add basic support for tuples

core/values.go

@@ -6,6 +6,7 @@ import (
 	"math/big"
 	"reflect"
 	"strconv"
+	"strings"
 )
 
 type ValueType int
@@ -17,6 +18,7 @@ const (
 	IntegerValueType
 	StringValueType
 	ListValueType
+	TupleValueType
 	ObjectValueType
 	FunctionValueType
 	BuiltinFunctionValueType
@@ -39,6 +41,8 @@ func (v ValueType) String() string {
 		return "string"
 	case ListValueType:
 		return "list"
+	case TupleValueType:
+		return "tuple"
 	case FunctionValueType:
 		return "function"
 	case BuiltinFunctionValueType:
@@ -278,7 +282,12 @@ func (v *FloatValue) Type() ValueType {
 }
 
 func (v *FloatValue) String() string {
-	return strconv.FormatFloat(v.Number, 'g', -1, FloatSize)
+	s := strconv.FormatFloat(v.Number, 'g', -1, FloatSize)
+	if strings.Index(s, ".") == -1 {
+		s += ".0"
+	}
+
+	return s
 }
 
 func (v *FloatValue) DebugString() string {
@@ -597,6 +606,88 @@ func (v *ListValue) Clone() Value {
 	}
 }
 
+type TupleValue struct {
+	Items []Value
+}
+
+func (v *TupleValue) Type() ValueType {
+	return TupleValueType
+}
+
+func (v *TupleValue) String() string {
+	out := "("
+	for i, item := range v.Items {
+		if i != 0 {
+			out += ", "
+		}
+		out += item.DebugString()
+	}
+
+	if len(v.Items) <= 1 {
+		out += ","
+	}
+	out += ")"
+
+	return out
+}
+
+func (v *TupleValue) DebugString() string {
+	return v.String()
+}
+
+func (v *TupleValue) Clone() Value {
+	n := make([]Value, len(v.Items))
+	for i, item := range v.Items {
+		n[i] = item.Clone()
+	}
+	return &TupleValue{
+		n,
+	}
+}
+
+func (v *TupleValue) Equals(other Value) bool {
+	if other.Type() != TupleValueType {
+		return false
+	}
+
+	t := other.(*TupleValue).Items
+	for i, item := range v.Items {
+		if !item.Equals(t[i]) {
+			return false
+		}
+	}
+
+	return true
+}
+
+var TuplePrototype = map[string]*BuiltinFunctionValue{
+	"at": &BuiltinFunctionValue{
+		"at",
+		&FunctionSignature{
+			[]TypeSignature{&IntegerSignature{}},
+			&InnerSignature{},
+		},
+		func(vm *VM, this Value, args []Value) (Value, error) {
+			i := args[0].(*IntegerValue).Number.Int64()
+
+			if i < 0 || i >= int64(len(this.(*TupleValue).Items)) {
+				return nil, errors.New(fmt.Sprintf("index %x out of range", i))
+			}
+
+			return this.(*TupleValue).Items[i], nil
+		},
+		nil,
+		true,
+	},
+}
+
+func (v *TupleValue) Get(key string) (Value, error) {
+	if prop, ok := TuplePrototype[key]; ok {
+		return prop, nil
+	}
+	return nil, errors.New(fmt.Sprintf("tuple has no property \"%s\"", key))
+}
+
 type FunctionValue struct {
 	Name   string
 	Params []FunctionParameter