1 // Copyright 2016 The Go Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style 3 // license that can be found in the LICENSE file. 4 5 package syntax 6 7 import "fmt" 8 9 type token uint 10 11 const ( 12 _ token = iota 13 _EOF 14 15 // names and literals 16 _Name 17 _Literal 18 19 // operators and operations 20 _Operator // excluding '*' (_Star) 21 _AssignOp 22 _IncOp 23 _Assign 24 _Define 25 _Arrow 26 _Star 27 28 // delimiters 29 _Lparen 30 _Lbrack 31 _Lbrace 32 _Rparen 33 _Rbrack 34 _Rbrace 35 _Comma 36 _Semi 37 _Colon 38 _Dot 39 _DotDotDot 40 41 // keywords 42 _Break 43 _Case 44 _Chan 45 _Const 46 _Continue 47 _Default 48 _Defer 49 _Else 50 _Fallthrough 51 _For 52 _Func 53 _Go 54 _Goto 55 _If 56 _Import 57 _Interface 58 _Map 59 _Package 60 _Range 61 _Return 62 _Select 63 _Struct 64 _Switch 65 _Type 66 _Var 67 68 tokenCount 69 ) 70 71 const ( 72 // for BranchStmt 73 Break = _Break 74 Continue = _Continue 75 Fallthrough = _Fallthrough 76 Goto = _Goto 77 78 // for CallStmt 79 Go = _Go 80 Defer = _Defer 81 ) 82 83 var tokstrings = [...]string{ 84 // source control 85 _EOF: "EOF", 86 87 // names and literals 88 _Name: "name", 89 _Literal: "literal", 90 91 // operators and operations 92 _Operator: "op", 93 _AssignOp: "op=", 94 _IncOp: "opop", 95 _Assign: "=", 96 _Define: ":=", 97 _Arrow: "<-", 98 _Star: "*", 99 100 // delimiters 101 _Lparen: "(", 102 _Lbrack: "[", 103 _Lbrace: "{", 104 _Rparen: ")", 105 _Rbrack: "]", 106 _Rbrace: "}", 107 _Comma: ",", 108 _Semi: ";", 109 _Colon: ":", 110 _Dot: ".", 111 _DotDotDot: "...", 112 113 // keywords 114 _Break: "break", 115 _Case: "case", 116 _Chan: "chan", 117 _Const: "const", 118 _Continue: "continue", 119 _Default: "default", 120 _Defer: "defer", 121 _Else: "else", 122 _Fallthrough: "fallthrough", 123 _For: "for", 124 _Func: "func", 125 _Go: "go", 126 _Goto: "goto", 127 _If: "if", 128 _Import: "import", 129 _Interface: "interface", 130 _Map: "map", 131 _Package: "package", 132 _Range: "range", 133 _Return: "return", 134 _Select: "select", 135 _Struct: "struct", 136 _Switch: "switch", 137 _Type: "type", 138 _Var: "var", 139 } 140 141 func (tok token) String() string { 142 var s string 143 if 0 <= tok && int(tok) < len(tokstrings) { 144 s = tokstrings[tok] 145 } 146 if s == "" { 147 s = fmt.Sprintf("<tok-%d>", tok) 148 } 149 return s 150 } 151 152 // Make sure we have at most 64 tokens so we can use them in a set. 153 const _ uint64 = 1 << (tokenCount - 1) 154 155 // contains reports whether tok is in tokset. 156 func contains(tokset uint64, tok token) bool { 157 return tokset&(1<<tok) != 0 158 } 159 160 type LitKind uint 161 162 const ( 163 IntLit LitKind = iota 164 FloatLit 165 ImagLit 166 RuneLit 167 StringLit 168 ) 169 170 type Operator uint 171 172 const ( 173 _ Operator = iota 174 Def // := 175 Not // ! 176 Recv // <- 177 178 // precOrOr 179 OrOr // || 180 181 // precAndAnd 182 AndAnd // && 183 184 // precCmp 185 Eql // == 186 Neq // != 187 Lss // < 188 Leq // <= 189 Gtr // > 190 Geq // >= 191 192 // precAdd 193 Add // + 194 Sub // - 195 Or // | 196 Xor // ^ 197 198 // precMul 199 Mul // * 200 Div // / 201 Rem // % 202 And // & 203 AndNot // &^ 204 Shl // << 205 Shr // >> 206 ) 207 208 var opstrings = [...]string{ 209 // prec == 0 210 Def: ":", // : in := 211 Not: "!", 212 Recv: "<-", 213 214 // precOrOr 215 OrOr: "||", 216 217 // precAndAnd 218 AndAnd: "&&", 219 220 // precCmp 221 Eql: "==", 222 Neq: "!=", 223 Lss: "<", 224 Leq: "<=", 225 Gtr: ">", 226 Geq: ">=", 227 228 // precAdd 229 Add: "+", 230 Sub: "-", 231 Or: "|", 232 Xor: "^", 233 234 // precMul 235 Mul: "*", 236 Div: "/", 237 Rem: "%", 238 And: "&", 239 AndNot: "&^", 240 Shl: "<<", 241 Shr: ">>", 242 } 243 244 func (op Operator) String() string { 245 var s string 246 if 0 <= op && int(op) < len(opstrings) { 247 s = opstrings[op] 248 } 249 if s == "" { 250 s = fmt.Sprintf("<op-%d>", op) 251 } 252 return s 253 } 254 255 // Operator precedences 256 const ( 257 _ = iota 258 precOrOr 259 precAndAnd 260 precCmp 261 precAdd 262 precMul 263 ) 264
