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2010-07-27 Paolo Carlini <paolo.carlini@oracle.com>
[official-gcc/alias-decl.git] / gcc / ada / par-ch6.adb
blobfc9a37413666d2f005fea568f0004e6830a4d82f
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- P A R . C H 6 --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2010, Free Software Foundation, Inc. --
10 -- --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 3, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING3. If not, go to --
19 -- http://www.gnu.org/licenses for a complete copy of the license. --
20 -- --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
23 -- --
24 ------------------------------------------------------------------------------
25
26 pragma Style_Checks (All_Checks);
27 -- Turn off subprogram body ordering check. Subprograms are in order
28 -- by RM section rather than alphabetical
29
30 with Sinfo.CN; use Sinfo.CN;
31
32 separate (Par)
33 package body Ch6 is
34
35 -- Local subprograms, used only in this chapter
36
37 function P_Defining_Designator return Node_Id;
38 function P_Defining_Operator_Symbol return Node_Id;
39 function P_Return_Object_Declaration return Node_Id;
40
41 procedure P_Return_Subtype_Indication (Decl_Node : Node_Id);
42 -- Decl_Node is a N_Object_Declaration.
43 -- Set the Null_Exclusion_Present and Object_Definition fields of
44 -- Decl_Node.
45
46 procedure Check_Junk_Semicolon_Before_Return;
47
48 -- Check for common error of junk semicolon before RETURN keyword of
49 -- function specification. If present, skip over it with appropriate
50 -- error message, leaving Scan_Ptr pointing to the RETURN after. This
51 -- routine also deals with a possibly misspelled version of Return.
52
53 ----------------------------------------
54 -- Check_Junk_Semicolon_Before_Return --
55 ----------------------------------------
56
57 procedure Check_Junk_Semicolon_Before_Return is
58 Scan_State : Saved_Scan_State;
59
60 begin
61 if Token = Tok_Semicolon then
62 Save_Scan_State (Scan_State);
63 Scan; -- past the semicolon
64
65 if Token = Tok_Return then
66 Restore_Scan_State (Scan_State);
67 Error_Msg_SC -- CODEFIX
68 ("|extra "";"" ignored");
69 Scan; -- rescan past junk semicolon
70 else
71 Restore_Scan_State (Scan_State);
72 end if;
73
74 elsif Bad_Spelling_Of (Tok_Return) then
75 null;
76 end if;
77 end Check_Junk_Semicolon_Before_Return;
78
79 -----------------------------------------------------
80 -- 6.1 Subprogram (Also 6.3, 8.5.4, 10.1.3, 12.3) --
81 -----------------------------------------------------
82
83 -- This routine scans out a subprogram declaration, subprogram body,
84 -- subprogram renaming declaration or subprogram generic instantiation.
85
86 -- SUBPROGRAM_DECLARATION ::= SUBPROGRAM_SPECIFICATION;
87
88 -- ABSTRACT_SUBPROGRAM_DECLARATION ::=
89 -- SUBPROGRAM_SPECIFICATION is abstract;
90
91 -- SUBPROGRAM_SPECIFICATION ::=
92 -- procedure DEFINING_PROGRAM_UNIT_NAME PARAMETER_PROFILE
93 -- | function DEFINING_DESIGNATOR PARAMETER_AND_RESULT_PROFILE
94
95 -- PARAMETER_PROFILE ::= [FORMAL_PART]
96
97 -- PARAMETER_AND_RESULT_PROFILE ::= [FORMAL_PART] return SUBTYPE_MARK
98
99 -- SUBPROGRAM_BODY ::=
100 -- SUBPROGRAM_SPECIFICATION is
101 -- DECLARATIVE_PART
102 -- begin
103 -- HANDLED_SEQUENCE_OF_STATEMENTS
104 -- end [DESIGNATOR];
105
106 -- SUBPROGRAM_RENAMING_DECLARATION ::=
107 -- SUBPROGRAM_SPECIFICATION renames callable_entity_NAME;
108
109 -- SUBPROGRAM_BODY_STUB ::=
110 -- SUBPROGRAM_SPECIFICATION is separate;
111
112 -- GENERIC_INSTANTIATION ::=
113 -- procedure DEFINING_PROGRAM_UNIT_NAME is
114 -- new generic_procedure_NAME [GENERIC_ACTUAL_PART];
115 -- | function DEFINING_DESIGNATOR is
116 -- new generic_function_NAME [GENERIC_ACTUAL_PART];
117
118 -- NULL_PROCEDURE_DECLARATION ::=
119 -- SUBPROGRAM_SPECIFICATION is null;
120
121 -- Null procedures are an Ada 2005 feature. A null procedure declaration
122 -- is classified as a basic declarative item, but it is parsed here, with
123 -- other subprogram constructs.
124
125 -- The value in Pf_Flags indicates which of these possible declarations
126 -- is acceptable to the caller:
127
128 -- Pf_Flags.Decl Set if declaration OK
129 -- Pf_Flags.Gins Set if generic instantiation OK
130 -- Pf_Flags.Pbod Set if proper body OK
131 -- Pf_Flags.Rnam Set if renaming declaration OK
132 -- Pf_Flags.Stub Set if body stub OK
133
134 -- If an inappropriate form is encountered, it is scanned out but an
135 -- error message indicating that it is appearing in an inappropriate
136 -- context is issued. The only possible values for Pf_Flags are those
137 -- defined as constants in the Par package.
138
139 -- The caller has checked that the initial token is FUNCTION, PROCEDURE,
140 -- NOT or OVERRIDING.
141
142 -- Error recovery: cannot raise Error_Resync
143
144 function P_Subprogram (Pf_Flags : Pf_Rec) return Node_Id is
145 Specification_Node : Node_Id;
146 Name_Node : Node_Id;
147 Fpart_List : List_Id;
148 Fpart_Sloc : Source_Ptr;
149 Result_Not_Null : Boolean := False;
150 Result_Node : Node_Id;
151 Inst_Node : Node_Id;
152 Body_Node : Node_Id;
153 Decl_Node : Node_Id;
154 Rename_Node : Node_Id;
155 Absdec_Node : Node_Id;
156 Stub_Node : Node_Id;
157 Fproc_Sloc : Source_Ptr;
158 Func : Boolean;
159 Scan_State : Saved_Scan_State;
160
161 -- Flags for optional overriding indication. Two flags are needed,
162 -- to distinguish positive and negative overriding indicators from
163 -- the absence of any indicator.
164
165 Is_Overriding : Boolean := False;
166 Not_Overriding : Boolean := False;
167
168 begin
169 -- Set up scope stack entry. Note that the Labl field will be set later
170
171 SIS_Entry_Active := False;
172 SIS_Missing_Semicolon_Message := No_Error_Msg;
173 Push_Scope_Stack;
174 Scope.Table (Scope.Last).Sloc := Token_Ptr;
175 Scope.Table (Scope.Last).Etyp := E_Name;
176 Scope.Table (Scope.Last).Ecol := Start_Column;
177 Scope.Table (Scope.Last).Lreq := False;
178
179 -- Ada2005: scan leading NOT OVERRIDING indicator
180
181 if Token = Tok_Not then
182 Scan; -- past NOT
183
184 if Token = Tok_Overriding then
185 Scan; -- past OVERRIDING
186 Not_Overriding := True;
187
188 -- Overriding keyword used in non Ada 2005 mode
189
190 elsif Token = Tok_Identifier
191 and then Token_Name = Name_Overriding
192 then
193 Error_Msg_SC ("overriding indicator is an Ada 2005 extension");
194 Error_Msg_SC ("\unit must be compiled with -gnat05 switch");
195 Scan; -- past Overriding
196 Not_Overriding := True;
197
198 else
199 Error_Msg_SC -- CODEFIX
200 ("OVERRIDING expected!");
201 end if;
202
203 -- Ada 2005: scan leading OVERRIDING indicator
204
205 -- Note: in the case of OVERRIDING keyword used in Ada 95 mode, the
206 -- declaration circuit already gave an error message and changed the
207 -- token to Tok_Overriding.
208
209 elsif Token = Tok_Overriding then
210 Scan; -- past OVERRIDING
211 Is_Overriding := True;
212 end if;
213
214 if (Is_Overriding or else Not_Overriding) then
215
216 -- Note that if we are not in Ada_05 mode, error messages have
217 -- already been given, so no need to give another message here.
218
219 -- An overriding indicator is allowed for subprogram declarations,
220 -- bodies (including subunits), renamings, stubs, and
221 -- instantiations. The test against Pf_Decl_Pbod is added to account
222 -- for the case of subprograms declared in a protected type, where
223 -- only subprogram declarations and bodies can occur. The Pf_Pbod
224 -- case is for subunits.
225
226 if Pf_Flags /= Pf_Decl_Gins_Pbod_Rnam_Stub
227 and then
228 Pf_Flags /= Pf_Decl_Pbod
229 and then
230 Pf_Flags /= Pf_Pbod
231 then
232 Error_Msg_SC ("overriding indicator not allowed here!");
233
234 elsif Token /= Tok_Function and then Token /= Tok_Procedure then
235 Error_Msg_SC -- CODEFIX
236 ("FUNCTION or PROCEDURE expected!");
237 end if;
238 end if;
239
240 Func := (Token = Tok_Function);
241 Fproc_Sloc := Token_Ptr;
242 Scan; -- past FUNCTION or PROCEDURE
243 Ignore (Tok_Type);
244 Ignore (Tok_Body);
245
246 if Func then
247 Name_Node := P_Defining_Designator;
248
249 if Nkind (Name_Node) = N_Defining_Operator_Symbol
250 and then Scope.Last = 1
251 then
252 Error_Msg_SP ("operator symbol not allowed at library level");
253 Name_Node := New_Entity (N_Defining_Identifier, Sloc (Name_Node));
254
255 -- Set name from file name, we need some junk name, and that's
256 -- as good as anything. This is only approximate, since we do
257 -- not do anything with non-standard name translations.
258
259 Get_Name_String (File_Name (Current_Source_File));
260
261 for J in 1 .. Name_Len loop
262 if Name_Buffer (J) = '.' then
263 Name_Len := J - 1;
264 exit;
265 end if;
266 end loop;
267
268 Set_Chars (Name_Node, Name_Find);
269 Set_Error_Posted (Name_Node);
270 end if;
271
272 else
273 Name_Node := P_Defining_Program_Unit_Name;
274 end if;
275
276 Scope.Table (Scope.Last).Labl := Name_Node;
277 Ignore (Tok_Colon);
278
279 -- Deal with generic instantiation, the one case in which we do not
280 -- have a subprogram specification as part of whatever we are parsing
281
282 if Token = Tok_Is then
283 Save_Scan_State (Scan_State); -- at the IS
284 T_Is; -- checks for redundant IS
285
286 if Token = Tok_New then
287 if not Pf_Flags.Gins then
288 Error_Msg_SC ("generic instantiation not allowed here!");
289 end if;
290
291 Scan; -- past NEW
292
293 if Func then
294 Inst_Node := New_Node (N_Function_Instantiation, Fproc_Sloc);
295 Set_Name (Inst_Node, P_Function_Name);
296 else
297 Inst_Node := New_Node (N_Procedure_Instantiation, Fproc_Sloc);
298 Set_Name (Inst_Node, P_Qualified_Simple_Name);
299 end if;
300
301 Set_Defining_Unit_Name (Inst_Node, Name_Node);
302 Set_Generic_Associations (Inst_Node, P_Generic_Actual_Part_Opt);
303 TF_Semicolon;
304 Pop_Scope_Stack; -- Don't need scope stack entry in this case
305
306 if Is_Overriding then
307 Set_Must_Override (Inst_Node);
308
309 elsif Not_Overriding then
310 Set_Must_Not_Override (Inst_Node);
311 end if;
312
313 return Inst_Node;
314
315 else
316 Restore_Scan_State (Scan_State); -- to the IS
317 end if;
318 end if;
319
320 -- If not a generic instantiation, then we definitely have a subprogram
321 -- specification (all possibilities at this stage include one here)
322
323 Fpart_Sloc := Token_Ptr;
324
325 Check_Misspelling_Of (Tok_Return);
326
327 -- Scan formal part. First a special error check. If we have an
328 -- identifier here, then we have a definite error. If this identifier
329 -- is on the same line as the designator, then we assume it is the
330 -- first formal after a missing left parenthesis
331
332 if Token = Tok_Identifier
333 and then not Token_Is_At_Start_Of_Line
334 then
335 T_Left_Paren; -- to generate message
336 Fpart_List := P_Formal_Part;
337
338 -- Otherwise scan out an optional formal part in the usual manner
339
340 else
341 Fpart_List := P_Parameter_Profile;
342 end if;
343
344 -- We treat what we have as a function specification if FUNCTION was
345 -- used, or if a RETURN is present. This gives better error recovery
346 -- since later RETURN statements will be valid in either case.
347
348 Check_Junk_Semicolon_Before_Return;
349 Result_Node := Error;
350
351 if Token = Tok_Return then
352 if not Func then
353 Error_Msg -- CODEFIX
354 ("PROCEDURE should be FUNCTION", Fproc_Sloc);
355 Func := True;
356 end if;
357
358 Scan; -- past RETURN
359
360 Result_Not_Null := P_Null_Exclusion; -- Ada 2005 (AI-231)
361
362 -- Ada 2005 (AI-318-02)
363
364 if Token = Tok_Access then
365 if Ada_Version < Ada_05 then
366 Error_Msg_SC
367 ("anonymous access result type is an Ada 2005 extension");
368 Error_Msg_SC ("\unit must be compiled with -gnat05 switch");
369 end if;
370
371 Result_Node := P_Access_Definition (Result_Not_Null);
372
373 else
374 Result_Node := P_Subtype_Mark;
375 No_Constraint;
376 end if;
377
378 else
379 if Func then
380 Ignore (Tok_Right_Paren);
381 TF_Return;
382 end if;
383 end if;
384
385 if Func then
386 Specification_Node :=
387 New_Node (N_Function_Specification, Fproc_Sloc);
388
389 Set_Null_Exclusion_Present (Specification_Node, Result_Not_Null);
390 Set_Result_Definition (Specification_Node, Result_Node);
391
392 else
393 Specification_Node :=
394 New_Node (N_Procedure_Specification, Fproc_Sloc);
395 end if;
396
397 Set_Defining_Unit_Name (Specification_Node, Name_Node);
398 Set_Parameter_Specifications (Specification_Node, Fpart_List);
399
400 if Is_Overriding then
401 Set_Must_Override (Specification_Node);
402
403 elsif Not_Overriding then
404 Set_Must_Not_Override (Specification_Node);
405 end if;
406
407 -- Error check: barriers not allowed on protected functions/procedures
408
409 if Token = Tok_When then
410 if Func then
411 Error_Msg_SC ("barrier not allowed on function, only on entry");
412 else
413 Error_Msg_SC ("barrier not allowed on procedure, only on entry");
414 end if;
415
416 Scan; -- past WHEN
417 Discard_Junk_Node (P_Expression);
418 end if;
419
420 -- Deal with semicolon followed by IS. We want to treat this as IS
421
422 if Token = Tok_Semicolon then
423 Save_Scan_State (Scan_State);
424 Scan; -- past semicolon
425
426 if Token = Tok_Is then
427 Error_Msg_SP -- CODEFIX
428 ("extra "";"" ignored");
429 else
430 Restore_Scan_State (Scan_State);
431 end if;
432 end if;
433
434 -- Deal with case of semicolon ending a subprogram declaration
435
436 if Token = Tok_Semicolon then
437 if not Pf_Flags.Decl then
438 T_Is;
439 end if;
440
441 Scan; -- past semicolon
442
443 -- If semicolon is immediately followed by IS, then ignore the
444 -- semicolon, and go process the body.
445
446 if Token = Tok_Is then
447 Error_Msg_SP -- CODEFIX
448 ("|extra "";"" ignored");
449 T_Is; -- scan past IS
450 goto Subprogram_Body;
451
452 -- If BEGIN follows in an appropriate column, we immediately
453 -- commence the error action of assuming that the previous
454 -- subprogram declaration should have been a subprogram body,
455 -- i.e. that the terminating semicolon should have been IS.
456
457 elsif Token = Tok_Begin
458 and then Start_Column >= Scope.Table (Scope.Last).Ecol
459 then
460 Error_Msg_SP -- CODEFIX
461 ("|"";"" should be IS!");
462 goto Subprogram_Body;
463
464 else
465 goto Subprogram_Declaration;
466 end if;
467
468 -- Case of not followed by semicolon
469
470 else
471 -- Subprogram renaming declaration case
472
473 Check_Misspelling_Of (Tok_Renames);
474
475 if Token = Tok_Renames then
476 if not Pf_Flags.Rnam then
477 Error_Msg_SC ("renaming declaration not allowed here!");
478 end if;
479
480 Rename_Node :=
481 New_Node (N_Subprogram_Renaming_Declaration, Token_Ptr);
482 Scan; -- past RENAMES
483 Set_Name (Rename_Node, P_Name);
484 Set_Specification (Rename_Node, Specification_Node);
485 TF_Semicolon;
486 Pop_Scope_Stack;
487 return Rename_Node;
488
489 -- Case of IS following subprogram specification
490
491 elsif Token = Tok_Is then
492 T_Is; -- ignore redundant Is's
493
494 if Token_Name = Name_Abstract then
495 Check_95_Keyword (Tok_Abstract, Tok_Semicolon);
496 end if;
497
498 -- Deal nicely with (now obsolete) use of <> in place of abstract
499
500 if Token = Tok_Box then
501 Error_Msg_SC -- CODEFIX
502 ("ABSTRACT expected");
503 Token := Tok_Abstract;
504 end if;
505
506 -- Abstract subprogram declaration case
507
508 if Token = Tok_Abstract then
509 Absdec_Node :=
510 New_Node (N_Abstract_Subprogram_Declaration, Token_Ptr);
511 Set_Specification (Absdec_Node, Specification_Node);
512 Pop_Scope_Stack; -- discard unneeded entry
513 Scan; -- past ABSTRACT
514 TF_Semicolon;
515 return Absdec_Node;
516
517 -- Ada 2005 (AI-248): Parse a null procedure declaration
518
519 elsif Token = Tok_Null then
520 if Ada_Version < Ada_05 then
521 Error_Msg_SP ("null procedures are an Ada 2005 extension");
522 Error_Msg_SP ("\unit must be compiled with -gnat05 switch");
523 end if;
524
525 Scan; -- past NULL
526
527 if Func then
528 Error_Msg_SP ("only procedures can be null");
529 else
530 Set_Null_Present (Specification_Node);
531 end if;
532
533 TF_Semicolon;
534 goto Subprogram_Declaration;
535
536 -- Check for IS NEW with Formal_Part present and handle nicely
537
538 elsif Token = Tok_New then
539 Error_Msg
540 ("formal part not allowed in instantiation", Fpart_Sloc);
541 Scan; -- past NEW
542
543 if Func then
544 Inst_Node := New_Node (N_Function_Instantiation, Fproc_Sloc);
545 else
546 Inst_Node :=
547 New_Node (N_Procedure_Instantiation, Fproc_Sloc);
548 end if;
549
550 Set_Defining_Unit_Name (Inst_Node, Name_Node);
551 Set_Name (Inst_Node, P_Name);
552 Set_Generic_Associations (Inst_Node, P_Generic_Actual_Part_Opt);
553 TF_Semicolon;
554 Pop_Scope_Stack; -- Don't need scope stack entry in this case
555 return Inst_Node;
556
557 else
558 goto Subprogram_Body;
559 end if;
560
561 -- Here we have a missing IS or missing semicolon, we always guess
562 -- a missing semicolon, since we are pretty good at fixing up a
563 -- semicolon which should really be an IS
564
565 else
566 Error_Msg_AP -- CODEFIX
567 ("|missing "";""");
568 SIS_Missing_Semicolon_Message := Get_Msg_Id;
569 goto Subprogram_Declaration;
570 end if;
571 end if;
572
573 -- Processing for subprogram body
574
575 <<Subprogram_Body>>
576 if not Pf_Flags.Pbod then
577 Error_Msg_SP ("subprogram body not allowed here!");
578 end if;
579
580 -- Subprogram body stub case
581
582 if Separate_Present then
583 if not Pf_Flags.Stub then
584 Error_Msg_SC ("body stub not allowed here!");
585 end if;
586
587 if Nkind (Name_Node) = N_Defining_Operator_Symbol then
588 Error_Msg
589 ("operator symbol cannot be used as subunit name",
590 Sloc (Name_Node));
591 end if;
592
593 Stub_Node :=
594 New_Node (N_Subprogram_Body_Stub, Sloc (Specification_Node));
595 Set_Specification (Stub_Node, Specification_Node);
596 Scan; -- past SEPARATE
597 Pop_Scope_Stack;
598 TF_Semicolon;
599 return Stub_Node;
600
601 -- Subprogram body case
602
603 else
604 -- Here is the test for a suspicious IS (i.e. one that looks
605 -- like it might more properly be a semicolon). See separate
606 -- section discussing use of IS instead of semicolon in
607 -- package Parse.
608
609 if (Token in Token_Class_Declk
610 or else
611 Token = Tok_Identifier)
612 and then Start_Column <= Scope.Table (Scope.Last).Ecol
613 and then Scope.Last /= 1
614 then
615 Scope.Table (Scope.Last).Etyp := E_Suspicious_Is;
616 Scope.Table (Scope.Last).S_Is := Prev_Token_Ptr;
617 end if;
618
619 Body_Node :=
620 New_Node (N_Subprogram_Body, Sloc (Specification_Node));
621 Set_Specification (Body_Node, Specification_Node);
622 Parse_Decls_Begin_End (Body_Node);
623 return Body_Node;
624 end if;
625
626 -- Processing for subprogram declaration
627
628 <<Subprogram_Declaration>>
629 Decl_Node :=
630 New_Node (N_Subprogram_Declaration, Sloc (Specification_Node));
631 Set_Specification (Decl_Node, Specification_Node);
632
633 -- If this is a context in which a subprogram body is permitted,
634 -- set active SIS entry in case (see section titled "Handling
635 -- Semicolon Used in Place of IS" in body of Parser package)
636 -- Note that SIS_Missing_Semicolon_Message is already set properly.
637
638 if Pf_Flags.Pbod then
639 SIS_Labl := Scope.Table (Scope.Last).Labl;
640 SIS_Sloc := Scope.Table (Scope.Last).Sloc;
641 SIS_Ecol := Scope.Table (Scope.Last).Ecol;
642 SIS_Declaration_Node := Decl_Node;
643 SIS_Semicolon_Sloc := Prev_Token_Ptr;
644 SIS_Entry_Active := True;
645 end if;
646
647 Pop_Scope_Stack;
648 return Decl_Node;
649
650 end P_Subprogram;
651
652 ---------------------------------
653 -- 6.1 Subprogram Declaration --
654 ---------------------------------
655
656 -- Parsed by P_Subprogram (6.1)
657
658 ------------------------------------------
659 -- 6.1 Abstract Subprogram Declaration --
660 ------------------------------------------
661
662 -- Parsed by P_Subprogram (6.1)
663
664 -----------------------------------
665 -- 6.1 Subprogram Specification --
666 -----------------------------------
667
668 -- SUBPROGRAM_SPECIFICATION ::=
669 -- procedure DEFINING_PROGRAM_UNIT_NAME PARAMETER_PROFILE
670 -- | function DEFINING_DESIGNATOR PARAMETER_AND_RESULT_PROFILE
671
672 -- PARAMETER_PROFILE ::= [FORMAL_PART]
673
674 -- PARAMETER_AND_RESULT_PROFILE ::= [FORMAL_PART] return SUBTYPE_MARK
675
676 -- Subprogram specifications that appear in subprogram declarations
677 -- are parsed by P_Subprogram (6.1). This routine is used in other
678 -- contexts where subprogram specifications occur.
679
680 -- Note: this routine does not affect the scope stack in any way
681
682 -- Error recovery: can raise Error_Resync
683
684 function P_Subprogram_Specification return Node_Id is
685 Specification_Node : Node_Id;
686 Result_Not_Null : Boolean;
687 Result_Node : Node_Id;
688
689 begin
690 if Token = Tok_Function then
691 Specification_Node := New_Node (N_Function_Specification, Token_Ptr);
692 Scan; -- past FUNCTION
693 Ignore (Tok_Body);
694 Set_Defining_Unit_Name (Specification_Node, P_Defining_Designator);
695 Set_Parameter_Specifications
696 (Specification_Node, P_Parameter_Profile);
697 Check_Junk_Semicolon_Before_Return;
698 TF_Return;
699
700 Result_Not_Null := P_Null_Exclusion; -- Ada 2005 (AI-231)
701
702 -- Ada 2005 (AI-318-02)
703
704 if Token = Tok_Access then
705 if Ada_Version < Ada_05 then
706 Error_Msg_SC
707 ("anonymous access result type is an Ada 2005 extension");
708 Error_Msg_SC ("\unit must be compiled with -gnat05 switch");
709 end if;
710
711 Result_Node := P_Access_Definition (Result_Not_Null);
712
713 else
714 Result_Node := P_Subtype_Mark;
715 No_Constraint;
716 end if;
717
718 Set_Null_Exclusion_Present (Specification_Node, Result_Not_Null);
719 Set_Result_Definition (Specification_Node, Result_Node);
720 return Specification_Node;
721
722 elsif Token = Tok_Procedure then
723 Specification_Node := New_Node (N_Procedure_Specification, Token_Ptr);
724 Scan; -- past PROCEDURE
725 Ignore (Tok_Body);
726 Set_Defining_Unit_Name
727 (Specification_Node, P_Defining_Program_Unit_Name);
728 Set_Parameter_Specifications
729 (Specification_Node, P_Parameter_Profile);
730 return Specification_Node;
731
732 else
733 Error_Msg_SC ("subprogram specification expected");
734 raise Error_Resync;
735 end if;
736 end P_Subprogram_Specification;
737
738 ---------------------
739 -- 6.1 Designator --
740 ---------------------
741
742 -- DESIGNATOR ::=
743 -- [PARENT_UNIT_NAME .] IDENTIFIER | OPERATOR_SYMBOL
744
745 -- The caller has checked that the initial token is an identifier,
746 -- operator symbol, or string literal. Note that we don't bother to
747 -- do much error diagnosis in this routine, since it is only used for
748 -- the label on END lines, and the routines in package Par.Endh will
749 -- check that the label is appropriate.
750
751 -- Error recovery: cannot raise Error_Resync
752
753 function P_Designator return Node_Id is
754 Ident_Node : Node_Id;
755 Name_Node : Node_Id;
756 Prefix_Node : Node_Id;
757
758 function Real_Dot return Boolean;
759 -- Tests if a current token is an interesting period, i.e. is followed
760 -- by an identifier or operator symbol or string literal. If not, it is
761 -- probably just incorrect punctuation to be caught by our caller. Note
762 -- that the case of an operator symbol or string literal is also an
763 -- error, but that is an error that we catch here. If the result is
764 -- True, a real dot has been scanned and we are positioned past it,
765 -- if the result is False, the scan position is unchanged.
766
767 --------------
768 -- Real_Dot --
769 --------------
770
771 function Real_Dot return Boolean is
772 Scan_State : Saved_Scan_State;
773
774 begin
775 if Token /= Tok_Dot then
776 return False;
777
778 else
779 Save_Scan_State (Scan_State);
780 Scan; -- past dot
781
782 if Token = Tok_Identifier
783 or else Token = Tok_Operator_Symbol
784 or else Token = Tok_String_Literal
785 then
786 return True;
787
788 else
789 Restore_Scan_State (Scan_State);
790 return False;
791 end if;
792 end if;
793 end Real_Dot;
794
795 -- Start of processing for P_Designator
796
797 begin
798 Ident_Node := Token_Node;
799 Scan; -- past initial token
800
801 if Prev_Token = Tok_Operator_Symbol
802 or else Prev_Token = Tok_String_Literal
803 or else not Real_Dot
804 then
805 return Ident_Node;
806
807 -- Child name case
808
809 else
810 Prefix_Node := Ident_Node;
811
812 -- Loop through child names, on entry to this loop, Prefix contains
813 -- the name scanned so far, and Ident_Node is the last identifier.
814
815 loop
816 Name_Node := New_Node (N_Selected_Component, Prev_Token_Ptr);
817 Set_Prefix (Name_Node, Prefix_Node);
818 Ident_Node := P_Identifier;
819 Set_Selector_Name (Name_Node, Ident_Node);
820 Prefix_Node := Name_Node;
821 exit when not Real_Dot;
822 end loop;
823
824 -- On exit from the loop, Ident_Node is the last identifier scanned,
825 -- i.e. the defining identifier, and Prefix_Node is a node for the
826 -- entire name, structured (incorrectly!) as a selected component.
827
828 Name_Node := Prefix (Prefix_Node);
829 Change_Node (Prefix_Node, N_Designator);
830 Set_Name (Prefix_Node, Name_Node);
831 Set_Identifier (Prefix_Node, Ident_Node);
832 return Prefix_Node;
833 end if;
834
835 exception
836 when Error_Resync =>
837 while Token = Tok_Dot or else Token = Tok_Identifier loop
838 Scan;
839 end loop;
840
841 return Error;
842 end P_Designator;
843
844 ------------------------------
845 -- 6.1 Defining Designator --
846 ------------------------------
847
848 -- DEFINING_DESIGNATOR ::=
849 -- DEFINING_PROGRAM_UNIT_NAME | DEFINING_OPERATOR_SYMBOL
850
851 -- Error recovery: cannot raise Error_Resync
852
853 function P_Defining_Designator return Node_Id is
854 begin
855 if Token = Tok_Operator_Symbol then
856 return P_Defining_Operator_Symbol;
857
858 elsif Token = Tok_String_Literal then
859 Error_Msg_SC ("invalid operator name");
860 Scan; -- past junk string
861 return Error;
862
863 else
864 return P_Defining_Program_Unit_Name;
865 end if;
866 end P_Defining_Designator;
867
868 -------------------------------------
869 -- 6.1 Defining Program Unit Name --
870 -------------------------------------
871
872 -- DEFINING_PROGRAM_UNIT_NAME ::=
873 -- [PARENT_UNIT_NAME .] DEFINING_IDENTIFIER
874
875 -- Note: PARENT_UNIT_NAME may be present only in 95 mode at the outer level
876
877 -- Error recovery: cannot raise Error_Resync
878
879 function P_Defining_Program_Unit_Name return Node_Id is
880 Ident_Node : Node_Id;
881 Name_Node : Node_Id;
882 Prefix_Node : Node_Id;
883
884 begin
885 -- Set identifier casing if not already set and scan initial identifier
886
887 if Token = Tok_Identifier
888 and then Identifier_Casing (Current_Source_File) = Unknown
889 then
890 Set_Identifier_Casing (Current_Source_File, Determine_Token_Casing);
891 end if;
892
893 Ident_Node := P_Identifier (C_Dot);
894 Merge_Identifier (Ident_Node, Tok_Return);
895
896 -- Normal case (not child library unit name)
897
898 if Token /= Tok_Dot then
899 Change_Identifier_To_Defining_Identifier (Ident_Node);
900 return Ident_Node;
901
902 -- Child library unit name case
903
904 else
905 if Scope.Last > 1 then
906 Error_Msg_SP ("child unit allowed only at library level");
907 raise Error_Resync;
908
909 elsif Ada_Version = Ada_83 then
910 Error_Msg_SP ("(Ada 83) child unit not allowed!");
911
912 end if;
913
914 Prefix_Node := Ident_Node;
915
916 -- Loop through child names, on entry to this loop, Prefix contains
917 -- the name scanned so far, and Ident_Node is the last identifier.
918
919 loop
920 exit when Token /= Tok_Dot;
921 Name_Node := New_Node (N_Selected_Component, Token_Ptr);
922 Scan; -- past period
923 Set_Prefix (Name_Node, Prefix_Node);
924 Ident_Node := P_Identifier (C_Dot);
925 Set_Selector_Name (Name_Node, Ident_Node);
926 Prefix_Node := Name_Node;
927 end loop;
928
929 -- On exit from the loop, Ident_Node is the last identifier scanned,
930 -- i.e. the defining identifier, and Prefix_Node is a node for the
931 -- entire name, structured (incorrectly!) as a selected component.
932
933 Name_Node := Prefix (Prefix_Node);
934 Change_Node (Prefix_Node, N_Defining_Program_Unit_Name);
935 Set_Name (Prefix_Node, Name_Node);
936 Change_Identifier_To_Defining_Identifier (Ident_Node);
937 Set_Defining_Identifier (Prefix_Node, Ident_Node);
938
939 -- All set with unit name parsed
940
941 return Prefix_Node;
942 end if;
943
944 exception
945 when Error_Resync =>
946 while Token = Tok_Dot or else Token = Tok_Identifier loop
947 Scan;
948 end loop;
949
950 return Error;
951 end P_Defining_Program_Unit_Name;
952
953 --------------------------
954 -- 6.1 Operator Symbol --
955 --------------------------
956
957 -- OPERATOR_SYMBOL ::= STRING_LITERAL
958
959 -- Operator symbol is returned by the scanner as Tok_Operator_Symbol
960
961 -----------------------------------
962 -- 6.1 Defining Operator Symbol --
963 -----------------------------------
964
965 -- DEFINING_OPERATOR_SYMBOL ::= OPERATOR_SYMBOL
966
967 -- The caller has checked that the initial symbol is an operator symbol
968
969 function P_Defining_Operator_Symbol return Node_Id is
970 Op_Node : Node_Id;
971
972 begin
973 Op_Node := Token_Node;
974 Change_Operator_Symbol_To_Defining_Operator_Symbol (Op_Node);
975 Scan; -- past operator symbol
976 return Op_Node;
977 end P_Defining_Operator_Symbol;
978
979 ----------------------------
980 -- 6.1 Parameter_Profile --
981 ----------------------------
982
983 -- PARAMETER_PROFILE ::= [FORMAL_PART]
984
985 -- Empty is returned if no formal part is present
986
987 -- Error recovery: cannot raise Error_Resync
988
989 function P_Parameter_Profile return List_Id is
990 begin
991 if Token = Tok_Left_Paren then
992 Scan; -- part left paren
993 return P_Formal_Part;
994 else
995 return No_List;
996 end if;
997 end P_Parameter_Profile;
998
999 ---------------------------------------
1000 -- 6.1 Parameter And Result Profile --
1001 ---------------------------------------
1002
1003 -- Parsed by its parent construct, which uses P_Parameter_Profile to
1004 -- parse the parameters, and P_Subtype_Mark to parse the return type.
1005
1006 ----------------------
1007 -- 6.1 Formal part --
1008 ----------------------
1009
1010 -- FORMAL_PART ::= (PARAMETER_SPECIFICATION {; PARAMETER_SPECIFICATION})
1011
1012 -- PARAMETER_SPECIFICATION ::=
1013 -- DEFINING_IDENTIFIER_LIST : MODE [NULL_EXCLUSION] SUBTYPE_MARK
1014 -- [:= DEFAULT_EXPRESSION]
1015 -- | DEFINING_IDENTIFIER_LIST : ACCESS_DEFINITION
1016 -- [:= DEFAULT_EXPRESSION]
1017
1018 -- This scans the construct Formal_Part. The caller has already checked
1019 -- that the initial token is a left parenthesis, and skipped past it, so
1020 -- that on entry Token is the first token following the left parenthesis.
1021
1022 -- Error recovery: cannot raise Error_Resync
1023
1024 function P_Formal_Part return List_Id is
1025 Specification_List : List_Id;
1026 Specification_Node : Node_Id;
1027 Scan_State : Saved_Scan_State;
1028 Num_Idents : Nat;
1029 Ident : Nat;
1030 Ident_Sloc : Source_Ptr;
1031 Not_Null_Present : Boolean := False;
1032 Not_Null_Sloc : Source_Ptr;
1033
1034 Idents : array (Int range 1 .. 4096) of Entity_Id;
1035 -- This array holds the list of defining identifiers. The upper bound
1036 -- of 4096 is intended to be essentially infinite, and we do not even
1037 -- bother to check for it being exceeded.
1038
1039 begin
1040 Specification_List := New_List;
1041 Specification_Loop : loop
1042 begin
1043 if Token = Tok_Pragma then
1044 Error_Msg_SC ("pragma not allowed in formal part");
1045 Discard_Junk_Node (P_Pragma (Skipping => True));
1046 end if;
1047
1048 Ignore (Tok_Left_Paren);
1049 Ident_Sloc := Token_Ptr;
1050 Idents (1) := P_Defining_Identifier (C_Comma_Colon);
1051 Num_Idents := 1;
1052
1053 Ident_Loop : loop
1054 exit Ident_Loop when Token = Tok_Colon;
1055
1056 -- The only valid tokens are colon and comma, so if we have
1057 -- neither do a bit of investigation to see which is the
1058 -- better choice for insertion.
1059
1060 if Token /= Tok_Comma then
1061
1062 -- Assume colon if IN or OUT keyword found
1063
1064 exit Ident_Loop when Token = Tok_In or else Token = Tok_Out;
1065
1066 -- Otherwise scan ahead
1067
1068 Save_Scan_State (Scan_State);
1069 Look_Ahead : loop
1070
1071 -- If we run into a semicolon, then assume that a
1072 -- colon was missing, e.g. Parms (X Y; ...). Also
1073 -- assume missing colon on EOF (a real disaster!)
1074 -- and on a right paren, e.g. Parms (X Y), and also
1075 -- on an assignment symbol, e.g. Parms (X Y := ..)
1076
1077 if Token = Tok_Semicolon
1078 or else Token = Tok_Right_Paren
1079 or else Token = Tok_EOF
1080 or else Token = Tok_Colon_Equal
1081 then
1082 Restore_Scan_State (Scan_State);
1083 exit Ident_Loop;
1084
1085 -- If we run into a colon, assume that we had a missing
1086 -- comma, e.g. Parms (A B : ...). Also assume a missing
1087 -- comma if we hit another comma, e.g. Parms (A B, C ..)
1088
1089 elsif Token = Tok_Colon
1090 or else Token = Tok_Comma
1091 then
1092 Restore_Scan_State (Scan_State);
1093 exit Look_Ahead;
1094 end if;
1095
1096 Scan;
1097 end loop Look_Ahead;
1098 end if;
1099
1100 -- Here if a comma is present, or to be assumed
1101
1102 T_Comma;
1103 Num_Idents := Num_Idents + 1;
1104 Idents (Num_Idents) := P_Defining_Identifier (C_Comma_Colon);
1105 end loop Ident_Loop;
1106
1107 -- Fall through the loop on encountering a colon, or deciding
1108 -- that there is a missing colon.
1109
1110 T_Colon;
1111
1112 -- If there are multiple identifiers, we repeatedly scan the
1113 -- type and initialization expression information by resetting
1114 -- the scan pointer (so that we get completely separate trees
1115 -- for each occurrence).
1116
1117 if Num_Idents > 1 then
1118 Save_Scan_State (Scan_State);
1119 end if;
1120
1121 -- Loop through defining identifiers in list
1122
1123 Ident := 1;
1124
1125 Ident_List_Loop : loop
1126 Specification_Node :=
1127 New_Node (N_Parameter_Specification, Ident_Sloc);
1128 Set_Defining_Identifier (Specification_Node, Idents (Ident));
1129
1130 -- Scan possible NOT NULL for Ada 2005 (AI-231, AI-447)
1131
1132 Not_Null_Sloc := Token_Ptr;
1133 Not_Null_Present :=
1134 P_Null_Exclusion (Allow_Anonymous_In_95 => True);
1135
1136 -- Case of ACCESS keyword present
1137
1138 if Token = Tok_Access then
1139 Set_Null_Exclusion_Present
1140 (Specification_Node, Not_Null_Present);
1141
1142 if Ada_Version = Ada_83 then
1143 Error_Msg_SC ("(Ada 83) access parameters not allowed");
1144 end if;
1145
1146 Set_Parameter_Type
1147 (Specification_Node,
1148 P_Access_Definition (Not_Null_Present));
1149
1150 -- Case of IN or OUT present
1151
1152 else
1153 if Token = Tok_In or else Token = Tok_Out then
1154 if Not_Null_Present then
1155 Error_Msg
1156 ("`NOT NULL` can only be used with `ACCESS`",
1157 Not_Null_Sloc);
1158
1159 if Token = Tok_In then
1160 Error_Msg
1161 ("\`IN` not allowed together with `ACCESS`",
1162 Not_Null_Sloc);
1163 else
1164 Error_Msg
1165 ("\`OUT` not allowed together with `ACCESS`",
1166 Not_Null_Sloc);
1167 end if;
1168 end if;
1169
1170 P_Mode (Specification_Node);
1171 Not_Null_Present := P_Null_Exclusion; -- Ada 2005 (AI-231)
1172 end if;
1173
1174 Set_Null_Exclusion_Present
1175 (Specification_Node, Not_Null_Present);
1176
1177 if Token = Tok_Procedure
1178 or else
1179 Token = Tok_Function
1180 then
1181 Error_Msg_SC ("formal subprogram parameter not allowed");
1182 Scan;
1183
1184 if Token = Tok_Left_Paren then
1185 Discard_Junk_List (P_Formal_Part);
1186 end if;
1187
1188 if Token = Tok_Return then
1189 Scan;
1190 Discard_Junk_Node (P_Subtype_Mark);
1191 end if;
1192
1193 Set_Parameter_Type (Specification_Node, Error);
1194
1195 else
1196 Set_Parameter_Type (Specification_Node, P_Subtype_Mark);
1197 No_Constraint;
1198 end if;
1199 end if;
1200
1201 Set_Expression (Specification_Node, Init_Expr_Opt (True));
1202
1203 if Ident > 1 then
1204 Set_Prev_Ids (Specification_Node, True);
1205 end if;
1206
1207 if Ident < Num_Idents then
1208 Set_More_Ids (Specification_Node, True);
1209 end if;
1210
1211 Append (Specification_Node, Specification_List);
1212 exit Ident_List_Loop when Ident = Num_Idents;
1213 Ident := Ident + 1;
1214 Restore_Scan_State (Scan_State);
1215 end loop Ident_List_Loop;
1216
1217 exception
1218 when Error_Resync =>
1219 Resync_Semicolon_List;
1220 end;
1221
1222 if Token = Tok_Semicolon then
1223 Save_Scan_State (Scan_State);
1224 Scan; -- past semicolon
1225
1226 -- If we have RETURN or IS after the semicolon, then assume
1227 -- that semicolon should have been a right parenthesis and exit
1228
1229 if Token = Tok_Is or else Token = Tok_Return then
1230 Error_Msg_SP -- CODEFIX
1231 ("|"";"" should be "")""");
1232 exit Specification_Loop;
1233 end if;
1234
1235 -- If we have a declaration keyword after the semicolon, then
1236 -- assume we had a missing right parenthesis and terminate list
1237
1238 if Token in Token_Class_Declk then
1239 Error_Msg_AP -- CODEFIX
1240 ("missing "")""");
1241 Restore_Scan_State (Scan_State);
1242 exit Specification_Loop;
1243 end if;
1244
1245 elsif Token = Tok_Right_Paren then
1246 Scan; -- past right paren
1247 exit Specification_Loop;
1248
1249 -- Special check for common error of using comma instead of semicolon
1250
1251 elsif Token = Tok_Comma then
1252 T_Semicolon;
1253 Scan; -- past comma
1254
1255 -- Special check for omitted separator
1256
1257 elsif Token = Tok_Identifier then
1258 T_Semicolon;
1259
1260 -- If nothing sensible, skip to next semicolon or right paren
1261
1262 else
1263 T_Semicolon;
1264 Resync_Semicolon_List;
1265
1266 if Token = Tok_Semicolon then
1267 Scan; -- past semicolon
1268 else
1269 T_Right_Paren;
1270 exit Specification_Loop;
1271 end if;
1272 end if;
1273 end loop Specification_Loop;
1274
1275 return Specification_List;
1276 end P_Formal_Part;
1277
1278 ----------------------------------
1279 -- 6.1 Parameter Specification --
1280 ----------------------------------
1281
1282 -- Parsed by P_Formal_Part (6.1)
1283
1284 ---------------
1285 -- 6.1 Mode --
1286 ---------------
1287
1288 -- MODE ::= [in] | in out | out
1289
1290 -- There is no explicit node in the tree for the Mode. Instead the
1291 -- In_Present and Out_Present flags are set in the parent node to
1292 -- record the presence of keywords specifying the mode.
1293
1294 -- Error_Recovery: cannot raise Error_Resync
1295
1296 procedure P_Mode (Node : Node_Id) is
1297 begin
1298 if Token = Tok_In then
1299 Scan; -- past IN
1300 Set_In_Present (Node, True);
1301
1302 if Style.Mode_In_Check and then Token /= Tok_Out then
1303 Error_Msg_SP -- CODEFIX
1304 ("(style) IN should be omitted");
1305 end if;
1306
1307 if Token = Tok_Access then
1308 Error_Msg_SP ("IN not allowed together with ACCESS");
1309 Scan; -- past ACCESS
1310 end if;
1311 end if;
1312
1313 if Token = Tok_Out then
1314 Scan; -- past OUT
1315 Set_Out_Present (Node, True);
1316 end if;
1317
1318 if Token = Tok_In then
1319 Error_Msg_SC ("IN must precede OUT in parameter mode");
1320 Scan; -- past IN
1321 Set_In_Present (Node, True);
1322 end if;
1323 end P_Mode;
1324
1325 --------------------------
1326 -- 6.3 Subprogram Body --
1327 --------------------------
1328
1329 -- Parsed by P_Subprogram (6.1)
1330
1331 -----------------------------------
1332 -- 6.4 Procedure Call Statement --
1333 -----------------------------------
1334
1335 -- Parsed by P_Sequence_Of_Statements (5.1)
1336
1337 ------------------------
1338 -- 6.4 Function Call --
1339 ------------------------
1340
1341 -- Parsed by P_Call_Or_Name (4.1)
1342
1343 --------------------------------
1344 -- 6.4 Actual Parameter Part --
1345 --------------------------------
1346
1347 -- Parsed by P_Call_Or_Name (4.1)
1348
1349 --------------------------------
1350 -- 6.4 Parameter Association --
1351 --------------------------------
1352
1353 -- Parsed by P_Call_Or_Name (4.1)
1354
1355 ------------------------------------
1356 -- 6.4 Explicit Actual Parameter --
1357 ------------------------------------
1358
1359 -- Parsed by P_Call_Or_Name (4.1)
1360
1361 ---------------------------
1362 -- 6.5 Return Statement --
1363 ---------------------------
1364
1365 -- SIMPLE_RETURN_STATEMENT ::= return [EXPRESSION];
1366 --
1367 -- EXTENDED_RETURN_STATEMENT ::=
1368 -- return DEFINING_IDENTIFIER : [aliased] RETURN_SUBTYPE_INDICATION
1369 -- [:= EXPRESSION] [do
1370 -- HANDLED_SEQUENCE_OF_STATEMENTS
1371 -- end return];
1372 --
1373 -- RETURN_SUBTYPE_INDICATION ::= SUBTYPE_INDICATION | ACCESS_DEFINITION
1374
1375 -- RETURN_STATEMENT ::= return [EXPRESSION];
1376
1377 -- Error recovery: can raise Error_Resync
1378
1379 procedure P_Return_Subtype_Indication (Decl_Node : Node_Id) is
1380
1381 -- Note: We don't need to check Ada_Version here, because this is
1382 -- only called in >= Ada 2005 cases anyway.
1383
1384 Not_Null_Present : constant Boolean := P_Null_Exclusion;
1385
1386 begin
1387 Set_Null_Exclusion_Present (Decl_Node, Not_Null_Present);
1388
1389 if Token = Tok_Access then
1390 Set_Object_Definition
1391 (Decl_Node, P_Access_Definition (Not_Null_Present));
1392 else
1393 Set_Object_Definition
1394 (Decl_Node, P_Subtype_Indication (Not_Null_Present));
1395 end if;
1396 end P_Return_Subtype_Indication;
1397
1398 -- Error recovery: can raise Error_Resync
1399
1400 function P_Return_Object_Declaration return Node_Id is
1401 Return_Obj : Node_Id;
1402 Decl_Node : Node_Id;
1403
1404 begin
1405 Return_Obj := Token_Node;
1406 Change_Identifier_To_Defining_Identifier (Return_Obj);
1407 Decl_Node := New_Node (N_Object_Declaration, Token_Ptr);
1408 Set_Defining_Identifier (Decl_Node, Return_Obj);
1409
1410 Scan; -- past identifier
1411 Scan; -- past :
1412
1413 -- First an error check, if we have two identifiers in a row, a likely
1414 -- possibility is that the first of the identifiers is an incorrectly
1415 -- spelled keyword. See similar check in P_Identifier_Declarations.
1416
1417 if Token = Tok_Identifier then
1418 declare
1419 SS : Saved_Scan_State;
1420 I2 : Boolean;
1421
1422 begin
1423 Save_Scan_State (SS);
1424 Scan; -- past initial identifier
1425 I2 := (Token = Tok_Identifier);
1426 Restore_Scan_State (SS);
1427
1428 if I2
1429 and then
1430 (Bad_Spelling_Of (Tok_Access) or else
1431 Bad_Spelling_Of (Tok_Aliased) or else
1432 Bad_Spelling_Of (Tok_Constant))
1433 then
1434 null;
1435 end if;
1436 end;
1437 end if;
1438
1439 -- We allow "constant" here (as in "return Result : constant
1440 -- T..."). This is not in the latest RM, but the ARG is considering an
1441 -- AI on the subject (see AI05-0015-1), which we expect to be approved.
1442
1443 if Token = Tok_Constant then
1444 Scan; -- past CONSTANT
1445 Set_Constant_Present (Decl_Node);
1446
1447 if Token = Tok_Aliased then
1448 Error_Msg_SC -- CODEFIX
1449 ("ALIASED should be before CONSTANT");
1450 Scan; -- past ALIASED
1451 Set_Aliased_Present (Decl_Node);
1452 end if;
1453
1454 elsif Token = Tok_Aliased then
1455 Scan; -- past ALIASED
1456 Set_Aliased_Present (Decl_Node);
1457
1458 if Token = Tok_Constant then
1459 Scan; -- past CONSTANT
1460 Set_Constant_Present (Decl_Node);
1461 end if;
1462 end if;
1463
1464 P_Return_Subtype_Indication (Decl_Node);
1465
1466 if Token = Tok_Colon_Equal then
1467 Scan; -- past :=
1468 Set_Expression (Decl_Node, P_Expression_No_Right_Paren);
1469 end if;
1470
1471 return Decl_Node;
1472 end P_Return_Object_Declaration;
1473
1474 -- Error recovery: can raise Error_Resync
1475
1476 function P_Return_Statement return Node_Id is
1477 -- The caller has checked that the initial token is RETURN
1478
1479 function Is_Simple return Boolean;
1480 -- Scan state is just after RETURN (and is left that way).
1481 -- Determine whether this is a simple or extended return statement
1482 -- by looking ahead for "identifier :", which implies extended.
1483
1484 ---------------
1485 -- Is_Simple --
1486 ---------------
1487
1488 function Is_Simple return Boolean is
1489 Scan_State : Saved_Scan_State;
1490 Result : Boolean := True;
1491
1492 begin
1493 if Token = Tok_Identifier then
1494 Save_Scan_State (Scan_State); -- at identifier
1495 Scan; -- past identifier
1496
1497 if Token = Tok_Colon then
1498 Result := False; -- It's an extended_return_statement.
1499 end if;
1500
1501 Restore_Scan_State (Scan_State); -- to identifier
1502 end if;
1503
1504 return Result;
1505 end Is_Simple;
1506
1507 Return_Sloc : constant Source_Ptr := Token_Ptr;
1508 Return_Node : Node_Id;
1509
1510 -- Start of processing for P_Return_Statement
1511
1512 begin
1513 Scan; -- past RETURN
1514
1515 -- Simple_return_statement, no expression, return an
1516 -- N_Simple_Return_Statement node with the expression field left Empty.
1517
1518 if Token = Tok_Semicolon then
1519 Scan; -- past ;
1520 Return_Node := New_Node (N_Simple_Return_Statement, Return_Sloc);
1521
1522 -- Non-trivial case
1523
1524 else
1525 -- Simple_return_statement with expression
1526
1527 -- We avoid trying to scan an expression if we are at an
1528 -- expression terminator since in that case the best error
1529 -- message is probably that we have a missing semicolon.
1530
1531 if Is_Simple then
1532 Return_Node := New_Node (N_Simple_Return_Statement, Return_Sloc);
1533
1534 if Token not in Token_Class_Eterm then
1535 Set_Expression (Return_Node, P_Expression_No_Right_Paren);
1536 end if;
1537
1538 -- Extended_return_statement (Ada 2005 only -- AI-318):
1539
1540 else
1541 if Ada_Version < Ada_05 then
1542 Error_Msg_SP
1543 (" extended_return_statement is an Ada 2005 extension");
1544 Error_Msg_SP ("\unit must be compiled with -gnat05 switch");
1545 end if;
1546
1547 Return_Node := New_Node (N_Extended_Return_Statement, Return_Sloc);
1548 Set_Return_Object_Declarations
1549 (Return_Node, New_List (P_Return_Object_Declaration));
1550
1551 if Token = Tok_Do then
1552 Push_Scope_Stack;
1553 Scope.Table (Scope.Last).Etyp := E_Return;
1554 Scope.Table (Scope.Last).Ecol := Start_Column;
1555 Scope.Table (Scope.Last).Sloc := Return_Sloc;
1556
1557 Scan; -- past DO
1558 Set_Handled_Statement_Sequence
1559 (Return_Node, P_Handled_Sequence_Of_Statements);
1560 End_Statements;
1561
1562 -- Do we need to handle Error_Resync here???
1563 end if;
1564 end if;
1565
1566 TF_Semicolon;
1567 end if;
1568
1569 return Return_Node;
1570 end P_Return_Statement;
1571
1572 end Ch6;