freepascal.compiler/compiler/pexpr.pas

{
    $Id$
    Copyright (c) 1998-2000 by Florian Klaempfl

    Does parsing of expression for Free Pascal

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

 ****************************************************************************
}
unit pexpr;

  interface

    uses symtable,tree;

    { reads a whole expression }
    function expr : ptree;

    { reads an expression without assignements and .. }
    function comp_expr(accept_equal : boolean):Ptree;

    { reads a single factor }
    function factor(getaddr : boolean) : ptree;

    { the ID token has to be consumed before calling this function }
    procedure do_member_read(getaddr : boolean;const sym : psym;var p1 : ptree;
      var pd : pdef;var again : boolean);

    function get_intconst:longint;

    function get_stringconst:string;

  implementation

    uses
       globtype,systems,tokens,
       cobjects,globals,scanner,
       symconst,aasm,
{$ifdef newcg}
       cgbase,
{$else}
       hcodegen,
{$endif}
       types,verbose,strings,
{$ifndef newcg}
       tccal,
{$endif newcg}
       pass_1,
       { parser specific stuff }
       pbase,ptype,
       { processor specific stuff }
       cpubase,cpuinfo;

    { sub_expr(opmultiply) is need to get -1 ** 4 to be
      read as - (1**4) and not (-1)**4 PM }

    type
      Toperator_precedence=(opcompare,opaddition,opmultiply,oppower);

    const
      highest_precedence = oppower;

    function sub_expr(pred_level:Toperator_precedence;accept_equal : boolean):Ptree;forward;

    const
      allow_type : boolean = true;
      got_addrn  : boolean = false;

    function parse_paras(__colon,in_prop_paras : boolean) : ptree;

      var
         p1,p2 : ptree;
         end_of_paras : ttoken;

      begin
         if in_prop_paras  then
           end_of_paras:=_RECKKLAMMER
         else
           end_of_paras:=_RKLAMMER;
         if token=end_of_paras then
           begin
              parse_paras:=nil;
              exit;
           end;
         p2:=nil;
         inc(parsing_para_level);
         while true do
           begin
              p1:=comp_expr(true);
              p2:=gencallparanode(p1,p2);
              { it's for the str(l:5,s); }
              if __colon and (token=_COLON) then
                begin
                   consume(_COLON);
                   p1:=comp_expr(true);
                   p2:=gencallparanode(p1,p2);
                   p2^.is_colon_para:=true;
                   if token=_COLON then
                     begin
                        consume(_COLON);
                        p1:=comp_expr(true);
                        p2:=gencallparanode(p1,p2);
                        p2^.is_colon_para:=true;
                     end
                end;
              if token=_COMMA then
                consume(_COMMA)
              else
                break;
           end;
         dec(parsing_para_level);
         parse_paras:=p2;
      end;


    procedure check_tp_procvar(var p : ptree);
      var
         p1 : ptree;

      begin
         if (m_tp_procvar in aktmodeswitches) and
            (not got_addrn) and
            (not in_args) and
            (p^.treetype=loadn) then
            begin
               { support if procvar then for tp7 and many other expression like this }
               do_firstpass(p);
               set_varstate(p,false);
               { reset varstateset to maybe set used state later web bug769 PM }
               p^.varstateset:=false;
               if not(getprocvar) and (p^.resulttype^.deftype=procvardef) then
                 begin
                    p1:=gencallnode(nil,nil);
                    p1^.right:=p;
                    p1^.resulttype:=pprocvardef(p^.resulttype)^.rettype.def;
                    firstpass(p1);
                    p:=p1;
                 end;
            end;
      end;


    function statement_syssym(l : longint;var pd : pdef) : ptree;
      var
        p1,p2,paras  : ptree;
        prev_in_args : boolean;
      begin
        prev_in_args:=in_args;
        case l of
          in_ord_x :
            begin
              consume(_LKLAMMER);
              in_args:=true;
              p1:=comp_expr(true);
              consume(_RKLAMMER);
              do_firstpass(p1);
              p1:=geninlinenode(in_ord_x,false,p1);
              do_firstpass(p1);
              statement_syssym := p1;
              pd:=p1^.resulttype;
            end;

          in_break :
            begin
              statement_syssym:=genzeronode(breakn);
              pd:=voiddef;
            end;

          in_continue :
            begin
              statement_syssym:=genzeronode(continuen);
              pd:=voiddef;
            end;

          in_typeof_x :
            begin
              consume(_LKLAMMER);
              in_args:=true;
              {allow_type:=true;}
              p1:=comp_expr(true);
              {allow_type:=false;}
              consume(_RKLAMMER);
              pd:=voidpointerdef;
              if p1^.treetype=typen then
               begin
                 if (p1^.typenodetype=nil) then
                  begin
                    Message(type_e_mismatch);
                    statement_syssym:=genzeronode(errorn);
                  end
                 else
                  if p1^.typenodetype^.deftype=objectdef then
                   begin
                      { we can use resulttype in pass_2 (PM) }
                      p1^.resulttype:=p1^.typenodetype;
                      statement_syssym:=geninlinenode(in_typeof_x,false,p1);
                   end
                 else
                  begin
                    Message(type_e_mismatch);
                    disposetree(p1);
                    statement_syssym:=genzeronode(errorn);
                  end;
               end
              else { not a type node }
               begin
                 do_firstpass(p1);
                 set_varstate(p1,false);
                 if (p1^.resulttype=nil) then
                  begin
                    Message(type_e_mismatch);
                    disposetree(p1);
                    statement_syssym:=genzeronode(errorn)
                  end
                 else
                  if p1^.resulttype^.deftype=objectdef then
                   statement_syssym:=geninlinenode(in_typeof_x,false,p1)
                 else
                  begin
                    Message(type_e_mismatch);
                    statement_syssym:=genzeronode(errorn);
                    disposetree(p1);
                  end;
               end;
            end;

          in_sizeof_x :
            begin
              consume(_LKLAMMER);
              in_args:=true;
              {allow_type:=true;}
              p1:=comp_expr(true);
              {allow_type:=false; }
              consume(_RKLAMMER);
              pd:=s32bitdef;
              if p1^.treetype=typen then
               begin
                 statement_syssym:=genordinalconstnode(p1^.typenodetype^.size,pd);
                 { p1 not needed !}
                 disposetree(p1);
               end
              else
               begin
                 do_firstpass(p1);
                 if ((p1^.resulttype^.deftype=objectdef) and
                     (oo_has_constructor in pobjectdef(p1^.resulttype)^.objectoptions)) or
                    is_open_array(p1^.resulttype) or
                    is_open_string(p1^.resulttype) then
                  statement_syssym:=geninlinenode(in_sizeof_x,false,p1)
                 else
                  begin
                    statement_syssym:=genordinalconstnode(p1^.resulttype^.size,pd);
                    { p1 not needed !}
                    disposetree(p1);
                  end;
               end;
            end;

          in_assigned_x :
            begin
              consume(_LKLAMMER);
              in_args:=true;
              p1:=comp_expr(true);
              do_firstpass(p1);
              if not codegenerror then
               begin
                 case p1^.resulttype^.deftype of
                   pointerdef,
                   procvardef,
                   classrefdef : ;
                   objectdef :
                     if not(pobjectdef(p1^.resulttype)^.is_class) then
                       Message(parser_e_illegal_parameter_list);
                   else
                     Message(parser_e_illegal_parameter_list);
                 end;
               end;
              p2:=gencallparanode(p1,nil);
              p2:=geninlinenode(in_assigned_x,false,p2);
              consume(_RKLAMMER);
              pd:=booldef;
              statement_syssym:=p2;
            end;

          in_ofs_x :
            begin
              consume(_LKLAMMER);
              in_args:=true;
              p1:=comp_expr(true);
              p1:=gensinglenode(addrn,p1);
              do_firstpass(p1);

              { Ofs() returns a longint, not a pointer }
              p1^.resulttype:=u32bitdef;
              pd:=p1^.resulttype;
              consume(_RKLAMMER);
              statement_syssym:=p1;
            end;

          in_addr_x :
            begin
              consume(_LKLAMMER);
              in_args:=true;
              p1:=comp_expr(true);
              p1:=gensinglenode(addrn,p1);
              do_firstpass(p1);
              pd:=p1^.resulttype;
              consume(_RKLAMMER);
              statement_syssym:=p1;
            end;

          in_seg_x :
            begin
              consume(_LKLAMMER);
              in_args:=true;
              p1:=comp_expr(true);
              do_firstpass(p1);
              set_varstate(p1,false);
              if p1^.location.loc<>LOC_REFERENCE then
                Message(cg_e_illegal_expression);
              p1:=genordinalconstnode(0,s32bitdef);
              pd:=s32bitdef;
              consume(_RKLAMMER);
              statement_syssym:=p1;
            end;

          in_high_x,
          in_low_x :
            begin
              consume(_LKLAMMER);
              in_args:=true;
              {allow_type:=true;}
              p1:=comp_expr(true);
              {allow_type:=false;}
              do_firstpass(p1);
              if p1^.treetype=typen then
                p1^.resulttype:=p1^.typenodetype;
              p2:=geninlinenode(l,false,p1);
              consume(_RKLAMMER);
              pd:=s32bitdef;
              statement_syssym:=p2;
            end;

          in_succ_x,
          in_pred_x :
            begin
              consume(_LKLAMMER);
              in_args:=true;
              p1:=comp_expr(true);
              do_firstpass(p1);
              p2:=geninlinenode(l,false,p1);
              consume(_RKLAMMER);
              pd:=p1^.resulttype;
              statement_syssym:=p2;
            end;

          in_inc_x,
          in_dec_x :
            begin
              consume(_LKLAMMER);
              in_args:=true;
              p1:=comp_expr(true);
              if token=_COMMA then
               begin
                 consume(_COMMA);
                 p2:=gencallparanode(comp_expr(true),nil);
               end
              else
               p2:=nil;
              p2:=gencallparanode(p1,p2);
              statement_syssym:=geninlinenode(l,false,p2);
              consume(_RKLAMMER);
              pd:=voiddef;
            end;

          in_concat_x :
            begin
              consume(_LKLAMMER);
              in_args:=true;
              p2:=nil;
              while true do
               begin
                 p1:=comp_expr(true);
                 do_firstpass(p1);
                 set_varstate(p1,true);
                 if not((p1^.resulttype^.deftype=stringdef) or
                        ((p1^.resulttype^.deftype=orddef) and
                         (porddef(p1^.resulttype)^.typ=uchar))) then
                   Message(parser_e_illegal_parameter_list);
                 if p2<>nil then
                  p2:=gennode(addn,p2,p1)
                 else
                  p2:=p1;
                 if token=_COMMA then
                  consume(_COMMA)
                 else
                  break;
               end;
              consume(_RKLAMMER);
              pd:=cshortstringdef;
              statement_syssym:=p2;
            end;

          in_read_x,
          in_readln_x :
            begin
              if token=_LKLAMMER then
               begin
                 consume(_LKLAMMER);
                 in_args:=true;
                 paras:=parse_paras(false,false);
                 consume(_RKLAMMER);
               end
              else
               paras:=nil;
              pd:=voiddef;
              p1:=geninlinenode(l,false,paras);
              do_firstpass(p1);
              statement_syssym := p1;
            end;

          in_write_x,
          in_writeln_x :
            begin
              if token=_LKLAMMER then
               begin
                 consume(_LKLAMMER);
                 in_args:=true;
                 paras:=parse_paras(true,false);
                 consume(_RKLAMMER);
               end
              else
               paras:=nil;
              pd:=voiddef;
              p1 := geninlinenode(l,false,paras);
              do_firstpass(p1);
              statement_syssym := p1;
            end;

          in_str_x_string :
            begin
              consume(_LKLAMMER);
              in_args:=true;
              paras:=parse_paras(true,false);
              consume(_RKLAMMER);
              p1 := geninlinenode(l,false,paras);
              do_firstpass(p1);
              statement_syssym := p1;
              pd:=voiddef;
            end;

          in_val_x:
            Begin
              consume(_LKLAMMER);
              in_args := true;
              p1:= gencallparanode(comp_expr(true), nil);
              consume(_COMMA);
              p2 := gencallparanode(comp_expr(true),p1);
              if (token = _COMMA) then
                Begin
                  consume(_COMMA);
                  p2 := gencallparanode(comp_expr(true),p2)
                End;
              consume(_RKLAMMER);
              p2 := geninlinenode(l,false,p2);
              do_firstpass(p2);
              statement_syssym := p2;
              pd := voiddef;
            End;

          in_include_x_y,
          in_exclude_x_y :
            begin
              consume(_LKLAMMER);
              in_args:=true;
              p1:=comp_expr(true);
              consume(_COMMA);
              p2:=comp_expr(true);
              statement_syssym:=geninlinenode(l,false,gencallparanode(p1,gencallparanode(p2,nil)));
              consume(_RKLAMMER);
              pd:=voiddef;
            end;

          in_assert_x_y :
            begin
              consume(_LKLAMMER);
              in_args:=true;
              p1:=comp_expr(true);
              if token=_COMMA then
               begin
                 consume(_COMMA);
                 p2:=comp_expr(true);
               end
              else
               begin
                 { then insert an empty string }
                 p2:=genstringconstnode('',st_default);
               end;
              statement_syssym:=geninlinenode(l,false,gencallparanode(p1,gencallparanode(p2,nil)));
              consume(_RKLAMMER);
              pd:=voiddef;
            end;

          else
            internalerror(15);

        end;
        in_args:=prev_in_args;
      end;


    { reads the parameter for a subroutine call }
    procedure do_proc_call(getaddr : boolean;var again : boolean;var p1:Ptree;var pd:Pdef);
      var
         prev_in_args : boolean;
         prevafterassn : boolean;
      begin
         prev_in_args:=in_args;
         prevafterassn:=afterassignment;
         afterassignment:=false;
         { want we only determine the address of }
         { a subroutine ?                       }
         if not(getaddr) then
           begin
              if token=_LKLAMMER then
                begin
                   consume(_LKLAMMER);
                   in_args:=true;
                   p1^.left:=parse_paras(false,false);
                   consume(_RKLAMMER);
                end
              else p1^.left:=nil;
              { do firstpass because we need the  }
              { result type                       }
              do_firstpass(p1);
              {set_var_state is handled inside firstcalln }
           end
        else
           begin
              { address operator @: }
              p1^.left:=nil;
              { forget pd }
              pd:=nil;
              if (p1^.symtableproc^.symtabletype=withsymtable) and
                (p1^.symtableproc^.defowner^.deftype=objectdef) then
                begin
                   p1^.methodpointer:=getcopy(pwithsymtable(p1^.symtableproc)^.withrefnode);
                end
              else if not(assigned(p1^.methodpointer)) then
                begin
                   { we must provide a method pointer, if it isn't given, }
                   { it is self                                           }
                   if assigned(procinfo) then
                    begin
                      p1^.methodpointer:=genselfnode(procinfo^._class);
                      p1^.methodpointer^.resulttype:=procinfo^._class;
                    end
                   else
                    begin
                      p1^.methodpointer:=genselfnode(nil);
                      p1^.methodpointer^.resulttype:=nil;
                    end;
                end;
              { no postfix operators }
              again:=false;
           end;
         pd:=p1^.resulttype;
         in_args:=prev_in_args;
         afterassignment:=prevafterassn;
      end;

    procedure handle_procvar(pv : pprocvardef;var p2 : ptree);

        procedure doconv(procvar : pprocvardef;var t : ptree);
        var
          hp : ptree;
        begin
          hp:=nil;
          if (proc_to_procvar_equal(pprocsym(t^.symtableentry)^.definition,procvar)) then
           begin
             if (po_methodpointer in procvar^.procoptions) then
               hp:=genloadmethodcallnode(pprocsym(t^.symtableprocentry),t^.symtable,getcopy(t^.methodpointer))
             else
               hp:=genloadcallnode(pprocsym(t^.symtableprocentry),t^.symtable);
           end;
          if assigned(hp) then
           begin
             disposetree(t);
             t:=hp;
           end;
        end;

      begin
        if (p2^.treetype=calln) then
         doconv(pv,p2)
        else
         if (p2^.treetype=typeconvn) and
            (p2^.left^.treetype=calln) then
          doconv(pv,p2^.left);
      end;


    { the following procedure handles the access to a property symbol }
    procedure handle_propertysym(sym : psym;st : psymtable;var p1 : ptree;
      var pd : pdef);

      var
         paras : ptree;
         p2 : ptree;
         plist : psymlistitem;

      begin
         paras:=nil;
         { property parameters? read them only if the property really }
         { has parameters                                             }
         if ppo_hasparameters in ppropertysym(sym)^.propoptions then
           begin
              if token=_LECKKLAMMER then
                begin
                   consume(_LECKKLAMMER);
                   paras:=parse_paras(false,true);
                   consume(_RECKKLAMMER);
                end;
              { indexed property }
              if (ppo_indexed in ppropertysym(sym)^.propoptions) then
                begin
                   p2:=genordinalconstnode(ppropertysym(sym)^.index,ppropertysym(sym)^.indextype.def);
                   paras:=gencallparanode(p2,paras);
                end;
           end;
         { we need only a write property if a := follows }
         { if not(afterassignment) and not(in_args) then }
         if token=_ASSIGNMENT then
           begin
              { write property: }
              { no result }
              pd:=voiddef;
              if not ppropertysym(sym)^.writeaccess^.empty then
                begin
                   case ppropertysym(sym)^.writeaccess^.firstsym^.sym^.typ of
                     procsym :
                       begin
                         { generate the method call }
                         p1:=genmethodcallnode(pprocsym(ppropertysym(sym)^.writeaccess^.firstsym^.sym),st,p1);
                         { we know the procedure to call, so
                           force the usage of that procedure }
                         p1^.procdefinition:=pprocdef(ppropertysym(sym)^.writeaccess^.def);
                         p1^.left:=paras;
                         consume(_ASSIGNMENT);
                         { read the expression }
                         getprocvar:=ppropertysym(sym)^.proptype.def^.deftype=procvardef;
                         p2:=comp_expr(true);
                         if getprocvar then
                           handle_procvar(pprocvardef(ppropertysym(sym)^.proptype.def),p2);
                         p1^.left:=gencallparanode(p2,p1^.left);
                         p1^.isproperty:=true;
                         getprocvar:=false;
                       end;
                     varsym :
                       begin
                         if assigned(paras) then
                           message(parser_e_no_paras_allowed);
                         { subscribed access? }
                         plist:=ppropertysym(sym)^.writeaccess^.firstsym;
                         while assigned(plist) do
                          begin
                            if p1=nil then
                              p1:=genloadnode(pvarsym(plist^.sym),st)
                            else
                              p1:=gensubscriptnode(pvarsym(plist^.sym),p1);
                            plist:=plist^.next;
                          end;
                         p1^.isproperty:=true;
                         consume(_ASSIGNMENT);
                         { read the expression }
                         p2:=comp_expr(true);
                         p1:=gennode(assignn,p1,p2);
                      end
                    else
                      begin
                        p1:=genzeronode(errorn);
                        Message(parser_e_no_procedure_to_access_property);
                      end;
                  end;
                end
              else
                begin
                   p1:=genzeronode(errorn);
                   Message(parser_e_no_procedure_to_access_property);
                end;
           end
         else
           begin
              { read property: }
              pd:=ppropertysym(sym)^.proptype.def;
              if not ppropertysym(sym)^.readaccess^.empty then
                begin
                   case ppropertysym(sym)^.readaccess^.firstsym^.sym^.typ of
                     varsym :
                       begin
                          if assigned(paras) then
                            message(parser_e_no_paras_allowed);
                          { subscribed access? }
                          plist:=ppropertysym(sym)^.readaccess^.firstsym;
                          while assigned(plist) do
                           begin
                             if p1=nil then
                               p1:=genloadnode(pvarsym(plist^.sym),st)
                             else
                               p1:=gensubscriptnode(pvarsym(plist^.sym),p1);
                             plist:=plist^.next;
                           end;
                          p1^.isproperty:=true;
                       end;
                     procsym :
                       begin
                          { generate the method call }
                          p1:=genmethodcallnode(pprocsym(ppropertysym(sym)^.readaccess^.firstsym^.sym),st,p1);
                          { we know the procedure to call, so
                            force the usage of that procedure }
                          p1^.procdefinition:=pprocdef(ppropertysym(sym)^.readaccess^.def);
                          { insert paras }
                          p1^.left:=paras;
                          p1^.isproperty:=true;
                       end
                     else
                       begin
                          p1:=genzeronode(errorn);
                          Message(type_e_mismatch);
                       end;
                  end;
                end
              else
                begin
                   { error, no function to read property }
                   p1:=genzeronode(errorn);
                   Message(parser_e_no_procedure_to_access_property);
                end;
           end;
      end;


    { the ID token has to be consumed before calling this function }
    procedure do_member_read(getaddr : boolean;const sym : psym;var p1 : ptree;
      var pd : pdef;var again : boolean);

      var
         static_name : string;
         isclassref : boolean;
         objdef : pobjectdef;

      begin
         if sym=nil then
           begin
              { pattern is still valid unless
              there is another ID just after the ID of sym }
              Message1(sym_e_id_no_member,pattern);
              disposetree(p1);
              p1:=genzeronode(errorn);
              { try to clean up }
              pd:=generrordef;
              again:=false;
           end
         else
           begin
              objdef:=pobjectdef(sym^.owner^.defowner);
              isclassref:=(pd^.deftype=classrefdef);

              { check protected and private members        }
              { please leave this code as it is,           }
              { it has now the same behaviaor as TP/Delphi }
              if (sp_private in sym^.symoptions) and
                 (objdef^.owner^.symtabletype=unitsymtable) then
               Message(parser_e_cant_access_private_member);

              if (sp_protected in sym^.symoptions) and
                 (objdef^.owner^.symtabletype=unitsymtable) then
                begin
                  if assigned(aktprocsym^.definition^._class) then
                    begin
                       if not aktprocsym^.definition^._class^.is_related(objdef) then
                         Message(parser_e_cant_access_protected_member);
                    end
                  else
                    Message(parser_e_cant_access_protected_member);
                end;

              { we assume, that only procsyms and varsyms are in an object }
              { symbol table, for classes, properties are allowed         }
              case sym^.typ of
                 procsym:
                   begin
                      p1:=genmethodcallnode(pprocsym(sym),srsymtable,p1);
                      do_proc_call(getaddr or
                        (getprocvar and
                         ((block_type=bt_const) or
                          ((m_tp_procvar in aktmodeswitches) and
                           proc_to_procvar_equal(pprocsym(sym)^.definition,getprocvardef)
                          )
                         )
                        ),again,p1,pd);
                      if (block_type=bt_const) and
                         getprocvar then
                        handle_procvar(getprocvardef,p1);
                      { now we know the real method e.g. we can check for a class method }
                      if isclassref and
                         assigned(p1^.procdefinition) and
                         not(po_classmethod in p1^.procdefinition^.procoptions) and
                         not(p1^.procdefinition^.proctypeoption=potype_constructor) then
                        Message(parser_e_only_class_methods_via_class_ref);
                   end;
                 varsym:
                   begin
                      if isclassref then
                        Message(parser_e_only_class_methods_via_class_ref);
                      if (sp_static in sym^.symoptions) then
                        begin
                           { static_name:=lower(srsymtable^.name^)+'_'+sym^.name;
                             this is wrong for static field in with symtable (PM) }
                           static_name:=lower(srsym^.owner^.name^)+'_'+sym^.name;
                           getsym(static_name,true);
                           disposetree(p1);
                           p1:=genloadnode(pvarsym(srsym),srsymtable);
                        end
                      else
                        p1:=gensubscriptnode(pvarsym(sym),p1);
                      pd:=pvarsym(sym)^.vartype.def;
                   end;
                 propertysym:
                   begin
                      if isclassref then
                        Message(parser_e_only_class_methods_via_class_ref);
                      handle_propertysym(sym,srsymtable,p1,pd);
                   end;
                 else internalerror(16);
              end;
           end;
      end;


{****************************************************************************
                               Factor
****************************************************************************}
{$ifdef fpc}
{$maxfpuregisters 0}
{$endif fpc}
    function factor(getaddr : boolean) : ptree;
      var
         l      : longint;
         oldp1,
         p1,p2,p3 : ptree;
         code     : integer;
         pd,pd2   : pdef;
         possible_error,
         unit_specific,
         again    : boolean;
         sym      : psym;
         classh   : pobjectdef;
         d      : bestreal;
         static_name : string;
         propsym  : ppropertysym;
         filepos  : tfileposinfo;

         {---------------------------------------------
                         Is_func_ret
         ---------------------------------------------}

        function is_func_ret(sym : psym) : boolean;
        var
           p : pprocinfo;
           storesymtablestack : psymtable;

        begin
          is_func_ret:=false;
          if not assigned(procinfo) or
             ((sym^.typ<>funcretsym) and ((procinfo^.flags and pi_operator)=0)) then
            exit;
          p:=procinfo;
          while assigned(p) do
            begin
               { is this an access to a function result? Accessing _RESULT is
                 always allowed and funcretn is generated }
               if assigned(p^.funcretsym) and
                  ((pfuncretsym(sym)=p^.resultfuncretsym) or
                   ((pfuncretsym(sym)=p^.funcretsym) or
                    ((pvarsym(sym)=opsym) and ((p^.flags and pi_operator)<>0))) and
                   (p^.returntype.def<>pdef(voiddef)) and
                   (token<>_LKLAMMER) and
                   (not ((m_tp in aktmodeswitches) and (afterassignment or in_args)))
                  ) then
                 begin
                    if ((pvarsym(sym)=opsym) and
                       ((p^.flags and pi_operator)<>0)) then
                       inc(opsym^.refs);
                    p1:=genzeronode(funcretn);
                    pd:=p^.returntype.def;
                    p1^.funcretprocinfo:=p;
                    p1^.rettype.def:=pd;
                    is_func_ret:=true;
                    if p^.funcret_state=vs_declared then
                      begin
                        p^.funcret_state:=vs_declared_and_first_found;
                        p1^.is_first_funcret:=true;
                      end;
                    exit;
                 end;
               p:=p^.parent;
            end;
          { we must use the function call }
          if (sym^.typ=funcretsym) then
            begin
               storesymtablestack:=symtablestack;
               symtablestack:=srsymtable^.next;
               getsym(sym^.name,true);
               if srsym^.typ<>procsym then
                 Message(cg_e_illegal_expression);
               symtablestack:=storesymtablestack;
            end;
        end;

         {---------------------------------------------
                         Factor_read_id
         ---------------------------------------------}

       procedure factor_read_id;
         var
           pc : pchar;
           len : longint;
         begin
           { allow post fix operators }
           again:=true;
            begin
              if lastsymknown then
               begin
                 srsym:=lastsrsym;
                 srsymtable:=lastsrsymtable;
                 lastsymknown:=false;
               end
              else
               getsym(pattern,true);
              consume(_ID);
               if not is_func_ret(srsym) then
              { else it's a normal symbol }
                begin
                { is it defined like UNIT.SYMBOL ? }
                  if srsym^.typ=unitsym then
                   begin
                     consume(_POINT);
                     getsymonlyin(punitsym(srsym)^.unitsymtable,pattern);
                     unit_specific:=true;
                     consume(_ID);
                   end
                  else
                   unit_specific:=false;
                  if not assigned(srsym) then
                   Begin
                     p1:=genzeronode(errorn);
                     { try to clean up }
                     pd:=generrordef;
                   end
                  else
                   Begin
                     { check semantics of private }
                     if (srsym^.typ in [propertysym,procsym,varsym]) and
                        (srsymtable^.symtabletype=objectsymtable) then
                      begin
                         if (sp_private in srsym^.symoptions) and
                            (pobjectdef(srsym^.owner^.defowner)^.owner^.symtabletype=unitsymtable) then
                            Message(parser_e_cant_access_private_member);
                      end;
                     case srsym^.typ of
              absolutesym : begin
                              p1:=genloadnode(pvarsym(srsym),srsymtable);
                              pd:=pabsolutesym(srsym)^.vartype.def;
                            end;
                   varsym : begin
                              { are we in a class method ? }
                              if (srsymtable^.symtabletype=objectsymtable) and
                                 assigned(aktprocsym) and
                                 (po_classmethod in aktprocsym^.definition^.procoptions) then
                                Message(parser_e_only_class_methods);
                              if (sp_static in srsym^.symoptions) then
                               begin
                                 static_name:=lower(srsym^.owner^.name^)+'_'+srsym^.name;
                                 getsym(static_name,true);
                               end;
                              p1:=genloadnode(pvarsym(srsym),srsymtable);
                              if pvarsym(srsym)^.varstate=vs_declared then
                               begin
                                 p1^.is_first := true;
                                 { set special between first loaded until checked in firstpass }
                                 pvarsym(srsym)^.varstate:=vs_declared_and_first_found;
                               end;
                              pd:=pvarsym(srsym)^.vartype.def;
                            end;
            typedconstsym : begin
                              p1:=gentypedconstloadnode(ptypedconstsym(srsym),srsymtable);
                              pd:=ptypedconstsym(srsym)^.typedconsttype.def;
                            end;
                   syssym : p1:=statement_syssym(psyssym(srsym)^.number,pd);
                  typesym : begin
                              pd:=ptypesym(srsym)^.restype.def;
                              if not assigned(pd) then
                               begin
                                 pd:=generrordef;
                                 again:=false;
                               end
                              else
                               begin
                                 { if we read a type declaration  }
                                 { we have to return the type and }
                                 { nothing else               }
                                  if block_type=bt_type then
                                   begin
                                     { we don't need sym reference when it's in the
                                       current unit or system unit, because those
                                       units are always loaded (PFV) }
                                     if not(assigned(pd^.owner)) or
                                        (pd^.owner^.unitid=0) or
                                        (pd^.owner^.unitid=1) then
                                      p1:=gentypenode(pd,nil)
                                     else
                                      p1:=gentypenode(pd,ptypesym(srsym));
                                     { here we can also set resulttype !! }
                                     p1^.resulttype:=pd;
                                     pd:=voiddef;
                                   end
                                 else { not type block }
                                  begin
                                    if token=_LKLAMMER then
                                     begin
                                       consume(_LKLAMMER);
                                       p1:=comp_expr(true);
                                       consume(_RKLAMMER);
                                       p1:=gentypeconvnode(p1,pd);
                                       p1^.explizit:=true;
                                     end
                                    else { not LKLAMMER}
                                     if (token=_POINT) and
                                        (pd^.deftype=objectdef) and
                                        not(pobjectdef(pd)^.is_class) then
                                       begin
                                         consume(_POINT);
                                         if assigned(procinfo) and
                                            assigned(procinfo^._class) and
                                            not(getaddr) then
                                          begin
                                            if procinfo^._class^.is_related(pobjectdef(pd)) then
                                             begin
                                               p1:=gentypenode(pd,ptypesym(srsym));
                                               p1^.resulttype:=pd;
                                               { search also in inherited methods }
                                               repeat
                                                 srsymtable:=pobjectdef(pd)^.symtable;
                                                 sym:=pvarsym(srsymtable^.search(pattern));
                                                 if assigned(sym) then
                                                  break;
                                                 pd:=pobjectdef(pd)^.childof;
                                               until not assigned(pd);
                                               consume(_ID);
                                               do_member_read(false,sym,p1,pd,again);
                                             end
                                            else
                                             begin
                                               Message(parser_e_no_super_class);
                                               pd:=generrordef;
                                               again:=false;
                                             end;
                                          end
                                         else
                                          begin
                                            { allows @TObject.Load }
                                            { also allows static methods and variables }
                                            p1:=genzeronode(typen);
                                            p1^.resulttype:=pd;
                                            { TP allows also @TMenu.Load if Load is only }
                                            { defined in an anchestor class              }
                                            sym:=pvarsym(search_class_member(pobjectdef(pd),pattern));
                                            if not assigned(sym) then
                                              Message1(sym_e_id_no_member,pattern)
                                            else if not(getaddr) and not(sp_static in sym^.symoptions) then
                                              Message(sym_e_only_static_in_static)
                                            else
                                             begin
                                               consume(_ID);
                                               do_member_read(getaddr,sym,p1,pd,again);
                                             end;
                                          end;
                                       end
                                     else
                                       begin
                                          { class reference ? }
                                          if (pd^.deftype=objectdef)
                                            and pobjectdef(pd)^.is_class then
                                            begin
                                               p1:=gentypenode(pd,nil);
                                               p1^.resulttype:=pd;
                                               pd:=new(pclassrefdef,init(pd));
                                               p1:=gensinglenode(loadvmtn,p1);
                                               p1^.resulttype:=pd;
                                            end
                                          else
                                            begin
                                               { generate a type node }
                                               { (for typeof etc)     }
                                               if allow_type then
                                                 begin
                                                    p1:=gentypenode(pd,nil);
                                                    { here we must use typenodetype explicitly !! PM
                                                    p1^.resulttype:=pd; }
                                                    pd:=voiddef;
                                                 end
                                               else
                                                 Message(parser_e_no_type_not_allowed_here);
                                            end;
                                       end;
                                  end;
                               end;
                            end;
                  enumsym : begin
                              p1:=genenumnode(penumsym(srsym));
                              pd:=p1^.resulttype;
                            end;
                 constsym : begin
                              case pconstsym(srsym)^.consttyp of
                                constint :
                                  p1:=genordinalconstnode(pconstsym(srsym)^.value,s32bitdef);
                                conststring :
                                  begin
                                    len:=pconstsym(srsym)^.len;
                                    if not(cs_ansistrings in aktlocalswitches) and (len>255) then
                                     len:=255;
                                    getmem(pc,len+1);
                                    move(pchar(pconstsym(srsym)^.value)^,pc^,len);
                                    pc[len]:=#0;
                                    p1:=genpcharconstnode(pc,len);
                                  end;
                                constchar :
                                  p1:=genordinalconstnode(pconstsym(srsym)^.value,cchardef);
                                constreal :
                                  p1:=genrealconstnode(pbestreal(pconstsym(srsym)^.value)^,bestrealdef^);
                                constbool :
                                  p1:=genordinalconstnode(pconstsym(srsym)^.value,booldef);
                                constset :
                                  p1:=gensetconstnode(pconstset(pconstsym(srsym)^.value),
                                        psetdef(pconstsym(srsym)^.consttype.def));
                                constord :
                                  p1:=genordinalconstnode(pconstsym(srsym)^.value,
                                        pconstsym(srsym)^.consttype.def);
                                constpointer :
                                  p1:=genpointerconstnode(pconstsym(srsym)^.value,
                                        pconstsym(srsym)^.consttype.def);
                                constnil :
                                  p1:=genzeronode(niln);
                                constresourcestring:
                                  begin
                                     p1:=genloadnode(pvarsym(srsym),srsymtable);
                                     p1^.resulttype:=cansistringdef;
                                  end;
                              end;
                              pd:=p1^.resulttype;
                            end;
                  procsym : begin
                              { are we in a class method ? }
                              possible_error:=(srsymtable^.symtabletype=objectsymtable) and
                                              assigned(aktprocsym) and
                                              (po_classmethod in aktprocsym^.definition^.procoptions);
                              p1:=gencallnode(pprocsym(srsym),srsymtable);
                              p1^.unit_specific:=unit_specific;
                              do_proc_call(getaddr or
                                (getprocvar and
                                 ((block_type=bt_const) or
                                  ((m_tp_procvar in aktmodeswitches) and
                                   proc_to_procvar_equal(pprocsym(srsym)^.definition,getprocvardef)
                                  )
                                 )
                                ),again,p1,pd);
                              if (block_type=bt_const) and
                                 getprocvar then
                                handle_procvar(getprocvardef,p1);
                              if possible_error and
                                 not(po_classmethod in p1^.procdefinition^.procoptions) then
                                Message(parser_e_only_class_methods);
                            end;
              propertysym : begin
                              { access to property in a method }
                              { are we in a class method ? }
                              if (srsymtable^.symtabletype=objectsymtable) and
                                 assigned(aktprocsym) and
                                 (po_classmethod in aktprocsym^.definition^.procoptions) then
                               Message(parser_e_only_class_methods);
                              { no method pointer }
                              p1:=nil;
                              handle_propertysym(srsym,srsymtable,p1,pd);
                            end;
                 errorsym : begin
                              p1:=genzeronode(errorn);
                              p1^.resulttype:=generrordef;
                              pd:=generrordef;
                              if token=_LKLAMMER then
                               begin
                                 consume(_LKLAMMER);
                                 parse_paras(false,false);
                                 consume(_RKLAMMER);
                               end;
                            end;
                     else
                       begin
                         p1:=genzeronode(errorn);
                         pd:=generrordef;
                         Message(cg_e_illegal_expression);
                       end;
                     end; { end case }
                   end;
                end;
            end;
         end;

         {---------------------------------------------
                         Factor_Read_Set
         ---------------------------------------------}

         { Read a set between [] }
         function factor_read_set:ptree;
         var
           p1,
           lastp,
           buildp : ptree;
         begin
           buildp:=nil;
         { be sure that a least one arrayconstructn is used, also for an
           empty [] }
           if token=_RECKKLAMMER then
            buildp:=gennode(arrayconstructn,nil,buildp)
           else
            begin
              while true do
               begin
                 p1:=comp_expr(true);
                 if token=_POINTPOINT then
                  begin
                    consume(_POINTPOINT);
                    p2:=comp_expr(true);
                    p1:=gennode(arrayconstructrangen,p1,p2);
                  end;
               { insert at the end of the tree, to get the correct order }
                 if not assigned(buildp) then
                  begin
                    buildp:=gennode(arrayconstructn,p1,nil);
                    lastp:=buildp;
                  end
                 else
                  begin
                    lastp^.right:=gennode(arrayconstructn,p1,nil);
                    lastp:=lastp^.right;
                  end;
               { there could be more elements }
                 if token=_COMMA then
                   consume(_COMMA)
                 else
                   break;
               end;
            end;
           factor_read_set:=buildp;
         end;

         {---------------------------------------------
                           Helpers
         ---------------------------------------------}

        procedure check_tokenpos;
        begin
          if (p1<>oldp1) then
           begin
             if assigned(p1) then
              set_tree_filepos(p1,filepos);
             oldp1:=p1;
             filepos:=tokenpos;
           end;
        end;



         {---------------------------------------------
                        PostFixOperators
         ---------------------------------------------}

      procedure postfixoperators;
        var
           store_static : boolean;

        { p1 and p2 must contain valid value_str }
        begin
          check_tokenpos;
          while again do
           begin
             { prevent crashes with unknown types }
             if not assigned(pd) then
              begin
                { try to recover }
                repeat
                  case token of
                  _CARET:
                     consume(_CARET);

                  _POINT:
                     begin
                        consume(_POINT);
                        consume(_ID);
                     end;

                  _LECKKLAMMER:
                     begin
                        repeat
                          consume(token);
                          until token in [_RECKKLAMMER,_SEMICOLON];
                     end;
                  else
                    break;
                  end;
                until false;
                exit;
              end;
           { handle token }
             case token of
               _CARET:
                  begin
                    consume(_CARET);
                    if (pd^.deftype<>pointerdef) then
                      begin
                         { ^ as binary operator is a problem!!!! (FK) }
                         again:=false;
                         Message(cg_e_invalid_qualifier);
                         disposetree(p1);
                         p1:=genzeronode(errorn);
                      end
                    else
                      begin
                         p1:=gensinglenode(derefn,p1);
                         pd:=ppointerdef(pd)^.pointertype.def;
                      end;
                  end;

               _LECKKLAMMER:
                  begin
                    if (pd^.deftype=objectdef) and pobjectdef(pd)^.is_class then
                      begin
                        { default property }
                        propsym:=search_default_property(pobjectdef(pd));
                        if not(assigned(propsym)) then
                          begin
                             disposetree(p1);
                             p1:=genzeronode(errorn);
                             again:=false;
                             message(parser_e_no_default_property_available);
                          end
                        else
                          handle_propertysym(propsym,propsym^.owner,p1,pd);
                      end
                    else
                      begin
                        consume(_LECKKLAMMER);
                        repeat
                          case pd^.deftype of
                            pointerdef:
                                begin
                                   p2:=comp_expr(true);
                                   p1:=gennode(vecn,p1,p2);
                                   pd:=ppointerdef(pd)^.pointertype.def;
                                 end;

                     stringdef : begin
                                   p2:=comp_expr(true);
                                   p1:=gennode(vecn,p1,p2);
                                   pd:=cchardef
                                 end;
                      arraydef : begin
                                   p2:=comp_expr(true);
                                 { support SEG:OFS for go32v2 Mem[] }
                                   if (target_info.target=target_i386_go32v2) and
                                      (p1^.treetype=loadn) and
                                      assigned(p1^.symtableentry) and
                                      assigned(p1^.symtableentry^.owner^.name) and
                                      (p1^.symtableentry^.owner^.name^='SYSTEM') and
                                      ((p1^.symtableentry^.name='MEM') or
                                       (p1^.symtableentry^.name='MEMW') or
                                       (p1^.symtableentry^.name='MEML')) then
                                     begin
                                       if (token=_COLON) then
                                        begin
                                          consume(_COLON);
                                          p3:=gennode(muln,genordinalconstnode($10,s32bitdef),p2);
                                          p2:=comp_expr(true);
                                          p2:=gennode(addn,p2,p3);
                                          p1:=gennode(vecn,p1,p2);
                                          p1^.memseg:=true;
                                          p1^.memindex:=true;
                                        end
                                       else
                                        begin
                                          p1:=gennode(vecn,p1,p2);
                                          p1^.memindex:=true;
                                        end;
                                     end
                                   else
                                     p1:=gennode(vecn,p1,p2);
                                   pd:=parraydef(pd)^.elementtype.def;
                                 end;
                          else
                            begin
                              Message(cg_e_invalid_qualifier);
                              disposetree(p1);
                              p1:=genzeronode(errorn);
                              again:=false;
                            end;
                          end;
                          if token=_COMMA then
                            consume(_COMMA)
                          else
                            break;
                        until false;
                        consume(_RECKKLAMMER);
                      end;
                  end;
         _POINT : begin
                    consume(_POINT);
                    if (pd^.deftype=pointerdef) and
                      (m_autoderef in aktmodeswitches) then
                      begin
                         p1:=gensinglenode(derefn,p1);
                         pd:=ppointerdef(pd)^.pointertype.def;
                      end;
                    case pd^.deftype of
                       recorddef:
                         begin
                            sym:=precorddef(pd)^.symtable^.search(pattern);
                            if assigned(sym) and
                               (sym^.typ=varsym) then
                              begin
                                p1:=gensubscriptnode(pvarsym(sym),p1);
                                pd:=pvarsym(sym)^.vartype.def;
                              end
                            else
                              begin
                                Message1(sym_e_illegal_field,pattern);
                                disposetree(p1);
                                p1:=genzeronode(errorn);
                              end;
                            consume(_ID);
                          end;

                        classrefdef:
                          begin
                             classh:=pobjectdef(pclassrefdef(pd)^.pointertype.def);
                             sym:=nil;
                             while assigned(classh) do
                              begin
                                sym:=classh^.symtable^.search(pattern);
                                srsymtable:=classh^.symtable;
                                if assigned(sym) then
                                 break;
                                classh:=classh^.childof;
                              end;
                              if sym=nil then
                                begin
                                   Message1(sym_e_id_no_member,pattern);
                                   disposetree(p1);
                                   p1:=genzeronode(errorn);
                                   { try to clean up }
                                   pd:=generrordef;
                                   consume(_ID);
                                end
                              else
                                begin
                                   consume(_ID);
                                   do_member_read(getaddr,sym,p1,pd,again);
                                end;
                           end;

                         objectdef:
                           begin
                              classh:=pobjectdef(pd);
                              sym:=nil;
                              store_static:=allow_only_static;
                              allow_only_static:=false;
                              while assigned(classh) do
                                begin
                                   sym:=classh^.symtable^.search(pattern);
                                   srsymtable:=classh^.symtable;
                                   if assigned(sym) then
                                     break;
                                   classh:=classh^.childof;
                                end;
                              allow_only_static:=store_static;
                              if sym=nil then
                                begin
                                   Message1(sym_e_id_no_member,pattern);
                                   disposetree(p1);
                                   p1:=genzeronode(errorn);
                                   { try to clean up }
                                   pd:=generrordef;
                                   consume(_ID);
                                end
                              else
                                begin
                                   consume(_ID);
                                   do_member_read(getaddr,sym,p1,pd,again);
                                end;
                           end;

                         pointerdef:
                           begin
                             Message(cg_e_invalid_qualifier);
                             if ppointerdef(pd)^.pointertype.def^.deftype in [recorddef,objectdef,classrefdef] then
                              Message(parser_h_maybe_deref_caret_missing);
                           end;
                    else
                      begin
                        Message(cg_e_invalid_qualifier);
                        disposetree(p1);
                        p1:=genzeronode(errorn);
                      end;
                    end;
                  end;
             else
               begin
               { is this a procedure variable ? }
                 if assigned(pd) then
                  begin
                    if (pd^.deftype=procvardef) then
                     begin
                       if getprocvar and is_equal(pd,getprocvardef) then
                         again:=false
                       else
                         if (token=_LKLAMMER) or
                            ((pprocvardef(pd)^.para^.empty) and
                             (not((token in [_ASSIGNMENT,_UNEQUAL,_EQUAL]))) and
                             (not afterassignment) and
                             (not in_args)) then
                           begin
                              { do this in a strange way  }
                              { it's not a clean solution }
                              p2:=p1;
                              p1:=gencallnode(nil,nil);
                              p1^.right:=p2;
                              p1^.unit_specific:=unit_specific;
                              p1^.symtableprocentry:=pprocsym(sym);
                              if token=_LKLAMMER then
                                begin
                                   consume(_LKLAMMER);
                                   p1^.left:=parse_paras(false,false);
                                   consume(_RKLAMMER);
                                end;
                              pd:=pprocvardef(pd)^.rettype.def;
                           { proc():= is never possible }
                              if token=_ASSIGNMENT then
                               begin
                                 Message(cg_e_illegal_expression);
                                 p1:=genzeronode(errorn);
                                 again:=false;
                               end;
                              p1^.resulttype:=pd;
                           end
                       else
                         again:=false;
                       p1^.resulttype:=pd;
                     end
                    else
                     again:=false;
                  end
                 else
                  again:=false;
                end;
             end;
             check_tokenpos;
           end; { while again }
        end;


      {---------------------------------------------
                      Factor (Main)
      ---------------------------------------------}

      begin
        oldp1:=nil;
        p1:=nil;
        filepos:=tokenpos;
        if token=_ID then
         begin
           factor_read_id;
           { handle post fix operators }
           postfixoperators;
         end
        else
         case token of
        _NEW : begin
                 consume(_NEW);
                 consume(_LKLAMMER);
                 {allow_type:=true;}
                 p1:=factor(false);
                 {allow_type:=false;}
                 if p1^.treetype<>typen then
                  begin
                    Message(type_e_type_id_expected);
                    disposetree(p1);
                    pd:=generrordef;
                  end
                 else
                  pd:=p1^.typenodetype;
                 pd2:=pd;

                 if (pd^.deftype<>pointerdef) then
                   Message1(type_e_pointer_type_expected,pd^.typename)
                 else
                  if token=_RKLAMMER then
                   begin
                     if (ppointerdef(pd)^.pointertype.def^.deftype=objectdef) and
                        (oo_has_vmt in pobjectdef(ppointerdef(pd)^.pointertype.def)^.objectoptions)  then
                      Message(parser_w_use_extended_syntax_for_objects);
                     p1:=gensinglenode(newn,nil);
                     p1^.resulttype:=pd2;
                     consume(_RKLAMMER);
                   end
                 else
                   begin
                     disposetree(p1);
                     p1:=genzeronode(hnewn);
                     p1^.resulttype:=ppointerdef(pd)^.pointertype.def;
                     consume(_COMMA);
                     afterassignment:=false;
                     { determines the current object defintion }
                     classh:=pobjectdef(ppointerdef(pd)^.pointertype.def);
                     if classh^.deftype<>objectdef then
                      Message(parser_e_pointer_to_class_expected)
                     else
                      begin
                        { check for an abstract class }
                        if (oo_has_abstract in classh^.objectoptions) then
                         Message(sym_e_no_instance_of_abstract_object);
                        { search the constructor also in the symbol tables of
                          the parents }
                        sym:=nil;
                        while assigned(classh) do
                         begin
                           sym:=classh^.symtable^.search(pattern);
                           srsymtable:=classh^.symtable;
                           if assigned(sym) then
                            break;
                           classh:=classh^.childof;
                         end;
                        consume(_ID);
                        do_member_read(false,sym,p1,pd,again);
                        if (p1^.treetype<>calln) or
                           (assigned(p1^.procdefinition) and
                           (p1^.procdefinition^.proctypeoption<>potype_constructor)) then
                         Message(parser_e_expr_have_to_be_constructor_call);
                      end;
                     p1:=gensinglenode(newn,p1);
                     { set the resulttype }
                     p1^.resulttype:=pd2;
                     consume(_RKLAMMER);
                   end;
                 postfixoperators;
               end;
       _SELF : begin
                 again:=true;
                 consume(_SELF);
                 if not assigned(procinfo^._class) then
                  begin
                    p1:=genzeronode(errorn);
                    pd:=generrordef;
                    again:=false;
                    Message(parser_e_self_not_in_method);
                  end
                 else
                  begin
                    if (po_classmethod in aktprocsym^.definition^.procoptions) then
                     begin
                       { self in class methods is a class reference type }
                       pd:=new(pclassrefdef,init(procinfo^._class));
                       p1:=genselfnode(pd);
                       p1^.resulttype:=pd;
                     end
                    else
                     begin
                       p1:=genselfnode(procinfo^._class);
                       p1^.resulttype:=procinfo^._class;
                     end;
                    pd:=p1^.resulttype;
                    postfixoperators;
                  end;
               end;
  _INHERITED : begin
                 again:=true;
                 consume(_INHERITED);
                 if assigned(procinfo^._class) then
                  begin
                    classh:=procinfo^._class^.childof;
                    while assigned(classh) do
                     begin
                       srsymtable:=pobjectdef(classh)^.symtable;
                       sym:=srsymtable^.search(pattern);
                       if assigned(sym) then
                        begin
                          { only for procsyms we need to set the type (PFV) }
                          case sym^.typ of
                            procsym :
                              begin
                                p1:=genzeronode(typen);
                                p1^.resulttype:=classh;
                                pd:=p1^.resulttype;
                              end;
                            varsym :
                              begin
                                p1:=nil;
                                pd:=pvarsym(sym)^.vartype.def;
                              end;
                            propertysym :
                              begin
                                p1:=nil;
                                pd:=ppropertysym(sym)^.proptype.def;
                              end;
                            else
                              internalerror(83251763);
                          end;
                          consume(_ID);
                          do_member_read(false,sym,p1,pd,again);
                          break;
                        end;
                       classh:=classh^.childof;
                     end;
                    if classh=nil then
                     begin
                       Message1(sym_e_id_no_member,pattern);
                       again:=false;
                       pd:=generrordef;
                       p1:=genzeronode(errorn);
                     end;
                  end
                 else
                   begin
                      Message(parser_e_generic_methods_only_in_methods);
                      again:=false;
                      pd:=generrordef;
                      p1:=genzeronode(errorn);
                   end;
                 postfixoperators;
               end;
   _INTCONST : begin
                 valint(pattern,l,code);
                 if code<>0 then
                  begin
                    val(pattern,d,code);
                    if code<>0 then
                     begin
                       Message(cg_e_invalid_integer);
                       consume(_INTCONST);
                       l:=1;
                       p1:=genordinalconstnode(l,s32bitdef);
                     end
                    else
                     begin
                       consume(_INTCONST);
                       p1:=genrealconstnode(d,bestrealdef^);
                     end;
                  end
                 else
                  begin
                    consume(_INTCONST);
                    p1:=genordinalconstnode(l,s32bitdef);
                  end;
               end;
 _REALNUMBER : begin
                 val(pattern,d,code);
                 if code<>0 then
                  begin
                    Message(parser_e_error_in_real);
                    d:=1.0;
                  end;
                 consume(_REALNUMBER);
                 p1:=genrealconstnode(d,bestrealdef^);
               end;
     _STRING : begin
                 pd:=string_dec;
                 { STRING can be also a type cast }
                 if token=_LKLAMMER then
                  begin
                    consume(_LKLAMMER);
                    p1:=comp_expr(true);
                    consume(_RKLAMMER);
                    p1:=gentypeconvnode(p1,pd);
                    p1^.explizit:=true;
                    { handle postfix operators here e.g. string(a)[10] }
                    again:=true;
                    postfixoperators;
                  end
                 else
                  p1:=gentypenode(pd,nil);
               end;
       _FILE : begin
                 pd:=cfiledef;
                 consume(_FILE);
                 { FILE can be also a type cast }
                 if token=_LKLAMMER then
                  begin
                    consume(_LKLAMMER);
                    p1:=comp_expr(true);
                    consume(_RKLAMMER);
                    p1:=gentypeconvnode(p1,pd);
                    p1^.explizit:=true;
                    { handle postfix operators here e.g. string(a)[10] }
                    again:=true;
                    postfixoperators;
                  end
                 else
                  p1:=gentypenode(pd,nil);
               end;
    _CSTRING : begin
                 p1:=genstringconstnode(pattern,st_default);
                 consume(_CSTRING);
               end;
      _CCHAR : begin
                 p1:=genordinalconstnode(ord(pattern[1]),cchardef);
                 consume(_CCHAR);
               end;
_KLAMMERAFFE : begin
                 consume(_KLAMMERAFFE);
                 got_addrn:=true;
                 { support both @<x> and @(<x>) }
                 if token=_LKLAMMER then
                  begin
                    consume(_LKLAMMER);
                    p1:=factor(true);
                    consume(_RKLAMMER);
                    if token in [_CARET,_POINT,_LECKKLAMMER] then
                     begin
                       { we need the resulttype  }
                       { of the expression in pd }
                       do_firstpass(p1);
                       pd:=p1^.resulttype;
                       again:=true;
                       postfixoperators;
                     end;
                  end
                 else
                  p1:=factor(true);
                 got_addrn:=false;
                 p1:=gensinglenode(addrn,p1);
               end;
   _LKLAMMER : begin
                 consume(_LKLAMMER);
                 p1:=comp_expr(true);
                 consume(_RKLAMMER);
                 { it's not a good solution     }
                 { but (a+b)^ makes some problems  }
                 if token in [_CARET,_POINT,_LECKKLAMMER] then
                  begin
                    { we need the resulttype  }
                    { of the expression in pd }
                    do_firstpass(p1);
                    pd:=p1^.resulttype;
                    again:=true;
                    postfixoperators;
                  end;
               end;
_LECKKLAMMER : begin
                 consume(_LECKKLAMMER);
                 p1:=factor_read_set;
                 consume(_RECKKLAMMER);
               end;
       _PLUS : begin
                 consume(_PLUS);
                 p1:=factor(false);
               end;
      _MINUS : begin
                 consume(_MINUS);
                 p1:=sub_expr(oppower,false);
                 p1:=gensinglenode(unaryminusn,p1);
               end;
        _NOT : begin
                 consume(_NOT);
                 p1:=factor(false);
                 p1:=gensinglenode(notn,p1);
               end;
       _TRUE : begin
                 consume(_TRUE);
                 p1:=genordinalconstnode(1,booldef);
               end;
      _FALSE : begin
                 consume(_FALSE);
                 p1:=genordinalconstnode(0,booldef);
               end;
        _NIL : begin
                 consume(_NIL);
                 p1:=genzeronode(niln);
               end;
        else
          begin
            p1:=genzeronode(errorn);
            consume(token);
            Message(cg_e_illegal_expression);
          end;
        end;
        { generate error node if no node is created }
        if not assigned(p1) then
          p1:=genzeronode(errorn);
        { tp7 procvar handling, but not if the next token
          will be a := }
        if (m_tp_procvar in aktmodeswitches) and
           (token<>_ASSIGNMENT) then
          check_tp_procvar(p1);
        factor:=p1;
        check_tokenpos;
      end;
{$ifdef fpc}
{$maxfpuregisters default}
{$endif fpc}

{****************************************************************************
                             Sub_Expr
****************************************************************************}

    type
      Ttok2nodeRec=record
        tok : ttoken;
        nod : ttreetyp;
      end;

    const
      tok2nodes=23;
      tok2node:array[1..tok2nodes] of ttok2noderec=(
        (tok:_PLUS    ;nod:addn),
        (tok:_MINUS   ;nod:subn),
        (tok:_STAR    ;nod:muln),
        (tok:_SLASH   ;nod:slashn),
        (tok:_EQUAL   ;nod:equaln),
        (tok:_GT      ;nod:gtn),
        (tok:_LT      ;nod:ltn),
        (tok:_GTE     ;nod:gten),
        (tok:_LTE     ;nod:lten),
        (tok:_SYMDIF  ;nod:symdifn),
        (tok:_STARSTAR;nod:starstarn),
        (tok:_OP_AS     ;nod:asn),
        (tok:_OP_IN     ;nod:inn),
        (tok:_OP_IS     ;nod:isn),
        (tok:_OP_OR     ;nod:orn),
        (tok:_OP_AND    ;nod:andn),
        (tok:_OP_DIV    ;nod:divn),
        (tok:_OP_MOD    ;nod:modn),
        (tok:_OP_SHL    ;nod:shln),
        (tok:_OP_SHR    ;nod:shrn),
        (tok:_OP_XOR    ;nod:xorn),
        (tok:_CARET   ;nod:caretn),
        (tok:_UNEQUAL ;nod:unequaln)
      );
      { Warning these stay be ordered !! }
      operator_levels:array[Toperator_precedence] of set of Ttoken=
         ([_LT,_LTE,_GT,_GTE,_EQUAL,_UNEQUAL,_OP_IN,_OP_IS],
          [_PLUS,_MINUS,_OP_OR,_OP_XOR],
          [_CARET,_SYMDIF,_STARSTAR,_STAR,_SLASH,
           _OP_AS,_OP_AND,_OP_DIV,_OP_MOD,_OP_SHL,_OP_SHR],
          [_STARSTAR] );

    function sub_expr(pred_level:Toperator_precedence;accept_equal : boolean):Ptree;
    {Reads a subexpression while the operators are of the current precedence
     level, or any higher level. Replaces the old term, simpl_expr and
     simpl2_expr.}
      var
        low,high,mid : longint;
        p1,p2   : Ptree;
        oldt    : Ttoken;
        filepos : tfileposinfo;
      begin
        if pred_level=highest_precedence then
          p1:=factor(false)
        else
          p1:=sub_expr(succ(pred_level),true);
        repeat
          if (token in operator_levels[pred_level]) and
             ((token<>_EQUAL) or accept_equal) then
           begin
             oldt:=token;
             filepos:=tokenpos;
             consume(token);
             if pred_level=highest_precedence then
               p2:=factor(false)
             else
               p2:=sub_expr(succ(pred_level),true);
             low:=1;
             high:=tok2nodes;
             while (low<high) do
              begin
                mid:=(low+high+1) shr 1;
                if oldt<tok2node[mid].tok then
                 high:=mid-1
                else
                 low:=mid;
              end;
             if tok2node[high].tok=oldt then
              p1:=gennode(tok2node[high].nod,p1,p2)
             else
              p1:=gennode(nothingn,p1,p2);
             set_tree_filepos(p1,filepos);
           end
          else
           break;
        until false;
        sub_expr:=p1;
      end;


    function comp_expr(accept_equal : boolean):Ptree;
      var
         oldafterassignment : boolean;
         p1 : ptree;
      begin
         oldafterassignment:=afterassignment;
         afterassignment:=true;
         p1:=sub_expr(opcompare,accept_equal);
         afterassignment:=oldafterassignment;
         comp_expr:=p1;
      end;

    function expr : ptree;

      var
         p1,p2 : ptree;
         oldafterassignment : boolean;
         oldp1 : ptree;
         filepos : tfileposinfo;

      begin
         oldafterassignment:=afterassignment;
         p1:=sub_expr(opcompare,true);
         filepos:=tokenpos;
         if (m_tp_procvar in aktmodeswitches) and
            (token<>_ASSIGNMENT) then
           check_tp_procvar(p1);
         if token in [_ASSIGNMENT,_PLUSASN,_MINUSASN,_STARASN,_SLASHASN] then
           afterassignment:=true;
         oldp1:=p1;
         case token of
           _POINTPOINT : begin
                            consume(_POINTPOINT);
                            p2:=sub_expr(opcompare,true);
                            p1:=gennode(rangen,p1,p2);
                         end;
           _ASSIGNMENT : begin
                            consume(_ASSIGNMENT);
                            { avoid a firstpass of a procedure if
                            it must be assigned to a procvar }
                            { should be recursive for a:=b:=c !!! }
                            if (p1^.resulttype<>nil) and (p1^.resulttype^.deftype=procvardef) then
                              begin
                                 getprocvar:=true;
                                 getprocvardef:=pprocvardef(p1^.resulttype);
                              end;
                            p2:=sub_expr(opcompare,true);
                            if getprocvar then
                              handle_procvar(getprocvardef,p2);
                            getprocvar:=false;
                            p1:=gennode(assignn,p1,p2);
                         end;
                         { this is the code for C like assignements }
                         { from an improvement of Peter Schaefer    }
            _PLUSASN   : begin
                            consume(_PLUSASN  );
                            p2:=sub_expr(opcompare,true);
                            p1:=gennode(assignn,p1,gennode(addn,getcopy(p1),p2));
                            { was first
                              p1:=gennode(assignn,p1,gennode(addn,p1,p2));
                              but disposetree assumes that we have a real
                              *** tree *** }
                         end;

            _MINUSASN   : begin
                            consume(_MINUSASN  );
                            p2:=sub_expr(opcompare,true);
                            p1:=gennode(assignn,p1,gennode(subn,getcopy(p1),p2));
                         end;
            _STARASN   : begin
                            consume(_STARASN  );
                            p2:=sub_expr(opcompare,true);
                            p1:=gennode(assignn,p1,gennode(muln,getcopy(p1),p2));
                         end;
            _SLASHASN   : begin
                            consume(_SLASHASN  );
                            p2:=sub_expr(opcompare,true);
                            p1:=gennode(assignn,p1,gennode(slashn,getcopy(p1),p2));
                         end;
         end;
         afterassignment:=oldafterassignment;
         if p1<>oldp1 then
           set_tree_filepos(p1,filepos);
         expr:=p1;
      end;


    function get_intconst:longint;
    {Reads an expression, tries to evalute it and check if it is an integer
     constant. Then the constant is returned.}
    var
      p:Ptree;
    begin
      p:=comp_expr(true);
      do_firstpass(p);
      if not codegenerror then
       begin
         if (p^.treetype<>ordconstn) and
            (p^.resulttype^.deftype=orddef) and
           not(Porddef(p^.resulttype)^.typ in [uvoid,uchar,bool8bit,bool16bit,bool32bit]) then
          Message(cg_e_illegal_expression)
         else
          get_intconst:=p^.value;
       end;
      disposetree(p);
    end;


    function get_stringconst:string;
    {Reads an expression, tries to evaluate it and checks if it is a string
     constant. Then the constant is returned.}
    var
      p:Ptree;
    begin
      get_stringconst:='';
      p:=comp_expr(true);
      do_firstpass(p);
      if p^.treetype<>stringconstn then
        begin
          if (p^.treetype=ordconstn) and is_char(p^.resulttype) then
            get_stringconst:=char(p^.value)
          else
            Message(cg_e_illegal_expression);
        end
      else
        get_stringconst:=strpas(p^.value_str);
      disposetree(p);
    end;

end.
{
  $Log$
  Revision 1.173  2000-03-23 15:56:59  peter
    * fixed crash with inherited with varsym/propsym

  Revision 1.172  2000/03/19 11:22:21  peter
    * protected member check for classes works

  Revision 1.171  2000/03/16 15:13:03  pierre
   + oppower

  Revision 1.170  2000/03/14 15:50:19  pierre
   * - 1**4 = -1 fix

  Revision 1.169  2000/02/13 14:21:50  jonas
    * modifications to make the compiler functional when compiled with
      -Or

  Revision 1.168  2000/02/09 13:22:56  peter
    * log truncated

  Revision 1.167  2000/01/19 22:41:58  florian
    * corrected wrong error message of a member of a class/object/classref wasn't found

  Revision 1.166  2000/01/09 23:16:05  peter
    * added st_default stringtype
    * genstringconstnode extended with stringtype parameter using st_default
      will do the old behaviour

  Revision 1.165  2000/01/07 01:14:28  peter
    * updated copyright to 2000

  Revision 1.164  1999/12/20 21:24:29  pierre
   * web bug769 fix

  Revision 1.163  1999/12/01 12:42:32  peter
    * fixed bug 698
    * removed some notes about unused vars

  Revision 1.162  1999/11/30 10:40:44  peter
    + ttype, tsymlist

  Revision 1.161  1999/11/18 15:34:47  pierre
    * Notes/Hints for local syms changed to
      Set_varstate function

  Revision 1.160  1999/11/17 17:05:01  pierre
   * Notes/hints changes

  Revision 1.159  1999/11/15 17:52:59  pierre
    + one field added for ttoken record for operator
      linking the id to the corresponding operator token that
      can now now all be overloaded
    * overloaded operators are resetted to nil in InitSymtable
      (bug when trying to compile a uint that overloads operators twice)

  Revision 1.158  1999/11/14 15:57:35  peter
    * fixed crash with an errordef

  Revision 1.157  1999/11/08 14:02:16  florian
    * problem with "index X"-properties solved
    * typed constants of class references are now allowed

  Revision 1.156  1999/11/07 23:21:30  florian
    * previous fix for 517 was imcomplete: there was a problem if the property
      had only an index

  Revision 1.155  1999/11/07 23:16:49  florian
    * finally bug 517 solved ...

  Revision 1.154  1999/11/06 14:34:21  peter
    * truncated log to 20 revs

  Revision 1.153  1999/11/05 00:10:30  peter
    * fixed inherited with properties

  Revision 1.152  1999/10/27 16:06:19  peter
    * check for object in extended new

  Revision 1.151  1999/10/26 12:30:44  peter
    * const parameter is now checked
    * better and generic check if a node can be used for assigning
    * export fixes
    * procvar equal works now (it never had worked at least from 0.99.8)
    * defcoll changed to linkedlist with pparaitem so it can easily be
      walked both directions

  Revision 1.150  1999/10/22 14:37:30  peter
    * error when properties are passed to var parameters

  Revision 1.149  1999/10/22 10:39:34  peter
    * split type reading from pdecl to ptype unit
    * parameter_dec routine is now used for procedure and procvars

  Revision 1.148  1999/10/14 14:57:52  florian
    - removed the hcodegen use in the new cg, use cgbase instead

}