WIP Factor out instruction parsing

go/vm/opcodes.go

@@ -1,10 +1,9 @@
 package vm
 
-import (
-	"encoding/binary"
-)
 const VERSION = 0
 
+type Opcode uint16
+
 // VM Opcodes
 const (
 	BACK = 0
@@ -18,21 +17,3 @@ const (
 	INCMP = 8
 	_MAX = 8
 )
-
-// NewLine creates a new instruction line for the VM.
-func NewLine(instructionList []byte, instruction uint16, strargs []string, byteargs []byte, numargs []uint8) []byte {
-	b := []byte{0x00, 0x00}
-	binary.BigEndian.PutUint16(b, instruction)
-	for _, arg := range strargs {
-		b = append(b, uint8(len(arg)))
-		b = append(b, []byte(arg)...)
-	}
-	if byteargs != nil {
-		b = append(b, uint8(len(byteargs)))
-		b = append(b, byteargs...)
-	}
-	if numargs != nil {
-		b = append(b, numargs...)
-	}
-	return append(instructionList, b...)
-}

go/vm/runner.go

@@ -0,0 +1,205 @@
+package vm
+
+import (
+	"encoding/binary"
+	"context"
+	"fmt"
+	"log"
+
+	"git.defalsify.org/festive/resource"
+	"git.defalsify.org/festive/state"
+)
+
+//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 Run(instruction []byte, st *state.State, rs resource.Resource, ctx context.Context) ([]byte, error) {
+	var err error
+	for len(instruction) > 0 {
+		log.Printf("instruction is now 0x%x", instruction)
+		op := binary.BigEndian.Uint16(instruction[:2])
+		if op > _MAX {
+			return instruction, fmt.Errorf("opcode value %v out of range (%v)", op, _MAX)
+		}
+		switch op {
+		case CATCH:
+			instruction, err = RunCatch(instruction[2:], st, rs, ctx)
+		case CROAK:
+			instruction, err = RunCroak(instruction[2:], st, rs, ctx)
+		case LOAD:
+			instruction, err = RunLoad(instruction[2:], st, rs, ctx)
+		case RELOAD:
+			instruction, err = RunReload(instruction[2:], st, rs, ctx)
+		case MAP:
+			instruction, err = RunMap(instruction[2:], st, rs, ctx)
+		case MOVE:
+			instruction, err = RunMove(instruction[2:], st, rs, ctx)
+		case BACK:
+			instruction, err = RunBack(instruction[2:], st, rs, ctx)
+		case INCMP:
+			instruction, err = RunIncmp(instruction[2:], st, rs, ctx)
+		case HALT:
+			return RunHalt(instruction[2:], st, rs, ctx)
+		default:
+			err = fmt.Errorf("Unhandled state: %v", op)
+		}
+		if err != nil {
+			return instruction, err
+		}
+	}
+	return instruction, nil
+}
+
+// RunMap executes the MAP opcode
+func RunMap(instruction []byte, st *state.State, rs resource.Resource, ctx context.Context) ([]byte, error) {
+	head, tail, err := instructionSplit(instruction)
+	if err != nil {
+		return instruction, err
+	}
+	err = st.Map(head)
+	return tail, err
+}
+
+// RunMap executes the CATCH opcode
+func RunCatch(instruction []byte, st *state.State, rs resource.Resource, ctx context.Context) ([]byte, error) {
+	head, tail, err := instructionSplit(instruction)
+	if err != nil {
+		return instruction, err
+	}
+	bitFieldSize := tail[0]
+	bitField := tail[1:1+bitFieldSize]
+	tail = tail[1+bitFieldSize:]
+	matchMode := tail[0] // matchmode 1 is match NOT set bit
+	tail = tail[1:]
+	match := false
+	if matchMode > 0 {
+		if !st.GetIndex(bitField) {
+			match = true
+		}
+	} else if st.GetIndex(bitField) {
+		match = true	
+	}
+
+	if match {
+		log.Printf("catch at flag %v, moving to %v", bitField, head)
+		st.Down(head)
+		tail = []byte{}
+	} 
+	return tail, nil
+}
+
+// RunMap executes the CROAK opcode
+func RunCroak(instruction []byte, st *state.State, rs resource.Resource, ctx context.Context) ([]byte, error) {
+	head, tail, err := instructionSplit(instruction)
+	if err != nil {
+		return instruction, err
+	}
+	_ = head
+	_ = tail
+	st.Reset()
+	return []byte{}, nil
+}
+
+// RunLoad executes the LOAD opcode
+func RunLoad(instruction []byte, st *state.State, rs resource.Resource, ctx context.Context) ([]byte, error) {
+	head, tail, err := instructionSplit(instruction)
+	if err != nil {
+		return instruction, err
+	}
+	if !st.Check(head) {
+		return instruction, fmt.Errorf("key %v already loaded", head)
+	}
+	sz := uint16(tail[0])
+	tail = tail[1:]
+
+	r, err := refresh(head, rs, ctx)
+	if err != nil {
+		return tail, err
+	}
+	err = st.Add(head, r, sz)
+	return tail, err
+}
+
+// RunLoad executes the RELOAD opcode
+func RunReload(instruction []byte, st *state.State, rs resource.Resource, ctx context.Context) ([]byte, error) {
+	head, tail, err := instructionSplit(instruction)
+	if err != nil {
+		return instruction, err
+	}
+	r, err := refresh(head, rs, ctx)
+	if err != nil {
+		return tail, err
+	}
+	st.Update(head, r)
+	return tail, nil
+}
+
+// RunLoad executes the MOVE opcode
+func RunMove(instruction []byte, st *state.State, rs resource.Resource, ctx context.Context) ([]byte, error) {
+	head, tail, err := instructionSplit(instruction)
+	if err != nil {
+		return instruction, err
+	}
+	st.Down(head)
+	return tail, nil
+}
+
+// RunLoad executes the BACK opcode
+func RunBack(instruction []byte, st *state.State, rs resource.Resource, ctx context.Context) ([]byte, error) {
+	st.Up()
+	return instruction, nil
+}
+
+// RunIncmp executes the INCMP opcode
+func RunIncmp(instruction []byte, st *state.State, rs resource.Resource, ctx context.Context) ([]byte, error) {
+	head, tail, err := instructionSplit(instruction)
+	if err != nil {
+		return instruction, err
+	}
+	sym, tail, err := instructionSplit(tail)
+	if err != nil {
+		return instruction, err
+	}
+	v, err := st.GetFlag(state.FLAG_INMATCH)
+	if err != nil {
+		return tail, err
+	}
+	if v {
+		return tail, nil
+	}
+	input, err := st.GetInput()
+	if err != nil {
+		return tail, err
+	}
+	log.Printf("checking input %v %v", input, head)
+	if head == string(input) {
+		log.Printf("input match for '%s'", input)
+		_, err = st.SetFlag(state.FLAG_INMATCH)
+		st.Down(sym)
+	}
+	return tail, err
+}
+
+// RunHalt executes the HALT opcode
+func RunHalt(instruction []byte, st *state.State, rs resource.Resource, ctx context.Context) ([]byte, error) {
+	log.Printf("found HALT, stopping")
+	_, err := st.ResetFlag(state.FLAG_INMATCH)
+	return instruction, err
+}
+
+
+// retrieve data for key
+func refresh(key string, rs resource.Resource, ctx context.Context) (string, error) {
+	fn, err := rs.FuncFor(key)
+	if err != nil {
+		return "", err
+	}
+	if fn == nil {
+		return "", fmt.Errorf("no retrieve function for external symbol %v", key)
+	}
+	return fn(ctx)
+}

go/vm/runner_test.go

@@ -0,0 +1,284 @@
+package vm
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"log"
+	"testing"
+	
+	"git.defalsify.org/festive/resource"
+	"git.defalsify.org/festive/state"
+)
+
+var dynVal = "three"
+
+type TestResource struct {
+	state *state.State
+}
+
+func getOne(ctx context.Context) (string, error) {
+	return "one", nil
+}
+
+func getTwo(ctx context.Context) (string, error) {
+	return "two", nil
+}
+
+func getDyn(ctx context.Context) (string, error) {
+	return dynVal, nil
+}
+
+type TestStatefulResolver struct {
+	state *state.State
+}
+
+func (r *TestResource) GetTemplate(sym string) (string, error) {
+	switch sym {
+	case "foo":
+		return "inky pinky blinky clyde", nil
+	case "bar":
+		return "inky pinky {{.one}} blinky {{.two}} clyde", nil
+	case "baz":
+		return "inky pinky {{.baz}} blinky clyde", nil
+	case "three":
+		return "{{.one}} inky pinky {{.three}} blinky clyde {{.two}}", nil
+	case "_catch":
+		return "aiee", nil
+	}
+	panic(fmt.Sprintf("unknown symbol %s", sym))
+	return "", fmt.Errorf("unknown symbol %s", sym)
+}
+
+func (r *TestResource) RenderTemplate(sym string, values map[string]string) (string, error) {
+	return resource.DefaultRenderTemplate(r, sym, values)
+}
+
+func (r *TestResource) FuncFor(sym string) (resource.EntryFunc, error) {
+	switch sym {
+	case "one":
+		return getOne, nil
+	case "two":
+		return getTwo, nil
+	case "dyn":
+		return getDyn, nil
+	case "arg":
+		return r.getInput, nil
+	}
+	return nil, fmt.Errorf("invalid function: '%s'", sym)
+}
+
+func(r *TestResource) getInput(ctx context.Context) (string, error) {
+	v, err := r.state.GetInput()
+	return string(v), err
+}
+
+func(r *TestResource) GetCode(sym string) ([]byte, error) {
+	return []byte{}, nil
+}
+
+func TestRun(t *testing.T) {
+	st := state.NewState(5)
+	rs := TestResource{}
+	b := []byte{0x00, MOVE, 0x03}
+	b = append(b, []byte("foo")...)
+	_, err := Run(b, &st, &rs, context.TODO())
+	if err != nil {
+		t.Errorf("error on valid opcode: %v", err)	
+	}
+
+	b = []byte{0x01, 0x02}
+	_, err = Run(b, &st, &rs, context.TODO())
+	if err == nil {
+		t.Errorf("no error on invalid opcode")	
+	}
+}
+
+func TestRunLoadRender(t *testing.T) {
+	st := state.NewState(5)
+	st.Down("barbarbar")
+	rs := TestResource{}
+	sym := "one"
+	ins := append([]byte{uint8(len(sym))}, []byte(sym)...)
+	ins = append(ins, 0x0a)
+	var err error
+	_, err = RunLoad(ins, &st, &rs, context.TODO())
+	if err != nil {
+		t.Error(err)
+	}
+	m, err := st.Get()
+	if err != nil {
+		t.Error(err)
+	}
+	r, err := rs.RenderTemplate("foo", m)
+	if err != nil {
+		t.Error(err)
+	}
+	expect := "inky pinky blinky clyde"
+	if r != expect {
+		t.Errorf("Expected %v, got %v", []byte(expect), []byte(r))
+	}
+
+	r, err = rs.RenderTemplate("bar", m)
+	if err == nil {
+		t.Errorf("expected error for render of bar: %v" ,err)
+	}
+
+	sym = "two"
+	ins = append([]byte{uint8(len(sym))}, []byte(sym)...)
+	ins = append(ins, 0)
+	_, err = RunLoad(ins, &st, &rs, context.TODO())
+	if err != nil {
+		t.Error(err)
+	}
+	m, err = st.Get()
+	if err != nil {
+		t.Error(err)
+	}
+	r, err = rs.RenderTemplate("bar", m)
+	if err != nil {
+		t.Error(err)
+	}
+	expect = "inky pinky one blinky two clyde"
+	if r != expect {
+		t.Errorf("Expected %v, got %v", expect, r)
+	}
+}
+
+func TestRunMultiple(t *testing.T) {
+	st := state.NewState(5)
+	rs := TestResource{}
+	b := []byte{}
+	b = NewLine(b, LOAD, []string{"one"}, nil, []uint8{0})
+	b = NewLine(b, LOAD, []string{"two"}, nil, []uint8{42})
+	_, err := Run(b, &st, &rs, context.TODO())
+	if err != nil {
+		t.Error(err)
+	}
+}
+
+func TestRunReload(t *testing.T) {
+	st := state.NewState(5)
+	rs := TestResource{}
+	b := []byte{}
+	b = NewLine(b, LOAD, []string{"dyn"}, nil, []uint8{0})
+	b = NewLine(b, MAP, []string{"dyn"}, nil, nil)
+	_, err := Run(b, &st, &rs, context.TODO())
+	if err != nil {
+		t.Error(err)
+	}
+	r, err := st.Val("dyn")
+	if err != nil {
+		t.Error(err)
+	}
+	if r != "three" {
+		t.Errorf("expected result 'three', got %v", r)
+	}
+	dynVal = "baz"
+	b = []byte{}
+	b = NewLine(b, RELOAD, []string{"dyn"}, nil, nil)
+	_, err = Run(b, &st, &rs, context.TODO())
+	if err != nil {
+		t.Error(err)
+	}
+	r, err = st.Val("dyn")
+	if err != nil {
+		t.Error(err)
+	}
+	log.Printf("dun now %s", r)
+	if r != "baz" {
+		t.Errorf("expected result 'baz', got %v", r)
+	}
+
+}
+
+func TestHalt(t *testing.T) {
+	st := state.NewState(5)
+	rs := TestResource{}
+	b := NewLine([]byte{}, LOAD, []string{"one"}, nil, []uint8{0})
+	b = NewLine(b, HALT, nil, nil, nil)
+	b = NewLine(b, MOVE, []string{"foo"}, nil, nil)
+	var err error
+	b, err = Run(b, &st, &rs, context.TODO())
+	if err != nil {
+		t.Error(err)
+	}
+	r := st.Where()
+	if r == "foo" {
+		t.Fatalf("Expected where-symbol not to be 'foo'")
+	}
+	if !bytes.Equal(b[:2], []byte{0x00, MOVE}) {
+		t.Fatalf("Expected MOVE instruction, found '%v'", b)
+	}
+}
+
+func TestRunArg(t *testing.T) {
+	st := state.NewState(5)
+	rs := TestResource{}
+	
+	input := []byte("bar")
+	_ = st.SetInput(input)
+
+	bi := NewLine([]byte{}, INCMP, []string{"bar", "baz"}, nil, nil)
+	b, err := Run(bi, &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 := st.Where()
+	if r != "baz" {
+		t.Errorf("expected where-state baz, got %v", r)
+	}
+}
+
+func TestRunInputHandler(t *testing.T) {
+	st := state.NewState(5)
+	rs := TestResource{}
+
+	_ = st.SetInput([]byte("baz"))
+
+	bi := NewLine([]byte{}, INCMP, []string{"bar", "aiee"}, nil, nil)
+	bi = NewLine(bi, INCMP, []string{"baz", "foo"}, nil, nil)
+	bi = NewLine(bi, LOAD, []string{"one"}, nil, []uint8{0})
+	bi = NewLine(bi, LOAD, []string{"two"}, nil, []uint8{3})
+	bi = NewLine(bi, MAP, []string{"one"}, nil, nil)
+	bi = NewLine(bi, MAP, []string{"two"}, nil, nil)
+
+	var err error
+	_, err = Run(bi, &st, &rs, context.TODO())
+	if err != nil {
+		t.Fatal(err)	
+	}
+	r := st.Where()
+	if r != "foo" {
+		t.Fatalf("expected where-sym 'foo', got '%v'", r)
+	}
+}
+
+func TestRunArgInvalid(t *testing.T) {
+	st := state.NewState(5)
+	rs := TestResource{}
+
+	_ = st.SetInput([]byte("foo"))
+
+	var err error
+
+	b := NewLine([]byte{}, INCMP, []string{"bar", "baz"}, nil, nil)
+	b = NewLine(b, CATCH, []string{"_catch"}, []byte{state.FLAG_INMATCH}, []uint8{1})
+
+	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 := st.Where()
+	if r != "_catch" {
+		t.Errorf("expected where-state _catch, got %v", r)
+	}
+}

go/vm/vm.go

@@ -2,215 +2,147 @@ package vm
 
 import (
 	"encoding/binary"
-	"context"
 	"fmt"
-	"log"
-
-	"git.defalsify.org/festive/resource"
-	"git.defalsify.org/festive/state"
 )
 
-//type Runner func(instruction []byte, st state.State, rs resource.Resource, ctx context.Context) (state.State, []byte, error)
 
-func argFromBytes(input []byte) (string, []byte, error) {
+func ParseLoad(b []byte) (string, uint32, []byte, error) {
-	if len(input) == 0 {
+	return parseSymLen(b, LOAD)
-		return "", input, fmt.Errorf("zero length input")
-	}
-	sz := input[0]
-	out := input[1:1+sz]
-	return string(out), input[1+sz:], nil
 }
 
-// Run extracts individual op codes and arguments and executes them.
+func ParseReload(b []byte) (string, []byte, error) {
-//
+	return parseSym(b, RELOAD)
-// Each step may update the state.
-//
-// On error, the remaining instructions will be returned. State will not be rolled back.
-func Run(instruction []byte, st *state.State, rs resource.Resource, ctx context.Context) ([]byte, error) {
-	var err error
-	for len(instruction) > 0 {
-		log.Printf("instruction is now 0x%x", instruction)
-		op := binary.BigEndian.Uint16(instruction[:2])
-		if op > _MAX {
-			return instruction, fmt.Errorf("opcode value %v out of range (%v)", op, _MAX)
-		}
-		switch op {
-		case CATCH:
-			instruction, err = RunCatch(instruction[2:], st, rs, ctx)
-		case CROAK:
-			instruction, err = RunCroak(instruction[2:], st, rs, ctx)
-		case LOAD:
-			instruction, err = RunLoad(instruction[2:], st, rs, ctx)
-		case RELOAD:
-			instruction, err = RunReload(instruction[2:], st, rs, ctx)
-		case MAP:
-			instruction, err = RunMap(instruction[2:], st, rs, ctx)
-		case MOVE:
-			instruction, err = RunMove(instruction[2:], st, rs, ctx)
-		case BACK:
-			instruction, err = RunBack(instruction[2:], st, rs, ctx)
-		case INCMP:
-			instruction, err = RunIncmp(instruction[2:], st, rs, ctx)
-		case HALT:
-			return RunHalt(instruction[2:], st, rs, ctx)
-		default:
-			err = fmt.Errorf("Unhandled state: %v", op)
-		}
-		if err != nil {
-			return instruction, err
-		}
-	}
-	return instruction, nil
 }
 
-// RunMap executes the MAP opcode
+func ParseMap(b []byte) (string, []byte, error) {
-func RunMap(instruction []byte, st *state.State, rs resource.Resource, ctx context.Context) ([]byte, error) {
+	return parseSym(b, MAP)
-	head, tail, err := instructionSplit(instruction)
-	if err != nil {
-		return instruction, err
-	}
-	err = st.Map(head)
-	return tail, err
 }
 
-// RunMap executes the CATCH opcode
+func ParseMove(b []byte) (string, []byte, error) {
-func RunCatch(instruction []byte, st *state.State, rs resource.Resource, ctx context.Context) ([]byte, error) {
+	return parseSym(b, MOVE)
-	head, tail, err := instructionSplit(instruction)
+}
+
+func ParseHalt(b []byte) ([]byte, error) {
+	return parseNoArg(b, HALT)
+}
+
+func ParseCatch(b []byte) (string, uint8, []byte, error) {
+	return parseSymSig(b, CATCH)
+}
+
+func ParseCroak(b []byte) (string, uint8, []byte, error) {
+	return parseSymSig(b, CROAK)
+}
+
+func ParseInCmp(b []byte) (string, string, []byte, error) {
+	return parseTwoSym(b, INCMP)
+}
+
+func parseNoArg(b []byte, op Opcode) ([]byte, error) {
+	return opCheck(b, op)
+}
+
+func parseSym(b []byte, op Opcode) (string, []byte, error) {
+	b, err := opCheck(b, op)
 	if err != nil {
-		return instruction, err
+		return "", b, err
 	}
-	bitFieldSize := tail[0]
+	sym, tail, err := instructionSplit(b)
-	bitField := tail[1:1+bitFieldSize]
+	if err != nil {
-	tail = tail[1+bitFieldSize:]
+		return "", b, err
-	matchMode := tail[0] // matchmode 1 is match NOT set bit
+	}
+	return sym, tail, nil
+}
+
+func parseTwoSym(b []byte, op Opcode) (string, string, []byte, error) {
+	b, err := opCheck(b, op)
+	if err != nil {
+		return "", "", b, err
+	}
+	symOne, tail, err := instructionSplit(b)
+	if err != nil {
+		return "", "", b, err
+	}
+	symTwo, tail, err := instructionSplit(tail)
+	if err != nil {
+		return "", "", tail, err
+	}
+	return symOne, symTwo, tail, nil
+}
+
+func parseSymLen(b []byte, op Opcode) (string, uint32, []byte, error) {
+	b, err := opCheck(b, op)
+	if err != nil {
+		return "", 0, b, err
+	}
+	sym, tail, err := instructionSplit(b)
+	if err != nil {
+		return "", 0, b, err
+	}
+	sz, tail, err := intSplit(tail)
+	if err != nil {
+		return "", 0, b, err
+	}
+	return sym, sz, tail, nil
+}
+
+func parseSymSig(b []byte, op Opcode) (string, uint8, []byte, error) {
+	b, err := opCheck(b, op)
+	if err != nil {
+		return "", 0, b, err
+	}
+	sym, tail, err := instructionSplit(b)
+	if err != nil {
+		return "", 0, b, err
+	}
+	if len(tail) == 0 {
+		return "", 0, b, fmt.Errorf("instruction too short")
+	}
+	n := tail[0]
 	tail = tail[1:]
-	match := false
+	return sym, n, tail, nil
-	if matchMode > 0 {
-		if !st.GetIndex(bitField) {
-			match = true
-		}
-	} else if st.GetIndex(bitField) {
-		match = true	
-	}
-
-	if match {
-		log.Printf("catch at flag %v, moving to %v", bitField, head)
-		st.Down(head)
-		tail = []byte{}
-	} 
-	return tail, nil
 }
 
-// RunMap executes the CROAK opcode
+// NewLine creates a new instruction line for the VM.
-func RunCroak(instruction []byte, st *state.State, rs resource.Resource, ctx context.Context) ([]byte, error) {
+func NewLine(instructionList []byte, instruction uint16, strargs []string, byteargs []byte, numargs []uint8) []byte {
-	head, tail, err := instructionSplit(instruction)
+	if instructionList == nil {
-	if err != nil {
+		instructionList = []byte{}
-		return instruction, err
 	}
-	_ = head
+	b := []byte{0x00, 0x00}
-	_ = tail
+	binary.BigEndian.PutUint16(b, instruction)
-	st.Reset()
+	for _, arg := range strargs {
-	return []byte{}, nil
+		b = append(b, uint8(len(arg)))
+		b = append(b, []byte(arg)...)
+	}
+	if byteargs != nil {
+		b = append(b, uint8(len(byteargs)))
+		b = append(b, byteargs...)
+	}
+	if numargs != nil {
+		b = append(b, numargs...)
+	}
+	return append(instructionList, b...)
 }
 
-// RunLoad executes the LOAD opcode
+func intSplit(b []byte) (uint32, []byte, error) {
-func RunLoad(instruction []byte, st *state.State, rs resource.Resource, ctx context.Context) ([]byte, error) {
+	l := uint8(b[0])
-	head, tail, err := instructionSplit(instruction)
+	sz := uint32(l)
-	if err != nil {
+	b = b[1:]
-		return instruction, err
+	if l > 0 {
+		r := []byte{0, 0, 0, 0}
+		c := 0
+		ll := 4 - l
+		var i uint8
+		for i = 0; i < 4; i++ {
+			if i >= ll {
+				r[i] = b[c]
+				c += 1
 			}
-	if !st.Check(head) {
-		return instruction, fmt.Errorf("key %v already loaded", head)
 		}
-	sz := uint16(tail[0])
+		sz = binary.BigEndian.Uint32(r)
-	tail = tail[1:]
+		b = b[l:]
-
-	r, err := refresh(head, rs, ctx)
-	if err != nil {
-		return tail, err
 	}
-	err = st.Add(head, r, sz)
+	return sz, b, nil
-	return tail, err
-}
-
-// RunLoad executes the RELOAD opcode
-func RunReload(instruction []byte, st *state.State, rs resource.Resource, ctx context.Context) ([]byte, error) {
-	head, tail, err := instructionSplit(instruction)
-	if err != nil {
-		return instruction, err
-	}
-	r, err := refresh(head, rs, ctx)
-	if err != nil {
-		return tail, err
-	}
-	st.Update(head, r)
-	return tail, nil
-}
-
-// RunLoad executes the MOVE opcode
-func RunMove(instruction []byte, st *state.State, rs resource.Resource, ctx context.Context) ([]byte, error) {
-	head, tail, err := instructionSplit(instruction)
-	if err != nil {
-		return instruction, err
-	}
-	st.Down(head)
-	return tail, nil
-}
-
-// RunLoad executes the BACK opcode
-func RunBack(instruction []byte, st *state.State, rs resource.Resource, ctx context.Context) ([]byte, error) {
-	st.Up()
-	return instruction, nil
-}
-
-// RunIncmp executes the INCMP opcode
-func RunIncmp(instruction []byte, st *state.State, rs resource.Resource, ctx context.Context) ([]byte, error) {
-	head, tail, err := instructionSplit(instruction)
-	if err != nil {
-		return instruction, err
-	}
-	sym, tail, err := instructionSplit(tail)
-	if err != nil {
-		return instruction, err
-	}
-	v, err := st.GetFlag(state.FLAG_INMATCH)
-	if err != nil {
-		return tail, err
-	}
-	if v {
-		return tail, nil
-	}
-	input, err := st.GetInput()
-	if err != nil {
-		return tail, err
-	}
-	log.Printf("checking input %v %v", input, head)
-	if head == string(input) {
-		log.Printf("input match for '%s'", input)
-		_, err = st.SetFlag(state.FLAG_INMATCH)
-		st.Down(sym)
-	}
-	return tail, err
-}
-
-// RunHalt executes the HALT opcode
-func RunHalt(instruction []byte, st *state.State, rs resource.Resource, ctx context.Context) ([]byte, error) {
-	log.Printf("found HALT, stopping")
-	_, err := st.ResetFlag(state.FLAG_INMATCH)
-	return instruction, err
-}
-
-
-// retrieve data for key
-func refresh(key string, rs resource.Resource, ctx context.Context) (string, error) {
-	fn, err := rs.FuncFor(key)
-	if err != nil {
-		return "", err
-	}
-	if fn == nil {
-		return "", fmt.Errorf("no retrieve function for external symbol %v", key)
-	}
-	return fn(ctx)
 }
 
 // split instruction into symbol and arguments
@@ -229,3 +161,26 @@ func instructionSplit(b []byte) (string, []byte, error) {
 	r := string(b[1:1+sz])
 	return r, b[1+sz:], nil
 }
+
+func opCheck(b []byte, opIn Opcode) ([]byte, error) {
+	op, b, err := opSplit(b)
+	if err != nil {
+		return b, err
+	}
+	if op != opIn {
+		return b, fmt.Errorf("not a %v instruction", op)
+	}
+	return b, nil
+}
+
+func opSplit(b []byte) (Opcode, []byte, error) {
+	l := len(b)
+	if l < 2 {
+		return 0, b, fmt.Errorf("input size %v too short for opcode", l)
+	}
+	op := binary.BigEndian.Uint16(b)
+	if op > _MAX {
+		return 0, b, fmt.Errorf("invalid opcode %v", op)
+	}
+	return Opcode(op), b[2:], nil
+}

go/vm/vm_test.go

@@ -1,284 +1,108 @@
 package vm
 
 import (
-	"bytes"
-	"context"
-	"fmt"
-	"log"
 	"testing"
-	
-	"git.defalsify.org/festive/resource"
-	"git.defalsify.org/festive/state"
 )
 
-var dynVal = "three"
+func TestParseNoArg(t *testing.T) {
-
+	b := NewLine(nil, HALT, nil, nil, nil)
-type TestResource struct {
+	b, err := ParseHalt(b)
-	state *state.State
-}
-
-func getOne(ctx context.Context) (string, error) {
-	return "one", nil
-}
-
-func getTwo(ctx context.Context) (string, error) {
-	return "two", nil
-}
-
-func getDyn(ctx context.Context) (string, error) {
-	return dynVal, nil
-}
-
-type TestStatefulResolver struct {
-	state *state.State
-}
-
-func (r *TestResource) GetTemplate(sym string) (string, error) {
-	switch sym {
-	case "foo":
-		return "inky pinky blinky clyde", nil
-	case "bar":
-		return "inky pinky {{.one}} blinky {{.two}} clyde", nil
-	case "baz":
-		return "inky pinky {{.baz}} blinky clyde", nil
-	case "three":
-		return "{{.one}} inky pinky {{.three}} blinky clyde {{.two}}", nil
-	case "_catch":
-		return "aiee", nil
-	}
-	panic(fmt.Sprintf("unknown symbol %s", sym))
-	return "", fmt.Errorf("unknown symbol %s", sym)
-}
-
-func (r *TestResource) RenderTemplate(sym string, values map[string]string) (string, error) {
-	return resource.DefaultRenderTemplate(r, sym, values)
-}
-
-func (r *TestResource) FuncFor(sym string) (resource.EntryFunc, error) {
-	switch sym {
-	case "one":
-		return getOne, nil
-	case "two":
-		return getTwo, nil
-	case "dyn":
-		return getDyn, nil
-	case "arg":
-		return r.getInput, nil
-	}
-	return nil, fmt.Errorf("invalid function: '%s'", sym)
-}
-
-func(r *TestResource) getInput(ctx context.Context) (string, error) {
-	v, err := r.state.GetInput()
-	return string(v), err
-}
-
-func(r *TestResource) GetCode(sym string) ([]byte, error) {
-	return []byte{}, nil
-}
-
-func TestRun(t *testing.T) {
-	st := state.NewState(5)
-	rs := TestResource{}
-	b := []byte{0x00, MOVE, 0x03}
-	b = append(b, []byte("foo")...)
-	_, err := Run(b, &st, &rs, context.TODO())
-	if err != nil {
-		t.Errorf("error on valid opcode: %v", err)	
-	}
-
-	b = []byte{0x01, 0x02}
-	_, err = Run(b, &st, &rs, context.TODO())
-	if err == nil {
-		t.Errorf("no error on invalid opcode")	
-	}
-}
-
-func TestRunLoadRender(t *testing.T) {
-	st := state.NewState(5)
-	st.Down("barbarbar")
-	rs := TestResource{}
-	sym := "one"
-	ins := append([]byte{uint8(len(sym))}, []byte(sym)...)
-	ins = append(ins, 0x0a)
-	var err error
-	_, err = RunLoad(ins, &st, &rs, context.TODO())
-	if err != nil {
-		t.Error(err)
-	}
-	m, err := st.Get()
-	if err != nil {
-		t.Error(err)
-	}
-	r, err := rs.RenderTemplate("foo", m)
-	if err != nil {
-		t.Error(err)
-	}
-	expect := "inky pinky blinky clyde"
-	if r != expect {
-		t.Errorf("Expected %v, got %v", []byte(expect), []byte(r))
-	}
-
-	r, err = rs.RenderTemplate("bar", m)
-	if err == nil {
-		t.Errorf("expected error for render of bar: %v" ,err)
-	}
-
-	sym = "two"
-	ins = append([]byte{uint8(len(sym))}, []byte(sym)...)
-	ins = append(ins, 0)
-	_, err = RunLoad(ins, &st, &rs, context.TODO())
-	if err != nil {
-		t.Error(err)
-	}
-	m, err = st.Get()
-	if err != nil {
-		t.Error(err)
-	}
-	r, err = rs.RenderTemplate("bar", m)
-	if err != nil {
-		t.Error(err)
-	}
-	expect = "inky pinky one blinky two clyde"
-	if r != expect {
-		t.Errorf("Expected %v, got %v", expect, r)
-	}
-}
-
-func TestRunMultiple(t *testing.T) {
-	st := state.NewState(5)
-	rs := TestResource{}
-	b := []byte{}
-	b = NewLine(b, LOAD, []string{"one"}, nil, []uint8{0})
-	b = NewLine(b, LOAD, []string{"two"}, nil, []uint8{42})
-	_, err := Run(b, &st, &rs, context.TODO())
-	if err != nil {
-		t.Error(err)
-	}
-}
-
-func TestRunReload(t *testing.T) {
-	st := state.NewState(5)
-	rs := TestResource{}
-	b := []byte{}
-	b = NewLine(b, LOAD, []string{"dyn"}, nil, []uint8{0})
-	b = NewLine(b, MAP, []string{"dyn"}, nil, nil)
-	_, err := Run(b, &st, &rs, context.TODO())
-	if err != nil {
-		t.Error(err)
-	}
-	r, err := st.Val("dyn")
-	if err != nil {
-		t.Error(err)
-	}
-	if r != "three" {
-		t.Errorf("expected result 'three', got %v", r)
-	}
-	dynVal = "baz"
-	b = []byte{}
-	b = NewLine(b, RELOAD, []string{"dyn"}, nil, nil)
-	_, err = Run(b, &st, &rs, context.TODO())
-	if err != nil {
-		t.Error(err)
-	}
-	r, err = st.Val("dyn")
-	if err != nil {
-		t.Error(err)
-	}
-	log.Printf("dun now %s", r)
-	if r != "baz" {
-		t.Errorf("expected result 'baz', got %v", r)
-	}
-
-}
-
-func TestHalt(t *testing.T) {
-	st := state.NewState(5)
-	rs := TestResource{}
-	b := NewLine([]byte{}, LOAD, []string{"one"}, nil, []uint8{0})
-	b = NewLine(b, HALT, nil, nil, nil)
-	b = NewLine(b, MOVE, []string{"foo"}, nil, nil)
-	var err error
-	b, err = Run(b, &st, &rs, context.TODO())
-	if err != nil {
-		t.Error(err)
-	}
-	r := st.Where()
-	if r == "foo" {
-		t.Fatalf("Expected where-symbol not to be 'foo'")
-	}
-	if !bytes.Equal(b[:2], []byte{0x00, MOVE}) {
-		t.Fatalf("Expected MOVE instruction, found '%v'", b)
-	}
-}
-
-func TestRunArg(t *testing.T) {
-	st := state.NewState(5)
-	rs := TestResource{}
-	
-	input := []byte("bar")
-	_ = st.SetInput(input)
-
-	bi := NewLine([]byte{}, INCMP, []string{"bar", "baz"}, nil, nil)
-	b, err := Run(bi, &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 := st.Where()
-	if r != "baz" {
-		t.Errorf("expected where-state baz, got %v", r)
-	}
-}
-
-func TestRunInputHandler(t *testing.T) {
-	st := state.NewState(5)
-	rs := TestResource{}
-
-	_ = st.SetInput([]byte("baz"))
-
-	bi := NewLine([]byte{}, INCMP, []string{"bar", "aiee"}, nil, nil)
-	bi = NewLine(bi, INCMP, []string{"baz", "foo"}, nil, nil)
-	bi = NewLine(bi, LOAD, []string{"one"}, nil, []uint8{0})
-	bi = NewLine(bi, LOAD, []string{"two"}, nil, []uint8{3})
-	bi = NewLine(bi, MAP, []string{"one"}, nil, nil)
-	bi = NewLine(bi, MAP, []string{"two"}, nil, nil)
-
-	var err error
-	_, err = Run(bi, &st, &rs, context.TODO())
 	if err != nil {
 		t.Fatal(err)
 	}
-	r := st.Where()
-	if r != "foo" {
-		t.Fatalf("expected where-sym 'foo', got '%v'", r)
-	}
 }
 
-func TestRunArgInvalid(t *testing.T) {
+func TestParseSym(t *testing.T) {
-	st := state.NewState(5)
+	b := NewLine(nil, MAP, []string{"baz"}, nil, nil)
-	rs := TestResource{}
+	sym, b, err := ParseMap(b)
-
-	_ = st.SetInput([]byte("foo"))
-
-	var err error
-
-	b := NewLine([]byte{}, INCMP, []string{"bar", "baz"}, nil, nil)
-	b = NewLine(b, CATCH, []string{"_catch"}, []byte{state.FLAG_INMATCH}, []uint8{1})
-
-	b, err = Run(b, &st, &rs, context.TODO())
 	if err != nil {
-		t.Error(err)	
+		t.Fatal(err)
 	}
-	l := len(b)
+	if sym != "baz" {
-	if l != 0 {
+		t.Fatalf("expected sym baz, got %v", sym)
-		t.Errorf("expected empty remainder, got length %v: %v", l, b)
 	}
-	r := st.Where()
+
-	if r != "_catch" {
+	b = NewLine(nil, RELOAD, []string{"xyzzy"}, nil, nil)
-		t.Errorf("expected where-state _catch, got %v", r)
+	sym, b, err = ParseReload(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if sym != "xyzzy" {
+		t.Fatalf("expected sym xyzzy, got %v", sym)
+	}
+
+	b = NewLine(nil, MOVE, []string{"plugh"}, nil, nil)
+	sym, b, err = ParseMove(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if sym != "plugh" {
+		t.Fatalf("expected sym plugh, got %v", sym)
+	}
+}
+
+func TestParseTwoSym(t *testing.T) {
+	b := NewLine(nil, INCMP, []string{"foo", "bar"}, nil, nil)
+	one, two, b, err := ParseInCmp(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if one != "foo" {
+		t.Fatalf("expected symone foo, got %v", one)
+	}
+	if two != "bar" {
+		t.Fatalf("expected symtwo bar, got %v", two)
+	}
+}
+
+func TestParseSymSig(t *testing.T) {
+	b := NewLine(nil, CATCH, []string{"baz"}, nil, []uint8{0x0d})
+	sym, n, b, err := ParseCatch(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if sym != "baz" {
+		t.Fatalf("expected sym baz, got %v", sym)
+	}
+	if n != 13 {
+		t.Fatalf("expected n 13, got %v", n)
+	}
+}
+
+func TestParseSymAndLen(t *testing.T) {
+	b := NewLine(nil, LOAD, []string{"foo"}, []byte{0x2a}, nil)
+	sym, n, b, err := ParseLoad(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if sym != "foo" {
+		t.Fatalf("expected sym foo, got %v", sym)
+	}
+	if n != 42 {
+		t.Fatalf("expected n 42, got %v", n)
+	}
+
+	b = NewLine(nil, LOAD, []string{"bar"}, []byte{0x02, 0x9a}, nil)
+	sym, n, b, err = ParseLoad(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if sym != "bar" {
+		t.Fatalf("expected sym foo, got %v", sym)
+	}
+	if n != 666 {
+		t.Fatalf("expected n 666, got %v", n)
+	}
+
+	b = NewLine(nil, LOAD, []string{"baz"}, []byte{0x0}, nil)
+	sym, n, b, err = ParseLoad(b)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if sym != "baz" {
+		t.Fatalf("expected sym foo, got %v", sym)
+	}
+	if n != 0 {
+		t.Fatalf("expected n 666, got %v", n)
 	}
 }