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
243
244
245
246
247
248
249
250
251
|
// Copyright 2016 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 syntax
import "fmt"
type token uint
const (
_ token = iota
_EOF
// names and literals
_Name
_Literal
// operators and operations
_Operator // excluding '*' (_Star)
_AssignOp
_IncOp
_Assign
_Define
_Arrow
_Star
// delimitors
_Lparen
_Lbrack
_Lbrace
_Rparen
_Rbrack
_Rbrace
_Comma
_Semi
_Colon
_Dot
_DotDotDot
// keywords
_Break
_Case
_Chan
_Const
_Continue
_Default
_Defer
_Else
_Fallthrough
_For
_Func
_Go
_Goto
_If
_Import
_Interface
_Map
_Package
_Range
_Return
_Select
_Struct
_Switch
_Type
_Var
tokenCount
)
const (
Go = _Go
Defer = _Defer
Break = _Break
Continue = _Continue
Fallthrough = _Fallthrough
Goto = _Goto
)
var tokstrings = [...]string{
// source control
_EOF: "EOF",
// names and literals
_Name: "name",
_Literal: "literal",
// operators and operations
_Operator: "op",
_AssignOp: "op=",
_IncOp: "opop",
_Assign: "=",
_Define: ":=",
_Arrow: "<-",
_Star: "*",
// delimitors
_Lparen: "(",
_Lbrack: "[",
_Lbrace: "{",
_Rparen: ")",
_Rbrack: "]",
_Rbrace: "}",
_Comma: ",",
_Semi: ";",
_Colon: ":",
_Dot: ".",
_DotDotDot: "...",
// keywords
_Break: "break",
_Case: "case",
_Chan: "chan",
_Const: "const",
_Continue: "continue",
_Default: "default",
_Defer: "defer",
_Else: "else",
_Fallthrough: "fallthrough",
_For: "for",
_Func: "func",
_Go: "go",
_Goto: "goto",
_If: "if",
_Import: "import",
_Interface: "interface",
_Map: "map",
_Package: "package",
_Range: "range",
_Return: "return",
_Select: "select",
_Struct: "struct",
_Switch: "switch",
_Type: "type",
_Var: "var",
}
func (tok token) String() string {
var s string
if 0 <= tok && int(tok) < len(tokstrings) {
s = tokstrings[tok]
}
if s == "" {
s = fmt.Sprintf("<tok-%d>", tok)
}
return s
}
// Make sure we have at most 64 tokens so we can use them in a set.
const _ uint64 = 1 << (tokenCount - 1)
// contains reports whether tok is in tokset.
func contains(tokset uint64, tok token) bool {
return tokset&(1<<tok) != 0
}
type Operator uint
const (
_ Operator = iota
Def // :=
Not // !
Recv // <-
// precOrOr
OrOr // ||
// precAndAnd
AndAnd // &&
// precCmp
Eql // ==
Neq // !=
Lss // <
Leq // <=
Gtr // >
Geq // >=
// precAdd
Add // +
Sub // -
Or // |
Xor // ^
// precMul
Mul // *
Div // /
Rem // %
And // &
AndNot // &^
Shl // <<
Shr // >>
)
var opstrings = [...]string{
// prec == 0
Def: ":", // : in :=
Not: "!",
Recv: "<-",
// precOrOr
OrOr: "||",
// precAndAnd
AndAnd: "&&",
// precCmp
Eql: "==",
Neq: "!=",
Lss: "<",
Leq: "<=",
Gtr: ">",
Geq: ">=",
// precAdd
Add: "+",
Sub: "-",
Or: "|",
Xor: "^",
// precMul
Mul: "*",
Div: "/",
Rem: "%",
And: "&",
AndNot: "&^",
Shl: "<<",
Shr: ">>",
}
func (op Operator) String() string {
var s string
if 0 <= op && int(op) < len(opstrings) {
s = opstrings[op]
}
if s == "" {
s = fmt.Sprintf("<op-%d>", op)
}
return s
}
// Operator precedences
const (
_ = iota
precOrOr
precAndAnd
precCmp
precAdd
precMul
)
|
