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PR27116, Spelling errors found by Debian style checker
[official-gcc.git] / gcc / ada / par-ch6.adb
blob3171c5c3ce11167277739a75ef8978415bc0d18a
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- P A R . C H 6 --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2023, 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. Set the Null_Exclusion_Present and
43 -- Object_Definition fields of Decl_Node.
44
45 procedure Check_Junk_Semicolon_Before_Return;
46 -- Check for common error of junk semicolon before RETURN keyword of
47 -- function specification. If present, skip over it with appropriate error
48 -- message, leaving Scan_Ptr pointing to the RETURN after. This routine
49 -- also deals with a possibly misspelled version of Return.
50
51 procedure No_Constraint_Maybe_Expr_Func;
52 -- Called after scanning return subtype to check for missing constraint,
53 -- taking into account the possibility of an occurrence of an expression
54 -- function where the IS has been forgotten.
55
56 ----------------------------------------
57 -- Check_Junk_Semicolon_Before_Return --
58 ----------------------------------------
59
60 procedure Check_Junk_Semicolon_Before_Return is
61 Scan_State : Saved_Scan_State;
62
63 begin
64 if Token = Tok_Semicolon then
65 Save_Scan_State (Scan_State);
66 Scan; -- past the semicolon
67
68 if Token = Tok_Return then
69 Restore_Scan_State (Scan_State);
70 Error_Msg_SC -- CODEFIX
71 ("|extra "";"" ignored");
72 Scan; -- rescan past junk semicolon
73 else
74 Restore_Scan_State (Scan_State);
75 end if;
76 end if;
77 end Check_Junk_Semicolon_Before_Return;
78
79 -----------------------------------
80 -- No_Constraint_Maybe_Expr_Func --
81 -----------------------------------
82
83 procedure No_Constraint_Maybe_Expr_Func is
84 begin
85 -- If we have a left paren at the start of the line, then assume this is
86 -- the case of an expression function with missing IS. We do not have to
87 -- diagnose the missing IS, that is done elsewhere. We do this game in
88 -- Ada 2012 mode where expression functions are legal.
89
90 if Token = Tok_Left_Paren
91 and Ada_Version >= Ada_2012
92 and Token_Is_At_Start_Of_Line
93 then
94 -- One exception if we have "(token .." then this is a constraint
95
96 declare
97 Scan_State : Saved_Scan_State;
98
99 begin
100 Save_Scan_State (Scan_State);
101 Scan; -- past left paren
102 Scan; -- past following token
103
104 -- If we have "(token .." then restore scan state and treat as
105 -- unexpected constraint.
106
107 if Token = Tok_Dot_Dot then
108 Restore_Scan_State (Scan_State);
109 No_Constraint;
110
111 -- Otherwise we treat this as an expression function
112
113 else
114 Restore_Scan_State (Scan_State);
115 end if;
116 end;
117
118 -- Otherwise use standard routine to check for no constraint present
119
120 else
121 No_Constraint;
122 end if;
123 end No_Constraint_Maybe_Expr_Func;
124
125 -----------------------------------------------------
126 -- 6.1 Subprogram (Also 6.3, 8.5.4, 10.1.3, 12.3) --
127 -----------------------------------------------------
128
129 -- This routine scans out a subprogram declaration, subprogram body,
130 -- subprogram renaming declaration or subprogram generic instantiation.
131 -- It also handles the new Ada 2012 expression function form
132
133 -- SUBPROGRAM_DECLARATION ::=
134 -- SUBPROGRAM_SPECIFICATION
135 -- [ASPECT_SPECIFICATIONS];
136
137 -- ABSTRACT_SUBPROGRAM_DECLARATION ::=
138 -- SUBPROGRAM_SPECIFICATION is abstract
139 -- [ASPECT_SPECIFICATIONS];
140
141 -- SUBPROGRAM_SPECIFICATION ::=
142 -- procedure DEFINING_PROGRAM_UNIT_NAME PARAMETER_PROFILE
143 -- | function DEFINING_DESIGNATOR PARAMETER_AND_RESULT_PROFILE
144
145 -- PARAMETER_PROFILE ::= [FORMAL_PART]
146
147 -- PARAMETER_AND_RESULT_PROFILE ::= [FORMAL_PART] return SUBTYPE_MARK
148
149 -- SUBPROGRAM_BODY ::=
150 -- SUBPROGRAM_SPECIFICATION [ASPECT_SPECIFICATIONS] is
151 -- DECLARATIVE_PART
152 -- begin
153 -- HANDLED_SEQUENCE_OF_STATEMENTS
154 -- end [DESIGNATOR];
155
156 -- SUBPROGRAM_RENAMING_DECLARATION ::=
157 -- SUBPROGRAM_SPECIFICATION renames callable_entity_NAME
158 -- [ASPECT_SPECIFICATIONS];
159
160 -- SUBPROGRAM_BODY_STUB ::=
161 -- SUBPROGRAM_SPECIFICATION is separate
162 -- [ASPECT_SPECIFICATIONS];
163
164 -- GENERIC_INSTANTIATION ::=
165 -- procedure DEFINING_PROGRAM_UNIT_NAME is
166 -- new generic_procedure_NAME [GENERIC_ACTUAL_PART]
167 -- [ASPECT_SPECIFICATIONS];
168 -- | function DEFINING_DESIGNATOR is
169 -- new generic_function_NAME [GENERIC_ACTUAL_PART]
170 -- [ASPECT_SPECIFICATIONS];
171
172 -- NULL_PROCEDURE_DECLARATION ::=
173 -- SUBPROGRAM_SPECIFICATION is null;
174
175 -- Null procedures are an Ada 2005 feature. A null procedure declaration
176 -- is classified as a basic declarative item, but it is parsed here, with
177 -- other subprogram constructs.
178
179 -- EXPRESSION_FUNCTION ::=
180 -- FUNCTION SPECIFICATION IS (EXPRESSION)
181 -- [ASPECT_SPECIFICATIONS];
182
183 -- The caller has checked that the initial token is FUNCTION, PROCEDURE,
184 -- NOT or OVERRIDING.
185
186 -- Error recovery: cannot raise Error_Resync
187
188 function P_Subprogram (Pf_Flags : Pf_Rec) return Node_Id is
189
190 function Contains_Import_Aspect (Aspects : List_Id) return Boolean;
191 -- Return True if Aspects contains an Import aspect.
192
193 ----------------------------
194 -- Contains_Import_Aspect --
195 ----------------------------
196
197 function Contains_Import_Aspect (Aspects : List_Id) return Boolean is
198 Aspect : Node_Id := First (Aspects);
199 begin
200 while Present (Aspect) loop
201 if Chars (Identifier (Aspect)) = Name_Import then
202 return True;
203 end if;
204
205 Next (Aspect);
206 end loop;
207
208 return False;
209 end Contains_Import_Aspect;
210
211 Specification_Node : Node_Id;
212 Name_Node : Node_Id;
213 Aspects : List_Id;
214 Fpart_List : List_Id;
215 Fpart_Sloc : Source_Ptr;
216 Result_Not_Null : Boolean := False;
217 Result_Node : Node_Id;
218 Inst_Node : Node_Id;
219 Body_Node : Node_Id;
220 Decl_Node : Node_Id;
221 Rename_Node : Node_Id;
222 Absdec_Node : Node_Id;
223 Stub_Node : Node_Id;
224 Fproc_Sloc : Source_Ptr;
225 Func : Boolean;
226 Scan_State : Saved_Scan_State;
227
228 -- Flags for optional overriding indication. Two flags are needed,
229 -- to distinguish positive and negative overriding indicators from
230 -- the absence of any indicator.
231
232 Is_Overriding : Boolean := False;
233 Not_Overriding : Boolean := False;
234
235 begin
236 -- Set up scope stack entry. Note that the Labl field will be set later
237
238 SIS_Entry_Active := False;
239 SIS_Aspect_Import_Seen := False;
240 SIS_Missing_Semicolon_Message := No_Error_Msg;
241 Push_Scope_Stack;
242 Scopes (Scope.Last).Sloc := Token_Ptr;
243 Scopes (Scope.Last).Etyp := E_Name;
244 Scopes (Scope.Last).Ecol := Start_Column;
245 Scopes (Scope.Last).Lreq := False;
246
247 Aspects := Empty_List;
248
249 -- Ada 2005: Scan leading NOT OVERRIDING indicator
250
251 if Token = Tok_Not then
252 Scan; -- past NOT
253
254 if Token = Tok_Overriding then
255 Scan; -- past OVERRIDING
256 Not_Overriding := True;
257
258 -- Overriding keyword used in non Ada 2005 mode
259
260 elsif Token = Tok_Identifier
261 and then Token_Name = Name_Overriding
262 then
263 Error_Msg_SC ("overriding indicator is an Ada 2005 extension");
264 Error_Msg_SC ("\unit must be compiled with -gnat05 switch");
265 Scan; -- past Overriding
266 Not_Overriding := True;
267
268 else
269 Error_Msg_SC -- CODEFIX
270 ("OVERRIDING expected!");
271 end if;
272
273 -- Ada 2005: scan leading OVERRIDING indicator
274
275 -- Note: in the case of OVERRIDING keyword used in Ada 95 mode, the
276 -- declaration circuit already gave an error message and changed the
277 -- token to Tok_Overriding.
278
279 elsif Token = Tok_Overriding then
280 Scan; -- past OVERRIDING
281 Is_Overriding := True;
282 end if;
283
284 if Is_Overriding or else Not_Overriding then
285
286 -- Note that if we are not in Ada_2005 mode, error messages have
287 -- already been given, so no need to give another message here.
288
289 -- An overriding indicator is allowed for subprogram declarations,
290 -- bodies (including subunits), renamings, stubs, and instantiations.
291 -- The test against Pf_Decl_Pbod is added to account for the case of
292 -- subprograms declared in a protected type, where only subprogram
293 -- declarations and bodies can occur. The Pf_Pbod case is for
294 -- subunits.
295
296 if Pf_Flags /= Pf_Decl_Gins_Pbod_Rnam_Stub_Pexp
297 and then
298 Pf_Flags /= Pf_Decl_Pbod_Pexp
299 and then
300 Pf_Flags /= Pf_Pbod_Pexp
301 then
302 Error_Msg_SC ("overriding indicator not allowed here!");
303
304 elsif Token not in Tok_Function | Tok_Procedure then
305 Error_Msg_SC -- CODEFIX
306 ("FUNCTION or PROCEDURE expected!");
307 end if;
308 end if;
309
310 Func := (Token = Tok_Function);
311 Fproc_Sloc := Token_Ptr;
312 Scan; -- past FUNCTION or PROCEDURE
313 Ignore (Tok_Type);
314 Ignore (Tok_Body);
315
316 if Func then
317 Name_Node := P_Defining_Designator;
318
319 if Nkind (Name_Node) = N_Defining_Operator_Symbol
320 and then Scope.Last = 1
321 then
322 Error_Msg_SP ("operator symbol not allowed at library level");
323 Name_Node := New_Entity (N_Defining_Identifier, Sloc (Name_Node));
324
325 -- Set name from file name, we need some junk name, and that's
326 -- as good as anything. This is only approximate, since we do
327 -- not do anything with non-standard name translations.
328
329 Get_Name_String (File_Name (Current_Source_File));
330
331 for J in 1 .. Name_Len loop
332 if Name_Buffer (J) = '.' then
333 Name_Len := J - 1;
334 exit;
335 end if;
336 end loop;
337
338 Set_Chars (Name_Node, Name_Find);
339 Set_Error_Posted (Name_Node);
340 end if;
341
342 else
343 Name_Node := P_Defining_Program_Unit_Name;
344 end if;
345
346 Scopes (Scope.Last).Labl := Name_Node;
347 Current_Node := Name_Node;
348 Ignore (Tok_Colon);
349
350 -- Deal with generic instantiation, the one case in which we do not
351 -- have a subprogram specification as part of whatever we are parsing
352
353 if Token = Tok_Is then
354 Save_Scan_State (Scan_State); -- at the IS
355 T_Is; -- checks for redundant IS
356
357 if Token = Tok_New then
358 if not Pf_Flags.Gins then
359 Error_Msg_SC ("generic instantiation not allowed here!");
360 end if;
361
362 Scan; -- past NEW
363
364 if Func then
365 Inst_Node := New_Node (N_Function_Instantiation, Fproc_Sloc);
366 Set_Name (Inst_Node, P_Function_Name);
367 else
368 Inst_Node := New_Node (N_Procedure_Instantiation, Fproc_Sloc);
369 Set_Name (Inst_Node, P_Qualified_Simple_Name);
370 end if;
371
372 Set_Defining_Unit_Name (Inst_Node, Name_Node);
373 Set_Generic_Associations (Inst_Node, P_Generic_Actual_Part_Opt);
374 P_Aspect_Specifications (Inst_Node);
375 Pop_Scope_Stack; -- Don't need scope stack entry in this case
376
377 if Is_Overriding then
378 Set_Must_Override (Inst_Node);
379
380 elsif Not_Overriding then
381 Set_Must_Not_Override (Inst_Node);
382 end if;
383
384 return Inst_Node;
385
386 else
387 Restore_Scan_State (Scan_State); -- to the IS
388 end if;
389 end if;
390
391 -- If not a generic instantiation, then we definitely have a subprogram
392 -- specification (all possibilities at this stage include one here)
393
394 Fpart_Sloc := Token_Ptr;
395
396 Check_Misspelling_Of (Tok_Return);
397
398 -- Scan formal part. First a special error check. If we have an
399 -- identifier here, then we have a definite error. If this identifier
400 -- is on the same line as the designator, then we assume it is the
401 -- first formal after a missing left parenthesis
402
403 if Token = Tok_Identifier
404 and then not Token_Is_At_Start_Of_Line
405 then
406 T_Left_Paren; -- to generate message
407 Fpart_List := P_Formal_Part;
408
409 -- Otherwise scan out an optional formal part in the usual manner
410
411 else
412 Fpart_List := P_Parameter_Profile;
413 end if;
414
415 -- We treat what we have as a function specification if FUNCTION was
416 -- used, or if a RETURN is present. This gives better error recovery
417 -- since later RETURN statements will be valid in either case.
418
419 Check_Junk_Semicolon_Before_Return;
420 Result_Node := Error;
421
422 if Token = Tok_Return then
423 if not Func then
424 Error_Msg -- CODEFIX
425 ("PROCEDURE should be FUNCTION", Fproc_Sloc);
426 Func := True;
427 end if;
428
429 Scan; -- past RETURN
430
431 Result_Not_Null := P_Null_Exclusion; -- Ada 2005 (AI-231)
432
433 -- Ada 2005 (AI-318-02)
434
435 if Token = Tok_Access then
436 Error_Msg_Ada_2005_Extension ("anonymous access result type");
437
438 Result_Node := P_Access_Definition (Result_Not_Null);
439
440 else
441 Result_Node := P_Subtype_Mark;
442 No_Constraint_Maybe_Expr_Func;
443 end if;
444
445 else
446 -- Skip extra parenthesis at end of formal part
447
448 Ignore (Tok_Right_Paren);
449
450 -- For function, scan result subtype
451
452 if Func then
453 TF_Return;
454
455 if Prev_Token = Tok_Return then
456 Result_Node := P_Subtype_Mark;
457 end if;
458 end if;
459 end if;
460
461 if Func then
462 Specification_Node :=
463 New_Node (N_Function_Specification, Fproc_Sloc);
464
465 Set_Null_Exclusion_Present (Specification_Node, Result_Not_Null);
466 Set_Result_Definition (Specification_Node, Result_Node);
467
468 else
469 Specification_Node :=
470 New_Node (N_Procedure_Specification, Fproc_Sloc);
471 end if;
472
473 Set_Defining_Unit_Name (Specification_Node, Name_Node);
474 Set_Parameter_Specifications (Specification_Node, Fpart_List);
475
476 if Is_Overriding then
477 Set_Must_Override (Specification_Node);
478
479 elsif Not_Overriding then
480 Set_Must_Not_Override (Specification_Node);
481 end if;
482
483 -- Error check: barriers not allowed on protected functions/procedures
484
485 if Token = Tok_When then
486 if Func then
487 Error_Msg_SC ("barrier not allowed on function, only on entry");
488 else
489 Error_Msg_SC ("barrier not allowed on procedure, only on entry");
490 end if;
491
492 Scan; -- past WHEN
493 Discard_Junk_Node (P_Expression);
494 end if;
495
496 -- Deal with semicolon followed by IS. We want to treat this as IS
497
498 if Token = Tok_Semicolon then
499 Save_Scan_State (Scan_State);
500 Scan; -- past semicolon
501
502 if Token = Tok_Is then
503 Error_Msg_SP -- CODEFIX
504 ("extra "";"" ignored");
505 else
506 Restore_Scan_State (Scan_State);
507 end if;
508 end if;
509
510 -- Subprogram declaration ended by aspect specifications
511
512 if Aspect_Specifications_Present then
513 goto Subprogram_Declaration;
514
515 -- Deal with case of semicolon ending a subprogram declaration
516
517 elsif Token = Tok_Semicolon then
518 if not Pf_Flags.Decl then
519 T_Is;
520 end if;
521
522 Save_Scan_State (Scan_State);
523 Scan; -- past semicolon
524
525 -- If semicolon is immediately followed by IS, then ignore the
526 -- semicolon, and go process the body.
527
528 if Token = Tok_Is then
529 Error_Msg_SP -- CODEFIX
530 ("|extra "";"" ignored");
531 T_Is; -- scan past IS
532 goto Subprogram_Body;
533
534 -- If BEGIN follows in an appropriate column, we immediately
535 -- commence the error action of assuming that the previous
536 -- subprogram declaration should have been a subprogram body,
537 -- i.e. that the terminating semicolon should have been IS.
538
539 elsif Token = Tok_Begin
540 and then Start_Column >= Scopes (Scope.Last).Ecol
541 then
542 Error_Msg_SP -- CODEFIX
543 ("|"";"" should be IS!");
544 goto Subprogram_Body;
545
546 else
547 Restore_Scan_State (Scan_State);
548 goto Subprogram_Declaration;
549 end if;
550
551 -- Case of not followed by semicolon
552
553 else
554 -- Subprogram renaming declaration case
555
556 Check_Misspelling_Of (Tok_Renames);
557
558 if Token = Tok_Renames then
559 if not Pf_Flags.Rnam then
560 Error_Msg_SC ("renaming declaration not allowed here!");
561 end if;
562
563 Rename_Node :=
564 New_Node (N_Subprogram_Renaming_Declaration, Token_Ptr);
565 Scan; -- past RENAMES
566 Set_Name (Rename_Node, P_Name);
567 Set_Specification (Rename_Node, Specification_Node);
568 P_Aspect_Specifications (Rename_Node);
569 TF_Semicolon;
570 Pop_Scope_Stack;
571 return Rename_Node;
572
573 -- Case of IS following subprogram specification
574
575 elsif Token = Tok_Is then
576 T_Is; -- ignore redundant Is's
577
578 if Token_Name = Name_Abstract then
579 Check_95_Keyword (Tok_Abstract, Tok_Semicolon);
580 end if;
581
582 -- Deal nicely with (now obsolete) use of <> in place of abstract
583
584 if Token = Tok_Box then
585 Error_Msg_SC -- CODEFIX
586 ("ABSTRACT expected");
587 Token := Tok_Abstract;
588 end if;
589
590 -- Abstract subprogram declaration case
591
592 if Token = Tok_Abstract then
593 Absdec_Node :=
594 New_Node (N_Abstract_Subprogram_Declaration, Token_Ptr);
595 Set_Specification (Absdec_Node, Specification_Node);
596 Pop_Scope_Stack; -- discard unneeded entry
597 Scan; -- past ABSTRACT
598 P_Aspect_Specifications (Absdec_Node);
599 return Absdec_Node;
600
601 -- Ada 2005 (AI-248): Parse a null procedure declaration
602
603 elsif Token = Tok_Null then
604 Error_Msg_Ada_2005_Extension ("null procedure");
605
606 Scan; -- past NULL
607
608 if Func then
609 Error_Msg_SP ("only procedures can be null");
610 else
611 Set_Null_Present (Specification_Node);
612 Set_Null_Statement (Specification_Node,
613 New_Node (N_Null_Statement, Prev_Token_Ptr));
614 end if;
615
616 goto Subprogram_Declaration;
617
618 -- Check for IS NEW with Formal_Part present and handle nicely
619
620 elsif Token = Tok_New then
621 Error_Msg
622 ("formal part not allowed in instantiation", Fpart_Sloc);
623 Scan; -- past NEW
624
625 if Func then
626 Inst_Node := New_Node (N_Function_Instantiation, Fproc_Sloc);
627 else
628 Inst_Node :=
629 New_Node (N_Procedure_Instantiation, Fproc_Sloc);
630 end if;
631
632 Set_Defining_Unit_Name (Inst_Node, Name_Node);
633 Set_Name (Inst_Node, P_Name);
634 Set_Generic_Associations (Inst_Node, P_Generic_Actual_Part_Opt);
635 TF_Semicolon;
636 Pop_Scope_Stack; -- Don't need scope stack entry in this case
637 return Inst_Node;
638
639 else
640 goto Subprogram_Body;
641 end if;
642
643 -- Aspect specifications present
644
645 elsif Aspect_Specifications_Present then
646 goto Subprogram_Declaration;
647
648 -- Here we have a missing IS or missing semicolon
649
650 else
651 -- If the next token is a left paren at the start of a line, then
652 -- this is almost certainly the start of the expression for an
653 -- expression function, so in this case guess a missing IS.
654
655 if Token = Tok_Left_Paren and then Token_Is_At_Start_Of_Line then
656 Error_Msg_AP -- CODEFIX
657 ("missing IS");
658
659 -- In all other cases, we guess a missing semicolon, since we are
660 -- good at fixing up a semicolon which should really be an IS.
661
662 else
663 Error_Msg_AP -- CODEFIX
664 ("|missing "";""");
665 SIS_Missing_Semicolon_Message := Get_Msg_Id;
666 goto Subprogram_Declaration;
667 end if;
668 end if;
669 end if;
670
671 -- Processing for stub or subprogram body or expression function
672
673 <<Subprogram_Body>>
674
675 -- Subprogram body stub case
676
677 if Separate_Present then
678 if not Pf_Flags.Stub then
679 Error_Msg_SC ("body stub not allowed here!");
680 end if;
681
682 if Nkind (Name_Node) = N_Defining_Operator_Symbol then
683 Error_Msg
684 ("operator symbol cannot be used as subunit name",
685 Sloc (Name_Node));
686 end if;
687
688 Scan; -- past SEPARATE
689
690 Stub_Node :=
691 New_Node (N_Subprogram_Body_Stub, Sloc (Specification_Node));
692 Set_Specification (Stub_Node, Specification_Node);
693
694 if Is_Non_Empty_List (Aspects) then
695 Error_Msg
696 ("aspect specifications must come after SEPARATE",
697 Sloc (First (Aspects)));
698 end if;
699
700 P_Aspect_Specifications (Stub_Node, Semicolon => False);
701 TF_Semicolon;
702 Pop_Scope_Stack;
703 return Stub_Node;
704
705 -- Subprogram body or expression function case
706
707 else
708 Scan_Body_Or_Expression_Function : declare
709
710 function Likely_Expression_Function return Boolean;
711 -- Returns True if we have a probable case of an expression
712 -- function omitting the parentheses, if so, returns True
713 -- and emits an appropriate error message, else returns False.
714
715 --------------------------------
716 -- Likely_Expression_Function --
717 --------------------------------
718
719 function Likely_Expression_Function return Boolean is
720 begin
721 -- If currently pointing to BEGIN or a declaration keyword
722 -- or a pragma, then we definitely have a subprogram body.
723 -- This is a common case, so worth testing first.
724
725 if Token in Tok_Begin | Token_Class_Declk | Tok_Pragma then
726 return False;
727
728 -- Test for tokens which could only start an expression and
729 -- thus signal the case of a expression function.
730
731 elsif Token in
732 Token_Class_Literal | Token_Class_Unary_Addop |
733 Tok_Left_Paren | Tok_Abs | Tok_Null | Tok_New | Tok_Not
734 then
735 null;
736
737 -- Anything other than an identifier must be a body
738
739 elsif Token /= Tok_Identifier then
740 return False;
741
742 -- Here for an identifier
743
744 else
745 -- If the identifier is the first token on its line, then
746 -- let's assume that we have a missing begin and this is
747 -- intended as a subprogram body. However, if the context
748 -- is a function and the unit is a package declaration, a
749 -- body would be illegal, so try for an unparenthesized
750 -- expression function.
751
752 if Token_Is_At_Start_Of_Line then
753 declare
754 -- The enclosing scope entry is a subprogram spec
755
756 Spec_Node : constant Node_Id :=
757 Parent
758 (Scopes (Scope.Last).Labl);
759 Lib_Node : Node_Id := Spec_Node;
760
761 begin
762 -- Check whether there is an enclosing scope that
763 -- is a package declaration.
764
765 if Scope.Last > 1 then
766 Lib_Node :=
767 Parent (Scopes (Scope.Last - 1).Labl);
768 end if;
769
770 if Ada_Version >= Ada_2012
771 and then
772 Nkind (Lib_Node) = N_Package_Specification
773 and then
774 Nkind (Spec_Node) = N_Function_Specification
775 then
776 null;
777 else
778 return False;
779 end if;
780 end;
781
782 -- Otherwise we have to scan ahead. If the identifier is
783 -- followed by a colon or a comma, it is a declaration
784 -- and hence we have a subprogram body. Otherwise assume
785 -- a expression function.
786
787 else
788 declare
789 Scan_State : Saved_Scan_State;
790 Tok : Token_Type;
791
792 begin
793 Save_Scan_State (Scan_State);
794 Scan; -- past identifier
795 Tok := Token;
796 Restore_Scan_State (Scan_State);
797
798 if Tok = Tok_Colon or else Tok = Tok_Comma then
799 return False;
800 end if;
801 end;
802 end if;
803 end if;
804
805 -- Fall through if we have a likely expression function.
806 -- If the starting keyword is not "function" the error
807 -- will be reported elsewhere.
808
809 if Func then
810 Error_Msg_SC
811 ("expression function must be enclosed in parentheses");
812 end if;
813
814 return True;
815 end Likely_Expression_Function;
816
817 -- Start of processing for Scan_Body_Or_Expression_Function
818
819 begin
820 -- Expression_Function case
821
822 -- If likely an aggregate, check we are in Ada 2022 mode
823
824 if Token = Tok_Left_Bracket then
825 Error_Msg_Ada_2022_Feature
826 ("!aggregates as expression function", Token_Ptr);
827 end if;
828
829 if Token in Tok_Left_Paren | Tok_Left_Bracket
830 or else Likely_Expression_Function
831 then
832 -- Check expression function allowed here
833
834 if not Pf_Flags.Pexp then
835 Error_Msg_SC ("expression function not allowed here!");
836 end if;
837
838 -- Check we are in Ada 2012 mode
839
840 Error_Msg_Ada_2012_Feature
841 ("!expression function", Token_Ptr);
842
843 -- Catch an illegal placement of the aspect specification
844 -- list:
845
846 -- function_specification
847 -- [aspect_specification] is (expression);
848
849 -- This case is correctly processed by the parser because
850 -- the expression function first appears as a subprogram
851 -- declaration to the parser. The starting keyword may
852 -- not have been "function" in which case the error is
853 -- on a malformed procedure.
854
855 if Is_Non_Empty_List (Aspects) then
856 if Func then
857 Error_Msg
858 ("aspect specifications must come after "
859 & "parenthesized expression",
860 Sloc (First (Aspects)));
861 else
862 Error_Msg
863 ("aspect specifications must come after subprogram "
864 & "specification", Sloc (First (Aspects)));
865 end if;
866 end if;
867
868 -- Parse out expression and build expression function
869
870 Body_Node :=
871 New_Node
872 (N_Expression_Function, Sloc (Specification_Node));
873 Set_Specification (Body_Node, Specification_Node);
874
875 declare
876 Expr : constant Node_Id := P_Expression;
877 begin
878 Set_Expression (Body_Node, Expr);
879
880 -- Check that the full expression is properly
881 -- parenthesized since we may have a left-operand that is
882 -- parenthesized but that is not one of the allowed cases
883 -- with syntactic parentheses.
884
885 if not (Paren_Count (Expr) /= 0
886 or else Nkind (Expr) in N_Aggregate
887 | N_Extension_Aggregate
888 | N_Quantified_Expression)
889 then
890 Error_Msg
891 ("expression function must be enclosed in "
892 & "parentheses", Sloc (Expr));
893 end if;
894 end;
895
896 -- Expression functions can carry pre/postconditions
897
898 P_Aspect_Specifications (Body_Node);
899 Pop_Scope_Stack;
900
901 -- Subprogram body case
902
903 else
904 -- Check body allowed here
905
906 if not Pf_Flags.Pbod then
907 Error_Msg_SP ("subprogram body not allowed here!");
908 end if;
909
910 -- Here is the test for a suspicious IS (i.e. one that
911 -- looks like it might more properly be a semicolon).
912 -- See separate section describing use of IS instead
913 -- of semicolon in package Parse.
914
915 if (Token in Token_Class_Declk
916 or else
917 Token = Tok_Identifier)
918 and then Start_Column <= Scopes (Scope.Last).Ecol
919 and then Scope.Last /= 1
920 then
921 Scopes (Scope.Last).Etyp := E_Suspicious_Is;
922 Scopes (Scope.Last).S_Is := Prev_Token_Ptr;
923 end if;
924
925 -- Build and return subprogram body, parsing declarations
926 -- and statement sequence that belong to the body.
927
928 Body_Node :=
929 New_Node (N_Subprogram_Body, Sloc (Specification_Node));
930 Set_Specification (Body_Node, Specification_Node);
931
932 -- If aspects are present, the specification is parsed as
933 -- a subprogram declaration, and we jump here after seeing
934 -- the keyword IS. Attach asspects previously collected to
935 -- the body.
936
937 if Is_Non_Empty_List (Aspects) then
938 Set_Parent (Aspects, Body_Node);
939 Set_Aspect_Specifications (Body_Node, Aspects);
940 end if;
941
942 Parse_Decls_Begin_End (Body_Node);
943 end if;
944
945 return Body_Node;
946 end Scan_Body_Or_Expression_Function;
947 end if;
948
949 -- Processing for subprogram declaration
950
951 <<Subprogram_Declaration>>
952 Decl_Node :=
953 New_Node (N_Subprogram_Declaration, Sloc (Specification_Node));
954 Set_Specification (Decl_Node, Specification_Node);
955 Aspects := Get_Aspect_Specifications (Semicolon => False);
956
957 -- Aspects may be present on a subprogram body. The source parsed
958 -- so far is that of its specification. Go parse the body and attach
959 -- the collected aspects, if any, to the body.
960
961 if Token = Tok_Is then
962
963 -- If the subprogram is a procedure and already has a
964 -- specification, we can't define another.
965
966 if Nkind (Specification (Decl_Node)) = N_Procedure_Specification
967 and then Null_Present (Specification (Decl_Node))
968 then
969 Error_Msg_AP ("null procedure cannot have a body");
970 end if;
971
972 Scan;
973 goto Subprogram_Body;
974
975 else
976 if Is_Non_Empty_List (Aspects) then
977 Set_Parent (Aspects, Decl_Node);
978 Set_Aspect_Specifications (Decl_Node, Aspects);
979 end if;
980
981 TF_Semicolon;
982 end if;
983
984 -- If this is a context in which a subprogram body is permitted,
985 -- set active SIS entry in case (see section titled "Handling
986 -- Semicolon Used in Place of IS" in body of Parser package)
987 -- Note that SIS_Missing_Semicolon_Message is already set properly.
988
989 if Pf_Flags.Pbod
990
991 -- Disconnect this processing if we have scanned a null procedure
992 -- or an Import aspect because in this case the spec is complete
993 -- anyway with no body.
994
995 and then (Nkind (Specification_Node) /= N_Procedure_Specification
996 or else not Null_Present (Specification_Node))
997 and then not Contains_Import_Aspect (Aspects)
998 then
999 SIS_Labl := Scopes (Scope.Last).Labl;
1000 SIS_Sloc := Scopes (Scope.Last).Sloc;
1001 SIS_Ecol := Scopes (Scope.Last).Ecol;
1002 SIS_Declaration_Node := Decl_Node;
1003 SIS_Semicolon_Sloc := Prev_Token_Ptr;
1004
1005 -- Do not activate the entry if we have "with Import"
1006
1007 if not SIS_Aspect_Import_Seen then
1008 SIS_Entry_Active := True;
1009 end if;
1010 end if;
1011
1012 Pop_Scope_Stack;
1013 return Decl_Node;
1014 end P_Subprogram;
1015
1016 ---------------------------------
1017 -- 6.1 Subprogram Declaration --
1018 ---------------------------------
1019
1020 -- Parsed by P_Subprogram (6.1)
1021
1022 ------------------------------------------
1023 -- 6.1 Abstract Subprogram Declaration --
1024 ------------------------------------------
1025
1026 -- Parsed by P_Subprogram (6.1)
1027
1028 -----------------------------------
1029 -- 6.1 Subprogram Specification --
1030 -----------------------------------
1031
1032 -- SUBPROGRAM_SPECIFICATION ::=
1033 -- procedure DEFINING_PROGRAM_UNIT_NAME PARAMETER_PROFILE
1034 -- | function DEFINING_DESIGNATOR PARAMETER_AND_RESULT_PROFILE
1035
1036 -- PARAMETER_PROFILE ::= [FORMAL_PART]
1037
1038 -- PARAMETER_AND_RESULT_PROFILE ::= [FORMAL_PART] return SUBTYPE_MARK
1039
1040 -- Subprogram specifications that appear in subprogram declarations
1041 -- are parsed by P_Subprogram (6.1). This routine is used in other
1042 -- contexts where subprogram specifications occur.
1043
1044 -- Note: this routine does not affect the scope stack in any way
1045
1046 -- Error recovery: can raise Error_Resync
1047
1048 function P_Subprogram_Specification return Node_Id is
1049 Specification_Node : Node_Id;
1050 Result_Not_Null : Boolean;
1051 Result_Node : Node_Id;
1052
1053 begin
1054 if Token = Tok_Function then
1055 Specification_Node := New_Node (N_Function_Specification, Token_Ptr);
1056 Scan; -- past FUNCTION
1057 Ignore (Tok_Body);
1058 Set_Defining_Unit_Name (Specification_Node, P_Defining_Designator);
1059 Set_Parameter_Specifications
1060 (Specification_Node, P_Parameter_Profile);
1061 Check_Junk_Semicolon_Before_Return;
1062 TF_Return;
1063
1064 Result_Not_Null := P_Null_Exclusion; -- Ada 2005 (AI-231)
1065
1066 -- Ada 2005 (AI-318-02)
1067
1068 if Token = Tok_Access then
1069 Error_Msg_Ada_2005_Extension ("anonymous access result type");
1070
1071 Result_Node := P_Access_Definition (Result_Not_Null);
1072
1073 else
1074 Result_Node := P_Subtype_Mark;
1075 No_Constraint_Maybe_Expr_Func;
1076 end if;
1077
1078 Set_Null_Exclusion_Present (Specification_Node, Result_Not_Null);
1079 Set_Result_Definition (Specification_Node, Result_Node);
1080 return Specification_Node;
1081
1082 elsif Token = Tok_Procedure then
1083 Specification_Node := New_Node (N_Procedure_Specification, Token_Ptr);
1084 Scan; -- past PROCEDURE
1085 Ignore (Tok_Body);
1086 Set_Defining_Unit_Name
1087 (Specification_Node, P_Defining_Program_Unit_Name);
1088 Set_Parameter_Specifications
1089 (Specification_Node, P_Parameter_Profile);
1090 return Specification_Node;
1091
1092 else
1093 Error_Msg_SC ("subprogram specification expected");
1094 raise Error_Resync;
1095 end if;
1096 end P_Subprogram_Specification;
1097
1098 ---------------------
1099 -- 6.1 Designator --
1100 ---------------------
1101
1102 -- DESIGNATOR ::=
1103 -- [PARENT_UNIT_NAME .] IDENTIFIER | OPERATOR_SYMBOL
1104
1105 -- The caller has checked that the initial token is an identifier,
1106 -- operator symbol, or string literal. Note that we don't bother to
1107 -- do much error diagnosis in this routine, since it is only used for
1108 -- the label on END lines, and the routines in package Par.Endh will
1109 -- check that the label is appropriate.
1110
1111 -- Error recovery: cannot raise Error_Resync
1112
1113 function P_Designator return Node_Id is
1114 Ident_Node : Node_Id;
1115 Name_Node : Node_Id;
1116 Prefix_Node : Node_Id;
1117
1118 function Real_Dot return Boolean;
1119 -- Tests if a current token is an interesting period, i.e. is followed
1120 -- by an identifier or operator symbol or string literal. If not, it is
1121 -- probably just incorrect punctuation to be caught by our caller. Note
1122 -- that the case of an operator symbol or string literal is also an
1123 -- error, but that is an error that we catch here. If the result is
1124 -- True, a real dot has been scanned and we are positioned past it,
1125 -- if the result is False, the scan position is unchanged.
1126
1127 --------------
1128 -- Real_Dot --
1129 --------------
1130
1131 function Real_Dot return Boolean is
1132 Scan_State : Saved_Scan_State;
1133
1134 begin
1135 if Token /= Tok_Dot then
1136 return False;
1137
1138 else
1139 Save_Scan_State (Scan_State);
1140 Scan; -- past dot
1141
1142 if Token in
1143 Tok_Identifier | Tok_Operator_Symbol | Tok_String_Literal
1144 then
1145 return True;
1146
1147 else
1148 Restore_Scan_State (Scan_State);
1149 return False;
1150 end if;
1151 end if;
1152 end Real_Dot;
1153
1154 -- Start of processing for P_Designator
1155
1156 begin
1157 Ident_Node := Token_Node;
1158 Scan; -- past initial token
1159
1160 if Prev_Token in Tok_Operator_Symbol | Tok_String_Literal
1161 or else not Real_Dot
1162 then
1163 return Ident_Node;
1164
1165 -- Child name case
1166
1167 else
1168 Prefix_Node := Ident_Node;
1169
1170 -- Loop through child names, on entry to this loop, Prefix contains
1171 -- the name scanned so far, and Ident_Node is the last identifier.
1172
1173 loop
1174 Name_Node := New_Node (N_Selected_Component, Prev_Token_Ptr);
1175 Set_Prefix (Name_Node, Prefix_Node);
1176 Ident_Node := P_Identifier;
1177 Set_Selector_Name (Name_Node, Ident_Node);
1178 Prefix_Node := Name_Node;
1179 exit when not Real_Dot;
1180 end loop;
1181
1182 -- On exit from the loop, Ident_Node is the last identifier scanned,
1183 -- i.e. the defining identifier, and Prefix_Node is a node for the
1184 -- entire name, structured (incorrectly) as a selected component.
1185
1186 Name_Node := Prefix (Prefix_Node);
1187 Change_Node (Prefix_Node, N_Designator);
1188 Set_Name (Prefix_Node, Name_Node);
1189 Set_Identifier (Prefix_Node, Ident_Node);
1190 return Prefix_Node;
1191 end if;
1192
1193 exception
1194 when Error_Resync =>
1195 while Token in Tok_Dot | Tok_Identifier loop
1196 Scan;
1197 end loop;
1198
1199 return Error;
1200 end P_Designator;
1201
1202 ------------------------------
1203 -- 6.1 Defining Designator --
1204 ------------------------------
1205
1206 -- DEFINING_DESIGNATOR ::=
1207 -- DEFINING_PROGRAM_UNIT_NAME | DEFINING_OPERATOR_SYMBOL
1208
1209 -- Error recovery: cannot raise Error_Resync
1210
1211 function P_Defining_Designator return Node_Id is
1212 begin
1213 if Token = Tok_Operator_Symbol then
1214 return P_Defining_Operator_Symbol;
1215
1216 elsif Token = Tok_String_Literal then
1217 Error_Msg_SC ("invalid operator name");
1218 Scan; -- past junk string
1219 return Error;
1220
1221 else
1222 return P_Defining_Program_Unit_Name;
1223 end if;
1224 end P_Defining_Designator;
1225
1226 -------------------------------------
1227 -- 6.1 Defining Program Unit Name --
1228 -------------------------------------
1229
1230 -- DEFINING_PROGRAM_UNIT_NAME ::=
1231 -- [PARENT_UNIT_NAME .] DEFINING_IDENTIFIER
1232
1233 -- Note: PARENT_UNIT_NAME may be present only in 95 mode at the outer level
1234
1235 -- Error recovery: cannot raise Error_Resync
1236
1237 function P_Defining_Program_Unit_Name return Node_Id is
1238 Ident_Node : Node_Id;
1239 Name_Node : Node_Id;
1240 Prefix_Node : Node_Id;
1241
1242 begin
1243 -- Set identifier casing if not already set and scan initial identifier
1244
1245 if Token = Tok_Identifier
1246 and then Identifier_Casing (Current_Source_File) = Unknown
1247 then
1248 Set_Identifier_Casing (Current_Source_File, Determine_Token_Casing);
1249 end if;
1250
1251 Ident_Node := P_Identifier (C_Dot);
1252 Merge_Identifier (Ident_Node, Tok_Return);
1253
1254 -- Normal case (not child library unit name)
1255
1256 if Token /= Tok_Dot then
1257 Change_Identifier_To_Defining_Identifier (Ident_Node);
1258 Warn_If_Standard_Redefinition (Ident_Node);
1259 return Ident_Node;
1260
1261 -- Child library unit name case
1262
1263 else
1264 if Scope.Last > 1 then
1265 Error_Msg_SP ("child unit allowed only at library level");
1266 raise Error_Resync;
1267
1268 elsif Ada_Version = Ada_83 then
1269 Error_Msg_SP ("(Ada 83) child unit not allowed!");
1270
1271 end if;
1272
1273 Prefix_Node := Ident_Node;
1274
1275 -- Loop through child names, on entry to this loop, Prefix contains
1276 -- the name scanned so far, and Ident_Node is the last identifier.
1277
1278 loop
1279 exit when Token /= Tok_Dot;
1280 Name_Node := New_Node (N_Selected_Component, Token_Ptr);
1281 Scan; -- past period
1282 Set_Prefix (Name_Node, Prefix_Node);
1283 Ident_Node := P_Identifier (C_Dot);
1284 Set_Selector_Name (Name_Node, Ident_Node);
1285 Prefix_Node := Name_Node;
1286 end loop;
1287
1288 -- On exit from the loop, Ident_Node is the last identifier scanned,
1289 -- i.e. the defining identifier, and Prefix_Node is a node for the
1290 -- entire name, structured (incorrectly) as a selected component.
1291
1292 Name_Node := Prefix (Prefix_Node);
1293 Change_Node (Prefix_Node, N_Defining_Program_Unit_Name);
1294 Set_Name (Prefix_Node, Name_Node);
1295 Change_Identifier_To_Defining_Identifier (Ident_Node);
1296 Warn_If_Standard_Redefinition (Ident_Node);
1297 Set_Defining_Identifier (Prefix_Node, Ident_Node);
1298
1299 -- All set with unit name parsed
1300
1301 return Prefix_Node;
1302 end if;
1303
1304 exception
1305 when Error_Resync =>
1306 while Token in Tok_Dot | Tok_Identifier loop
1307 Scan;
1308 end loop;
1309
1310 return Error;
1311 end P_Defining_Program_Unit_Name;
1312
1313 --------------------------
1314 -- 6.1 Operator Symbol --
1315 --------------------------
1316
1317 -- OPERATOR_SYMBOL ::= STRING_LITERAL
1318
1319 -- Operator symbol is returned by the scanner as Tok_Operator_Symbol
1320
1321 -----------------------------------
1322 -- 6.1 Defining Operator Symbol --
1323 -----------------------------------
1324
1325 -- DEFINING_OPERATOR_SYMBOL ::= OPERATOR_SYMBOL
1326
1327 -- The caller has checked that the initial symbol is an operator symbol
1328
1329 function P_Defining_Operator_Symbol return Node_Id is
1330 Op_Node : Node_Id;
1331
1332 begin
1333 Op_Node := Token_Node;
1334 Change_Operator_Symbol_To_Defining_Operator_Symbol (Op_Node);
1335 Scan; -- past operator symbol
1336 return Op_Node;
1337 end P_Defining_Operator_Symbol;
1338
1339 ----------------------------
1340 -- 6.1 Parameter_Profile --
1341 ----------------------------
1342
1343 -- PARAMETER_PROFILE ::= [FORMAL_PART]
1344
1345 -- Empty is returned if no formal part is present
1346
1347 -- Error recovery: cannot raise Error_Resync
1348
1349 function P_Parameter_Profile return List_Id is
1350 begin
1351 if Token = Tok_Left_Paren then
1352 Scan; -- part left paren
1353 return P_Formal_Part;
1354 else
1355 return No_List;
1356 end if;
1357 end P_Parameter_Profile;
1358
1359 ---------------------------------------
1360 -- 6.1 Parameter And Result Profile --
1361 ---------------------------------------
1362
1363 -- Parsed by its parent construct, which uses P_Parameter_Profile to
1364 -- parse the parameters, and P_Subtype_Mark to parse the return type.
1365
1366 ----------------------
1367 -- 6.1 Formal part --
1368 ----------------------
1369
1370 -- FORMAL_PART ::= (PARAMETER_SPECIFICATION {; PARAMETER_SPECIFICATION})
1371
1372 -- PARAMETER_SPECIFICATION ::=
1373 -- DEFINING_IDENTIFIER_LIST : [ALIASED] MODE [NULL_EXCLUSION]
1374 -- SUBTYPE_MARK [:= DEFAULT_EXPRESSION]
1375 -- | DEFINING_IDENTIFIER_LIST : ACCESS_DEFINITION
1376 -- [:= DEFAULT_EXPRESSION]
1377
1378 -- This scans the construct Formal_Part. The caller has already checked
1379 -- that the initial token is a left parenthesis, and skipped past it, so
1380 -- that on entry Token is the first token following the left parenthesis.
1381
1382 -- Note: The ALIASED keyword is allowed only in Ada 2012 mode (AI 142)
1383
1384 -- Error recovery: cannot raise Error_Resync
1385
1386 function P_Formal_Part return List_Id is
1387 Specification_List : List_Id;
1388 Specification_Node : Node_Id;
1389 Scan_State : Saved_Scan_State;
1390 Num_Idents : Nat;
1391 Ident : Nat;
1392 Ident_Sloc : Source_Ptr;
1393 Not_Null_Present : Boolean := False;
1394 Not_Null_Sloc : Source_Ptr;
1395
1396 Idents : array (Int range 1 .. 4096) of Entity_Id;
1397 -- This array holds the list of defining identifiers. The upper bound
1398 -- of 4096 is intended to be essentially infinite, and we do not even
1399 -- bother to check for it being exceeded.
1400
1401 begin
1402 Specification_List := New_List;
1403 Specification_Loop : loop
1404 begin
1405 if Token = Tok_Pragma then
1406 Error_Msg_SC ("pragma not allowed in formal part");
1407 Discard_Junk_Node (P_Pragma (Skipping => True));
1408 end if;
1409
1410 Ignore (Tok_Left_Paren);
1411 Ident_Sloc := Token_Ptr;
1412 Idents (1) := P_Defining_Identifier (C_Comma_Colon);
1413 Num_Idents := 1;
1414
1415 Ident_Loop : loop
1416 exit Ident_Loop when Token = Tok_Colon;
1417
1418 -- The only valid tokens are colon and comma, so if we have
1419 -- neither do a bit of investigation to see which is the
1420 -- better choice for insertion.
1421
1422 if Token /= Tok_Comma then
1423
1424 -- Assume colon if ALIASED, IN or OUT keyword found
1425
1426 exit Ident_Loop when Token = Tok_Aliased or else
1427 Token = Tok_In or else
1428 Token = Tok_Out;
1429
1430 -- Otherwise scan ahead
1431
1432 Save_Scan_State (Scan_State);
1433 Look_Ahead : loop
1434
1435 -- If we run into a semicolon, then assume that a
1436 -- colon was missing, e.g. Parms (X Y; ...). Also
1437 -- assume missing colon on EOF (a real disaster)
1438 -- and on a right paren, e.g. Parms (X Y), and also
1439 -- on an assignment symbol, e.g. Parms (X Y := ..)
1440
1441 if Token in Tok_Semicolon | Tok_Right_Paren |
1442 Tok_EOF | Tok_Colon_Equal
1443 then
1444 Restore_Scan_State (Scan_State);
1445 exit Ident_Loop;
1446
1447 -- If we run into a colon, assume that we had a missing
1448 -- comma, e.g. Parms (A B : ...). Also assume a missing
1449 -- comma if we hit another comma, e.g. Parms (A B, C ..)
1450
1451 elsif Token in Tok_Colon | Tok_Comma then
1452 Restore_Scan_State (Scan_State);
1453 exit Look_Ahead;
1454 end if;
1455
1456 Scan;
1457 end loop Look_Ahead;
1458 end if;
1459
1460 -- Here if a comma is present, or to be assumed
1461
1462 T_Comma;
1463 Num_Idents := Num_Idents + 1;
1464 Idents (Num_Idents) := P_Defining_Identifier (C_Comma_Colon);
1465 end loop Ident_Loop;
1466
1467 -- Fall through the loop on encountering a colon, or deciding
1468 -- that there is a missing colon.
1469
1470 T_Colon;
1471
1472 -- If there are multiple identifiers, we repeatedly scan the
1473 -- type and initialization expression information by resetting
1474 -- the scan pointer (so that we get completely separate trees
1475 -- for each occurrence).
1476
1477 if Num_Idents > 1 then
1478 Save_Scan_State (Scan_State);
1479 end if;
1480
1481 -- Loop through defining identifiers in list
1482
1483 Ident := 1;
1484
1485 Ident_List_Loop : loop
1486 Specification_Node :=
1487 New_Node (N_Parameter_Specification, Ident_Sloc);
1488 Set_Defining_Identifier (Specification_Node, Idents (Ident));
1489
1490 -- Scan possible ALIASED for Ada 2012 (AI-142)
1491
1492 if Token = Tok_Aliased then
1493 if Ada_Version < Ada_2012 then
1494 Error_Msg_Ada_2012_Feature
1495 ("ALIASED parameter", Token_Ptr);
1496 else
1497 Set_Aliased_Present (Specification_Node);
1498 end if;
1499
1500 Scan; -- past ALIASED
1501 end if;
1502
1503 -- Scan possible NOT NULL for Ada 2005 (AI-231, AI-447)
1504
1505 Not_Null_Sloc := Token_Ptr;
1506 Not_Null_Present :=
1507 P_Null_Exclusion (Allow_Anonymous_In_95 => True);
1508
1509 -- Case of ACCESS keyword present
1510
1511 if Token = Tok_Access then
1512 Set_Null_Exclusion_Present
1513 (Specification_Node, Not_Null_Present);
1514
1515 if Ada_Version = Ada_83 then
1516 Error_Msg_SC ("(Ada 83) access parameters not allowed");
1517 end if;
1518
1519 Set_Parameter_Type
1520 (Specification_Node,
1521 P_Access_Definition (Not_Null_Present));
1522
1523 -- Case of IN or OUT present
1524
1525 else
1526 if Token in Tok_In | Tok_Out then
1527 if Not_Null_Present then
1528 Error_Msg
1529 ("`NOT NULL` can only be used with `ACCESS`",
1530 Not_Null_Sloc);
1531
1532 if Token = Tok_In then
1533 Error_Msg
1534 ("\`IN` not allowed together with `ACCESS`",
1535 Not_Null_Sloc);
1536 else
1537 Error_Msg
1538 ("\`OUT` not allowed together with `ACCESS`",
1539 Not_Null_Sloc);
1540 end if;
1541 end if;
1542
1543 P_Mode (Specification_Node);
1544 Not_Null_Present := P_Null_Exclusion; -- Ada 2005 (AI-231)
1545 end if;
1546
1547 Set_Null_Exclusion_Present
1548 (Specification_Node, Not_Null_Present);
1549
1550 if Token = Tok_Procedure
1551 or else
1552 Token = Tok_Function
1553 then
1554 Error_Msg_SC ("formal subprogram parameter not allowed");
1555 Scan;
1556
1557 if Token = Tok_Left_Paren then
1558 Discard_Junk_List (P_Formal_Part);
1559 end if;
1560
1561 if Token = Tok_Return then
1562 Scan;
1563 Discard_Junk_Node (P_Subtype_Mark);
1564 end if;
1565
1566 Set_Parameter_Type (Specification_Node, Error);
1567
1568 else
1569 Set_Parameter_Type (Specification_Node, P_Subtype_Mark);
1570 No_Constraint;
1571 end if;
1572 end if;
1573
1574 Set_Expression (Specification_Node, Init_Expr_Opt (True));
1575
1576 if Ident > 1 then
1577 Set_Prev_Ids (Specification_Node, True);
1578 end if;
1579
1580 if Ident < Num_Idents then
1581 Set_More_Ids (Specification_Node, True);
1582 end if;
1583
1584 Append (Specification_Node, Specification_List);
1585 exit Ident_List_Loop when Ident = Num_Idents;
1586 Ident := Ident + 1;
1587 Restore_Scan_State (Scan_State);
1588 end loop Ident_List_Loop;
1589
1590 exception
1591 when Error_Resync =>
1592 Resync_Semicolon_List;
1593 end;
1594
1595 if Token = Tok_Semicolon then
1596 Save_Scan_State (Scan_State);
1597 Scan; -- past semicolon
1598
1599 -- If we have RETURN or IS after the semicolon, then assume
1600 -- that semicolon should have been a right parenthesis and exit
1601
1602 if Token in Tok_Is | Tok_Return then
1603 Error_Msg_SP -- CODEFIX
1604 ("|"";"" should be "")""");
1605 exit Specification_Loop;
1606 end if;
1607
1608 -- If we have a declaration keyword after the semicolon, then
1609 -- assume we had a missing right parenthesis and terminate list
1610
1611 if Token in Token_Class_Declk then
1612 Error_Msg_AP -- CODEFIX
1613 ("missing "")""");
1614 Restore_Scan_State (Scan_State);
1615 exit Specification_Loop;
1616 end if;
1617
1618 elsif Token = Tok_Right_Paren then
1619 Scan; -- past right paren
1620 exit Specification_Loop;
1621
1622 -- Support for aspects on formal parameters is a GNAT extension for
1623 -- the time being.
1624
1625 elsif Token = Tok_With then
1626 Error_Msg_Ada_2022_Feature
1627 ("aspect on formal parameter", Token_Ptr);
1628
1629 P_Aspect_Specifications (Specification_Node, False);
1630
1631 -- Set the aspect specifications for previous Ids
1632
1633 if Has_Aspects (Specification_Node)
1634 and then Prev_Ids (Specification_Node)
1635 then
1636 -- Loop through each previous id
1637
1638 declare
1639 Prev_Id : Node_Id := Prev (Specification_Node);
1640 begin
1641 loop
1642 Set_Aspect_Specifications
1643 (Prev_Id, Aspect_Specifications (Specification_Node));
1644
1645 -- Exit when we reach the first parameter in the list
1646
1647 exit when not Prev_Ids (Prev_Id);
1648 Prev_Id := Prev (Prev_Id);
1649 end loop;
1650 end;
1651 end if;
1652
1653 if Token = Tok_Right_Paren then
1654 Scan; -- past right paren
1655 exit Specification_Loop;
1656
1657 elsif Token = Tok_Semicolon then
1658 Save_Scan_State (Scan_State);
1659 Scan; -- past semicolon
1660 end if;
1661
1662 -- Special check for common error of using comma instead of semicolon
1663
1664 elsif Token = Tok_Comma then
1665 T_Semicolon;
1666
1667 -- Special check for omitted separator
1668
1669 elsif Token = Tok_Identifier then
1670 T_Semicolon;
1671
1672 -- If nothing sensible, skip to next semicolon or right paren
1673
1674 else
1675 T_Semicolon;
1676 Resync_Semicolon_List;
1677
1678 if Token = Tok_Semicolon then
1679 Scan; -- past semicolon
1680 else
1681 T_Right_Paren;
1682 exit Specification_Loop;
1683 end if;
1684 end if;
1685 end loop Specification_Loop;
1686
1687 return Specification_List;
1688 end P_Formal_Part;
1689
1690 ----------------------------------
1691 -- 6.1 Parameter Specification --
1692 ----------------------------------
1693
1694 -- Parsed by P_Formal_Part (6.1)
1695
1696 ---------------
1697 -- 6.1 Mode --
1698 ---------------
1699
1700 -- MODE ::= [in] | in out | out
1701
1702 -- There is no explicit node in the tree for the Mode. Instead the
1703 -- In_Present and Out_Present flags are set in the parent node to
1704 -- record the presence of keywords specifying the mode.
1705
1706 -- Error_Recovery: cannot raise Error_Resync
1707
1708 procedure P_Mode (Node : Node_Id) is
1709 begin
1710 if Token = Tok_In then
1711 Scan; -- past IN
1712 Set_In_Present (Node, True);
1713
1714 if Style.Mode_In_Check and then Token /= Tok_Out then
1715 Error_Msg_SP -- CODEFIX
1716 ("(style) IN should be omitted?I?");
1717 end if;
1718
1719 -- Since Ada 2005, formal objects can have an anonymous access type,
1720 -- and of course carry a mode indicator.
1721
1722 if Token = Tok_Access
1723 and then Nkind (Node) /= N_Formal_Object_Declaration
1724 then
1725 Error_Msg_SP ("IN not allowed together with ACCESS");
1726 Scan; -- past ACCESS
1727 end if;
1728 end if;
1729
1730 if Token = Tok_Out then
1731 Scan; -- past OUT
1732 Set_Out_Present (Node, True);
1733 end if;
1734
1735 if Token = Tok_In then
1736 Error_Msg_SC ("IN must precede OUT in parameter mode");
1737 Scan; -- past IN
1738 Set_In_Present (Node, True);
1739 end if;
1740 end P_Mode;
1741
1742 --------------------------
1743 -- 6.3 Subprogram Body --
1744 --------------------------
1745
1746 -- Parsed by P_Subprogram (6.1)
1747
1748 -----------------------------------
1749 -- 6.4 Procedure Call Statement --
1750 -----------------------------------
1751
1752 -- Parsed by P_Sequence_Of_Statements (5.1)
1753
1754 ------------------------
1755 -- 6.4 Function Call --
1756 ------------------------
1757
1758 -- Parsed by P_Name (4.1)
1759
1760 --------------------------------
1761 -- 6.4 Actual Parameter Part --
1762 --------------------------------
1763
1764 -- Parsed by P_Name (4.1)
1765
1766 --------------------------------
1767 -- 6.4 Parameter Association --
1768 --------------------------------
1769
1770 -- Parsed by P_Name (4.1)
1771
1772 ------------------------------------
1773 -- 6.4 Explicit Actual Parameter --
1774 ------------------------------------
1775
1776 -- Parsed by P_Name (4.1)
1777
1778 ---------------------------
1779 -- 6.5 Return Statement --
1780 ---------------------------
1781
1782 -- SIMPLE_RETURN_STATEMENT ::= return [EXPRESSION];
1783 --
1784 -- EXTENDED_RETURN_STATEMENT ::=
1785 -- return DEFINING_IDENTIFIER : [aliased] RETURN_SUBTYPE_INDICATION
1786 -- [:= EXPRESSION]
1787 -- [ASPECT_SPECIFICATION] [do
1788 -- HANDLED_SEQUENCE_OF_STATEMENTS
1789 -- end return];
1790 --
1791 -- RETURN_SUBTYPE_INDICATION ::= SUBTYPE_INDICATION | ACCESS_DEFINITION
1792
1793 -- RETURN_STATEMENT ::= return [EXPRESSION];
1794
1795 -- Error recovery: can raise Error_Resync
1796
1797 procedure P_Return_Subtype_Indication (Decl_Node : Node_Id) is
1798
1799 -- Note: We don't need to check Ada_Version here, because this is
1800 -- only called in >= Ada 2005 cases anyway.
1801
1802 Not_Null_Present : constant Boolean := P_Null_Exclusion;
1803
1804 begin
1805 Set_Null_Exclusion_Present (Decl_Node, Not_Null_Present);
1806
1807 if Token = Tok_Access then
1808 Set_Object_Definition
1809 (Decl_Node, P_Access_Definition (Not_Null_Present));
1810 else
1811 Set_Object_Definition
1812 (Decl_Node, P_Subtype_Indication (Not_Null_Present));
1813 end if;
1814 end P_Return_Subtype_Indication;
1815
1816 -- Error recovery: can raise Error_Resync
1817
1818 function P_Return_Object_Declaration return Node_Id is
1819 Return_Obj : Node_Id;
1820 Decl_Node : Node_Id;
1821
1822 begin
1823 Return_Obj := Token_Node;
1824 Change_Identifier_To_Defining_Identifier (Return_Obj);
1825 Warn_If_Standard_Redefinition (Return_Obj);
1826 Decl_Node := New_Node (N_Object_Declaration, Token_Ptr);
1827 Set_Defining_Identifier (Decl_Node, Return_Obj);
1828
1829 Scan; -- past identifier
1830 Scan; -- past :
1831
1832 -- First an error check, if we have two identifiers in a row, a likely
1833 -- possibility is that the first of the identifiers is an incorrectly
1834 -- spelled keyword. See similar check in P_Identifier_Declarations.
1835
1836 if Token = Tok_Identifier then
1837 declare
1838 SS : Saved_Scan_State;
1839 I2 : Boolean;
1840
1841 begin
1842 Save_Scan_State (SS);
1843 Scan; -- past initial identifier
1844 I2 := (Token = Tok_Identifier);
1845 Restore_Scan_State (SS);
1846
1847 if I2
1848 and then
1849 (Bad_Spelling_Of (Tok_Access) or else
1850 Bad_Spelling_Of (Tok_Aliased) or else
1851 Bad_Spelling_Of (Tok_Constant))
1852 then
1853 null;
1854 end if;
1855 end;
1856 end if;
1857
1858 -- We allow "constant" here (as in "return Result : constant
1859 -- T..."). This is not in the latest RM, but the ARG is considering an
1860 -- AI on the subject (see AI05-0015-1), which we expect to be approved.
1861
1862 if Token = Tok_Constant then
1863 Scan; -- past CONSTANT
1864 Set_Constant_Present (Decl_Node);
1865
1866 if Token = Tok_Aliased then
1867 Error_Msg_SC -- CODEFIX
1868 ("ALIASED should be before CONSTANT");
1869 Scan; -- past ALIASED
1870 Set_Aliased_Present (Decl_Node);
1871 end if;
1872
1873 elsif Token = Tok_Aliased then
1874 Scan; -- past ALIASED
1875 Set_Aliased_Present (Decl_Node);
1876
1877 -- The restrictions on the use of aliased in an extended return
1878 -- are semantic, not syntactic.
1879
1880 if Token = Tok_Constant then
1881 Scan; -- past CONSTANT
1882 Set_Constant_Present (Decl_Node);
1883 end if;
1884 end if;
1885
1886 P_Return_Subtype_Indication (Decl_Node);
1887
1888 if Token = Tok_Colon_Equal then
1889 Scan; -- past :=
1890 Set_Expression (Decl_Node, P_Expression_No_Right_Paren);
1891 Set_Has_Init_Expression (Decl_Node);
1892 end if;
1893
1894 return Decl_Node;
1895 end P_Return_Object_Declaration;
1896
1897 -- Error recovery: can raise Error_Resync
1898
1899 function P_Return_Statement return Node_Id is
1900 -- The caller has checked that the initial token is RETURN
1901
1902 function Is_Extended return Boolean;
1903 -- Scan state is just after RETURN (and is left that way). Determine
1904 -- whether this is a simple or extended return statement by looking
1905 -- ahead for "identifier :", which implies extended.
1906
1907 -----------------
1908 -- Is_Extended --
1909 -----------------
1910
1911 function Is_Extended return Boolean is
1912 Scan_State : Saved_Scan_State;
1913 Is_Extended : Boolean := False;
1914
1915 begin
1916
1917 if Token = Tok_Identifier then
1918 Save_Scan_State (Scan_State); -- at identifier
1919 Scan; -- past identifier
1920
1921 if Token = Tok_Colon then
1922 Is_Extended := True;
1923 end if;
1924
1925 Restore_Scan_State (Scan_State); -- to identifier
1926 end if;
1927
1928 return Is_Extended;
1929 end Is_Extended;
1930
1931 Ret_Sloc : constant Source_Ptr := Token_Ptr;
1932 Ret_Strt : constant Column_Number := Start_Column;
1933 Ret_Node : Node_Id;
1934 Decl : Node_Id;
1935
1936 -- Start of processing for P_Return_Statement
1937
1938 begin
1939 Scan; -- past RETURN
1940
1941 -- Simple_return_statement, no expression, return an
1942 -- N_Simple_Return_Statement node with the expression field left Empty.
1943
1944 if Token = Tok_Semicolon then
1945 Scan; -- past ;
1946 Ret_Node := New_Node (N_Simple_Return_Statement, Ret_Sloc);
1947
1948 -- Nontrivial case
1949
1950 else
1951 -- Extended_return_statement (Ada 2005 only -- AI-318):
1952
1953 if Is_Extended then
1954 Error_Msg_Ada_2005_Extension ("extended return statement");
1955
1956 Ret_Node := New_Node (N_Extended_Return_Statement, Ret_Sloc);
1957 Decl := P_Return_Object_Declaration;
1958 Set_Return_Object_Declarations (Ret_Node, New_List (Decl));
1959
1960 if Token = Tok_With then
1961 P_Aspect_Specifications (Decl, False);
1962 end if;
1963
1964 if Token = Tok_Do then
1965 Push_Scope_Stack;
1966 Scopes (Scope.Last).Ecol := Ret_Strt;
1967 Scopes (Scope.Last).Etyp := E_Return;
1968 Scopes (Scope.Last).Labl := Error;
1969 Scopes (Scope.Last).Sloc := Ret_Sloc;
1970 Scan; -- past DO
1971 Set_Handled_Statement_Sequence
1972 (Ret_Node, P_Handled_Sequence_Of_Statements);
1973 End_Statements;
1974
1975 -- Do we need to handle Error_Resync here???
1976 end if;
1977
1978 -- Simple_return_statement or Return_when_Statement
1979 -- with expression.
1980
1981 -- We avoid trying to scan an expression if we are at an
1982 -- expression terminator since in that case the best error
1983 -- message is probably that we have a missing semicolon.
1984
1985 else
1986 Ret_Node := New_Node (N_Simple_Return_Statement, Ret_Sloc);
1987
1988 if Token not in Token_Class_Eterm then
1989 Set_Expression (Ret_Node, P_Expression_No_Right_Paren);
1990 end if;
1991
1992 -- When the next token is WHEN or IF we know that we are looking
1993 -- at a Return_when_statement
1994
1995 if Token = Tok_When and then not Missing_Semicolon_On_When then
1996 Error_Msg_GNAT_Extension ("return when statement", Token_Ptr);
1997 Mutate_Nkind (Ret_Node, N_Return_When_Statement);
1998
1999 Scan; -- past WHEN
2000 Set_Condition (Ret_Node, P_Condition);
2001
2002 -- Allow IF instead of WHEN, giving error message
2003
2004 elsif Token = Tok_If then
2005 Error_Msg_GNAT_Extension ("return when statement", Token_Ptr);
2006 Mutate_Nkind (Ret_Node, N_Return_When_Statement);
2007
2008 T_When;
2009 Scan; -- past IF used in place of WHEN
2010 Set_Condition (Ret_Node, P_Condition);
2011 end if;
2012 end if;
2013
2014 TF_Semicolon;
2015 end if;
2016
2017 return Ret_Node;
2018 end P_Return_Statement;
2019
2020 end Ch6;
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