Mercurial > projects > dang
annotate parser/Parser.d @ 12:6282db07115f
Added some ekstra tests, and allowed bool as a type
| author | Anders Halager <halager@gmail.com> |
|---|---|
| date | Fri, 18 Apr 2008 13:58:27 +0200 |
| parents | 642c6a998fd9 |
| children | 0fb2d13dce37 |
| rev | line source |
|---|---|
| 1 | 1 module parser.Parser; |
| 2 | |
| 3 import lexer.Lexer, | |
| 4 lexer.Token; | |
| 5 | |
| 6 import ast.Exp, | |
| 7 ast.Stmt, | |
| 8 ast.Decl; | |
| 9 | |
| 10 import tango.io.Stdout, | |
| 11 Integer = tango.text.convert.Integer; | |
| 12 | |
| 13 class Parser | |
| 14 { | |
| 15 | |
| 16 public: | |
| 17 Decl[] parse(Lexer lexer) | |
| 18 { | |
| 19 this.lexer = lexer; | |
| 20 | |
| 21 | |
| 22 Decl[] declarations; | |
| 23 | |
| 24 while(lexer.peek.type != Tok.EOF) | |
| 25 { | |
| 26 declarations ~= parseDecl; | |
| 27 } | |
| 28 | |
| 29 return declarations; | |
| 30 } | |
| 31 | |
| 32 Decl parseDecl() | |
| 33 { | |
| 34 Token t = lexer.next; | |
| 35 | |
| 36 switch(t.type) | |
| 37 { | |
| 38 case Tok.Byte, Tok.Ubyte, | |
| 39 Tok.Short, Tok.Ushort, | |
| 40 Tok.Int, Tok.Uint, | |
| 41 Tok.Long, Tok.Ulong, | |
| 42 Tok.Float, Tok.Double, | |
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Added some ekstra tests, and allowed bool as a type
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parents:
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43 Tok.Bool, |
| 1 | 44 Tok.Identifier: |
| 45 Identifier type = new Identifier(t); | |
| 46 | |
| 47 Token iden = lexer.next; | |
| 48 switch(iden.type) | |
| 49 { | |
| 50 case Tok.Identifier: | |
| 51 Identifier identifier = new Identifier(iden); | |
| 52 Token p = lexer.peek(); | |
| 53 switch(p.type) | |
| 54 { | |
| 55 case Tok.OpenParentheses: | |
| 56 return parseFunc(type, identifier); | |
| 57 case Tok.Seperator: | |
| 58 require(Tok.Seperator); | |
| 59 return new VarDecl(type, identifier, null); | |
| 60 case Tok.Assign: | |
| 61 lexer.next(); | |
| 62 auto exp = parseExpression(); | |
| 63 require(Tok.Seperator); | |
| 64 return new VarDecl(type, identifier, exp); | |
| 65 default: | |
| 66 char[] c = t.getType; | |
| 67 error("Unexpexted token "~c~" at line "~Integer.toString(__LINE__)); | |
| 68 } | |
| 69 break; | |
| 70 default: | |
| 71 char[] c = t.getType; | |
| 72 error("Unexpexted token "~c~" at line "~Integer.toString(__LINE__)); | |
| 73 } | |
| 74 break; | |
| 75 | |
| 76 case Tok.EOF: | |
| 77 return null; | |
| 78 default: | |
| 79 char[] c = t.getType; | |
| 80 error("Unexpexted token "~c~" at line "~Integer.toString(__LINE__)); | |
| 81 } | |
| 82 } | |
| 83 | |
| 84 Stmt parseStatement() | |
| 85 { | |
| 86 Token t = lexer.peek; | |
| 87 | |
| 88 switch(t.type) | |
| 89 { | |
| 90 case Tok.Return: | |
| 91 lexer.next; | |
| 92 auto ret = new ReturnStmt(); | |
| 93 ret.exp = parseExpression(); | |
| 94 require(Tok.Seperator); | |
| 95 return ret; | |
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96 |
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97 case Tok.If: |
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98 lexer.next; |
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99 require(Tok.OpenParentheses); |
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100 auto condition = parseExpression(); |
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101 require(Tok.CloseParentheses); |
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102 |
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103 auto then_body = parseBlockOrSingleStmt(); |
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104 |
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105 Stmt[] else_body; |
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106 if (lexer.peek.type == Tok.Else) |
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107 { |
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108 lexer.next; |
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109 else_body = parseBlockOrSingleStmt(); |
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110 } |
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111 |
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112 return new IfStmt(condition, then_body, else_body); |
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113 |
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114 case Tok.While: |
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115 lexer.next; |
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116 require(Tok.OpenParentheses); |
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117 auto condition = parseExpression(); |
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118 require(Tok.CloseParentheses); |
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119 return new WhileStmt(condition, parseBlockOrSingleStmt()); |
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120 |
| 1 | 121 case Tok.Identifier: |
| 122 Token n = lexer.peek(1); | |
| 123 switch(n.type) | |
| 124 { | |
| 125 case Tok.Assign: | |
| 126 lexer.next; | |
| 127 lexer.next; | |
| 128 auto stmt = new ExpStmt(new AssignExp(new Identifier(t), parseExpression())); | |
| 129 require(Tok.Seperator); | |
| 130 return stmt; | |
| 131 break; | |
| 132 | |
| 133 default: | |
| 134 auto e = new ExpStmt(parseExpression()); | |
| 135 require(Tok.Seperator); | |
| 136 return e; | |
| 137 | |
| 138 } | |
| 139 break; | |
| 140 | |
| 141 default: | |
| 142 auto decl = new DeclStmt(parseDecl()); | |
| 143 //require(Tok.Seperator); | |
| 144 return decl; | |
| 145 } | |
| 146 return new Stmt(); | |
| 147 } | |
| 148 | |
| 149 FuncDecl parseFunc(Identifier type, Identifier identifier) | |
| 150 { | |
| 151 VarDecl[] funcArgs = parseFuncArgs(); | |
| 152 | |
| 153 lexer.next; // Remove the "{" | |
| 154 | |
| 155 Stmt[] statements; | |
| 156 | |
| 157 while(lexer.peek.type != Tok.CloseBrace) | |
| 158 statements ~= parseStatement(); | |
| 159 | |
| 160 lexer.next; // Remove "}" | |
| 161 | |
| 162 return new FuncDecl(type, identifier, funcArgs, statements); | |
| 163 } | |
| 164 | |
| 165 VarDecl[] parseFuncArgs() | |
| 166 { | |
| 167 lexer.next; // Remove the "(" token. | |
| 168 | |
| 169 VarDecl[] funcArgs; | |
| 170 | |
| 171 while(lexer.peek.type != Tok.CloseParentheses) | |
| 172 { | |
| 173 funcArgs ~= new VarDecl(parseType, parseIdentifier); | |
| 174 | |
| 175 if(lexer.peek.type == Tok.Comma) | |
| 176 lexer.next; | |
| 177 } | |
| 178 | |
| 179 lexer.next; // Remove the ")" | |
| 180 | |
| 181 return funcArgs; | |
| 182 } | |
| 183 | |
| 184 Identifier parseIdentifier() | |
| 185 { | |
| 186 Token identifier = lexer.next; | |
| 187 | |
| 188 switch(identifier.type) | |
| 189 { | |
| 190 case Tok.Identifier: | |
| 191 return new Identifier(identifier); | |
| 192 break; | |
| 193 default: | |
| 194 error("Unexpexted token in Identifier parsing"); | |
| 195 } | |
| 196 } | |
| 197 | |
| 198 Identifier parseType() | |
| 199 { | |
| 200 Token type = lexer.next; | |
| 201 | |
| 202 switch(type.type) | |
| 203 { | |
| 204 case Tok.Byte, Tok.Ubyte, | |
| 205 Tok.Short, Tok.Ushort, | |
| 206 Tok.Int, Tok.Uint, | |
| 207 Tok.Long, Tok.Ulong, | |
| 208 Tok.Float, Tok.Double, | |
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6282db07115f
Added some ekstra tests, and allowed bool as a type
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parents:
11
diff
changeset
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209 Tok.Bool, |
| 1 | 210 Tok.Identifier: |
| 211 return new Identifier(type); | |
| 212 break; | |
| 213 default: | |
| 214 char[] c = type.getType; | |
| 215 error("Unexpexted token in Type parsing. Got "~c); | |
| 216 } | |
| 217 } | |
| 218 | |
| 219 // -- Expression parsing -- // | |
| 220 private: | |
| 221 Exp parseExpression(int p = 0) | |
| 222 { | |
| 223 auto exp = P(); | |
| 224 Token next = lexer.peek(); | |
| 225 BinOp* op = null; | |
| 226 while ((op = binary(next.type)) != null && op.prec >= p) | |
| 227 { | |
| 228 lexer.next(); | |
| 229 int q = op.leftAssoc? 1 + op.prec : op.prec; | |
| 230 auto exp2 = parseExpression(q); | |
| 231 exp = new BinaryExp(op.operator, exp, exp2); | |
| 232 next = lexer.peek(); | |
| 233 } | |
| 234 | |
| 235 return exp; | |
| 236 } | |
| 237 | |
| 238 Exp P() | |
| 239 { | |
| 240 Token next = lexer.next(); | |
| 241 if (auto op = unary(next.type)) | |
| 242 return new NegateExp(parseExpression(op.prec)); | |
| 243 else if (next.type == Tok.OpenParentheses) | |
| 244 { | |
| 245 auto e = parseExpression(0); | |
| 246 require(Tok.CloseParentheses); | |
| 247 return e; | |
| 248 } | |
| 249 else if (next.type == Tok.Identifier) | |
| 250 { | |
| 251 switch(lexer.peek.type) | |
| 252 { | |
| 253 case Tok.OpenParentheses: | |
| 254 lexer.next; | |
| 255 Exp[] args; | |
| 256 while(lexer.peek.type != Tok.CloseParentheses) | |
| 257 { | |
| 258 if(lexer.peek.type == Tok.Comma) | |
| 259 { | |
| 260 lexer.next; | |
| 261 } | |
| 262 args ~= parseExpression(); | |
| 263 } | |
| 264 | |
| 265 lexer.next(); | |
| 266 return new CallExp(new Identifier(next), args); | |
| 267 | |
| 268 default: | |
| 269 return new Identifier(next); | |
| 270 } | |
| 271 } | |
| 272 else if (next.type == Tok.Integer) | |
| 273 return new IntegerLit(next); | |
| 274 | |
| 275 Stdout.formatln("{}", next.getType); | |
| 276 assert(0, "Should not happen"); | |
| 277 } | |
| 278 | |
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279 private Stmt[] parseBlockOrSingleStmt() |
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280 { |
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281 Stmt[] stmts; |
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282 if (lexer.peek.type == Tok.OpenBrace) |
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283 { |
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284 lexer.next; |
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285 while(lexer.peek.type != Tok.CloseBrace) |
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286 stmts ~= parseStatement(); |
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287 lexer.next; |
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288 } |
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289 else |
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290 stmts ~= parseStatement(); |
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291 |
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292 return stmts; |
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293 } |
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294 |
| 1 | 295 struct UnOp |
| 296 { | |
| 297 Tok tokenType; | |
| 298 int prec; | |
| 299 } | |
| 300 | |
| 301 static UnOp[] _unary = [{Tok.Sub, 4}]; | |
| 302 UnOp* unary(Tok t) | |
| 303 { | |
| 304 foreach (ref op; _unary) | |
| 305 if (op.tokenType == t) | |
| 306 return &op; | |
| 307 return null; | |
| 308 } | |
| 309 | |
| 310 struct BinOp | |
| 311 { | |
| 312 Tok tokenType; | |
| 313 int prec; | |
| 314 bool leftAssoc; | |
| 315 BinaryExp.Operator operator; | |
| 316 } | |
| 317 | |
| 318 static BinOp[] _binary = | |
| 319 [ | |
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320 {Tok.Eq, 2, true, BinaryExp.Operator.Eq}, |
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321 {Tok.Ne, 2, true, BinaryExp.Operator.Ne}, |
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322 {Tok.Lt, 2, true, BinaryExp.Operator.Lt}, |
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323 {Tok.Le, 2, true, BinaryExp.Operator.Le}, |
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324 {Tok.Gt, 2, true, BinaryExp.Operator.Gt}, |
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325 {Tok.Ge, 2, true, BinaryExp.Operator.Ge}, |
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326 |
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327 {Tok.Add, 3, true, BinaryExp.Operator.Add}, |
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328 {Tok.Sub, 3, true, BinaryExp.Operator.Sub}, |
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329 |
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330 {Tok.Mul, 5, true, BinaryExp.Operator.Mul}, |
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331 {Tok.Div, 5, true, BinaryExp.Operator.Div} |
| 1 | 332 ]; |
| 333 BinOp* binary(Tok t) | |
| 334 { | |
| 335 foreach (ref op; _binary) | |
| 336 if (op.tokenType == t) | |
| 337 return &op; | |
| 338 return null; | |
| 339 } | |
| 340 | |
| 341 private: | |
| 342 | |
| 343 void require(Tok t) | |
| 344 { | |
| 345 if (lexer.peek().type != t) | |
| 346 error("Unexpexted token: Got '"~lexer.peek.getType~"' Expected '"~typeToString[t]~"'"); | |
| 347 lexer.next(); | |
| 348 } | |
| 349 | |
| 350 void error(char[] errMsg) | |
| 351 { | |
| 352 throw new Exception("Parser error: " ~errMsg); | |
| 353 } | |
| 354 | |
| 355 Lexer lexer; | |
| 356 } |