Hide fields in vm.Program

Author: antonmedv

compiler/compiler.go

@@ -47,17 +47,16 @@ func Compile(tree *parser.Tree, config *conf.Config) (program *Program, err erro
 		c.emit(OpCast, 2)
 	}
 
-	program = &Program{
-		Node:      tree.Node,
-		Source:    tree.Source,
-		Locations: c.locations,
-		Variables: c.variables,
-		Constants: c.constants,
-		Bytecode:  c.bytecode,
-		Arguments: c.arguments,
-		Functions: c.functions,
-		DebugInfo: c.debugInfo,
-	}
+	program = NewProgram(
+		tree.Source,
+		c.locations,
+		c.variables,
+		c.constants,
+		c.bytecode,
+		c.arguments,
+		c.functions,
+		c.debugInfo,
+	)
 	return
 }
 
@@ -145,7 +144,7 @@ func (c *compiler) addVariable(name string) int {
 	return p
 }
 
-// emitFunction adds builtin.Function.Func to the program.Functions and emits call opcode.
+// emitFunction adds builtin.Function.Func to the program.functions and emits call opcode.
 func (c *compiler) emitFunction(fn *ast.Function, argsLen int) {
 	switch argsLen {
 	case 0:
@@ -162,7 +161,7 @@ func (c *compiler) emitFunction(fn *ast.Function, argsLen int) {
 	}
 }
 
-// addFunction adds builtin.Function.Func to the program.Functions and returns its index.
+// addFunction adds builtin.Function.Func to the program.functions and returns its index.
 func (c *compiler) addFunction(fn *ast.Function) int {
 	if fn == nil {
 		panic("function is nil")

file/source.go

@@ -40,6 +40,9 @@ func (s *Source) Content() string {
 }
 
 func (s *Source) Snippet(line int) (string, bool) {
+	if s == nil {
+		return "", false
+	}
 	charStart, found := s.findLineOffset(line)
 	if !found || len(s.contents) == 0 {
 		return "", false

vm/program.go

@@ -9,22 +9,43 @@ import (
 	"strings"
 	"text/tabwriter"
 
-	"github.com/antonmedv/expr/ast"
 	"github.com/antonmedv/expr/builtin"
 	"github.com/antonmedv/expr/file"
 	"github.com/antonmedv/expr/vm/runtime"
 )
 
 type Program struct {
-	Node      ast.Node
-	Source    *file.Source
-	Locations []file.Location
-	Variables []any
-	Constants []any
 	Bytecode  []Opcode
 	Arguments []int
-	Functions []Function
-	DebugInfo map[string]string
+	Constants []any
+
+	source    *file.Source
+	locations []file.Location
+	variables []any
+	functions []Function
+	debugInfo map[string]string
+}
+
+func NewProgram(
+	source *file.Source,
+	locations []file.Location,
+	variables []any,
+	constants []any,
+	bytecode []Opcode,
+	arguments []int,
+	functions []Function,
+	debugInfo map[string]string,
+) *Program {
+	return &Program{
+		source:    source,
+		locations: locations,
+		variables: variables,
+		Constants: constants,
+		Bytecode:  bytecode,
+		Arguments: arguments,
+		functions: functions,
+		debugInfo: debugInfo,
+	}
 }
 
 func (program *Program) Disassemble() string {
@@ -56,7 +77,7 @@ func (program *Program) Opcodes(w io.Writer) {
 			_, _ = fmt.Fprintf(w, "%v\t%v\t<%v>\n", pp, label, arg)
 		}
 		argumentWithInfo := func(label string, prefix string) {
-			_, _ = fmt.Fprintf(w, "%v\t%v\t<%v>\t%v\n", pp, label, arg, program.DebugInfo[fmt.Sprintf("%s_%d", prefix, arg)])
+			_, _ = fmt.Fprintf(w, "%v\t%v\t<%v>\t%v\n", pp, label, arg, program.debugInfo[fmt.Sprintf("%s_%d", prefix, arg)])
 		}
 		constant := func(label string) {
 			var c any

vm/vm.go

@@ -59,14 +59,18 @@ func Debug() *VM {
 func (vm *VM) Run(program *Program, env any) (_ any, err error) {
 	defer func() {
 		if r := recover(); r != nil {
+			var location file.Location
+			if vm.ip-1 < len(program.locations) {
+				location = program.locations[vm.ip-1]
+			}
 			f := &file.Error{
-				Location: program.Locations[vm.ip-1],
+				Location: location,
 				Message:  fmt.Sprintf("%v", r),
 			}
 			if err, ok := r.(error); ok {
 				f.Wrap(err)
 			}
-			err = f.Bind(program.Source)
+			err = f.Bind(program.source)
 		}
 	}()
 
@@ -108,10 +112,10 @@ func (vm *VM) Run(program *Program, env any) (_ any, err error) {
 			vm.pop()
 
 		case OpStore:
-			program.Variables[arg] = vm.pop()
+			program.variables[arg] = vm.pop()
 
 		case OpLoadVar:
-			vm.push(program.Variables[arg])
+			vm.push(program.variables[arg])
 
 		case OpLoadConst:
 			vm.push(runtime.Fetch(env, program.Constants[arg]))
@@ -126,7 +130,7 @@ func (vm *VM) Run(program *Program, env any) (_ any, err error) {
 			vm.push(runtime.FetchMethod(env, program.Constants[arg].(*runtime.Method)))
 
 		case OpLoadFunc:
-			vm.push(program.Functions[arg])
+			vm.push(program.functions[arg])
 
 		case OpFetch:
 			b := vm.pop()
@@ -332,15 +336,15 @@ func (vm *VM) Run(program *Program, env any) (_ any, err error) {
 			vm.push(out[0].Interface())
 
 		case OpCall0:
-			out, err := program.Functions[arg]()
+			out, err := program.functions[arg]()
 			if err != nil {
 				panic(err)
 			}
 			vm.push(out)
 
 		case OpCall1:
 			a := vm.pop()
-			out, err := program.Functions[arg](a)
+			out, err := program.functions[arg](a)
 			if err != nil {
 				panic(err)
 			}
@@ -349,7 +353,7 @@ func (vm *VM) Run(program *Program, env any) (_ any, err error) {
 		case OpCall2:
 			b := vm.pop()
 			a := vm.pop()
-			out, err := program.Functions[arg](a, b)
+			out, err := program.functions[arg](a, b)
 			if err != nil {
 				panic(err)
 			}
@@ -359,7 +363,7 @@ func (vm *VM) Run(program *Program, env any) (_ any, err error) {
 			c := vm.pop()
 			b := vm.pop()
 			a := vm.pop()
-			out, err := program.Functions[arg](a, b, c)
+			out, err := program.functions[arg](a, b, c)
 			if err != nil {
 				panic(err)
 			}

vm/vm_test.go

@@ -6,14 +6,14 @@ import (
 	"reflect"
 	"testing"
 
+	"github.com/stretchr/testify/require"
+
 	"github.com/antonmedv/expr/ast"
 	"github.com/antonmedv/expr/checker"
 	"github.com/antonmedv/expr/compiler"
 	"github.com/antonmedv/expr/conf"
-	"github.com/antonmedv/expr/file"
 	"github.com/antonmedv/expr/parser"
 	"github.com/antonmedv/expr/vm"
-	"github.com/stretchr/testify/require"
 )
 
 func TestRun_NilProgram(t *testing.T) {
@@ -282,7 +282,6 @@ func TestRun_TaggedFieldName(t *testing.T) {
 
 func TestRun_OpInvalid(t *testing.T) {
 	program := &vm.Program{
-		Locations: []file.Location{{0, 0}},
 		Bytecode:  []vm.Opcode{vm.OpInvalid},
 		Arguments: []int{0},
 	}