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