yu/resolver.lua

   1 require "yu.visitor"
   2 require "yu.type"
   3
   4
   5 module("yu",package.seeall)
   6
   7 local is=is
   8 local getType,getTypeDecl,newTypeRef,checkType=getType,getTypeDecl,newTypeRef,checkType
   9 local getExprTypeList=getExprTypeList
  10
  11 local pre={}
  12 local post={}
  13
  14 local __searchSeq=0
  15
  16 local function _findExternSymbol(entryModule,name,found)
  17         found=found or {}
  18         local externModules=entryModule.externModules
  19
  20         if externModules then
  21                 for p,m in pairs(externModules) do
  22                         if m.__seq~=__searchSeq then
  23                                 m.__seq=__searchSeq
  24                                 local decl=m.scope[name]
  25                                 if decl and not decl.private then
  26                                         found[#found+1]={module=m,decl=decl}
  27                                 end
  28                                 _findExternSymbol(m,name,found)
  29                         end
  30                 end
  31         end
  32
  33         return found
  34 end
  35
  36 local function _findSymbol(vi,name,token,limit)
  37         local t=vi.nodeStack.stack
  38         local outClas,outFunc,outMethod=0,0,0
  39
  40         for i=#t,1,-1 do
  41                 local node=t[i]
  42                 local scope=node.scope
  43
  44                 if scope then
  45                         local tag=node.tag
  46                         if tag=='clasdecl' then outClas =outClas +1 end
  47                         if tag=='funcdecl' then outFunc =outFunc +1 end
  48                         if tag=='methoddecl' then outMethod =outMethod +1 end
  49
  50                         local decl
  51                         if tag=='classdecl' then
  52                                 local clas=node
  53                                 while clas do
  54                                         decl=clas.scope[name]
  55                                         if decl then break end
  56                                         clas=clas.superclass
  57                                 end
  58                         else
  59                                 decl=scope[name]
  60                         end
  61
  62                         if decl then
  63                                 -- print('found:',scope,decl.name,node.tag,decl.p0,token.p0)
  64                                 if not (
  65                                                 (limit=='global' and isMemberDecl(decl))
  66                                 ) then
  67                                         local dtag=decl.tag
  68                                         if dtag=='var' then --variable?
  69                                                 if decl.vtype=='local' then --local?
  70                                                         if not ((outFunc>0 and limit~='upvalue') or decl.p0>token.p0) then return decl end
  71                                                 elseif decl.vtype=='field' then
  72                                                         if outMethod==1 then return decl end
  73                                                 else
  74                                                         return decl
  75                                                 end
  76                                         elseif dtag=='methoddecl' then
  77                                                 if outMethod==1 then return decl end
  78                                         else
  79                                                 return decl
  80                                         end
  81
  82                                         if not (
  83                                                 decl.tag=='var' and decl.vtype=='local'
  84                                                                 and (decl.p0>token.p0 or outFunc)
  85                                         ) then
  86
  87                                         end
  88                                 end
  89                         end
  90
  91                 end
  92
  93         end
  94
  95         --search extern modules
  96         __searchSeq=__searchSeq+1
  97
  98         if not token.module then
  99                 -- print(token.tag)
 100         end
 101
 102         local found=_findExternSymbol(token.module,name)
 103
 104         local i=0
 105         local foundCount=#found
 106         if foundCount>1 then
 107                 msg='multiple declaration found:'..name..'\n'
 108                 for i,f in pairs(found) do
 109                         msg=msg..getTokenPosString(f.decl)..'\n'
 110                 end
 111                 return vi:err(msg,token)
 112
 113         elseif foundCount==1 then
 114                 return found[1].decl
 115         end
 116
 117         return nil
 118 end
 119
 120 function newResolver()
 121         local r={
 122                                 pre=pre,
 123                                 post=post,
 124                                 findSymbol=_findSymbol
 125                         }
 126         return yu.newVisitor(r)
 127 end
 128
 129
 130 ----------------TOPLEVEL
 131         function pre:any(n)
 132                 -- print('resoving..',n.tag)
 133                 local state=n.resolveState
 134                 if state=='done' then
 135                         return 'skip'
 136                 elseif state=='resolving' then
 137                         self:err('cyclic delcaration dependecy',n)
 138                 end
 139
 140                 n.resolveState='resolving'
 141
 142                 local b=self.currentBlock
 143                 if b and b.endState then
 144                         self:err('unreachable statement',n)
 145                 end
 146
 147         end
 148
 149         function post:any(n)
 150                 n.resolveState='done'
 151         end
 152
 153         function pre:module(m)
 154                 m.resolving=true
 155         end
 156
 157         function post:module(m)
 158         end
 159
 160         -- function pre:block(b)
 161
 162         -- end
 163
 164         -- function post:block(b)
 165
 166         -- end
 167
 168 ---------------Directive
 169         -- function post:import(im)
 170                 -- local m=im.mod
 171                 -- --TODO!
 172         -- end
 173
 174         -- function post:private()
 175                 -- return true
 176         -- end
 177
 178         -- function post:public()
 179                 -- return true
 180         -- end
 181
 182         function post:rawlua(r)
 183                 local f,err=loadstring(r.src)
 184                 if not f then
 185                         self:err('error in Lua code:'..err,r)
 186                 end
 187         end
 188
 189         ------------------------------CONTROL
 190         function post:exprstmt(e)
 191                 local expr=e.expr
 192                 if not is(expr.tag,'new','call') then
 193                         self:err("call/new/statement expected, given "..expr.tag,e)
 194                 end
 195         end
 196
 197
 198         function post:continuestmt(c)
 199                 local l=self:findParentLoop()
 200                 if not l then
 201                         self:err("'continue' must be inside loop block",c)
 202                 end
 203                 l.hasContinue=true
 204                 self.currentBlock.endState=true
 205                 return true
 206         end
 207
 208         function post:breakstmt(b)
 209                 local l=self:findParentLoop()
 210                 if not l then
 211                         self:err("'break' must be inside loop block",b)
 212                 end
 213                 l.hasBreak=true
 214                 self.currentBlock.endState=true
 215                 return true
 216         end
 217
 218         function post:returnstmt(r)
 219                 local f=self:findParentFunc()
 220                 if not f then
 221                         self:err("'return'/'yield' should be inside function",r)
 222                 end
 223                 self.currentBlock.endState=true
 224                 local rettype=getTypeDecl(f.type.rettype)
 225
 226                 if r.values then
 227                         if rettype==voidType then
 228                                 if not (#r.values==1 and getType(r.values[1])==voidType) then
 229                                         self:err('function should return no value',r)
 230                                 end
 231                         elseif rettype.tag=='mulrettype' then
 232                                 f.hasReturn=true
 233                                 --TODO!!!!!!!!!!!!!!!!!
 234                         else
 235                                 f.hasReturn=true
 236                                 if #r.values>1 then
 237                                         self:err('unexpected return value',r.values[2])
 238                                 end
 239                                 local rt=getType(r.values[1])
 240                                 if not checkType(rettype,'>=',rt) then
 241                                         self:err('return type mismatch:'..rettype.name..'<-'..rt.name,r.values[1])
 242                                 end
 243                         end
 244                 elseif rettype~=voidType then
 245                         self:err('return value expected',r)
 246                 end
 247
 248                 return true
 249         end
 250
 251         function post:yieldstmt(y,p)
 252                 return post.returnstmt(self,y,p)
 253         end
 254
 255         -- function post:dostmt(d)
 256                 -- return true
 257         -- end
 258
 259         function post:ifstmt(s)
 260                 s.cond=convertToBool(s.cond)
 261                 self:visitNode(s.cond)
 262                 return true
 263         end
 264
 265         function post:switchstmt(s)
 266                 local condtype=getType(s.cond)
 267
 268                 for i,c in ipairs(s.cases) do
 269                         for i,v in ipairs(c.conds) do
 270                                 if not checkType(condtype,'>=',getType(v)) then
 271                                         self:err('case expression type mismatch',v)
 272                                 end
 273                         end
 274                 end
 275
 276                 return true
 277         end
 278
 279         -- function post:case(c)
 280                 -- return true
 281         -- end
 282
 283
 284         function post:forstmt(f)
 285                 local tt,mulret=getExprTypeList(f.range)
 286                 for i,t in ipairs(tt) do
 287                         if t~=numberType then
 288                                 self:err('for-loop range must be number type, given:'..t.name,f)
 289                         end
 290                 end
 291         end
 292
 293         function post:foreachstmt(f)
 294                 --todo:!!!!
 295                 --todo:typecheck vars type <=iterator return type
 296         end
 297
 298         function post:whilestmt(s)
 299                 s.cond=convertToBool(s.cond)
 300                 self:visitNode(s.cond)
 301                 return true
 302         end
 303
 304         -- function post:trystmt(t)
 305                 -- return true
 306         -- end
 307
 308         -- function post:throwstmt(t)
 309                 -- return true
 310         -- end
 311
 312         function post:catch(c)
 313                 --todo:!!!!
 314                 return true
 315         end
 316
 317 -----------------#ASSIGNSTMT
 318         local function isAssignable(var)
 319                 local tag=var.tag
 320
 321
 322
 323                 if tag=='varacc' or tag=='member' then
 324                         local decl=var.decl
 325                         local dtag=decl.tag
 326
 327                         if dtag=='var' then
 328                                 return decl.vtype~='const'
 329                         end
 330
 331                 elseif tag=='index' then
 332                         return true
 333                 end
 334                 return false
 335         end
 336
 337
 338         function post:assignstmt(a)
 339
 340                 local vars,values=a.vars,a.values
 341
 342                 for i,var in ipairs(vars) do
 343                         if not isAssignable(var) then
 344                                 self:err('non-assignable symbol:'..var.id)
 345                         end
 346                 end
 347
 348                 --todo: different variable type(member/index/indexoverride)
 349
 350                 --todo typecheck for value/var
 351                 local valtypes,mulretcount=getExprTypeList(values)
 352                 local valcount,varcount=#valtypes,#vars
 353
 354                 if valcount<varcount or (valcount-mulretcount+(mulretcount>0 and 1 or 0))>varcount then
 355                         self:err('variable/value count mismatch:'..varcount..'<-'..valcount)
 356                 end
 357
 358                 for i,var in ipairs(vars) do
 359                         local vt=valtypes[i]
 360                         local vart=getType(var)
 361
 362                         if not checkType(vart,'>=',vt) then
 363                                 self:err('variable/value type mismatch:'..vart.name..'<-'..vt.name)
 364                         end
 365                 end
 366
 367                 return true
 368         end
 369
 370         function post:assopstmt(a)
 371                 --todo: check is isAssignable
 372                 --todo: different variable type(member/index/indexoverride)
 373                 -- pendTypeCheck('==',a.var,a.value)
 374
 375                 return true
 376         end
 377
 378         function post:batchassign(a)
 379                 --todo: replace batch with assigns?
 380                 --todo: check is isAssignable
 381                 --todo: different variable type(member/index/indexoverride)
 382                 --todo typecheck for value/var
 383
 384                 -- return 'replace',{
 385                         -- tag='dostmt',
 386                         -- block={tag='block',
 387                                 -- {tag='vardecl', vars={
 388                                         -- }
 389                         -- }
 390                 -- }
 391         end
 392
 393
 394 -----------------#DECLARATION
 395         -- function pre:vardecl(vd)
 396
 397         -- end
 398
 399
 400         function post:tvar(v)
 401                 --todo:!!!!!!!!!!!!!!!!!!!
 402                 return true
 403         end
 404
 405         function post:var(v)
 406                 if v.vtype=='const' and not v.value then
 407                         self:err('const variable has no value:'..v.name,v)
 408                 end
 409
 410                 local td=getType(v)
 411                 if not td then
 412                         self:err('unresolved type',v)
 413                 else
 414                         v.type=td
 415                 end
 416
 417                 if v.value then
 418                         if not checkType(v.type,'>=',getType(v.value)) then
 419                                 self:err('type mismatch',v)
 420                         end
 421                 end
 422                 --TODO:
 423                 return true
 424         end
 425
 426         function post:arg(a)
 427
 428                 return true
 429         end
 430
 431         function post:enumdecl(e)
 432                 local ii={}
 433                 for i,item in ipairs(e.items) do
 434                         local iv=item.value
 435                         if ii[iv] then self:err('duplicated enum item value',item) end
 436                         ii[iv]=true
 437                 end
 438                 e.type=enumMetaType
 439         end
 440
 441         function post:enumitem(i,e)
 442
 443                 if i.value then
 444                         local v=getConstNode(i.value)
 445                         i.value=v
 446                         if not v or getType(v).tag~='numbertype' then
 447                                 self:err('enum item must be constant number')
 448                         end
 449                         e.currentValue=v
 450                 else
 451                         local cv=e.currentValue
 452                         if not cv then
 453                                 cv=makeNumberConst(1)
 454                         else
 455                                 cv=makeNumberConst(tonumber(cv.v)+1)
 456                         end
 457                         i.value=cv
 458                         e.currentValue=cv
 459                 end
 460                 i.type=i.value.type
 461         end
 462
 463         local function checkConst(n)
 464                 local tag=n.tag
 465                 if is(tag,'number','nil','boolean','string') then return true
 466                 elseif tag=='var' and n.vtype=='const' then return true
 467                 elseif tag=='varacc' or tag=='member' then
 468                         if checkConst(n.decl) then return true end
 469                 elseif tag=='binop' then
 470                         if checkConst(n.l) and checkConst(n.r) then return true end
 471                 elseif tag=='unop' then
 472                         return checkConst(n.l)
 473                 end
 474                 return false
 475         end
 476
 477         function pre:classdecl(c)
 478                 local supername=c.supername
 479                 if supername then
 480                         local s=self:findSymbol(supername.id,c)
 481                         --todo check template
 482                         if not s then
 483                                 self:err('symbol not found:'..supername.id,c)
 484                         end
 485                         if s.tag~='classdecl' then self:err(supername.id..'is not a class',c) end
 486                         c.superclass=s
 487                 end
 488                 c.resolveState='done'
 489         end
 490
 491         function post:classdecl(c)
 492                 ------------TODO:!
 493         end
 494
 495         function pre:methoddecl(m,parent)
 496                 return pre.funcdecl(self,m,parent)
 497         end
 498
 499         function post:methoddecl(m,parent)
 500                 if m.extern then return end
 501                 local ftype=m.type
 502                 assert(m.block or m.abstract,'abstract?'..m.name)
 503                 if m.inherit then
 504                         local c=parent.superclass
 505                         local superMethod
 506                         while c do
 507                                 local m=c.scope[m.name]
 508                                 if m then
 509                                         if m.tag=='methoddecl' then superMethod=m end
 510                                         break
 511                                 end
 512                                 c=c.superclass
 513                         end
 514
 515                         if not superMethod then
 516                                 self:err('cannot find method to inherit:'..m.name,m)
 517                         end
 518                 end
 519                 return post.funcdecl(self,m)
 520         end
 521
 522         function pre:funcdecl(f)
 523                 if f.extern then return end
 524                 if f.block.tag=='exprbody' and f.type.rettype==voidType then
 525                         local expr=f.block.expr
 526                         f.type.rettype=newTypeRef(expr)
 527                 end
 528                 f.resolveState='done'
 529         end
 530
 531         function post:funcdecl(f)
 532                 if f.extern then return end
 533
 534                 local rettype=f.type.rettype
 535                 if not f.hasReturn and rettype.tag~='voidtype' then
 536                         self:err('return statement not found in function block',f)
 537                 end
 538                 return true
 539         end
 540
 541         function post:exprbody(e)
 542                 self:findParentFunc().hasReturn=true
 543                 --TODO:check type
 544                 return true
 545         end
 546 ----------------------EXPRESSION
 547         function post:varacc(v)
 548                 local d=self:findSymbol(v.id, v, v.global and 'global' or nil)
 549                 if not d then self:err("symbol not found:'"..v.id.."'",v ) end
 550
 551                 if isMemberDecl(d) then
 552                         return 'replace', {tag='member',l={tag='self'},id=v.id, decl=d, type=getType(d)}
 553                 end
 554
 555                 self:visitNode(d)
 556
 557                 v.decl=d
 558                 local td=getType(d)
 559                 if td then
 560                         v.type=td
 561                 else
 562                         v.type=d.type
 563                         assert(d.type)
 564                 end
 565
 566                 return false
 567         end
 568
 569         local function rateFuncProto(f,c)
 570                 local t=getType(f)
 571                 local cargs=c.args or {}
 572                 local targs=t.args or {}
 573
 574                 local ctypes,mulret=getExprTypeList(cargs)
 575
 576                 if #ctypes<#targs then
 577                         return 0, 'argument count mismatch', c
 578                 end
 579
 580                 local varargType
 581                 local lastArg=targs[#targs] --last func decl arg
 582                 if lastArg and lastArg.vararg then
 583                         varargType=getType(lastArg)
 584                 end
 585
 586                 for i,ca in ipairs(cargs) do
 587                         local ta=targs[i]
 588                         local tat
 589
 590                         if not ta then
 591                                 if not varargType then
 592                                         return 0,'argument count mismatch', c
 593                                 end
 594                                 tat=varargType
 595                         else
 596                                 tat=getType(ta)
 597                         end
 598
 599                         local cat=getType(ca)
 600
 601                         if not checkType(tat,'>=',cat) then
 602                                 return 0, 'argument type mismatch,expecting:'..tat.name..',given:'..cat.name, ca
 603                         end
 604                 end
 605                 --TODO:rate by type matches
 606                 return 1
 607         end
 608
 609         local function findCallProto(f,c)
 610                 -- local rates={}
 611                 local topRate=0
 612                 local topProto={}
 613
 614                 while f do
 615                         local rate,err,errnode=rateFuncProto(f,c)
 616
 617                         if rate==0 then
 618
 619                         elseif rate>topRate then
 620                                 topRate=rate
 621                                 topProto={f}
 622                         elseif rate==topRate then
 623                                 topProto[#topProto+1]=f
 624                         end
 625
 626                         f=f.nextProto
 627                 end
 628
 629                 --TODO:with same rate? order by argument type(the more specific, the better)
 630                 --fixed arg > optional arg > vararg
 631                 return topProto[1]
 632         end
 633
 634
 635         function post:call(c)
 636                 local f=c.l
 637                 if f.tag=='closure' then
 638                         self:err('cannot call a closure directly',c)
 639                 end
 640
 641                 if f.decl and is(f.decl.tag,'funcdecl','methoddecl') then
 642
 643                         local proto=findCallProto(f.decl,c)
 644                         if not proto then
 645                                 self:err('cannot find match function overload',c)
 646                         end
 647                         f.decl=proto
 648                         f.type=getType(proto)
 649                 end
 650
 651                 local lt=getType(c.l)
 652                 yu.resolveCall(lt,c)
 653                 return true
 654         end
 655
 656         function post:spawn(s)
 657                 local pt=getType(s.proto)
 658                 if pt.tag~='functype' then
 659                         self:err('coroutine proto must be a function,given:'..pt.name,s)
 660                 end
 661                 s.type=pt
 662                 return true
 663         end
 664
 665         function post:new(n)
 666                 --todo: find constructor proto
 667                 local c=n.class
 668                 local clas=getTypeDecl(c)
 669
 670                 if clas.tag~='classdecl' then
 671                         self:err('instance can be only create from a class',n)
 672                 end
 673
 674                 if clas.abstract then
 675                         local msg=''
 676                         for i, m in ipairs(clas.decls) do
 677                                 if m.abstract then
 678                                         msg=msg..'\n'..m.name
 679                                 end
 680                         end
 681                         self:err('class has abstract method(s):'..msg,n)
 682                 end
 683
 684                 n.type=n.class
 685                 return true
 686         end
 687
 688         function post:binop(b)
 689                 local tl=getType(b.l)
 690                 local tr=getType(b.r)
 691                 yu.resolveOP(tl,b)
 692                 return false
 693         end
 694
 695         function post:unop(u)
 696                 local tl=getType(u.l)
 697                 yu.resolveOP(tl,u)
 698                 return true
 699         end
 700
 701         function post:ternary(t)
 702                 t.l=convertToBool(t.l)
 703
 704                 local tt,tf=getType(t.vtrue),getType(t.vfalse)
 705                 local ts=getSharedSuperType(tt,tf)
 706                 if not ts then
 707                         self:err('ternary result values must be of same type',t)
 708                 end
 709                 t.type=ts
 710                 return true
 711         end
 712
 713         function post:member(m)
 714                 local td=getType(m.l)
 715
 716                 if not td then
 717                         self:err('unresolved type<member>',m)
 718                 end
 719
 720                 resolveMember(td,m)
 721
 722         end
 723
 724         function post:index(i)
 725
 726                 local td=getType(i.l)
 727                 if not td then
 728                         self:err('unresolved type<index>',i)
 729                 end
 730                 if not yu.resolveIndex(td,i) then
 731                         self:err('invalid index expression',i)
 732                 end
 733
 734                 return false
 735         end
 736
 737         function post:table(t)
 738                 local kts={}
 739                 for i,item in ipairs(t.items) do
 740                         kts[#kts+1]=getType(item.key)
 741                 end
 742
 743                 local vts={}
 744                 for i,item in ipairs(t.items) do
 745                         vts[#vts+1]=getType(item.value)
 746                 end
 747                 local kt=getSharedSuperType(unpack(kts))
 748                 local vt=getSharedSuperType(unpack(vts))
 749
 750                 if not kt then
 751                         self:err('cannot determine table key type',t)
 752                 end
 753                 if not vt then
 754                         self:err('cannot determine table value type',t)
 755                 end
 756
 757                 t.type={tag='tabletype',etype=vt,ktype=kt,name=vt.name..'['..kt.name..']'}
 758                 return true
 759         end
 760
 761         function post:item(i)
 762                 return true
 763         end
 764
 765         -- function pre:seq(t)
 766
 767         -- end
 768
 769         function post:seq(t)
 770                 local vts={}
 771                 if t.items then
 772                         for i,item in ipairs(t.items) do
 773                                 vts[#vts+1]=getType(item)
 774                         end
 775                         local vt=getSharedSuperType(unpack(vts))
 776
 777                         if not vt then
 778                                 self:err('cannot determine table value type',t)
 779                         end
 780
 781                         t.type={tag='tabletype',etype=vt,ktype=numberType,name=vt.name..'[]'}
 782                 else
 783                         --TODO:empty one
 784                         t.type=emptyTableType
 785                 end
 786
 787                 return true
 788         end
 789
 790         function post:cast(a)
 791                 --todo: typecheck l><a.dst
 792                 resolveCast(getType(a.l),a)
 793         end
 794
 795         function post:is(i)
 796                 --todo: typecheck l>=a.dst
 797                 -- pendTypeCheck('>=',i.l,i.dst)
 798
 799                 local lt=getType(i.l)
 800                 if not checkType(lt,'><',i.dst) then
 801                         self:err('unrelated type:'..lt.name..','..i.dst.name)
 802                 end
 803
 804                 i.type=booleanType
 805         end
 806
 807         function pre:closure(c)
 808                 return pre.funcdecl(self,c)
 809         end
 810
 811         function post:closure(c)
 812                 return post.funcdecl(self,c)
 813         end
 814
 815         function post:self(s)
 816                 local c=self:findParentClass()
 817                 local f=self:findParentFunc()
 818
 819                 if not (c and f and f.tag=='methoddecl') then
 820                         self:err("'self' should be inside method",s)
 821                 end
 822                 s.type=c
 823                 return true
 824         end
 825
 826         function post:super(s)
 827                 local c=self:findParentClass()
 828                 local f=self:findParentFunc()
 829
 830                 if not (c and f and f.tag=='methoddecl') then
 831                         self:err("'super' should be inside method",s)
 832                 end
 833                 local sc=c.superclass
 834                 if not sc then
 835                         self:err("super type not defined",s)
 836                 end
 837                 s.type=sc
 838                 return true
 839         end
 840
 841 ---------------------EXTERN
 842         -- function post:extern(e)
 843                 -- return true
 844         -- end
 845
 846         -- function post:externfunc(f)
 847                 -- return true
 848         -- end
 849
 850         -- function post:externclass(c)
 851                 -- return true
 852         -- end
 853
 854         -- function post:externmethod(m)
 855                 -- return true
 856         -- end
 857
 858 ------------------TYPE
 859         function post:ttype(t) --template type
 860                 local d=self:findSymbol(t.name,t)
 861
 862                 if not d or d.tag~='classdecl' then
 863                         self:err("class not found:'"..t.name.."'",t )
 864                 end
 865                 t.class=d
 866
 867                 --TODO:check argument
 868                 local args=t.args
 869                 local tvars=d.tvars
 870
 871                 local ac=#args
 872                 local tc=#tvars
 873
 874                 if ac~=tc then
 875                         self:err("expecting"..tc.."template variable count,given"..ac,t )
 876                 end
 877                 for i,a in ipairs(args) do
 878                         if getType(a).tag=='nil' then
 879                                 self:err("invalid type for template variable:".."nil",t)
 880                         end
 881                 end
 882         end
 883
 884         function post:type(t,parent)  --symbol type
 885                 if isBuiltinType(t.name) then
 886                         t.decl=getBuiltinType(t.name)
 887
 888                         if t.decl==anyType then
 889                                 local isExternArg=false
 890                                 repeat
 891                                         if parent.tag~='arg' then break end
 892                                         local f=self:findParentFunc()
 893                                         if not (f and f.extern) then break end
 894                                         isExternArg=true
 895                                 until true
 896                                 if not isExternArg then
 897                                         self:err("'any' type can only used for extern function argument",t)
 898                                 end
 899                         end
 900
 901                         return
 902                 end
 903
 904                 local d=self:findSymbol(t.name,t)
 905                 if not (d and isTypeDecl(d)) then self:err("type symbol not found:'"..t.name.."'",t ) end
 906                 t.decl=d
 907
 908         end
 909
 910         function post:tabletype(t)
 911                 --TODO:make proper tabletype name
 912                 t.name='TABLE'
 913         end
 914
 915         function post.mulrettype(vi,t)
 916                 --TODO:make proper tabletype name
 917                 t.name='(...'..')'
 918         end
 919
 920         function pre:functype(ft)
 921                 local rt=ft.rettype
 922                 --TODO:make proper functype name
 923                 ft.name='FUNCTION'
 924                 local ac=#ft.args
 925                 for i=ac,1,-1 do
 926                         local arg=ft.args[i]
 927                         if arg.vararg then
 928                                 if i==ac then
 929                                         --ok, vararg
 930                                 else
 931                                         self:err('only the last argument can be defined as vararg',arg)
 932                                 end
 933                         end
 934                 end
 935         end
 936