1 files changed, 586 insertions, 0 deletions
diff --git a/libgo/go/exp/eval/value.go b/libgo/go/exp/eval/value.go
new file mode 100644
index 000000000..daa691897
--- /dev/null
+++ b/libgo/go/exp/eval/value.go
@@ -0,0 +1,586 @@
+// Copyright 2009 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package eval
+
+import (
+	"big"
+	"fmt"
+)
+
+type Value interface {
+	String() string
+	// Assign copies another value into this one.  It should
+	// assume that the other value satisfies the same specific
+	// value interface (BoolValue, etc.), but must not assume
+	// anything about its specific type.
+	Assign(t *Thread, o Value)
+}
+
+type BoolValue interface {
+	Value
+	Get(*Thread) bool
+	Set(*Thread, bool)
+}
+
+type UintValue interface {
+	Value
+	Get(*Thread) uint64
+	Set(*Thread, uint64)
+}
+
+type IntValue interface {
+	Value
+	Get(*Thread) int64
+	Set(*Thread, int64)
+}
+
+// TODO(austin) IdealIntValue and IdealFloatValue should not exist
+// because ideals are not l-values.
+type IdealIntValue interface {
+	Value
+	Get() *big.Int
+}
+
+type FloatValue interface {
+	Value
+	Get(*Thread) float64
+	Set(*Thread, float64)
+}
+
+type IdealFloatValue interface {
+	Value
+	Get() *big.Rat
+}
+
+type StringValue interface {
+	Value
+	Get(*Thread) string
+	Set(*Thread, string)
+}
+
+type ArrayValue interface {
+	Value
+	// TODO(austin) Get() is here for uniformity, but is
+	// completely useless.  If a lot of other types have similarly
+	// useless Get methods, just special-case these uses.
+	Get(*Thread) ArrayValue
+	Elem(*Thread, int64) Value
+	// Sub returns an ArrayValue backed by the same array that
+	// starts from element i and has length len.
+	Sub(i int64, len int64) ArrayValue
+}
+
+type StructValue interface {
+	Value
+	// TODO(austin) This is another useless Get()
+	Get(*Thread) StructValue
+	Field(*Thread, int) Value
+}
+
+type PtrValue interface {
+	Value
+	Get(*Thread) Value
+	Set(*Thread, Value)
+}
+
+type Func interface {
+	NewFrame() *Frame
+	Call(*Thread)
+}
+
+type FuncValue interface {
+	Value
+	Get(*Thread) Func
+	Set(*Thread, Func)
+}
+
+type Interface struct {
+	Type  Type
+	Value Value
+}
+
+type InterfaceValue interface {
+	Value
+	Get(*Thread) Interface
+	Set(*Thread, Interface)
+}
+
+type Slice struct {
+	Base     ArrayValue
+	Len, Cap int64
+}
+
+type SliceValue interface {
+	Value
+	Get(*Thread) Slice
+	Set(*Thread, Slice)
+}
+
+type Map interface {
+	Len(*Thread) int64
+	// Retrieve an element from the map, returning nil if it does
+	// not exist.
+	Elem(t *Thread, key interface{}) Value
+	// Set an entry in the map.  If val is nil, delete the entry.
+	SetElem(t *Thread, key interface{}, val Value)
+	// TODO(austin)  Perhaps there should be an iterator interface instead.
+	Iter(func(key interface{}, val Value) bool)
+}
+
+type MapValue interface {
+	Value
+	Get(*Thread) Map
+	Set(*Thread, Map)
+}
+
+/*
+ * Bool
+ */
+
+type boolV bool
+
+func (v *boolV) String() string { return fmt.Sprint(*v) }
+
+func (v *boolV) Assign(t *Thread, o Value) { *v = boolV(o.(BoolValue).Get(t)) }
+
+func (v *boolV) Get(*Thread) bool { return bool(*v) }
+
+func (v *boolV) Set(t *Thread, x bool) { *v = boolV(x) }
+
+/*
+ * Uint
+ */
+
+type uint8V uint8
+
+func (v *uint8V) String() string { return fmt.Sprint(*v) }
+
+func (v *uint8V) Assign(t *Thread, o Value) { *v = uint8V(o.(UintValue).Get(t)) }
+
+func (v *uint8V) Get(*Thread) uint64 { return uint64(*v) }
+
+func (v *uint8V) Set(t *Thread, x uint64) { *v = uint8V(x) }
+
+type uint16V uint16
+
+func (v *uint16V) String() string { return fmt.Sprint(*v) }
+
+func (v *uint16V) Assign(t *Thread, o Value) { *v = uint16V(o.(UintValue).Get(t)) }
+
+func (v *uint16V) Get(*Thread) uint64 { return uint64(*v) }
+
+func (v *uint16V) Set(t *Thread, x uint64) { *v = uint16V(x) }
+
+type uint32V uint32
+
+func (v *uint32V) String() string { return fmt.Sprint(*v) }
+
+func (v *uint32V) Assign(t *Thread, o Value) { *v = uint32V(o.(UintValue).Get(t)) }
+
+func (v *uint32V) Get(*Thread) uint64 { return uint64(*v) }
+
+func (v *uint32V) Set(t *Thread, x uint64) { *v = uint32V(x) }
+
+type uint64V uint64
+
+func (v *uint64V) String() string { return fmt.Sprint(*v) }
+
+func (v *uint64V) Assign(t *Thread, o Value) { *v = uint64V(o.(UintValue).Get(t)) }
+
+func (v *uint64V) Get(*Thread) uint64 { return uint64(*v) }
+
+func (v *uint64V) Set(t *Thread, x uint64) { *v = uint64V(x) }
+
+type uintV uint
+
+func (v *uintV) String() string { return fmt.Sprint(*v) }
+
+func (v *uintV) Assign(t *Thread, o Value) { *v = uintV(o.(UintValue).Get(t)) }
+
+func (v *uintV) Get(*Thread) uint64 { return uint64(*v) }
+
+func (v *uintV) Set(t *Thread, x uint64) { *v = uintV(x) }
+
+type uintptrV uintptr
+
+func (v *uintptrV) String() string { return fmt.Sprint(*v) }
+
+func (v *uintptrV) Assign(t *Thread, o Value) { *v = uintptrV(o.(UintValue).Get(t)) }
+
+func (v *uintptrV) Get(*Thread) uint64 { return uint64(*v) }
+
+func (v *uintptrV) Set(t *Thread, x uint64) { *v = uintptrV(x) }
+
+/*
+ * Int
+ */
+
+type int8V int8
+
+func (v *int8V) String() string { return fmt.Sprint(*v) }
+
+func (v *int8V) Assign(t *Thread, o Value) { *v = int8V(o.(IntValue).Get(t)) }
+
+func (v *int8V) Get(*Thread) int64 { return int64(*v) }
+
+func (v *int8V) Set(t *Thread, x int64) { *v = int8V(x) }
+
+type int16V int16
+
+func (v *int16V) String() string { return fmt.Sprint(*v) }
+
+func (v *int16V) Assign(t *Thread, o Value) { *v = int16V(o.(IntValue).Get(t)) }
+
+func (v *int16V) Get(*Thread) int64 { return int64(*v) }
+
+func (v *int16V) Set(t *Thread, x int64) { *v = int16V(x) }
+
+type int32V int32
+
+func (v *int32V) String() string { return fmt.Sprint(*v) }
+
+func (v *int32V) Assign(t *Thread, o Value) { *v = int32V(o.(IntValue).Get(t)) }
+
+func (v *int32V) Get(*Thread) int64 { return int64(*v) }
+
+func (v *int32V) Set(t *Thread, x int64) { *v = int32V(x) }
+
+type int64V int64
+
+func (v *int64V) String() string { return fmt.Sprint(*v) }
+
+func (v *int64V) Assign(t *Thread, o Value) { *v = int64V(o.(IntValue).Get(t)) }
+
+func (v *int64V) Get(*Thread) int64 { return int64(*v) }
+
+func (v *int64V) Set(t *Thread, x int64) { *v = int64V(x) }
+
+type intV int
+
+func (v *intV) String() string { return fmt.Sprint(*v) }
+
+func (v *intV) Assign(t *Thread, o Value) { *v = intV(o.(IntValue).Get(t)) }
+
+func (v *intV) Get(*Thread) int64 { return int64(*v) }
+
+func (v *intV) Set(t *Thread, x int64) { *v = intV(x) }
+
+/*
+ * Ideal int
+ */
+
+type idealIntV struct {
+	V *big.Int
+}
+
+func (v *idealIntV) String() string { return v.V.String() }
+
+func (v *idealIntV) Assign(t *Thread, o Value) {
+	v.V = o.(IdealIntValue).Get()
+}
+
+func (v *idealIntV) Get() *big.Int { return v.V }
+
+/*
+ * Float
+ */
+
+type float32V float32
+
+func (v *float32V) String() string { return fmt.Sprint(*v) }
+
+func (v *float32V) Assign(t *Thread, o Value) { *v = float32V(o.(FloatValue).Get(t)) }
+
+func (v *float32V) Get(*Thread) float64 { return float64(*v) }
+
+func (v *float32V) Set(t *Thread, x float64) { *v = float32V(x) }
+
+type float64V float64
+
+func (v *float64V) String() string { return fmt.Sprint(*v) }
+
+func (v *float64V) Assign(t *Thread, o Value) { *v = float64V(o.(FloatValue).Get(t)) }
+
+func (v *float64V) Get(*Thread) float64 { return float64(*v) }
+
+func (v *float64V) Set(t *Thread, x float64) { *v = float64V(x) }
+
+/*
+ * Ideal float
+ */
+
+type idealFloatV struct {
+	V *big.Rat
+}
+
+func (v *idealFloatV) String() string { return v.V.FloatString(6) }
+
+func (v *idealFloatV) Assign(t *Thread, o Value) {
+	v.V = o.(IdealFloatValue).Get()
+}
+
+func (v *idealFloatV) Get() *big.Rat { return v.V }
+
+/*
+ * String
+ */
+
+type stringV string
+
+func (v *stringV) String() string { return fmt.Sprint(*v) }
+
+func (v *stringV) Assign(t *Thread, o Value) { *v = stringV(o.(StringValue).Get(t)) }
+
+func (v *stringV) Get(*Thread) string { return string(*v) }
+
+func (v *stringV) Set(t *Thread, x string) { *v = stringV(x) }
+
+/*
+ * Array
+ */
+
+type arrayV []Value
+
+func (v *arrayV) String() string {
+	res := "{"
+	for i, e := range *v {
+		if i > 0 {
+			res += ", "
+		}
+		res += e.String()
+	}
+	return res + "}"
+}
+
+func (v *arrayV) Assign(t *Thread, o Value) {
+	oa := o.(ArrayValue)
+	l := int64(len(*v))
+	for i := int64(0); i < l; i++ {
+		(*v)[i].Assign(t, oa.Elem(t, i))
+	}
+}
+
+func (v *arrayV) Get(*Thread) ArrayValue { return v }
+
+func (v *arrayV) Elem(t *Thread, i int64) Value {
+	return (*v)[i]
+}
+
+func (v *arrayV) Sub(i int64, len int64) ArrayValue {
+	res := (*v)[i : i+len]
+	return &res
+}
+
+/*
+ * Struct
+ */
+
+type structV []Value
+
+// TODO(austin) Should these methods (and arrayV's) be on structV
+// instead of *structV?
+func (v *structV) String() string {
+	res := "{"
+	for i, v := range *v {
+		if i > 0 {
+			res += ", "
+		}
+		res += v.String()
+	}
+	return res + "}"
+}
+
+func (v *structV) Assign(t *Thread, o Value) {
+	oa := o.(StructValue)
+	l := len(*v)
+	for i := 0; i < l; i++ {
+		(*v)[i].Assign(t, oa.Field(t, i))
+	}
+}
+
+func (v *structV) Get(*Thread) StructValue { return v }
+
+func (v *structV) Field(t *Thread, i int) Value {
+	return (*v)[i]
+}
+
+/*
+ * Pointer
+ */
+
+type ptrV struct {
+	// nil if the pointer is nil
+	target Value
+}
+
+func (v *ptrV) String() string {
+	if v.target == nil {
+		return "<nil>"
+	}
+	return "&" + v.target.String()
+}
+
+func (v *ptrV) Assign(t *Thread, o Value) { v.target = o.(PtrValue).Get(t) }
+
+func (v *ptrV) Get(*Thread) Value { return v.target }
+
+func (v *ptrV) Set(t *Thread, x Value) { v.target = x }
+
+/*
+ * Functions
+ */
+
+type funcV struct {
+	target Func
+}
+
+func (v *funcV) String() string {
+	// TODO(austin) Rob wants to see the definition
+	return "func {...}"
+}
+
+func (v *funcV) Assign(t *Thread, o Value) { v.target = o.(FuncValue).Get(t) }
+
+func (v *funcV) Get(*Thread) Func { return v.target }
+
+func (v *funcV) Set(t *Thread, x Func) { v.target = x }
+
+/*
+ * Interfaces
+ */
+
+type interfaceV struct {
+	Interface
+}
+
+func (v *interfaceV) String() string {
+	if v.Type == nil || v.Value == nil {
+		return "<nil>"
+	}
+	return v.Value.String()
+}
+
+func (v *interfaceV) Assign(t *Thread, o Value) {
+	v.Interface = o.(InterfaceValue).Get(t)
+}
+
+func (v *interfaceV) Get(*Thread) Interface { return v.Interface }
+
+func (v *interfaceV) Set(t *Thread, x Interface) {
+	v.Interface = x
+}
+
+/*
+ * Slices
+ */
+
+type sliceV struct {
+	Slice
+}
+
+func (v *sliceV) String() string {
+	if v.Base == nil {
+		return "<nil>"
+	}
+	return v.Base.Sub(0, v.Len).String()
+}
+
+func (v *sliceV) Assign(t *Thread, o Value) { v.Slice = o.(SliceValue).Get(t) }
+
+func (v *sliceV) Get(*Thread) Slice { return v.Slice }
+
+func (v *sliceV) Set(t *Thread, x Slice) { v.Slice = x }
+
+/*
+ * Maps
+ */
+
+type mapV struct {
+	target Map
+}
+
+func (v *mapV) String() string {
+	if v.target == nil {
+		return "<nil>"
+	}
+	res := "map["
+	i := 0
+	v.target.Iter(func(key interface{}, val Value) bool {
+		if i > 0 {
+			res += ", "
+		}
+		i++
+		res += fmt.Sprint(key) + ":" + val.String()
+		return true
+	})
+	return res + "]"
+}
+
+func (v *mapV) Assign(t *Thread, o Value) { v.target = o.(MapValue).Get(t) }
+
+func (v *mapV) Get(*Thread) Map { return v.target }
+
+func (v *mapV) Set(t *Thread, x Map) { v.target = x }
+
+type evalMap map[interface{}]Value
+
+func (m evalMap) Len(t *Thread) int64 { return int64(len(m)) }
+
+func (m evalMap) Elem(t *Thread, key interface{}) Value {
+	return m[key]
+}
+
+func (m evalMap) SetElem(t *Thread, key interface{}, val Value) {
+	if val == nil {
+		m[key] = nil, false
+	} else {
+		m[key] = val
+	}
+}
+
+func (m evalMap) Iter(cb func(key interface{}, val Value) bool) {
+	for k, v := range m {
+		if !cb(k, v) {
+			break
+		}
+	}
+}
+
+/*
+ * Multi-values
+ */
+
+type multiV []Value
+
+func (v multiV) String() string {
+	res := "("
+	for i, v := range v {
+		if i > 0 {
+			res += ", "
+		}
+		res += v.String()
+	}
+	return res + ")"
+}
+
+func (v multiV) Assign(t *Thread, o Value) {
+	omv := o.(multiV)
+	for i := range v {
+		v[i].Assign(t, omv[i])
+	}
+}
+
+/*
+ * Universal constants
+ */
+
+func init() {
+	s := universe
+
+	true := boolV(true)
+	s.DefineConst("true", universePos, BoolType, &true)
+	false := boolV(false)
+	s.DefineConst("false", universePos, BoolType, &false)
+}