1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
|
// 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.
// This file implements scopes, the objects they contain,
// and object types.
package ast
// A Scope maintains the set of named language entities declared
// in the scope and a link to the immediately surrounding (outer)
// scope.
//
type Scope struct {
Outer *Scope
Objects []*Object // in declaration order
// Implementation note: In some cases (struct fields,
// function parameters) we need the source order of
// variables. Thus for now, we store scope entries
// in a linear list. If scopes become very large
// (say, for packages), we may need to change this
// to avoid slow lookups.
}
// NewScope creates a new scope nested in the outer scope.
func NewScope(outer *Scope) *Scope {
const n = 4 // initial scope capacity, must be > 0
return &Scope{outer, make([]*Object, 0, n)}
}
// Lookup returns the object with the given name if it is
// found in scope s, otherwise it returns nil. Outer scopes
// are ignored.
//
// Lookup always returns nil if name is "_", even if the scope
// contains objects with that name.
//
func (s *Scope) Lookup(name string) *Object {
if name != "_" {
for _, obj := range s.Objects {
if obj.Name == name {
return obj
}
}
}
return nil
}
// Insert attempts to insert a named object into the scope s.
// If the scope does not contain an object with that name yet
// or if the object is named "_", Insert inserts the object
// and returns it. Otherwise, Insert leaves the scope unchanged
// and returns the object found in the scope instead.
//
func (s *Scope) Insert(obj *Object) *Object {
alt := s.Lookup(obj.Name)
if alt == nil {
s.append(obj)
alt = obj
}
return alt
}
func (s *Scope) append(obj *Object) {
s.Objects = append(s.Objects, obj)
}
// ----------------------------------------------------------------------------
// Objects
// An Object describes a language entity such as a package,
// constant, type, variable, or function (incl. methods).
//
type Object struct {
Kind Kind
Name string // declared name
Type *Type
Decl interface{} // corresponding Field, XxxSpec or FuncDecl
N int // value of iota for this declaration
}
// NewObj creates a new object of a given kind and name.
func NewObj(kind Kind, name string) *Object {
return &Object{Kind: kind, Name: name}
}
// Kind describes what an object represents.
type Kind int
// The list of possible Object kinds.
const (
Bad Kind = iota // for error handling
Pkg // package
Con // constant
Typ // type
Var // variable
Fun // function or method
)
var objKindStrings = [...]string{
Bad: "bad",
Pkg: "package",
Con: "const",
Typ: "type",
Var: "var",
Fun: "func",
}
func (kind Kind) String() string { return objKindStrings[kind] }
// IsExported returns whether obj is exported.
func (obj *Object) IsExported() bool { return IsExported(obj.Name) }
// ----------------------------------------------------------------------------
// Types
// A Type represents a Go type.
type Type struct {
Form Form
Obj *Object // corresponding type name, or nil
Scope *Scope // fields and methods, always present
N uint // basic type id, array length, number of function results, or channel direction
Key, Elt *Type // map key and array, pointer, slice, map or channel element
Params *Scope // function (receiver, input and result) parameters, tuple expressions (results of function calls), or nil
Expr Expr // corresponding AST expression
}
// NewType creates a new type of a given form.
func NewType(form Form) *Type {
return &Type{Form: form, Scope: NewScope(nil)}
}
// Form describes the form of a type.
type Form int
// The list of possible type forms.
const (
BadType Form = iota // for error handling
Unresolved // type not fully setup
Basic
Array
Struct
Pointer
Function
Method
Interface
Slice
Map
Channel
Tuple
)
var formStrings = [...]string{
BadType: "badType",
Unresolved: "unresolved",
Basic: "basic",
Array: "array",
Struct: "struct",
Pointer: "pointer",
Function: "function",
Method: "method",
Interface: "interface",
Slice: "slice",
Map: "map",
Channel: "channel",
Tuple: "tuple",
}
func (form Form) String() string { return formStrings[form] }
// The list of basic type id's.
const (
Bool = iota
Byte
Uint
Int
Float
Complex
Uintptr
String
Uint8
Uint16
Uint32
Uint64
Int8
Int16
Int32
Int64
Float32
Float64
Complex64
Complex128
// TODO(gri) ideal types are missing
)
var BasicTypes = map[uint]string{
Bool: "bool",
Byte: "byte",
Uint: "uint",
Int: "int",
Float: "float",
Complex: "complex",
Uintptr: "uintptr",
String: "string",
Uint8: "uint8",
Uint16: "uint16",
Uint32: "uint32",
Uint64: "uint64",
Int8: "int8",
Int16: "int16",
Int32: "int32",
Int64: "int64",
Float32: "float32",
Float64: "float64",
Complex64: "complex64",
Complex128: "complex128",
}
|
