mirror of
https://github.com/golang/go
synced 2024-10-04 12:21:26 -06:00
90ffb7b8f5
all type-specific value functions, and use ZeroVal to create new frames. Remove Value.Type; it was unused and difficult for values with composite types. Add Value.Assign methods. R=rsc APPROVED=rsc DELTA=282 (135 added, 90 deleted, 57 changed) OCL=31894 CL=31930
161 lines
3.0 KiB
Go
161 lines
3.0 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package eval
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import (
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"bignum";
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)
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/*
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* Types
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*/
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type Value interface
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type Type interface {
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// literal returns this type with all names recursively
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// stripped.
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// TODO(austin) Eliminate the need for this
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literal() Type;
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// compatible returns true if this type is compatible with o.
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// XXX Assignment versus comparison compatibility?
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compatible(o Type) bool;
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// isBoolean returns true if this is a boolean type.
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isBoolean() bool;
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// isInteger returns true if this is an integer type.
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isInteger() bool;
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// isFloat returns true if this is a floating type.
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isFloat() bool;
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// isIdeal returns true if this is an ideal int or float.
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isIdeal() bool;
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// ZeroVal returns a new zero value of this type.
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Zero() Value;
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// String returns the string representation of this type.
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String() string;
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}
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type BoundedType interface {
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Type;
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// minVal returns the smallest value of this type.
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minVal() *bignum.Rational;
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// maxVal returns the largest value of this type.
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maxVal() *bignum.Rational;
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}
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/*
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* Values
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*/
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type Value interface {
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String() string;
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// Assign copies another value into this one. It should
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// assume that the other value satisfies the same specific
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// value interface (BoolValue, etc.), but must not assume
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// anything about its specific type.
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Assign(o Value);
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}
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type BoolValue interface {
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Value;
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Get() bool;
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Set(bool);
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}
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type UintValue interface {
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Value;
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Get() uint64;
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Set(uint64);
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}
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type IntValue interface {
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Value;
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Get() int64;
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Set(int64);
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}
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type IdealIntValue interface {
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Value;
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Get() *bignum.Integer;
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}
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type FloatValue interface {
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Value;
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Get() float64;
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Set(float64);
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}
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type IdealFloatValue interface {
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Value;
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Get() *bignum.Rational;
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}
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type StringValue interface {
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Value;
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Get() string;
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Set(string);
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}
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type ArrayValue interface {
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Value;
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// TODO(austin) Get() is here for uniformity, but is
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// completely useless. If a lot of other types have similarly
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// useless Get methods, just special-case these uses.
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Get() ArrayValue;
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Elem(i int64) Value;
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}
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type PtrValue interface {
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Value;
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Get() Value;
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Set(Value);
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}
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/*
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* Scopes
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*/
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type Variable struct {
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// Index of this variable in the Frame structure
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Index int;
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// Static type of this variable
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Type Type;
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}
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type Constant struct {
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Type Type;
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Value Value;
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}
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// A definition can be a *Variable, *Constant, or Type.
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type Def interface {}
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type Scope struct {
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outer *Scope;
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defs map[string] Def;
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numVars int;
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varTypes []Type;
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}
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func NewRootScope() *Scope
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func (s *Scope) Fork() *Scope
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func (s *Scope) DefineVar(name string, t Type) *Variable
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func (s *Scope) DefineConst(name string, t Type, v Value) *Constant
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func (s *Scope) DefineType(name string, t Type) bool
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func (s *Scope) Lookup(name string) (Def, *Scope)
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/*
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* Frames
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*/
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type Frame struct {
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Outer *Frame;
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Scope *Scope;
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Vars []Value;
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}
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func (f *Frame) Get(s *Scope, index int) Value
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func (s *Scope) NewFrame(outer *Frame) *Frame
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