?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
PR tree-optimization/43833
[official-gcc/alias-decl.git] / gcc / ada / par-ch6.adb
blobea5df6dfb3b4ed3b8a8a3b43f95733fc795383ea
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- P A R . C H 6 --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2009, 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 ("|extra "";"" ignored");
68 Scan; -- rescan past junk semicolon
69 else
70 Restore_Scan_State (Scan_State);
71 end if;
72
73 elsif Bad_Spelling_Of (Tok_Return) then
74 null;
75 end if;
76 end Check_Junk_Semicolon_Before_Return;
77
78 -----------------------------------------------------
79 -- 6.1 Subprogram (Also 6.3, 8.5.4, 10.1.3, 12.3) --
80 -----------------------------------------------------
81
82 -- This routine scans out a subprogram declaration, subprogram body,
83 -- subprogram renaming declaration or subprogram generic instantiation.
84
85 -- SUBPROGRAM_DECLARATION ::= SUBPROGRAM_SPECIFICATION;
86
87 -- ABSTRACT_SUBPROGRAM_DECLARATION ::=
88 -- SUBPROGRAM_SPECIFICATION is abstract;
89
90 -- SUBPROGRAM_SPECIFICATION ::=
91 -- procedure DEFINING_PROGRAM_UNIT_NAME PARAMETER_PROFILE
92 -- | function DEFINING_DESIGNATOR PARAMETER_AND_RESULT_PROFILE
93
94 -- PARAMETER_PROFILE ::= [FORMAL_PART]
95
96 -- PARAMETER_AND_RESULT_PROFILE ::= [FORMAL_PART] return SUBTYPE_MARK
97
98 -- SUBPROGRAM_BODY ::=
99 -- SUBPROGRAM_SPECIFICATION is
100 -- DECLARATIVE_PART
101 -- begin
102 -- HANDLED_SEQUENCE_OF_STATEMENTS
103 -- end [DESIGNATOR];
104
105 -- SUBPROGRAM_RENAMING_DECLARATION ::=
106 -- SUBPROGRAM_SPECIFICATION renames callable_entity_NAME;
107
108 -- SUBPROGRAM_BODY_STUB ::=
109 -- SUBPROGRAM_SPECIFICATION is separate;
110
111 -- GENERIC_INSTANTIATION ::=
112 -- procedure DEFINING_PROGRAM_UNIT_NAME is
113 -- new generic_procedure_NAME [GENERIC_ACTUAL_PART];
114 -- | function DEFINING_DESIGNATOR is
115 -- new generic_function_NAME [GENERIC_ACTUAL_PART];
116
117 -- NULL_PROCEDURE_DECLARATION ::=
118 -- SUBPROGRAM_SPECIFICATION is null;
119
120 -- Null procedures are an Ada 2005 feature. A null procedure declaration
121 -- is classified as a basic declarative item, but it is parsed here, with
122 -- other subprogram constructs.
123
124 -- The value in Pf_Flags indicates which of these possible declarations
125 -- is acceptable to the caller:
126
127 -- Pf_Flags.Decl Set if declaration OK
128 -- Pf_Flags.Gins Set if generic instantiation OK
129 -- Pf_Flags.Pbod Set if proper body OK
130 -- Pf_Flags.Rnam Set if renaming declaration OK
131 -- Pf_Flags.Stub Set if body stub OK
132
133 -- If an inappropriate form is encountered, it is scanned out but an
134 -- error message indicating that it is appearing in an inappropriate
135 -- context is issued. The only possible values for Pf_Flags are those
136 -- defined as constants in the Par package.
137
138 -- The caller has checked that the initial token is FUNCTION, PROCEDURE,
139 -- NOT or OVERRIDING.
140
141 -- Error recovery: cannot raise Error_Resync
142
143 function P_Subprogram (Pf_Flags : Pf_Rec) return Node_Id is
144 Specification_Node : Node_Id;
145 Name_Node : Node_Id;
146 Fpart_List : List_Id;
147 Fpart_Sloc : Source_Ptr;
148 Result_Not_Null : Boolean := False;
149 Result_Node : Node_Id;
150 Inst_Node : Node_Id;
151 Body_Node : Node_Id;
152 Decl_Node : Node_Id;
153 Rename_Node : Node_Id;
154 Absdec_Node : Node_Id;
155 Stub_Node : Node_Id;
156 Fproc_Sloc : Source_Ptr;
157 Func : Boolean;
158 Scan_State : Saved_Scan_State;
159
160 -- Flags for optional overriding indication. Two flags are needed,
161 -- to distinguish positive and negative overriding indicators from
162 -- the absence of any indicator.
163
164 Is_Overriding : Boolean := False;
165 Not_Overriding : Boolean := False;
166
167 begin
168 -- Set up scope stack entry. Note that the Labl field will be set later
169
170 SIS_Entry_Active := False;
171 SIS_Missing_Semicolon_Message := No_Error_Msg;
172 Push_Scope_Stack;
173 Scope.Table (Scope.Last).Sloc := Token_Ptr;
174 Scope.Table (Scope.Last).Etyp := E_Name;
175 Scope.Table (Scope.Last).Ecol := Start_Column;
176 Scope.Table (Scope.Last).Lreq := False;
177
178 -- Ada2005: scan leading NOT OVERRIDING indicator
179
180 if Token = Tok_Not then
181 Scan; -- past NOT
182
183 if Token = Tok_Overriding then
184 Scan; -- past OVERRIDING
185 Not_Overriding := True;
186
187 -- Overriding keyword used in non Ada 2005 mode
188
189 elsif Token = Tok_Identifier
190 and then Token_Name = Name_Overriding
191 then
192 Error_Msg_SC ("overriding indicator is an Ada 2005 extension");
193 Error_Msg_SC ("\unit must be compiled with -gnat05 switch");
194 Scan; -- past Overriding
195 Not_Overriding := True;
196
197 else
198 Error_Msg_SC ("OVERRIDING expected!");
199 end if;
200
201 -- Ada 2005: scan leading OVERRIDING indicator
202
203 -- Note: in the case of OVERRIDING keyword used in Ada 95 mode, the
204 -- declaration circuit already gave an error message and changed the
205 -- token to Tok_Overriding.
206
207 elsif Token = Tok_Overriding then
208 Scan; -- past OVERRIDING
209 Is_Overriding := True;
210 end if;
211
212 if (Is_Overriding or else Not_Overriding) then
213
214 -- Note that if we are not in Ada_05 mode, error messages have
215 -- already been given, so no need to give another message here.
216
217 -- An overriding indicator is allowed for subprogram declarations,
218 -- bodies, renamings, stubs, and instantiations. The test against
219 -- Pf_Decl_Pbod is added to account for the case of subprograms
220 -- declared in a protected type, where only subprogram declarations
221 -- and bodies can occur.
222
223 if Pf_Flags /= Pf_Decl_Gins_Pbod_Rnam_Stub
224 and then
225 Pf_Flags /= Pf_Decl_Pbod
226 then
227 Error_Msg_SC ("overriding indicator not allowed here!");
228
229 elsif Token /= Tok_Function and then Token /= Tok_Procedure then
230 Error_Msg_SC -- CODEFIX
231 ("FUNCTION or PROCEDURE expected!");
232 end if;
233 end if;
234
235 Func := (Token = Tok_Function);
236 Fproc_Sloc := Token_Ptr;
237 Scan; -- past FUNCTION or PROCEDURE
238 Ignore (Tok_Type);
239 Ignore (Tok_Body);
240
241 if Func then
242 Name_Node := P_Defining_Designator;
243
244 if Nkind (Name_Node) = N_Defining_Operator_Symbol
245 and then Scope.Last = 1
246 then
247 Error_Msg_SP ("operator symbol not allowed at library level");
248 Name_Node := New_Entity (N_Defining_Identifier, Sloc (Name_Node));
249
250 -- Set name from file name, we need some junk name, and that's
251 -- as good as anything. This is only approximate, since we do
252 -- not do anything with non-standard name translations.
253
254 Get_Name_String (File_Name (Current_Source_File));
255
256 for J in 1 .. Name_Len loop
257 if Name_Buffer (J) = '.' then
258 Name_Len := J - 1;
259 exit;
260 end if;
261 end loop;
262
263 Set_Chars (Name_Node, Name_Find);
264 Set_Error_Posted (Name_Node);
265 end if;
266
267 else
268 Name_Node := P_Defining_Program_Unit_Name;
269 end if;
270
271 Scope.Table (Scope.Last).Labl := Name_Node;
272 Ignore (Tok_Colon);
273
274 -- Deal with generic instantiation, the one case in which we do not
275 -- have a subprogram specification as part of whatever we are parsing
276
277 if Token = Tok_Is then
278 Save_Scan_State (Scan_State); -- at the IS
279 T_Is; -- checks for redundant IS
280
281 if Token = Tok_New then
282 if not Pf_Flags.Gins then
283 Error_Msg_SC ("generic instantiation not allowed here!");
284 end if;
285
286 Scan; -- past NEW
287
288 if Func then
289 Inst_Node := New_Node (N_Function_Instantiation, Fproc_Sloc);
290 Set_Name (Inst_Node, P_Function_Name);
291 else
292 Inst_Node := New_Node (N_Procedure_Instantiation, Fproc_Sloc);
293 Set_Name (Inst_Node, P_Qualified_Simple_Name);
294 end if;
295
296 Set_Defining_Unit_Name (Inst_Node, Name_Node);
297 Set_Generic_Associations (Inst_Node, P_Generic_Actual_Part_Opt);
298 TF_Semicolon;
299 Pop_Scope_Stack; -- Don't need scope stack entry in this case
300
301 if Is_Overriding then
302 Set_Must_Override (Inst_Node);
303
304 elsif Not_Overriding then
305 Set_Must_Not_Override (Inst_Node);
306 end if;
307
308 return Inst_Node;
309
310 else
311 Restore_Scan_State (Scan_State); -- to the IS
312 end if;
313 end if;
314
315 -- If not a generic instantiation, then we definitely have a subprogram
316 -- specification (all possibilities at this stage include one here)
317
318 Fpart_Sloc := Token_Ptr;
319
320 Check_Misspelling_Of (Tok_Return);
321
322 -- Scan formal part. First a special error check. If we have an
323 -- identifier here, then we have a definite error. If this identifier
324 -- is on the same line as the designator, then we assume it is the
325 -- first formal after a missing left parenthesis
326
327 if Token = Tok_Identifier
328 and then not Token_Is_At_Start_Of_Line
329 then
330 T_Left_Paren; -- to generate message
331 Fpart_List := P_Formal_Part;
332
333 -- Otherwise scan out an optional formal part in the usual manner
334
335 else
336 Fpart_List := P_Parameter_Profile;
337 end if;
338
339 -- We treat what we have as a function specification if FUNCTION was
340 -- used, or if a RETURN is present. This gives better error recovery
341 -- since later RETURN statements will be valid in either case.
342
343 Check_Junk_Semicolon_Before_Return;
344 Result_Node := Error;
345
346 if Token = Tok_Return then
347 if not Func then
348 Error_Msg ("PROCEDURE should be FUNCTION", Fproc_Sloc);
349 Func := True;
350 end if;
351
352 Scan; -- past RETURN
353
354 Result_Not_Null := P_Null_Exclusion; -- Ada 2005 (AI-231)
355
356 -- Ada 2005 (AI-318-02)
357
358 if Token = Tok_Access then
359 if Ada_Version < Ada_05 then
360 Error_Msg_SC
361 ("anonymous access result type is an Ada 2005 extension");
362 Error_Msg_SC ("\unit must be compiled with -gnat05 switch");
363 end if;
364
365 Result_Node := P_Access_Definition (Result_Not_Null);
366
367 else
368 Result_Node := P_Subtype_Mark;
369 No_Constraint;
370 end if;
371
372 else
373 if Func then
374 Ignore (Tok_Right_Paren);
375 TF_Return;
376 end if;
377 end if;
378
379 if Func then
380 Specification_Node :=
381 New_Node (N_Function_Specification, Fproc_Sloc);
382
383 Set_Null_Exclusion_Present (Specification_Node, Result_Not_Null);
384 Set_Result_Definition (Specification_Node, Result_Node);
385
386 else
387 Specification_Node :=
388 New_Node (N_Procedure_Specification, Fproc_Sloc);
389 end if;
390
391 Set_Defining_Unit_Name (Specification_Node, Name_Node);
392 Set_Parameter_Specifications (Specification_Node, Fpart_List);
393
394 if Is_Overriding then
395 Set_Must_Override (Specification_Node);
396
397 elsif Not_Overriding then
398 Set_Must_Not_Override (Specification_Node);
399 end if;
400
401 -- Error check: barriers not allowed on protected functions/procedures
402
403 if Token = Tok_When then
404 if Func then
405 Error_Msg_SC ("barrier not allowed on function, only on entry");
406 else
407 Error_Msg_SC ("barrier not allowed on procedure, only on entry");
408 end if;
409
410 Scan; -- past WHEN
411 Discard_Junk_Node (P_Expression);
412 end if;
413
414 -- Deal with semicolon followed by IS. We want to treat this as IS
415
416 if Token = Tok_Semicolon then
417 Save_Scan_State (Scan_State);
418 Scan; -- past semicolon
419
420 if Token = Tok_Is then
421 Error_Msg_SP ("extra "";"" ignored");
422 else
423 Restore_Scan_State (Scan_State);
424 end if;
425 end if;
426
427 -- Deal with case of semicolon ending a subprogram declaration
428
429 if Token = Tok_Semicolon then
430 if not Pf_Flags.Decl then
431 T_Is;
432 end if;
433
434 Scan; -- past semicolon
435
436 -- If semicolon is immediately followed by IS, then ignore the
437 -- semicolon, and go process the body.
438
439 if Token = Tok_Is then
440 Error_Msg_SP ("|extra "";"" ignored");
441 T_Is; -- scan past IS
442 goto Subprogram_Body;
443
444 -- If BEGIN follows in an appropriate column, we immediately
445 -- commence the error action of assuming that the previous
446 -- subprogram declaration should have been a subprogram body,
447 -- i.e. that the terminating semicolon should have been IS.
448
449 elsif Token = Tok_Begin
450 and then Start_Column >= Scope.Table (Scope.Last).Ecol
451 then
452 Error_Msg_SP ("|"";"" should be IS!");
453 goto Subprogram_Body;
454
455 else
456 goto Subprogram_Declaration;
457 end if;
458
459 -- Case of not followed by semicolon
460
461 else
462 -- Subprogram renaming declaration case
463
464 Check_Misspelling_Of (Tok_Renames);
465
466 if Token = Tok_Renames then
467 if not Pf_Flags.Rnam then
468 Error_Msg_SC ("renaming declaration not allowed here!");
469 end if;
470
471 Rename_Node :=
472 New_Node (N_Subprogram_Renaming_Declaration, Token_Ptr);
473 Scan; -- past RENAMES
474 Set_Name (Rename_Node, P_Name);
475 Set_Specification (Rename_Node, Specification_Node);
476 TF_Semicolon;
477 Pop_Scope_Stack;
478 return Rename_Node;
479
480 -- Case of IS following subprogram specification
481
482 elsif Token = Tok_Is then
483 T_Is; -- ignore redundant Is's
484
485 if Token_Name = Name_Abstract then
486 Check_95_Keyword (Tok_Abstract, Tok_Semicolon);
487 end if;
488
489 -- Deal nicely with (now obsolete) use of <> in place of abstract
490
491 if Token = Tok_Box then
492 Error_Msg_SC ("ABSTRACT expected");
493 Token := Tok_Abstract;
494 end if;
495
496 -- Abstract subprogram declaration case
497
498 if Token = Tok_Abstract then
499 Absdec_Node :=
500 New_Node (N_Abstract_Subprogram_Declaration, Token_Ptr);
501 Set_Specification (Absdec_Node, Specification_Node);
502 Pop_Scope_Stack; -- discard unneeded entry
503 Scan; -- past ABSTRACT
504 TF_Semicolon;
505 return Absdec_Node;
506
507 -- Ada 2005 (AI-248): Parse a null procedure declaration
508
509 elsif Token = Tok_Null then
510 if Ada_Version < Ada_05 then
511 Error_Msg_SP ("null procedures are an Ada 2005 extension");
512 Error_Msg_SP ("\unit must be compiled with -gnat05 switch");
513 end if;
514
515 Scan; -- past NULL
516
517 if Func then
518 Error_Msg_SP ("only procedures can be null");
519 else
520 Set_Null_Present (Specification_Node);
521 end if;
522
523 TF_Semicolon;
524 goto Subprogram_Declaration;
525
526 -- Check for IS NEW with Formal_Part present and handle nicely
527
528 elsif Token = Tok_New then
529 Error_Msg
530 ("formal part not allowed in instantiation", Fpart_Sloc);
531 Scan; -- past NEW
532
533 if Func then
534 Inst_Node := New_Node (N_Function_Instantiation, Fproc_Sloc);
535 else
536 Inst_Node :=
537 New_Node (N_Procedure_Instantiation, Fproc_Sloc);
538 end if;
539
540 Set_Defining_Unit_Name (Inst_Node, Name_Node);
541 Set_Name (Inst_Node, P_Name);
542 Set_Generic_Associations (Inst_Node, P_Generic_Actual_Part_Opt);
543 TF_Semicolon;
544 Pop_Scope_Stack; -- Don't need scope stack entry in this case
545 return Inst_Node;
546
547 else
548 goto Subprogram_Body;
549 end if;
550
551 -- Here we have a missing IS or missing semicolon, we always guess
552 -- a missing semicolon, since we are pretty good at fixing up a
553 -- semicolon which should really be an IS
554
555 else
556 Error_Msg_AP ("|missing "";""");
557 SIS_Missing_Semicolon_Message := Get_Msg_Id;
558 goto Subprogram_Declaration;
559 end if;
560 end if;
561
562 -- Processing for subprogram body
563
564 <<Subprogram_Body>>
565 if not Pf_Flags.Pbod then
566 Error_Msg_SP ("subprogram body not allowed here!");
567 end if;
568
569 -- Subprogram body stub case
570
571 if Separate_Present then
572 if not Pf_Flags.Stub then
573 Error_Msg_SC ("body stub not allowed here!");
574 end if;
575
576 if Nkind (Name_Node) = N_Defining_Operator_Symbol then
577 Error_Msg
578 ("operator symbol cannot be used as subunit name",
579 Sloc (Name_Node));
580 end if;
581
582 Stub_Node :=
583 New_Node (N_Subprogram_Body_Stub, Sloc (Specification_Node));
584 Set_Specification (Stub_Node, Specification_Node);
585 Scan; -- past SEPARATE
586 Pop_Scope_Stack;
587 TF_Semicolon;
588 return Stub_Node;
589
590 -- Subprogram body case
591
592 else
593 -- Here is the test for a suspicious IS (i.e. one that looks
594 -- like it might more properly be a semicolon). See separate
595 -- section discussing use of IS instead of semicolon in
596 -- package Parse.
597
598 if (Token in Token_Class_Declk
599 or else
600 Token = Tok_Identifier)
601 and then Start_Column <= Scope.Table (Scope.Last).Ecol
602 and then Scope.Last /= 1
603 then
604 Scope.Table (Scope.Last).Etyp := E_Suspicious_Is;
605 Scope.Table (Scope.Last).S_Is := Prev_Token_Ptr;
606 end if;
607
608 Body_Node :=
609 New_Node (N_Subprogram_Body, Sloc (Specification_Node));
610 Set_Specification (Body_Node, Specification_Node);
611 Parse_Decls_Begin_End (Body_Node);
612 return Body_Node;
613 end if;
614
615 -- Processing for subprogram declaration
616
617 <<Subprogram_Declaration>>
618 Decl_Node :=
619 New_Node (N_Subprogram_Declaration, Sloc (Specification_Node));
620 Set_Specification (Decl_Node, Specification_Node);
621
622 -- If this is a context in which a subprogram body is permitted,
623 -- set active SIS entry in case (see section titled "Handling
624 -- Semicolon Used in Place of IS" in body of Parser package)
625 -- Note that SIS_Missing_Semicolon_Message is already set properly.
626
627 if Pf_Flags.Pbod then
628 SIS_Labl := Scope.Table (Scope.Last).Labl;
629 SIS_Sloc := Scope.Table (Scope.Last).Sloc;
630 SIS_Ecol := Scope.Table (Scope.Last).Ecol;
631 SIS_Declaration_Node := Decl_Node;
632 SIS_Semicolon_Sloc := Prev_Token_Ptr;
633 SIS_Entry_Active := True;
634 end if;
635
636 Pop_Scope_Stack;
637 return Decl_Node;
638
639 end P_Subprogram;
640
641 ---------------------------------
642 -- 6.1 Subprogram Declaration --
643 ---------------------------------
644
645 -- Parsed by P_Subprogram (6.1)
646
647 ------------------------------------------
648 -- 6.1 Abstract Subprogram Declaration --
649 ------------------------------------------
650
651 -- Parsed by P_Subprogram (6.1)
652
653 -----------------------------------
654 -- 6.1 Subprogram Specification --
655 -----------------------------------
656
657 -- SUBPROGRAM_SPECIFICATION ::=
658 -- procedure DEFINING_PROGRAM_UNIT_NAME PARAMETER_PROFILE
659 -- | function DEFINING_DESIGNATOR PARAMETER_AND_RESULT_PROFILE
660
661 -- PARAMETER_PROFILE ::= [FORMAL_PART]
662
663 -- PARAMETER_AND_RESULT_PROFILE ::= [FORMAL_PART] return SUBTYPE_MARK
664
665 -- Subprogram specifications that appear in subprogram declarations
666 -- are parsed by P_Subprogram (6.1). This routine is used in other
667 -- contexts where subprogram specifications occur.
668
669 -- Note: this routine does not affect the scope stack in any way
670
671 -- Error recovery: can raise Error_Resync
672
673 function P_Subprogram_Specification return Node_Id is
674 Specification_Node : Node_Id;
675 Result_Not_Null : Boolean;
676 Result_Node : Node_Id;
677
678 begin
679 if Token = Tok_Function then
680 Specification_Node := New_Node (N_Function_Specification, Token_Ptr);
681 Scan; -- past FUNCTION
682 Ignore (Tok_Body);
683 Set_Defining_Unit_Name (Specification_Node, P_Defining_Designator);
684 Set_Parameter_Specifications
685 (Specification_Node, P_Parameter_Profile);
686 Check_Junk_Semicolon_Before_Return;
687 TF_Return;
688
689 Result_Not_Null := P_Null_Exclusion; -- Ada 2005 (AI-231)
690
691 -- Ada 2005 (AI-318-02)
692
693 if Token = Tok_Access then
694 if Ada_Version < Ada_05 then
695 Error_Msg_SC
696 ("anonymous access result type is an Ada 2005 extension");
697 Error_Msg_SC ("\unit must be compiled with -gnat05 switch");
698 end if;
699
700 Result_Node := P_Access_Definition (Result_Not_Null);
701
702 else
703 Result_Node := P_Subtype_Mark;
704 No_Constraint;
705 end if;
706
707 Set_Null_Exclusion_Present (Specification_Node, Result_Not_Null);
708 Set_Result_Definition (Specification_Node, Result_Node);
709 return Specification_Node;
710
711 elsif Token = Tok_Procedure then
712 Specification_Node := New_Node (N_Procedure_Specification, Token_Ptr);
713 Scan; -- past PROCEDURE
714 Ignore (Tok_Body);
715 Set_Defining_Unit_Name
716 (Specification_Node, P_Defining_Program_Unit_Name);
717 Set_Parameter_Specifications
718 (Specification_Node, P_Parameter_Profile);
719 return Specification_Node;
720
721 else
722 Error_Msg_SC ("subprogram specification expected");
723 raise Error_Resync;
724 end if;
725 end P_Subprogram_Specification;
726
727 ---------------------
728 -- 6.1 Designator --
729 ---------------------
730
731 -- DESIGNATOR ::=
732 -- [PARENT_UNIT_NAME .] IDENTIFIER | OPERATOR_SYMBOL
733
734 -- The caller has checked that the initial token is an identifier,
735 -- operator symbol, or string literal. Note that we don't bother to
736 -- do much error diagnosis in this routine, since it is only used for
737 -- the label on END lines, and the routines in package Par.Endh will
738 -- check that the label is appropriate.
739
740 -- Error recovery: cannot raise Error_Resync
741
742 function P_Designator return Node_Id is
743 Ident_Node : Node_Id;
744 Name_Node : Node_Id;
745 Prefix_Node : Node_Id;
746
747 function Real_Dot return Boolean;
748 -- Tests if a current token is an interesting period, i.e. is followed
749 -- by an identifier or operator symbol or string literal. If not, it is
750 -- probably just incorrect punctuation to be caught by our caller. Note
751 -- that the case of an operator symbol or string literal is also an
752 -- error, but that is an error that we catch here. If the result is
753 -- True, a real dot has been scanned and we are positioned past it,
754 -- if the result is False, the scan position is unchanged.
755
756 --------------
757 -- Real_Dot --
758 --------------
759
760 function Real_Dot return Boolean is
761 Scan_State : Saved_Scan_State;
762
763 begin
764 if Token /= Tok_Dot then
765 return False;
766
767 else
768 Save_Scan_State (Scan_State);
769 Scan; -- past dot
770
771 if Token = Tok_Identifier
772 or else Token = Tok_Operator_Symbol
773 or else Token = Tok_String_Literal
774 then
775 return True;
776
777 else
778 Restore_Scan_State (Scan_State);
779 return False;
780 end if;
781 end if;
782 end Real_Dot;
783
784 -- Start of processing for P_Designator
785
786 begin
787 Ident_Node := Token_Node;
788 Scan; -- past initial token
789
790 if Prev_Token = Tok_Operator_Symbol
791 or else Prev_Token = Tok_String_Literal
792 or else not Real_Dot
793 then
794 return Ident_Node;
795
796 -- Child name case
797
798 else
799 Prefix_Node := Ident_Node;
800
801 -- Loop through child names, on entry to this loop, Prefix contains
802 -- the name scanned so far, and Ident_Node is the last identifier.
803
804 loop
805 Name_Node := New_Node (N_Selected_Component, Prev_Token_Ptr);
806 Set_Prefix (Name_Node, Prefix_Node);
807 Ident_Node := P_Identifier;
808 Set_Selector_Name (Name_Node, Ident_Node);
809 Prefix_Node := Name_Node;
810 exit when not Real_Dot;
811 end loop;
812
813 -- On exit from the loop, Ident_Node is the last identifier scanned,
814 -- i.e. the defining identifier, and Prefix_Node is a node for the
815 -- entire name, structured (incorrectly!) as a selected component.
816
817 Name_Node := Prefix (Prefix_Node);
818 Change_Node (Prefix_Node, N_Designator);
819 Set_Name (Prefix_Node, Name_Node);
820 Set_Identifier (Prefix_Node, Ident_Node);
821 return Prefix_Node;
822 end if;
823
824 exception
825 when Error_Resync =>
826 while Token = Tok_Dot or else Token = Tok_Identifier loop
827 Scan;
828 end loop;
829
830 return Error;
831 end P_Designator;
832
833 ------------------------------
834 -- 6.1 Defining Designator --
835 ------------------------------
836
837 -- DEFINING_DESIGNATOR ::=
838 -- DEFINING_PROGRAM_UNIT_NAME | DEFINING_OPERATOR_SYMBOL
839
840 -- Error recovery: cannot raise Error_Resync
841
842 function P_Defining_Designator return Node_Id is
843 begin
844 if Token = Tok_Operator_Symbol then
845 return P_Defining_Operator_Symbol;
846
847 elsif Token = Tok_String_Literal then
848 Error_Msg_SC ("invalid operator name");
849 Scan; -- past junk string
850 return Error;
851
852 else
853 return P_Defining_Program_Unit_Name;
854 end if;
855 end P_Defining_Designator;
856
857 -------------------------------------
858 -- 6.1 Defining Program Unit Name --
859 -------------------------------------
860
861 -- DEFINING_PROGRAM_UNIT_NAME ::=
862 -- [PARENT_UNIT_NAME .] DEFINING_IDENTIFIER
863
864 -- Note: PARENT_UNIT_NAME may be present only in 95 mode at the outer level
865
866 -- Error recovery: cannot raise Error_Resync
867
868 function P_Defining_Program_Unit_Name return Node_Id is
869 Ident_Node : Node_Id;
870 Name_Node : Node_Id;
871 Prefix_Node : Node_Id;
872
873 begin
874 -- Set identifier casing if not already set and scan initial identifier
875
876 if Token = Tok_Identifier
877 and then Identifier_Casing (Current_Source_File) = Unknown
878 then
879 Set_Identifier_Casing (Current_Source_File, Determine_Token_Casing);
880 end if;
881
882 Ident_Node := P_Identifier (C_Dot);
883 Merge_Identifier (Ident_Node, Tok_Return);
884
885 -- Normal case (not child library unit name)
886
887 if Token /= Tok_Dot then
888 Change_Identifier_To_Defining_Identifier (Ident_Node);
889 return Ident_Node;
890
891 -- Child library unit name case
892
893 else
894 if Scope.Last > 1 then
895 Error_Msg_SP ("child unit allowed only at library level");
896 raise Error_Resync;
897
898 elsif Ada_Version = Ada_83 then
899 Error_Msg_SP ("(Ada 83) child unit not allowed!");
900
901 end if;
902
903 Prefix_Node := Ident_Node;
904
905 -- Loop through child names, on entry to this loop, Prefix contains
906 -- the name scanned so far, and Ident_Node is the last identifier.
907
908 loop
909 exit when Token /= Tok_Dot;
910 Name_Node := New_Node (N_Selected_Component, Token_Ptr);
911 Scan; -- past period
912 Set_Prefix (Name_Node, Prefix_Node);
913 Ident_Node := P_Identifier (C_Dot);
914 Set_Selector_Name (Name_Node, Ident_Node);
915 Prefix_Node := Name_Node;
916 end loop;
917
918 -- On exit from the loop, Ident_Node is the last identifier scanned,
919 -- i.e. the defining identifier, and Prefix_Node is a node for the
920 -- entire name, structured (incorrectly!) as a selected component.
921
922 Name_Node := Prefix (Prefix_Node);
923 Change_Node (Prefix_Node, N_Defining_Program_Unit_Name);
924 Set_Name (Prefix_Node, Name_Node);
925 Change_Identifier_To_Defining_Identifier (Ident_Node);
926 Set_Defining_Identifier (Prefix_Node, Ident_Node);
927
928 -- All set with unit name parsed
929
930 return Prefix_Node;
931 end if;
932
933 exception
934 when Error_Resync =>
935 while Token = Tok_Dot or else Token = Tok_Identifier loop
936 Scan;
937 end loop;
938
939 return Error;
940 end P_Defining_Program_Unit_Name;
941
942 --------------------------
943 -- 6.1 Operator Symbol --
944 --------------------------
945
946 -- OPERATOR_SYMBOL ::= STRING_LITERAL
947
948 -- Operator symbol is returned by the scanner as Tok_Operator_Symbol
949
950 -----------------------------------
951 -- 6.1 Defining Operator Symbol --
952 -----------------------------------
953
954 -- DEFINING_OPERATOR_SYMBOL ::= OPERATOR_SYMBOL
955
956 -- The caller has checked that the initial symbol is an operator symbol
957
958 function P_Defining_Operator_Symbol return Node_Id is
959 Op_Node : Node_Id;
960
961 begin
962 Op_Node := Token_Node;
963 Change_Operator_Symbol_To_Defining_Operator_Symbol (Op_Node);
964 Scan; -- past operator symbol
965 return Op_Node;
966 end P_Defining_Operator_Symbol;
967
968 ----------------------------
969 -- 6.1 Parameter_Profile --
970 ----------------------------
971
972 -- PARAMETER_PROFILE ::= [FORMAL_PART]
973
974 -- Empty is returned if no formal part is present
975
976 -- Error recovery: cannot raise Error_Resync
977
978 function P_Parameter_Profile return List_Id is
979 begin
980 if Token = Tok_Left_Paren then
981 Scan; -- part left paren
982 return P_Formal_Part;
983 else
984 return No_List;
985 end if;
986 end P_Parameter_Profile;
987
988 ---------------------------------------
989 -- 6.1 Parameter And Result Profile --
990 ---------------------------------------
991
992 -- Parsed by its parent construct, which uses P_Parameter_Profile to
993 -- parse the parameters, and P_Subtype_Mark to parse the return type.
994
995 ----------------------
996 -- 6.1 Formal part --
997 ----------------------
998
999 -- FORMAL_PART ::= (PARAMETER_SPECIFICATION {; PARAMETER_SPECIFICATION})
1000
1001 -- PARAMETER_SPECIFICATION ::=
1002 -- DEFINING_IDENTIFIER_LIST : MODE [NULL_EXCLUSION] SUBTYPE_MARK
1003 -- [:= DEFAULT_EXPRESSION]
1004 -- | DEFINING_IDENTIFIER_LIST : ACCESS_DEFINITION
1005 -- [:= DEFAULT_EXPRESSION]
1006
1007 -- This scans the construct Formal_Part. The caller has already checked
1008 -- that the initial token is a left parenthesis, and skipped past it, so
1009 -- that on entry Token is the first token following the left parenthesis.
1010
1011 -- Error recovery: cannot raise Error_Resync
1012
1013 function P_Formal_Part return List_Id is
1014 Specification_List : List_Id;
1015 Specification_Node : Node_Id;
1016 Scan_State : Saved_Scan_State;
1017 Num_Idents : Nat;
1018 Ident : Nat;
1019 Ident_Sloc : Source_Ptr;
1020 Not_Null_Present : Boolean := False;
1021 Not_Null_Sloc : Source_Ptr;
1022
1023 Idents : array (Int range 1 .. 4096) of Entity_Id;
1024 -- This array holds the list of defining identifiers. The upper bound
1025 -- of 4096 is intended to be essentially infinite, and we do not even
1026 -- bother to check for it being exceeded.
1027
1028 begin
1029 Specification_List := New_List;
1030 Specification_Loop : loop
1031 begin
1032 if Token = Tok_Pragma then
1033 Error_Msg_SC ("pragma not allowed in formal part");
1034 Discard_Junk_Node (P_Pragma (Skipping => True));
1035 end if;
1036
1037 Ignore (Tok_Left_Paren);
1038 Ident_Sloc := Token_Ptr;
1039 Idents (1) := P_Defining_Identifier (C_Comma_Colon);
1040 Num_Idents := 1;
1041
1042 Ident_Loop : loop
1043 exit Ident_Loop when Token = Tok_Colon;
1044
1045 -- The only valid tokens are colon and comma, so if we have
1046 -- neither do a bit of investigation to see which is the
1047 -- better choice for insertion.
1048
1049 if Token /= Tok_Comma then
1050
1051 -- Assume colon if IN or OUT keyword found
1052
1053 exit Ident_Loop when Token = Tok_In or else Token = Tok_Out;
1054
1055 -- Otherwise scan ahead
1056
1057 Save_Scan_State (Scan_State);
1058 Look_Ahead : loop
1059
1060 -- If we run into a semicolon, then assume that a
1061 -- colon was missing, e.g. Parms (X Y; ...). Also
1062 -- assume missing colon on EOF (a real disaster!)
1063 -- and on a right paren, e.g. Parms (X Y), and also
1064 -- on an assignment symbol, e.g. Parms (X Y := ..)
1065
1066 if Token = Tok_Semicolon
1067 or else Token = Tok_Right_Paren
1068 or else Token = Tok_EOF
1069 or else Token = Tok_Colon_Equal
1070 then
1071 Restore_Scan_State (Scan_State);
1072 exit Ident_Loop;
1073
1074 -- If we run into a colon, assume that we had a missing
1075 -- comma, e.g. Parms (A B : ...). Also assume a missing
1076 -- comma if we hit another comma, e.g. Parms (A B, C ..)
1077
1078 elsif Token = Tok_Colon
1079 or else Token = Tok_Comma
1080 then
1081 Restore_Scan_State (Scan_State);
1082 exit Look_Ahead;
1083 end if;
1084
1085 Scan;
1086 end loop Look_Ahead;
1087 end if;
1088
1089 -- Here if a comma is present, or to be assumed
1090
1091 T_Comma;
1092 Num_Idents := Num_Idents + 1;
1093 Idents (Num_Idents) := P_Defining_Identifier (C_Comma_Colon);
1094 end loop Ident_Loop;
1095
1096 -- Fall through the loop on encountering a colon, or deciding
1097 -- that there is a missing colon.
1098
1099 T_Colon;
1100
1101 -- If there are multiple identifiers, we repeatedly scan the
1102 -- type and initialization expression information by resetting
1103 -- the scan pointer (so that we get completely separate trees
1104 -- for each occurrence).
1105
1106 if Num_Idents > 1 then
1107 Save_Scan_State (Scan_State);
1108 end if;
1109
1110 -- Loop through defining identifiers in list
1111
1112 Ident := 1;
1113
1114 Ident_List_Loop : loop
1115 Specification_Node :=
1116 New_Node (N_Parameter_Specification, Ident_Sloc);
1117 Set_Defining_Identifier (Specification_Node, Idents (Ident));
1118
1119 -- Scan possible NOT NULL for Ada 2005 (AI-231, AI-447)
1120
1121 Not_Null_Sloc := Token_Ptr;
1122 Not_Null_Present :=
1123 P_Null_Exclusion (Allow_Anonymous_In_95 => True);
1124
1125 -- Case of ACCESS keyword present
1126
1127 if Token = Tok_Access then
1128 Set_Null_Exclusion_Present
1129 (Specification_Node, Not_Null_Present);
1130
1131 if Ada_Version = Ada_83 then
1132 Error_Msg_SC ("(Ada 83) access parameters not allowed");
1133 end if;
1134
1135 Set_Parameter_Type
1136 (Specification_Node,
1137 P_Access_Definition (Not_Null_Present));
1138
1139 -- Case of IN or OUT present
1140
1141 else
1142 if Token = Tok_In or else Token = Tok_Out then
1143 if Not_Null_Present then
1144 Error_Msg
1145 ("`NOT NULL` can only be used with `ACCESS`",
1146 Not_Null_Sloc);
1147
1148 if Token = Tok_In then
1149 Error_Msg
1150 ("\`IN` not allowed together with `ACCESS`",
1151 Not_Null_Sloc);
1152 else
1153 Error_Msg
1154 ("\`OUT` not allowed together with `ACCESS`",
1155 Not_Null_Sloc);
1156 end if;
1157 end if;
1158
1159 P_Mode (Specification_Node);
1160 Not_Null_Present := P_Null_Exclusion; -- Ada 2005 (AI-231)
1161 end if;
1162
1163 Set_Null_Exclusion_Present
1164 (Specification_Node, Not_Null_Present);
1165
1166 if Token = Tok_Procedure
1167 or else
1168 Token = Tok_Function
1169 then
1170 Error_Msg_SC ("formal subprogram parameter not allowed");
1171 Scan;
1172
1173 if Token = Tok_Left_Paren then
1174 Discard_Junk_List (P_Formal_Part);
1175 end if;
1176
1177 if Token = Tok_Return then
1178 Scan;
1179 Discard_Junk_Node (P_Subtype_Mark);
1180 end if;
1181
1182 Set_Parameter_Type (Specification_Node, Error);
1183
1184 else
1185 Set_Parameter_Type (Specification_Node, P_Subtype_Mark);
1186 No_Constraint;
1187 end if;
1188 end if;
1189
1190 Set_Expression (Specification_Node, Init_Expr_Opt (True));
1191
1192 if Ident > 1 then
1193 Set_Prev_Ids (Specification_Node, True);
1194 end if;
1195
1196 if Ident < Num_Idents then
1197 Set_More_Ids (Specification_Node, True);
1198 end if;
1199
1200 Append (Specification_Node, Specification_List);
1201 exit Ident_List_Loop when Ident = Num_Idents;
1202 Ident := Ident + 1;
1203 Restore_Scan_State (Scan_State);
1204 end loop Ident_List_Loop;
1205
1206 exception
1207 when Error_Resync =>
1208 Resync_Semicolon_List;
1209 end;
1210
1211 if Token = Tok_Semicolon then
1212 Save_Scan_State (Scan_State);
1213 Scan; -- past semicolon
1214
1215 -- If we have RETURN or IS after the semicolon, then assume
1216 -- that semicolon should have been a right parenthesis and exit
1217
1218 if Token = Tok_Is or else Token = Tok_Return then
1219 Error_Msg_SP ("|"";"" should be "")""");
1220 exit Specification_Loop;
1221 end if;
1222
1223 -- If we have a declaration keyword after the semicolon, then
1224 -- assume we had a missing right parenthesis and terminate list
1225
1226 if Token in Token_Class_Declk then
1227 Error_Msg_AP ("missing "")""");
1228 Restore_Scan_State (Scan_State);
1229 exit Specification_Loop;
1230 end if;
1231
1232 elsif Token = Tok_Right_Paren then
1233 Scan; -- past right paren
1234 exit Specification_Loop;
1235
1236 -- Special check for common error of using comma instead of semicolon
1237
1238 elsif Token = Tok_Comma then
1239 T_Semicolon;
1240 Scan; -- past comma
1241
1242 -- Special check for omitted separator
1243
1244 elsif Token = Tok_Identifier then
1245 T_Semicolon;
1246
1247 -- If nothing sensible, skip to next semicolon or right paren
1248
1249 else
1250 T_Semicolon;
1251 Resync_Semicolon_List;
1252
1253 if Token = Tok_Semicolon then
1254 Scan; -- past semicolon
1255 else
1256 T_Right_Paren;
1257 exit Specification_Loop;
1258 end if;
1259 end if;
1260 end loop Specification_Loop;
1261
1262 return Specification_List;
1263 end P_Formal_Part;
1264
1265 ----------------------------------
1266 -- 6.1 Parameter Specification --
1267 ----------------------------------
1268
1269 -- Parsed by P_Formal_Part (6.1)
1270
1271 ---------------
1272 -- 6.1 Mode --
1273 ---------------
1274
1275 -- MODE ::= [in] | in out | out
1276
1277 -- There is no explicit node in the tree for the Mode. Instead the
1278 -- In_Present and Out_Present flags are set in the parent node to
1279 -- record the presence of keywords specifying the mode.
1280
1281 -- Error_Recovery: cannot raise Error_Resync
1282
1283 procedure P_Mode (Node : Node_Id) is
1284 begin
1285 if Token = Tok_In then
1286 Scan; -- past IN
1287 Set_In_Present (Node, True);
1288
1289 if Style.Mode_In_Check and then Token /= Tok_Out then
1290 Error_Msg_SP ("(style) IN should be omitted");
1291 end if;
1292
1293 if Token = Tok_Access then
1294 Error_Msg_SP ("IN not allowed together with ACCESS");
1295 Scan; -- past ACCESS
1296 end if;
1297 end if;
1298
1299 if Token = Tok_Out then
1300 Scan; -- past OUT
1301 Set_Out_Present (Node, True);
1302 end if;
1303
1304 if Token = Tok_In then
1305 Error_Msg_SC -- CODEFIX ???
1306 ("IN must precede OUT in parameter mode");
1307 Scan; -- past IN
1308 Set_In_Present (Node, True);
1309 end if;
1310 end P_Mode;
1311
1312 --------------------------
1313 -- 6.3 Subprogram Body --
1314 --------------------------
1315
1316 -- Parsed by P_Subprogram (6.1)
1317
1318 -----------------------------------
1319 -- 6.4 Procedure Call Statement --
1320 -----------------------------------
1321
1322 -- Parsed by P_Sequence_Of_Statements (5.1)
1323
1324 ------------------------
1325 -- 6.4 Function Call --
1326 ------------------------
1327
1328 -- Parsed by P_Call_Or_Name (4.1)
1329
1330 --------------------------------
1331 -- 6.4 Actual Parameter Part --
1332 --------------------------------
1333
1334 -- Parsed by P_Call_Or_Name (4.1)
1335
1336 --------------------------------
1337 -- 6.4 Parameter Association --
1338 --------------------------------
1339
1340 -- Parsed by P_Call_Or_Name (4.1)
1341
1342 ------------------------------------
1343 -- 6.4 Explicit Actual Parameter --
1344 ------------------------------------
1345
1346 -- Parsed by P_Call_Or_Name (4.1)
1347
1348 ---------------------------
1349 -- 6.5 Return Statement --
1350 ---------------------------
1351
1352 -- SIMPLE_RETURN_STATEMENT ::= return [EXPRESSION];
1353 --
1354 -- EXTENDED_RETURN_STATEMENT ::=
1355 -- return DEFINING_IDENTIFIER : [aliased] RETURN_SUBTYPE_INDICATION
1356 -- [:= EXPRESSION] [do
1357 -- HANDLED_SEQUENCE_OF_STATEMENTS
1358 -- end return];
1359 --
1360 -- RETURN_SUBTYPE_INDICATION ::= SUBTYPE_INDICATION | ACCESS_DEFINITION
1361
1362 -- RETURN_STATEMENT ::= return [EXPRESSION];
1363
1364 -- Error recovery: can raise Error_Resync
1365
1366 procedure P_Return_Subtype_Indication (Decl_Node : Node_Id) is
1367
1368 -- Note: We don't need to check Ada_Version here, because this is
1369 -- only called in >= Ada 2005 cases anyway.
1370
1371 Not_Null_Present : constant Boolean := P_Null_Exclusion;
1372
1373 begin
1374 Set_Null_Exclusion_Present (Decl_Node, Not_Null_Present);
1375
1376 if Token = Tok_Access then
1377 Set_Object_Definition
1378 (Decl_Node, P_Access_Definition (Not_Null_Present));
1379 else
1380 Set_Object_Definition
1381 (Decl_Node, P_Subtype_Indication (Not_Null_Present));
1382 end if;
1383 end P_Return_Subtype_Indication;
1384
1385 -- Error recovery: can raise Error_Resync
1386
1387 function P_Return_Object_Declaration return Node_Id is
1388 Return_Obj : Node_Id;
1389 Decl_Node : Node_Id;
1390
1391 begin
1392 Return_Obj := Token_Node;
1393 Change_Identifier_To_Defining_Identifier (Return_Obj);
1394 Decl_Node := New_Node (N_Object_Declaration, Token_Ptr);
1395 Set_Defining_Identifier (Decl_Node, Return_Obj);
1396
1397 Scan; -- past identifier
1398 Scan; -- past :
1399
1400 -- First an error check, if we have two identifiers in a row, a likely
1401 -- possibility is that the first of the identifiers is an incorrectly
1402 -- spelled keyword. See similar check in P_Identifier_Declarations.
1403
1404 if Token = Tok_Identifier then
1405 declare
1406 SS : Saved_Scan_State;
1407 I2 : Boolean;
1408
1409 begin
1410 Save_Scan_State (SS);
1411 Scan; -- past initial identifier
1412 I2 := (Token = Tok_Identifier);
1413 Restore_Scan_State (SS);
1414
1415 if I2
1416 and then
1417 (Bad_Spelling_Of (Tok_Access) or else
1418 Bad_Spelling_Of (Tok_Aliased) or else
1419 Bad_Spelling_Of (Tok_Constant))
1420 then
1421 null;
1422 end if;
1423 end;
1424 end if;
1425
1426 -- We allow "constant" here (as in "return Result : constant
1427 -- T..."). This is not in the latest RM, but the ARG is considering an
1428 -- AI on the subject (see AI05-0015-1), which we expect to be approved.
1429
1430 if Token = Tok_Constant then
1431 Scan; -- past CONSTANT
1432 Set_Constant_Present (Decl_Node);
1433
1434 if Token = Tok_Aliased then
1435 Error_Msg_SC -- CODEFIX
1436 ("ALIASED should be before CONSTANT");
1437 Scan; -- past ALIASED
1438 Set_Aliased_Present (Decl_Node);
1439 end if;
1440
1441 elsif Token = Tok_Aliased then
1442 Scan; -- past ALIASED
1443 Set_Aliased_Present (Decl_Node);
1444
1445 if Token = Tok_Constant then
1446 Scan; -- past CONSTANT
1447 Set_Constant_Present (Decl_Node);
1448 end if;
1449 end if;
1450
1451 P_Return_Subtype_Indication (Decl_Node);
1452
1453 if Token = Tok_Colon_Equal then
1454 Scan; -- past :=
1455 Set_Expression (Decl_Node, P_Expression_No_Right_Paren);
1456 end if;
1457
1458 return Decl_Node;
1459 end P_Return_Object_Declaration;
1460
1461 -- Error recovery: can raise Error_Resync
1462
1463 function P_Return_Statement return Node_Id is
1464 -- The caller has checked that the initial token is RETURN
1465
1466 function Is_Simple return Boolean;
1467 -- Scan state is just after RETURN (and is left that way).
1468 -- Determine whether this is a simple or extended return statement
1469 -- by looking ahead for "identifier :", which implies extended.
1470
1471 ---------------
1472 -- Is_Simple --
1473 ---------------
1474
1475 function Is_Simple return Boolean is
1476 Scan_State : Saved_Scan_State;
1477 Result : Boolean := True;
1478
1479 begin
1480 if Token = Tok_Identifier then
1481 Save_Scan_State (Scan_State); -- at identifier
1482 Scan; -- past identifier
1483
1484 if Token = Tok_Colon then
1485 Result := False; -- It's an extended_return_statement.
1486 end if;
1487
1488 Restore_Scan_State (Scan_State); -- to identifier
1489 end if;
1490
1491 return Result;
1492 end Is_Simple;
1493
1494 Return_Sloc : constant Source_Ptr := Token_Ptr;
1495 Return_Node : Node_Id;
1496
1497 -- Start of processing for P_Return_Statement
1498
1499 begin
1500 Scan; -- past RETURN
1501
1502 -- Simple_return_statement, no expression, return an
1503 -- N_Simple_Return_Statement node with the expression field left Empty.
1504
1505 if Token = Tok_Semicolon then
1506 Scan; -- past ;
1507 Return_Node := New_Node (N_Simple_Return_Statement, Return_Sloc);
1508
1509 -- Non-trivial case
1510
1511 else
1512 -- Simple_return_statement with expression
1513
1514 -- We avoid trying to scan an expression if we are at an
1515 -- expression terminator since in that case the best error
1516 -- message is probably that we have a missing semicolon.
1517
1518 if Is_Simple then
1519 Return_Node := New_Node (N_Simple_Return_Statement, Return_Sloc);
1520
1521 if Token not in Token_Class_Eterm then
1522 Set_Expression (Return_Node, P_Expression_No_Right_Paren);
1523 end if;
1524
1525 -- Extended_return_statement (Ada 2005 only -- AI-318):
1526
1527 else
1528 if Ada_Version < Ada_05 then
1529 Error_Msg_SP
1530 (" extended_return_statement is an Ada 2005 extension");
1531 Error_Msg_SP ("\unit must be compiled with -gnat05 switch");
1532 end if;
1533
1534 Return_Node := New_Node (N_Extended_Return_Statement, Return_Sloc);
1535 Set_Return_Object_Declarations
1536 (Return_Node, New_List (P_Return_Object_Declaration));
1537
1538 if Token = Tok_Do then
1539 Push_Scope_Stack;
1540 Scope.Table (Scope.Last).Etyp := E_Return;
1541 Scope.Table (Scope.Last).Ecol := Start_Column;
1542 Scope.Table (Scope.Last).Sloc := Return_Sloc;
1543
1544 Scan; -- past DO
1545 Set_Handled_Statement_Sequence
1546 (Return_Node, P_Handled_Sequence_Of_Statements);
1547 End_Statements;
1548
1549 -- Do we need to handle Error_Resync here???
1550 end if;
1551 end if;
1552
1553 TF_Semicolon;
1554 end if;
1555
1556 return Return_Node;
1557 end P_Return_Statement;
1558
1559 end Ch6;