clean up builtins

compiler/compiler.go

@@ -42,8 +42,8 @@ func New() *Compiler {
 
 	symbolTable := NewSymbolTable()
 
-	for i, v := range object.Builtins {
-		symbolTable.DefineBuiltin(i, v.Name)
+	for i, builtin := range object.BuiltinsIndex {
+		symbolTable.DefineBuiltin(i, builtin.Name)
 	}
 
 	return &Compiler{

compiler/compiler_test.go

@@ -977,11 +977,11 @@ func TestBuiltins(t *testing.T) {
             `,
 			expectedConstants: []interface{}{1},
 			expectedInstructions: []code.Instructions{
-				code.Make(code.OpGetBuiltin, 0),
+				code.Make(code.OpGetBuiltin, 4),
 				code.Make(code.OpArray, 0),
 				code.Make(code.OpCall, 1),
 				code.Make(code.OpPop),
-				code.Make(code.OpGetBuiltin, 6),
+				code.Make(code.OpGetBuiltin, 7),
 				code.Make(code.OpArray, 0),
 				code.Make(code.OpConstant, 0),
 				code.Make(code.OpCall, 2),
@@ -992,7 +992,7 @@ func TestBuiltins(t *testing.T) {
 			input: `fn() { len([]) }`,
 			expectedConstants: []interface{}{
 				[]code.Instructions{
-					code.Make(code.OpGetBuiltin, 0),
+					code.Make(code.OpGetBuiltin, 4),
 					code.Make(code.OpArray, 0),
 					code.Make(code.OpCall, 1),
 					code.Make(code.OpReturn),

evaluator/builtins.go

@@ -4,14 +4,4 @@ import (
 	"monkey/object"
 )
 
-var builtins = map[string]*object.Builtin{
-	"len":   object.GetBuiltinByName("len"),
-	"input": object.GetBuiltinByName("input"),
-	"print": object.GetBuiltinByName("print"),
-	"first": object.GetBuiltinByName("first"),
-	"last":  object.GetBuiltinByName("last"),
-	"rest":  object.GetBuiltinByName("rest"),
-	"push":  object.GetBuiltinByName("push"),
-	"pop":   object.GetBuiltinByName("pop"),
-	"exit":  object.GetBuiltinByName("exit"),
-}
+var builtins = object.Builtins

object/builtins.go

@@ -5,16 +5,41 @@ import (
 	"fmt"
 	"io"
 	"os"
+	"sort"
 	"unicode/utf8"
 )
 
-var Builtins = []struct {
-	Name    string
-	Builtin *Builtin
-}{
-	{
-		"len",
-		&Builtin{Name: "len", Fn: func(args ...Object) Object {
+var Builtins = map[string]*Builtin{
+	"len":   {Name: "len", Fn: Len},
+	"input": {Name: "input", Fn: Input},
+	"print": {Name: "print", Fn: Print},
+	"first": {Name: "first", Fn: First},
+	"last":  {Name: "last", Fn: Last},
+	"rest":  {Name: "rest", Fn: Rest},
+	"push":  {Name: "push", Fn: Push},
+	"pop":   {Name: "pop", Fn: Pop},
+	"exit":  {Name: "exit", Fn: Exit},
+}
+
+var BuiltinsIndex []*Builtin
+
+func init() {
+	var keys []string
+	for k := range Builtins {
+		keys = append(keys, k)
+	}
+	sort.Strings(keys)
+
+	for _, k := range keys {
+		BuiltinsIndex = append(BuiltinsIndex, Builtins[k])
+	}
+}
+
+func newError(format string, a ...interface{}) *Error {
+	return &Error{Message: fmt.Sprintf(format, a...)}
+}
+
+func Len(args ...Object) Object {
 	if len(args) != 1 {
 		return newError("wrong number of arguments. got=%d, want=1",
 			len(args))
@@ -29,12 +54,9 @@ var Builtins = []struct {
 		return newError("argument to `len` not supported, got %s",
 			args[0].Type())
 	}
-		},
-		},
-	},
-	{
-		"input",
-		&Builtin{Name: "input", Fn: func(args ...Object) Object {
+}
+
+func Input(args ...Object) Object {
 	if len(args) > 0 {
 		obj, ok := args[0].(*String)
 		if !ok {
@@ -53,27 +75,24 @@ var Builtins = []struct {
 		return newError(fmt.Sprintf("error reading input from stdin: %s", err))
 	}
 	return &String{Value: string(line)}
-		}},
-	},
-	{
-		"print",
-		&Builtin{Name: "print", Fn: func(args ...Object) Object {
+}
+
+func Print(args ...Object) Object {
 	for _, arg := range args {
 		fmt.Println(arg.Inspect())
 	}
 
 	return nil
-		},
-		},
-	},
-	{
-		"first",
-		&Builtin{Name: "first", Fn: func(args ...Object) Object {
+}
+
+func First(args ...Object) Object {
 	if len(args) != 1 {
-				return newError("wrong number of arguments. got=%d, want=1", len(args))
+		return newError("wrong number of arguments. got=%d, want=1",
+			len(args))
 	}
 	if args[0].Type() != ARRAY_OBJ {
-				return newError("argument to `first` must be ARRAY, got %s", args[0].Type())
+		return newError("argument to `first` must be ARRAY, got %s",
+			args[0].Type())
 	}
 
 	arr := args[0].(*Array)
@@ -82,17 +101,16 @@ var Builtins = []struct {
 	}
 
 	return nil
-		},
-		},
-	},
-	{
-		"last",
-		&Builtin{Name: "last", Fn: func(args ...Object) Object {
+}
+
+func Last(args ...Object) Object {
 	if len(args) != 1 {
-				return newError("wrong number of arguments. got=%d, want=1", len(args))
+		return newError("wrong number of arguments. got=%d, want=1",
+			len(args))
 	}
 	if args[0].Type() != ARRAY_OBJ {
-				return newError("argument to `last` must be ARRAY, got %s", args[0].Type())
+		return newError("argument to `last` must be ARRAY, got %s",
+			args[0].Type())
 	}
 
 	arr := args[0].(*Array)
@@ -102,12 +120,9 @@ var Builtins = []struct {
 	}
 
 	return nil
-		},
-		},
-	},
-	{
-		"rest",
-		&Builtin{Name: "rest", Fn: func(args ...Object) Object {
+}
+
+func Rest(args ...Object) Object {
 	if len(args) != 1 {
 		return newError("wrong number of arguments. got=%d, want=1",
 			len(args))
@@ -126,12 +141,9 @@ var Builtins = []struct {
 	}
 
 	return nil
-		},
-		},
-	},
-	{
-		"push",
-		&Builtin{Name: "push", Fn: func(args ...Object) Object {
+}
+
+func Push(args ...Object) Object {
 	if len(args) != 2 {
 		return newError("wrong number of arguments. got=%d, want=2",
 			len(args))
@@ -144,7 +156,7 @@ var Builtins = []struct {
 	arr := args[0].(*Array)
 	length := len(arr.Elements)
 
-			newElements := make([]Object, length+1, length+1)
+	newElements := make([]Object, length+1)
 	copy(newElements, arr.Elements)
 	if immutable, ok := args[1].(Immutable); ok {
 		newElements[length] = immutable.Clone()
@@ -153,12 +165,9 @@ var Builtins = []struct {
 	}
 
 	return &Array{Elements: newElements}
-		},
-		},
-	},
-	{
-		"pop",
-		&Builtin{Name: "pop", Fn: func(args ...Object) Object {
+}
+
+func Pop(args ...Object) Object {
 	if len(args) != 1 {
 		return newError("wrong number of arguments. got=%d, want=1",
 			len(args))
@@ -179,12 +188,9 @@ var Builtins = []struct {
 	arr.Elements = arr.Elements[:length-1]
 
 	return element
-		},
-		},
-	},
-	{
-		"exit",
-		&Builtin{Name: "exit", Fn: func(args ...Object) Object {
+}
+
+func Exit(args ...Object) Object {
 	if len(args) == 1 {
 		if args[0].Type() != INTEGER_OBJ {
 			return newError("argument to `exit` must be INTEGER, got %s",
@@ -195,20 +201,4 @@ var Builtins = []struct {
 		os.Exit(0)
 	}
 	return nil
-		},
-		},
-	},
-}
-
-func newError(format string, a ...interface{}) *Error {
-	return &Error{Message: fmt.Sprintf(format, a...)}
-}
-
-func GetBuiltinByName(name string) *Builtin {
-	for _, def := range Builtins {
-		if def.Name == name {
-			return def.Builtin
-		}
-	}
-	return nil
 }

repl/repl.go

@@ -50,8 +50,8 @@ type VMState struct {
 
 func NewVMState() *VMState {
 	symbolTable := compiler.NewSymbolTable()
-	for i, v := range object.Builtins {
-		symbolTable.DefineBuiltin(i, v.Name)
+	for i, builtin := range object.BuiltinsIndex {
+		symbolTable.DefineBuiltin(i, builtin.Name)
 	}
 
 	return &VMState{

vm/vm.go

@@ -281,9 +281,9 @@ func (vm *VM) Run() error {
 			builtinIndex := code.ReadUint8(ins[ip+1:])
 			vm.currentFrame().ip += 1
 
-			definition := object.Builtins[builtinIndex]
+			builtin := object.BuiltinsIndex[builtinIndex]
 
-			err := vm.push(definition.Builtin)
+			err := vm.push(builtin)
 			if err != nil {
 				return err
 			}