

@@ -9,6 +9,7 @@ import (
 )
 
 type FsResource struct {
+	MenuResource
 	Path string
 }
 

go/resource/render.go

@@ -22,3 +22,4 @@ func DefaultRenderTemplate(r Resource, sym string, values map[string]string) (st
 	}
 	return b.String(), err
 }
+

go/resource/resource.go

@@ -2,6 +2,8 @@ package resource
 
 import (
 	"context"
+	"fmt"
+	"log"
 )
 
 // EntryFunc is a function signature for retrieving value for a key
@@ -11,6 +13,47 @@ type EntryFunc func(ctx context.Context) (string, error)
 type Resource interface {
 	GetTemplate(sym string) (string, error) // Get the template for a given symbol.
 	GetCode(sym string) ([]byte, error) // Get the bytecode for the given symbol.
+	PutMenu(string, string) error // Add a menu item
+	ShiftMenu() (string, string, error)
 	RenderTemplate(sym string, values map[string]string) (string, error) // Render the given data map using the template of the symbol.
+	RenderMenu() (string, error)
 	FuncFor(sym string) (EntryFunc, error) // Resolve symbol code point for.
 }
+
+type MenuResource struct {
+	menu [][2]string
+}
+
+func(m *MenuResource) PutMenu(selector string, title string) error {
+	m.menu = append(m.menu, [2]string{selector, title})
+	log.Printf("menu %v", m.menu)
+	return nil
+}
+
+func(m *MenuResource) ShiftMenu() (string, string, error) {
+	if len(m.menu) == 0 {
+		return "", "", fmt.Errorf("menu is empty")
+	}
+	r := m.menu[0]
+	m.menu = m.menu[1:]
+	return r[0], r[1], nil
+}
+
+func(m *MenuResource) RenderMenu() (string, error) {
+	r := ""
+	for true {
+		l := len(r)
+		choice, title, err := m.ShiftMenu()
+		if err != nil {
+			//if l == 0 { // TODO: replace with EOF
+			//	return "", err
+			//}
+			break
+		}
+		if l > 0 {
+			r += "\n"
+		}
+		r += fmt.Sprintf("%s:%s", choice, title)
+	}
+	return r, nil
+}

go/testdata/testdata.go

@@ -37,6 +37,7 @@ func out(sym string, b []byte, tpl string) error {
 
 func root() error {
 	b := []byte{}
+	b = vm.NewLine(b, vm.HALT, nil, nil, nil)
 	b = vm.NewLine(b, vm.INCMP, []string{"1", "foo"}, nil, nil)
 	b = vm.NewLine(b, vm.INCMP, []string{"2", "bar"}, nil, nil)
 
@@ -47,9 +48,11 @@ func root() error {
 
 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.LOAD, []string{"inky"}, []byte{20}, nil)
 	b = vm.NewLine(b, vm.HALT, nil, nil, nil)
-	b = vm.NewLine(b, vm.INCMP, []string{"0", "_back"}, 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})
 

go/vm/debug.go

@@ -83,6 +83,20 @@ func ToString(b []byte) (string, error) {
 			if err != nil {
 				return "", err
 			}
+		case MSIZE:
+			r, bb, err := ParseMSize(b)
+			b = bb
+			if err != nil {
+				return "", err
+			}
+			s = fmt.Sprintf("%s %v", s, r)
+		case MOUT:
+			r, v, bb, err := ParseMOut(b)
+			b = bb
+			if err != nil {
+				return "", err
+			}
+			s = fmt.Sprintf("%s %s \"%s\"", s, r, v)
 		}
 		s += "\n"
 		if len(b) == 0 {

go/vm/opcodes.go

@@ -15,7 +15,9 @@ const (
 	MOVE = 6
 	HALT = 7
 	INCMP = 8
-	_MAX = 8
+	MSIZE = 9
+	MOUT = 10
+	_MAX = 10
 )
 
 var (
@@ -29,5 +31,7 @@ var (
 		MOVE: "MOVE",
 		HALT: "HALT",
 		INCMP: "INCMP",
+		MSIZE: "MSIZE",
+		MOUT: "MOUT",
 	}
 )

go/vm/runner.go

@@ -19,6 +19,7 @@ import (
 func Run(b []byte, st *state.State, rs resource.Resource, ctx context.Context) ([]byte, error) {
 	running := true
 	for running {
+		log.Printf("execute code %x", b)
 		op, bb, err := opSplit(b)
 		if err != nil {
 			return b, err
@@ -39,6 +40,10 @@ func Run(b []byte, st *state.State, rs resource.Resource, ctx context.Context) (
 			b, err = RunMove(b, st, rs, ctx)
 		case INCMP:
 			b, err = RunInCmp(b, st, rs, ctx)
+		case MSIZE:
+			b, err = RunMSize(b, st, rs, ctx)
+		case MOUT:
+			b, err = RunMOut(b, st, rs, ctx)
 		case HALT:
 			b, err = RunHalt(b, st, rs, ctx)
 			return b, err
@@ -149,6 +154,12 @@ func RunMove(b []byte, st *state.State, rs resource.Resource, ctx context.Contex
 		return b, err
 	}
 	st.Down(sym)
+	code, err := rs.GetCode(sym)
+	if err != nil {
+		return b, err
+	}
+	log.Printf("loaded additional code: %x", code)
+	b = append(b, code...)
 	return b, nil
 }
 
@@ -175,7 +186,12 @@ func RunInCmp(b []byte, st *state.State, rs resource.Resource, ctx context.Conte
 		_, err = st.SetFlag(state.FLAG_INMATCH)
 		st.Down(target)
 	}
-	log.Printf("b last %v", b)
+	code, err := rs.GetCode(target)
+	if err != nil {
+		return b, err
+	}
+	log.Printf("loaded additional code: %x", code)
+	b = append(b, code...)
 	return b, err
 }
 
@@ -191,6 +207,19 @@ func RunHalt(b []byte, st *state.State, rs resource.Resource, ctx context.Contex
 	return b, err
 }
 
+// RunMSize
+func RunMSize(b []byte, st *state.State, rs resource.Resource, ctx context.Context) ([]byte, error) {
+	return b, nil
+}
+
+func RunMOut(b []byte, st *state.State, rs resource.Resource, ctx context.Context) ([]byte, error) {
+	choice, title, b, err := ParseMOut(b)
+	if err != nil {
+		return b, err
+	}
+	err = rs.PutMenu(choice, title)
+	return b, err
+}
 
 // retrieve data for key
 func refresh(key string, rs resource.Resource, ctx context.Context) (string, error) {

go/vm/runner_test.go

@@ -14,6 +14,7 @@ import (
 var dynVal = "three"
 
 type TestResource struct {
+	resource.MenuResource
 	state *state.State
 }
 
@@ -287,3 +288,32 @@ func TestRunArgInvalid(t *testing.T) {
 		t.Errorf("expected where-state _catch, got %v", r)
 	}
 }
+
+func TestRunMenu(t *testing.T) {
+	st := state.NewState(5)
+	rs := TestResource{}
+
+	var err error
+
+	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, err = Run(b, &st, &rs, context.TODO())
+	if err != nil {
+		t.Error(err)	
+	}
+	l := len(b)
+	if l != 0 {
+		t.Errorf("expected empty remainder, got length %v: %v", l, b)
+	}
+	
+	r, err := rs.RenderMenu()
+	if err != nil {
+		t.Fatal(err)
+	}
+	expect := "0:one\n1:two"
+	if r != expect {
+		t.Fatalf("expected:\n\t%s\ngot:\n\t%s\n", expect, r)
+	}
+}

go/vm/vm.go

@@ -47,6 +47,19 @@ func ParseInCmp(b []byte) (string, string, []byte, error) {
 	return parseTwoSym(b)
 }
 
+func ParseMSize(b []byte) (uint32, []byte, error) {
+	if len(b) < 1 {
+		return 0, b, fmt.Errorf("zero-length argument")
+	}
+	r := uint32(b[0])
+	b = b[1:]
+	return r, b, nil
+}
+
+func ParseMOut(b []byte) (string, string, []byte, error) {
+	return parseTwoSym(b)
+}
+
 func parseNoArg(b []byte) ([]byte, error) {
 	return b, nil
 }