248 } 248 } 249 249 250 AST BaseExpression() 250 AST BaseExpression() 251 { 251 { 252 if( lex.empty ) 252 if( lex.empty ) 253 throw genex!UnexpectedEOF(currentPosition(), "Reached EO 253 throw genex!UnexpectedEOF(currentPosition(), "Reached EO 254 254 255 auto pos = lex.front.pos; | 255 auto pos = currentPosition(); 256 if( lex.front.quoted ) 256 if( lex.front.quoted ) 257 { 257 { 258 scope(exit) lex.popFront; 258 scope(exit) lex.popFront; 259 return new Str(pos, lex.front.str); 259 return new Str(pos, lex.front.str); 260 } 260 } 261 if( isNumber(lex.front.str) ) 261 if( isNumber(lex.front.str) ) 262 { 262 { ................................................................................................................................................................................ 321 { 321 { 322 // case pmExpr CASES 322 // case pmExpr CASES 323 //==> 323 //==> 324 // let pmVar = pmExpr in (... let pmTryFirst = ... in pmTryFir 324 // let pmVar = pmExpr in (... let pmTryFirst = ... in pmTryFir 325 AST pmExpr = E(0); 325 AST pmExpr = E(0); 326 string pmVar = freshVarName(); 326 string pmVar = freshVarName(); 327 string pmTryFirst = freshVarName(); 327 string pmTryFirst = freshVarName(); 328 AST pmBody = parsePatternMatchCases(pmVar, pmTryFirst, | 328 AST pmBody = parsePatternMatchCases(pos, pmVar, pmTryFirst, 329 new App(pos, new Var(pos, pmTryFirst))); 329 new App(pos, new Var(pos, pmTryFirst))); 330 return new Let(pos, pmVar, [], pmExpr, pmBody); 330 return new Let(pos, pmVar, [], pmExpr, pmBody); 331 } 331 } 332 332 333 AST parsePatternMatchCases(string pmVar, string tryThisBranchVar, AST th | 333 AST parsePatternMatchCases(LexPosition casePos, string pmVar, string try 334 { 334 { 335 // when pat: cBody 335 // when pat: cBody 336 //==> 336 //==> 337 // ... let failBranchVar = ... in 337 // ... let failBranchVar = ... in 338 // let tryThisBranchVar = fun(){ if(test){cBody}else{failBran 338 // let tryThisBranchVar = fun(){ if(test){cBody}else{failBran 339 if( tryEat("when") ) 339 if( tryEat("when") ) 340 { 340 { ................................................................................................................................................................................ 343 343 344 auto pr = parsePattern(); 344 auto pr = parsePattern(); 345 eat(":", "after when pattern"); 345 eat(":", "after when pattern"); 346 AST cBody = E(0); 346 AST cBody = E(0); 347 AST judgement = new App(pos, new Var(pos, "if"), 347 AST judgement = new App(pos, new Var(pos, "if"), 348 ppTest(pmVar, pr), new Fun(pos,[],ppBind(pmVar, 348 ppTest(pmVar, pr), new Fun(pos,[],ppBind(pmVar, 349 new Var(pos, failBranchVar)); 349 new Var(pos, failBranchVar)); 350 return parsePatternMatchCases(pmVar, failBranchVar, | 350 return parsePatternMatchCases(casePos, pmVar, failBranch 351 new Let(pos, tryThisBranchVar, [], 351 new Let(pos, tryThisBranchVar, [], 352 new Fun(pos,[],judgement), thenDoThis) 352 new Fun(pos,[],judgement), thenDoThis) 353 ); 353 ); 354 } 354 } 355 else 355 else 356 { 356 { 357 auto pos = currentPosition(); < 358 AST doNothing = new Fun(pos,[], | 357 AST doNothing = new Fun(casePos,[], 359 new Str(pos, sprintf!"(pattern match failure:%s) | 358 new Str(casePos, sprintf!"(pattern match failure 360 return new Let(currentPosition(), tryThisBranchVar, [], | 359 return new Let(casePos, tryThisBranchVar, [], doNothing, 361 } 360 } 362 } 361 } 363 362 364 // hageshiku tenuki 363 // hageshiku tenuki 365 abstract class SinglePattern 364 abstract class SinglePattern 366 { 365 { 367 string[] path; 366 string[] path; ................................................................................................................................................................................ 555 AST doNothingExpression() 554 AST doNothingExpression() 556 { 555 { 557 return new Str(currentPosition(), "(empty function body)"); 556 return new Str(currentPosition(), "(empty function body)"); 558 } 557 } 559 558 560 LexPosition currentPosition() 559 LexPosition currentPosition() 561 { 560 { 562 return lex.empty ? null : lex.front.pos; | 561 return lex.empty ? new LexPosition("EOF",0,0) : lex.front.pos; 563 } 562 } 564 } 563 } 565 564 566 unittest 565 unittest 567 { 566 { 568 mixin EasyAST; 567 mixin EasyAST; 569 568