This patch allows forward object declarations, in the same manner as delphi. To pre-declare an object, use a semicolon after the object keyword.

Example:

Type

forwardObject = Object;  {forward declaration}
myObject = Object
  count: integer;
  procedure init;
  function createForwardObject: forwardObject;
end;

fowardObject = Object (myObject)
  procedure init; override;
end;

---
outstanding issues:

new(forward_declared_object); -> error 44, "error in type of standard procedure parameter"

OtherObject = Object (ForwardDeclaredObject) end; -> errror 129, "type of variable must be object"

debugger symbol tables

call.pas

@@ -1281,7 +1281,7 @@ if gattr.typtr <> nil then
           lsp := eltype^.recvar;
 	end; {if}
       end {if}
-    else if form = objects then begin
+    else if (form = objects) and (objdef) then begin
       lsize := objsize;
       ofld := objfld;
       end {else if}

parser.pas

@@ -117,6 +117,7 @@ var
   objectcp: ctp;			{last procedure or function identifier}
   objectName: pString;			{object name (for methods)}
   objectType: stp;			{type of method's object}
+  objptr: ctp;                          {linked list of objects}
 
 					{structured constants:}
 					{---------------------}
@@ -356,7 +357,7 @@ end; {DoConstant}
       Duplicate(ncp^.llink, ocp^.llink);
       Duplicate(ncp^.rlink, ocp^.rlink);
       end; {if}
-    end; {Dulpicate}
+    end; {Duplicate}
 
 
     procedure SimpleType (fsys:setofsys; var fsp:stp; var fsize:addrrange);
@@ -979,6 +980,42 @@ end; {DoConstant}
         if not isType then
           Error(127);
 
+        { check for previous foward declaration }
+        lsp := nil;
+        lcp := objptr;
+        while (lcp <> nil) and (CompNames(objectName, lcp^.name^) <> 0)
+	  do lcp := lcp^.next;
+
+        if lcp <> nil then lsp := lcp^.idtype;
+        if (sy <> semicolon) and (lsp <> nil) and (lsp^.objdef) then lsp := nil;
+
+        if lsp = nil then begin
+          {set up the type}
+          lsp := pointer(Malloc(sizeof(structure)));
+            with lsp^ do begin
+	    form := objects;
+            objname := nil;
+            objsize := 6;
+            objlevel := 1;
+            objparent := nil;
+            objdef := true;
+	    size := ptrsize;
+            hasSFile := false;
+      	    end; {with}
+        end;
+
+	{ handle forward declaration }
+        if sy = semicolon then begin
+            { if lcp is defined, then we're already inserted, nothing to do}
+            if lcp = nil then begin
+              lsp^.objdef := false;
+              objectcp^.idtype := lsp;
+              EnterId(objectcp);
+              objectcp^.next := objptr;
+   	      objptr := objectcp;
+           end;       
+        end else begin
+          
           {set up a new display}
 	  oldtop := top;
 	  if top < displimit then begin
@@ -994,17 +1031,6 @@ end; {DoConstant}
             Error(107);
 	  disp1 := 6;
  	
-        {set up the type}
-        lsp := pointer(Malloc(sizeof(structure)));
-	with lsp^ do begin
-	  form := objects;
-          objname := nil;
-          objsize := 6;
-          objlevel := 1;
-          objparent := nil;
-	  size := ptrsize;
-          hasSFile := false;
-	  end; {with}
 
           {handle inheritance}
           if sy = lparent then begin
@@ -1013,7 +1039,8 @@ end; {DoConstant}
               SearchId([types], lcp2);
               if lcp2 <> nil then begin
                 if lcp2^.idtype <> nil then
-                if lcp2^.idtype^.form = objects then begin
+                  if (lcp2^.idtype^.form = objects) and (lcp2^.idtype^.objdef)
+                  then begin
                     Duplicate(display[top].fname, lcp2^.idtype^.objfld);
                     disp1 := lcp2^.idtype^.objsize;
                     lsp^.objparent := lcp2^.idtype;
@@ -1036,11 +1063,17 @@ end; {DoConstant}
        	    FieldList(fsys-[semicolon]+[endsy,procsy,funcsy], lsp1,
               lsp^.hasSFile, true);
           objectType := lsp;
+          if lsp^.objdef then begin
             ttop := top;
             top := oldtop;
-        EnterId(objectcp);
-        top := ttop;
             objectcp^.idtype := lsp;
+            EnterId(objectcp);
+            objectcp^.next := objptr;
+   	    objptr := objectcp;
+            top := ttop;
+          end;
+          lsp^.objdef := true;
+
           ProcList(fsys-[semicolon]+[endsy]);
           if disp1 > $010000 then
             if SmallMemoryModel then
@@ -1052,6 +1085,7 @@ end; {DoConstant}
 	  ExportUses;
 	  top := oldtop;
   	  Match(endsy,13);
+        end; {if not forward declaration}
       end {else if}
 {set} else if sy = setsy then begin
 	InSymbol;
@@ -1268,7 +1302,7 @@ end; {DoConstant}
     else
       Error(16);
     objectName := lcp^.name^;
-    objectCp := lcp;
+    objectcp := lcp;
     Typ(fsys+[semicolon], lsp, lsize, true); {get the type}
     if lsp^.form = objects then
       lsp^.objname := lcp^.name;
@@ -5020,6 +5054,7 @@ end; {DoConstant}
   code := pointer(Calloc(sizeof(intermediate_code)));
   {code^.lab := nil;}
   fwptr := nil;
+  objptr := nil;
   fextfilep := nil;
   thisType := nil;			{not declaring a type}
   tempList := nil; 			{no temp variables}

pcommon.pas

@@ -132,6 +132,7 @@ type
                          objname: pstringptr;	{object name}
                          objlevel: integer;	{generation level}
                          objparent: stp;	{parent or nil}
+                         objdef: boolean;       {false if not defined}
                          );
 	 files:		(filtype: stp; filsize: addrrange);
 	 tagfld: 	(tagfieldp: ctp; fstvar: stp);