Implemented block instruction parsing

src/build/Function.go

@@ -28,28 +28,40 @@ type Function struct {
 // Compile turns a function into machine code.
 func (f *Function) Compile() {
 	f.Assembler.Label(f.Name)
+	err := f.CompileTokens(f.Body)
+
+	if err != nil {
+		f.Error = err
+		return
+	}
+
+	f.Assembler.Return()
+}
+
+// CompileTokens compiles a token list.
+func (f *Function) CompileTokens(body token.List) error {
 	start := 0
 	groupLevel := 0
+	blockLevel := 0
 
-	for i, t := range f.Body {
-		if start == i && (t.Kind == token.NewLine || t.Kind == token.BlockStart || t.Kind == token.BlockEnd) {
+	for i, t := range body {
+		if start == i && t.Kind == token.NewLine {
 			start = i + 1
 			continue
 		}
 
 		switch t.Kind {
 		case token.NewLine:
-			if groupLevel > 0 {
+			if groupLevel > 0 || blockLevel > 0 {
 				continue
 			}
 
 			if start != -1 {
-				instruction := f.Body[start:i]
+				instruction := body[start:i]
 				err := f.CompileInstruction(instruction)
 
 				if err != nil {
-					f.Error = err
-					return
+					return err
 				}
 
 				start = -1
@@ -62,10 +74,16 @@ func (f *Function) Compile() {
 
 		case token.GroupEnd:
 			groupLevel--
+
+		case token.BlockStart:
+			blockLevel++
+
+		case token.BlockEnd:
+			blockLevel--
 		}
 	}
 
-	f.Assembler.Return()
+	return nil
 }
 
 // CompileInstruction compiles a single instruction.
@@ -109,6 +127,20 @@ func (f *Function) CompileKeyword(line token.List) error {
 
 		f.Assembler.Return()
 
+	case "loop":
+		blockStart := line.IndexKind(token.BlockStart) + 1
+		blockEnd := line.LastIndexKind(token.BlockEnd)
+
+		if blockStart == -1 {
+			return errors.New(errors.MissingBlockStart, f.File, line[0].End())
+		}
+
+		if blockEnd == -1 {
+			return errors.New(errors.MissingBlockEnd, f.File, line[len(line)-1].End())
+		}
+
+		return f.CompileTokens(line[blockStart:blockEnd])
+
 	default:
 		return errors.New(&errors.KeywordNotImplemented{Keyword: line[0].Text()}, f.File, line[0].Position)
 	}
@@ -119,7 +151,7 @@ func (f *Function) CompileKeyword(line token.List) error {
 // CompileVariableDefinition compiles a variable definition.
 func (f *Function) CompileVariableDefinition(expr *expression.Expression) error {
 	if len(expr.Children) < 2 {
-		return errors.New(errors.MissingAssignValue, f.File, expr.LastChild().Token.After())
+		return errors.New(errors.MissingAssignValue, f.File, expr.LastChild().Token.End())
 	}
 
 	name := expr.Children[0].Token.Text()