Mercurial > projects > dang
annotate parser/Parser.d @ 10:2f493057cf17
Some support for the rest of the boolean operators
| author | Anders Halager <halager@gmail.com> |
|---|---|
| date | Fri, 18 Apr 2008 13:01:11 +0200 |
| parents | 2ce5209f1954 |
| children | 642c6a998fd9 |
| 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, | |
| 43 Tok.Identifier: | |
| 44 Identifier type = new Identifier(t); | |
| 45 | |
| 46 Token iden = lexer.next; | |
| 47 switch(iden.type) | |
| 48 { | |
| 49 case Tok.Identifier: | |
| 50 Identifier identifier = new Identifier(iden); | |
| 51 Token p = lexer.peek(); | |
| 52 switch(p.type) | |
| 53 { | |
| 54 case Tok.OpenParentheses: | |
| 55 return parseFunc(type, identifier); | |
| 56 case Tok.Seperator: | |
| 57 require(Tok.Seperator); | |
| 58 return new VarDecl(type, identifier, null); | |
| 59 case Tok.Assign: | |
| 60 lexer.next(); | |
| 61 auto exp = parseExpression(); | |
| 62 require(Tok.Seperator); | |
| 63 return new VarDecl(type, identifier, exp); | |
| 64 default: | |
| 65 char[] c = t.getType; | |
| 66 error("Unexpexted token "~c~" at line "~Integer.toString(__LINE__)); | |
| 67 } | |
| 68 break; | |
| 69 default: | |
| 70 char[] c = t.getType; | |
| 71 error("Unexpexted token "~c~" at line "~Integer.toString(__LINE__)); | |
| 72 } | |
| 73 break; | |
| 74 | |
| 75 case Tok.EOF: | |
| 76 return null; | |
| 77 default: | |
| 78 char[] c = t.getType; | |
| 79 error("Unexpexted token "~c~" at line "~Integer.toString(__LINE__)); | |
| 80 } | |
| 81 } | |
| 82 | |
| 83 Stmt parseStatement() | |
| 84 { | |
| 85 Token t = lexer.peek; | |
| 86 | |
| 87 switch(t.type) | |
| 88 { | |
| 89 case Tok.Return: | |
| 90 lexer.next; | |
| 91 auto ret = new ReturnStmt(); | |
| 92 ret.exp = parseExpression(); | |
| 93 require(Tok.Seperator); | |
| 94 return ret; | |
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95 |
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96 case Tok.If: |
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97 lexer.next; |
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98 require(Tok.OpenParentheses); |
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99 auto condition = parseExpression(); |
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100 require(Tok.CloseParentheses); |
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101 |
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102 Stmt[] stmts; |
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103 if (lexer.peek.type == Tok.OpenBrace) |
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104 { |
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105 lexer.next; |
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106 while(lexer.peek.type != Tok.CloseBrace) |
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107 stmts ~= parseStatement(); |
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108 lexer.next; |
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109 } |
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110 else |
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111 stmts ~= parseStatement(); |
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112 |
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113 return new IfStmt(condition, stmts); |
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114 |
| 1 | 115 case Tok.Identifier: |
| 116 Token n = lexer.peek(1); | |
| 117 switch(n.type) | |
| 118 { | |
| 119 case Tok.Assign: | |
| 120 lexer.next; | |
| 121 lexer.next; | |
| 122 auto stmt = new ExpStmt(new AssignExp(new Identifier(t), parseExpression())); | |
| 123 require(Tok.Seperator); | |
| 124 return stmt; | |
| 125 break; | |
| 126 | |
| 127 default: | |
| 128 auto e = new ExpStmt(parseExpression()); | |
| 129 require(Tok.Seperator); | |
| 130 return e; | |
| 131 | |
| 132 } | |
| 133 break; | |
| 134 | |
| 135 default: | |
| 136 auto decl = new DeclStmt(parseDecl()); | |
| 137 //require(Tok.Seperator); | |
| 138 return decl; | |
| 139 } | |
| 140 return new Stmt(); | |
| 141 } | |
| 142 | |
| 143 FuncDecl parseFunc(Identifier type, Identifier identifier) | |
| 144 { | |
| 145 VarDecl[] funcArgs = parseFuncArgs(); | |
| 146 | |
| 147 lexer.next; // Remove the "{" | |
| 148 | |
| 149 Stmt[] statements; | |
| 150 | |
| 151 while(lexer.peek.type != Tok.CloseBrace) | |
| 152 statements ~= parseStatement(); | |
| 153 | |
| 154 lexer.next; // Remove "}" | |
| 155 | |
| 156 return new FuncDecl(type, identifier, funcArgs, statements); | |
| 157 } | |
| 158 | |
| 159 VarDecl[] parseFuncArgs() | |
| 160 { | |
| 161 lexer.next; // Remove the "(" token. | |
| 162 | |
| 163 VarDecl[] funcArgs; | |
| 164 | |
| 165 while(lexer.peek.type != Tok.CloseParentheses) | |
| 166 { | |
| 167 funcArgs ~= new VarDecl(parseType, parseIdentifier); | |
| 168 | |
| 169 if(lexer.peek.type == Tok.Comma) | |
| 170 lexer.next; | |
| 171 } | |
| 172 | |
| 173 lexer.next; // Remove the ")" | |
| 174 | |
| 175 return funcArgs; | |
| 176 } | |
| 177 | |
| 178 Identifier parseIdentifier() | |
| 179 { | |
| 180 Token identifier = lexer.next; | |
| 181 | |
| 182 switch(identifier.type) | |
| 183 { | |
| 184 case Tok.Identifier: | |
| 185 return new Identifier(identifier); | |
| 186 break; | |
| 187 default: | |
| 188 error("Unexpexted token in Identifier parsing"); | |
| 189 } | |
| 190 } | |
| 191 | |
| 192 Identifier parseType() | |
| 193 { | |
| 194 Token type = lexer.next; | |
| 195 | |
| 196 switch(type.type) | |
| 197 { | |
| 198 case Tok.Byte, Tok.Ubyte, | |
| 199 Tok.Short, Tok.Ushort, | |
| 200 Tok.Int, Tok.Uint, | |
| 201 Tok.Long, Tok.Ulong, | |
| 202 Tok.Float, Tok.Double, | |
| 203 Tok.Identifier: | |
| 204 return new Identifier(type); | |
| 205 break; | |
| 206 default: | |
| 207 char[] c = type.getType; | |
| 208 error("Unexpexted token in Type parsing. Got "~c); | |
| 209 } | |
| 210 } | |
| 211 | |
| 212 // -- Expression parsing -- // | |
| 213 private: | |
| 214 Exp parseExpression(int p = 0) | |
| 215 { | |
| 216 auto exp = P(); | |
| 217 Token next = lexer.peek(); | |
| 218 BinOp* op = null; | |
| 219 while ((op = binary(next.type)) != null && op.prec >= p) | |
| 220 { | |
| 221 lexer.next(); | |
| 222 int q = op.leftAssoc? 1 + op.prec : op.prec; | |
| 223 auto exp2 = parseExpression(q); | |
| 224 exp = new BinaryExp(op.operator, exp, exp2); | |
| 225 next = lexer.peek(); | |
| 226 } | |
| 227 | |
| 228 return exp; | |
| 229 } | |
| 230 | |
| 231 Exp P() | |
| 232 { | |
| 233 Token next = lexer.next(); | |
| 234 if (auto op = unary(next.type)) | |
| 235 return new NegateExp(parseExpression(op.prec)); | |
| 236 else if (next.type == Tok.OpenParentheses) | |
| 237 { | |
| 238 auto e = parseExpression(0); | |
| 239 require(Tok.CloseParentheses); | |
| 240 return e; | |
| 241 } | |
| 242 else if (next.type == Tok.Identifier) | |
| 243 { | |
| 244 switch(lexer.peek.type) | |
| 245 { | |
| 246 case Tok.OpenParentheses: | |
| 247 lexer.next; | |
| 248 Exp[] args; | |
| 249 while(lexer.peek.type != Tok.CloseParentheses) | |
| 250 { | |
| 251 if(lexer.peek.type == Tok.Comma) | |
| 252 { | |
| 253 lexer.next; | |
| 254 } | |
| 255 args ~= parseExpression(); | |
| 256 } | |
| 257 | |
| 258 lexer.next(); | |
| 259 return new CallExp(new Identifier(next), args); | |
| 260 | |
| 261 default: | |
| 262 return new Identifier(next); | |
| 263 } | |
| 264 } | |
| 265 else if (next.type == Tok.Integer) | |
| 266 return new IntegerLit(next); | |
| 267 | |
| 268 Stdout.formatln("{}", next.getType); | |
| 269 assert(0, "Should not happen"); | |
| 270 } | |
| 271 | |
| 272 struct UnOp | |
| 273 { | |
| 274 Tok tokenType; | |
| 275 int prec; | |
| 276 } | |
| 277 | |
| 278 static UnOp[] _unary = [{Tok.Sub, 4}]; | |
| 279 UnOp* unary(Tok t) | |
| 280 { | |
| 281 foreach (ref op; _unary) | |
| 282 if (op.tokenType == t) | |
| 283 return &op; | |
| 284 return null; | |
| 285 } | |
| 286 | |
| 287 struct BinOp | |
| 288 { | |
| 289 Tok tokenType; | |
| 290 int prec; | |
| 291 bool leftAssoc; | |
| 292 BinaryExp.Operator operator; | |
| 293 } | |
| 294 | |
| 295 static BinOp[] _binary = | |
| 296 [ | |
|
10
2f493057cf17
Some support for the rest of the boolean operators
Anders Halager <halager@gmail.com>
parents:
7
diff
changeset
|
297 {Tok.Eq, 2, true, BinaryExp.Operator.Eq}, |
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2f493057cf17
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parents:
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298 {Tok.Ne, 2, true, BinaryExp.Operator.Ne}, |
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299 {Tok.Lt, 2, true, BinaryExp.Operator.Lt}, |
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300 {Tok.Le, 2, true, BinaryExp.Operator.Le}, |
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301 {Tok.Gt, 2, true, BinaryExp.Operator.Gt}, |
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302 {Tok.Ge, 2, true, BinaryExp.Operator.Ge}, |
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parents:
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303 |
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parents:
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304 {Tok.Add, 3, true, BinaryExp.Operator.Add}, |
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parents:
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diff
changeset
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305 {Tok.Sub, 3, true, BinaryExp.Operator.Sub}, |
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Some support for the rest of the boolean operators
Anders Halager <halager@gmail.com>
parents:
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diff
changeset
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306 |
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parents:
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307 {Tok.Mul, 5, true, BinaryExp.Operator.Mul}, |
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2ce5209f1954
Starting to work on bool support, for now == works
Anders Halager <halager@gmail.com>
parents:
5
diff
changeset
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308 {Tok.Div, 5, true, BinaryExp.Operator.Div} |
| 1 | 309 ]; |
| 310 BinOp* binary(Tok t) | |
| 311 { | |
| 312 foreach (ref op; _binary) | |
| 313 if (op.tokenType == t) | |
| 314 return &op; | |
| 315 return null; | |
| 316 } | |
| 317 | |
| 318 private: | |
| 319 | |
| 320 void require(Tok t) | |
| 321 { | |
| 322 if (lexer.peek().type != t) | |
| 323 error("Unexpexted token: Got '"~lexer.peek.getType~"' Expected '"~typeToString[t]~"'"); | |
| 324 lexer.next(); | |
| 325 } | |
| 326 | |
| 327 void error(char[] errMsg) | |
| 328 { | |
| 329 throw new Exception("Parser error: " ~errMsg); | |
| 330 } | |
| 331 | |
| 332 Lexer lexer; | |
| 333 } |