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2013-03-08 François Dumont <fdumont@gcc.gnu.org>
[official-gcc.git] / gcc / ada / par-ch6.adb
blob2243acea2eb308bd55f6342a1e329efcdc3911a9
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- P A R . C H 6 --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2012, 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
77 elsif Bad_Spelling_Of (Tok_Return) then
78 null;
79 end if;
80 end Check_Junk_Semicolon_Before_Return;
81
82 -----------------------------------
83 -- No_Constraint_Maybe_Expr_Func --
84 -----------------------------------
85
86 procedure No_Constraint_Maybe_Expr_Func is
87 begin
88 -- If we have a left paren at the start of the line, then assume this is
89 -- the case of an expression function with missing IS. We do not have to
90 -- diagnose the missing IS, that is done elsewhere. We do this game in
91 -- Ada 2012 mode where expression functions are legal.
92
93 if Token = Tok_Left_Paren
94 and Ada_Version >= Ada_2012
95 and Token_Is_At_Start_Of_Line
96 then
97 -- One exception if we have "(token .." then this is a constraint
98
99 declare
100 Scan_State : Saved_Scan_State;
101
102 begin
103 Save_Scan_State (Scan_State);
104 Scan; -- past left paren
105 Scan; -- past following token
106
107 -- If we have "(token .." then restore scan state and treat as
108 -- unexpected constraint.
109
110 if Token = Tok_Dot_Dot then
111 Restore_Scan_State (Scan_State);
112 No_Constraint;
113
114 -- Otherwise we treat this as an expression function
115
116 else
117 Restore_Scan_State (Scan_State);
118 end if;
119 end;
120
121 -- Otherwise use standard routine to check for no constraint present
122
123 else
124 No_Constraint;
125 end if;
126 end No_Constraint_Maybe_Expr_Func;
127
128 -----------------------------------------------------
129 -- 6.1 Subprogram (Also 6.3, 8.5.4, 10.1.3, 12.3) --
130 -----------------------------------------------------
131
132 -- This routine scans out a subprogram declaration, subprogram body,
133 -- subprogram renaming declaration or subprogram generic instantiation.
134 -- It also handles the new Ada 2012 expression function form
135
136 -- SUBPROGRAM_DECLARATION ::=
137 -- SUBPROGRAM_SPECIFICATION
138 -- [ASPECT_SPECIFICATIONS];
139
140 -- ABSTRACT_SUBPROGRAM_DECLARATION ::=
141 -- SUBPROGRAM_SPECIFICATION is abstract
142 -- [ASPECT_SPECIFICATIONS];
143
144 -- SUBPROGRAM_SPECIFICATION ::=
145 -- procedure DEFINING_PROGRAM_UNIT_NAME PARAMETER_PROFILE
146 -- | function DEFINING_DESIGNATOR PARAMETER_AND_RESULT_PROFILE
147
148 -- PARAMETER_PROFILE ::= [FORMAL_PART]
149
150 -- PARAMETER_AND_RESULT_PROFILE ::= [FORMAL_PART] return SUBTYPE_MARK
151
152 -- SUBPROGRAM_BODY ::=
153 -- SUBPROGRAM_SPECIFICATION is
154 -- DECLARATIVE_PART
155 -- begin
156 -- HANDLED_SEQUENCE_OF_STATEMENTS
157 -- end [DESIGNATOR];
158
159 -- SUBPROGRAM_RENAMING_DECLARATION ::=
160 -- SUBPROGRAM_SPECIFICATION renames callable_entity_NAME
161 -- [ASPECT_SPECIFICATIONS];
162
163 -- SUBPROGRAM_BODY_STUB ::=
164 -- SUBPROGRAM_SPECIFICATION is separate;
165
166 -- GENERIC_INSTANTIATION ::=
167 -- procedure DEFINING_PROGRAM_UNIT_NAME is
168 -- new generic_procedure_NAME [GENERIC_ACTUAL_PART];
169 -- | function DEFINING_DESIGNATOR is
170 -- new generic_function_NAME [GENERIC_ACTUAL_PART];
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 value in Pf_Flags indicates which of these possible declarations
184 -- is acceptable to the caller:
185
186 -- Pf_Flags.Decl Set if declaration OK
187 -- Pf_Flags.Gins Set if generic instantiation OK
188 -- Pf_Flags.Pbod Set if proper body OK
189 -- Pf_Flags.Rnam Set if renaming declaration OK
190 -- Pf_Flags.Stub Set if body stub OK
191 -- Pf_Flags.Pexp Set if expression function OK
192
193 -- If an inappropriate form is encountered, it is scanned out but an
194 -- error message indicating that it is appearing in an inappropriate
195 -- context is issued. The only possible values for Pf_Flags are those
196 -- defined as constants in the Par package.
197
198 -- The caller has checked that the initial token is FUNCTION, PROCEDURE,
199 -- NOT or OVERRIDING.
200
201 -- Error recovery: cannot raise Error_Resync
202
203 function P_Subprogram (Pf_Flags : Pf_Rec) return Node_Id is
204 Specification_Node : Node_Id;
205 Name_Node : Node_Id;
206 Aspects : List_Id;
207 Fpart_List : List_Id;
208 Fpart_Sloc : Source_Ptr;
209 Result_Not_Null : Boolean := False;
210 Result_Node : Node_Id;
211 Inst_Node : Node_Id;
212 Body_Node : Node_Id;
213 Decl_Node : Node_Id;
214 Rename_Node : Node_Id;
215 Absdec_Node : Node_Id;
216 Stub_Node : Node_Id;
217 Fproc_Sloc : Source_Ptr;
218 Func : Boolean;
219 Scan_State : Saved_Scan_State;
220
221 -- Flags for optional overriding indication. Two flags are needed,
222 -- to distinguish positive and negative overriding indicators from
223 -- the absence of any indicator.
224
225 Is_Overriding : Boolean := False;
226 Not_Overriding : Boolean := False;
227
228 begin
229 -- Set up scope stack entry. Note that the Labl field will be set later
230
231 SIS_Entry_Active := False;
232 SIS_Missing_Semicolon_Message := No_Error_Msg;
233 Push_Scope_Stack;
234 Scope.Table (Scope.Last).Sloc := Token_Ptr;
235 Scope.Table (Scope.Last).Etyp := E_Name;
236 Scope.Table (Scope.Last).Ecol := Start_Column;
237 Scope.Table (Scope.Last).Lreq := False;
238
239 Aspects := Empty_List;
240
241 -- Ada 2005: Scan leading NOT OVERRIDING indicator
242
243 if Token = Tok_Not then
244 Scan; -- past NOT
245
246 if Token = Tok_Overriding then
247 Scan; -- past OVERRIDING
248 Not_Overriding := True;
249
250 -- Overriding keyword used in non Ada 2005 mode
251
252 elsif Token = Tok_Identifier
253 and then Token_Name = Name_Overriding
254 then
255 Error_Msg_SC ("overriding indicator is an Ada 2005 extension");
256 Error_Msg_SC ("\unit must be compiled with -gnat05 switch");
257 Scan; -- past Overriding
258 Not_Overriding := True;
259
260 else
261 Error_Msg_SC -- CODEFIX
262 ("OVERRIDING expected!");
263 end if;
264
265 -- Ada 2005: scan leading OVERRIDING indicator
266
267 -- Note: in the case of OVERRIDING keyword used in Ada 95 mode, the
268 -- declaration circuit already gave an error message and changed the
269 -- token to Tok_Overriding.
270
271 elsif Token = Tok_Overriding then
272 Scan; -- past OVERRIDING
273 Is_Overriding := True;
274 end if;
275
276 if Is_Overriding or else Not_Overriding then
277
278 -- Note that if we are not in Ada_2005 mode, error messages have
279 -- already been given, so no need to give another message here.
280
281 -- An overriding indicator is allowed for subprogram declarations,
282 -- bodies (including subunits), renamings, stubs, and instantiations.
283 -- The test against Pf_Decl_Pbod is added to account for the case of
284 -- subprograms declared in a protected type, where only subprogram
285 -- declarations and bodies can occur. The Pf_Pbod case is for
286 -- subunits.
287
288 if Pf_Flags /= Pf_Decl_Gins_Pbod_Rnam_Stub_Pexp
289 and then
290 Pf_Flags /= Pf_Decl_Pbod_Pexp
291 and then
292 Pf_Flags /= Pf_Pbod_Pexp
293 then
294 Error_Msg_SC ("overriding indicator not allowed here!");
295
296 elsif Token /= Tok_Function and then Token /= Tok_Procedure then
297 Error_Msg_SC -- CODEFIX
298 ("FUNCTION or PROCEDURE expected!");
299 end if;
300 end if;
301
302 Func := (Token = Tok_Function);
303 Fproc_Sloc := Token_Ptr;
304 Scan; -- past FUNCTION or PROCEDURE
305 Ignore (Tok_Type);
306 Ignore (Tok_Body);
307
308 if Func then
309 Name_Node := P_Defining_Designator;
310
311 if Nkind (Name_Node) = N_Defining_Operator_Symbol
312 and then Scope.Last = 1
313 then
314 Error_Msg_SP ("operator symbol not allowed at library level");
315 Name_Node := New_Entity (N_Defining_Identifier, Sloc (Name_Node));
316
317 -- Set name from file name, we need some junk name, and that's
318 -- as good as anything. This is only approximate, since we do
319 -- not do anything with non-standard name translations.
320
321 Get_Name_String (File_Name (Current_Source_File));
322
323 for J in 1 .. Name_Len loop
324 if Name_Buffer (J) = '.' then
325 Name_Len := J - 1;
326 exit;
327 end if;
328 end loop;
329
330 Set_Chars (Name_Node, Name_Find);
331 Set_Error_Posted (Name_Node);
332 end if;
333
334 else
335 Name_Node := P_Defining_Program_Unit_Name;
336 end if;
337
338 Scope.Table (Scope.Last).Labl := Name_Node;
339 Ignore (Tok_Colon);
340
341 -- Deal with generic instantiation, the one case in which we do not
342 -- have a subprogram specification as part of whatever we are parsing
343
344 if Token = Tok_Is then
345 Save_Scan_State (Scan_State); -- at the IS
346 T_Is; -- checks for redundant IS
347
348 if Token = Tok_New then
349 if not Pf_Flags.Gins then
350 Error_Msg_SC ("generic instantiation not allowed here!");
351 end if;
352
353 Scan; -- past NEW
354
355 if Func then
356 Inst_Node := New_Node (N_Function_Instantiation, Fproc_Sloc);
357 Set_Name (Inst_Node, P_Function_Name);
358 else
359 Inst_Node := New_Node (N_Procedure_Instantiation, Fproc_Sloc);
360 Set_Name (Inst_Node, P_Qualified_Simple_Name);
361 end if;
362
363 Set_Defining_Unit_Name (Inst_Node, Name_Node);
364 Set_Generic_Associations (Inst_Node, P_Generic_Actual_Part_Opt);
365 P_Aspect_Specifications (Inst_Node);
366 Pop_Scope_Stack; -- Don't need scope stack entry in this case
367
368 if Is_Overriding then
369 Set_Must_Override (Inst_Node);
370
371 elsif Not_Overriding then
372 Set_Must_Not_Override (Inst_Node);
373 end if;
374
375 return Inst_Node;
376
377 else
378 Restore_Scan_State (Scan_State); -- to the IS
379 end if;
380 end if;
381
382 -- If not a generic instantiation, then we definitely have a subprogram
383 -- specification (all possibilities at this stage include one here)
384
385 Fpart_Sloc := Token_Ptr;
386
387 Check_Misspelling_Of (Tok_Return);
388
389 -- Scan formal part. First a special error check. If we have an
390 -- identifier here, then we have a definite error. If this identifier
391 -- is on the same line as the designator, then we assume it is the
392 -- first formal after a missing left parenthesis
393
394 if Token = Tok_Identifier
395 and then not Token_Is_At_Start_Of_Line
396 then
397 T_Left_Paren; -- to generate message
398 Fpart_List := P_Formal_Part;
399
400 -- Otherwise scan out an optional formal part in the usual manner
401
402 else
403 Fpart_List := P_Parameter_Profile;
404 end if;
405
406 -- We treat what we have as a function specification if FUNCTION was
407 -- used, or if a RETURN is present. This gives better error recovery
408 -- since later RETURN statements will be valid in either case.
409
410 Check_Junk_Semicolon_Before_Return;
411 Result_Node := Error;
412
413 if Token = Tok_Return then
414 if not Func then
415 Error_Msg -- CODEFIX
416 ("PROCEDURE should be FUNCTION", Fproc_Sloc);
417 Func := True;
418 end if;
419
420 Scan; -- past RETURN
421
422 Result_Not_Null := P_Null_Exclusion; -- Ada 2005 (AI-231)
423
424 -- Ada 2005 (AI-318-02)
425
426 if Token = Tok_Access then
427 if Ada_Version < Ada_2005 then
428 Error_Msg_SC
429 ("anonymous access result type is an Ada 2005 extension");
430 Error_Msg_SC ("\unit must be compiled with -gnat05 switch");
431 end if;
432
433 Result_Node := P_Access_Definition (Result_Not_Null);
434
435 else
436 Result_Node := P_Subtype_Mark;
437 No_Constraint_Maybe_Expr_Func;
438 end if;
439
440 else
441 -- Skip extra parenthesis at end of formal part
442
443 Ignore (Tok_Right_Paren);
444
445 -- For function, scan result subtype
446
447 if Func then
448 TF_Return;
449
450 if Prev_Token = Tok_Return then
451 Result_Node := P_Subtype_Mark;
452 end if;
453 end if;
454 end if;
455
456 if Func then
457 Specification_Node :=
458 New_Node (N_Function_Specification, Fproc_Sloc);
459
460 Set_Null_Exclusion_Present (Specification_Node, Result_Not_Null);
461 Set_Result_Definition (Specification_Node, Result_Node);
462
463 else
464 Specification_Node :=
465 New_Node (N_Procedure_Specification, Fproc_Sloc);
466 end if;
467
468 Set_Defining_Unit_Name (Specification_Node, Name_Node);
469 Set_Parameter_Specifications (Specification_Node, Fpart_List);
470
471 if Is_Overriding then
472 Set_Must_Override (Specification_Node);
473
474 elsif Not_Overriding then
475 Set_Must_Not_Override (Specification_Node);
476 end if;
477
478 -- Error check: barriers not allowed on protected functions/procedures
479
480 if Token = Tok_When then
481 if Func then
482 Error_Msg_SC ("barrier not allowed on function, only on entry");
483 else
484 Error_Msg_SC ("barrier not allowed on procedure, only on entry");
485 end if;
486
487 Scan; -- past WHEN
488 Discard_Junk_Node (P_Expression);
489 end if;
490
491 -- Deal with semicolon followed by IS. We want to treat this as IS
492
493 if Token = Tok_Semicolon then
494 Save_Scan_State (Scan_State);
495 Scan; -- past semicolon
496
497 if Token = Tok_Is then
498 Error_Msg_SP -- CODEFIX
499 ("extra "";"" ignored");
500 else
501 Restore_Scan_State (Scan_State);
502 end if;
503 end if;
504
505 -- Subprogram declaration ended by aspect specifications
506
507 if Aspect_Specifications_Present then
508 goto Subprogram_Declaration;
509
510 -- Deal with case of semicolon ending a subprogram declaration
511
512 elsif Token = Tok_Semicolon then
513 if not Pf_Flags.Decl then
514 T_Is;
515 end if;
516
517 Save_Scan_State (Scan_State);
518 Scan; -- past semicolon
519
520 -- If semicolon is immediately followed by IS, then ignore the
521 -- semicolon, and go process the body.
522
523 if Token = Tok_Is then
524 Error_Msg_SP -- CODEFIX
525 ("|extra "";"" ignored");
526 T_Is; -- scan past IS
527 goto Subprogram_Body;
528
529 -- If BEGIN follows in an appropriate column, we immediately
530 -- commence the error action of assuming that the previous
531 -- subprogram declaration should have been a subprogram body,
532 -- i.e. that the terminating semicolon should have been IS.
533
534 elsif Token = Tok_Begin
535 and then Start_Column >= Scope.Table (Scope.Last).Ecol
536 then
537 Error_Msg_SP -- CODEFIX
538 ("|"";"" should be IS!");
539 goto Subprogram_Body;
540
541 else
542 Restore_Scan_State (Scan_State);
543 goto Subprogram_Declaration;
544 end if;
545
546 -- Case of not followed by semicolon
547
548 else
549 -- Subprogram renaming declaration case
550
551 Check_Misspelling_Of (Tok_Renames);
552
553 if Token = Tok_Renames then
554 if not Pf_Flags.Rnam then
555 Error_Msg_SC ("renaming declaration not allowed here!");
556 end if;
557
558 Rename_Node :=
559 New_Node (N_Subprogram_Renaming_Declaration, Token_Ptr);
560 Scan; -- past RENAMES
561 Set_Name (Rename_Node, P_Name);
562 Set_Specification (Rename_Node, Specification_Node);
563 P_Aspect_Specifications (Rename_Node);
564 TF_Semicolon;
565 Pop_Scope_Stack;
566 return Rename_Node;
567
568 -- Case of IS following subprogram specification
569
570 elsif Token = Tok_Is then
571 T_Is; -- ignore redundant Is's
572
573 if Token_Name = Name_Abstract then
574 Check_95_Keyword (Tok_Abstract, Tok_Semicolon);
575 end if;
576
577 -- Deal nicely with (now obsolete) use of <> in place of abstract
578
579 if Token = Tok_Box then
580 Error_Msg_SC -- CODEFIX
581 ("ABSTRACT expected");
582 Token := Tok_Abstract;
583 end if;
584
585 -- Abstract subprogram declaration case
586
587 if Token = Tok_Abstract then
588 Absdec_Node :=
589 New_Node (N_Abstract_Subprogram_Declaration, Token_Ptr);
590 Set_Specification (Absdec_Node, Specification_Node);
591 Pop_Scope_Stack; -- discard unneeded entry
592 Scan; -- past ABSTRACT
593 P_Aspect_Specifications (Absdec_Node);
594 return Absdec_Node;
595
596 -- Ada 2005 (AI-248): Parse a null procedure declaration
597
598 elsif Token = Tok_Null then
599 if Ada_Version < Ada_2005 then
600 Error_Msg_SP ("null procedures are an Ada 2005 extension");
601 Error_Msg_SP ("\unit must be compiled with -gnat05 switch");
602 end if;
603
604 Scan; -- past NULL
605
606 if Func then
607 Error_Msg_SP ("only procedures can be null");
608 else
609 Set_Null_Present (Specification_Node);
610 end if;
611
612 goto Subprogram_Declaration;
613
614 -- Check for IS NEW with Formal_Part present and handle nicely
615
616 elsif Token = Tok_New then
617 Error_Msg
618 ("formal part not allowed in instantiation", Fpart_Sloc);
619 Scan; -- past NEW
620
621 if Func then
622 Inst_Node := New_Node (N_Function_Instantiation, Fproc_Sloc);
623 else
624 Inst_Node :=
625 New_Node (N_Procedure_Instantiation, Fproc_Sloc);
626 end if;
627
628 Set_Defining_Unit_Name (Inst_Node, Name_Node);
629 Set_Name (Inst_Node, P_Name);
630 Set_Generic_Associations (Inst_Node, P_Generic_Actual_Part_Opt);
631 TF_Semicolon;
632 Pop_Scope_Stack; -- Don't need scope stack entry in this case
633 return Inst_Node;
634
635 else
636 goto Subprogram_Body;
637 end if;
638
639 -- Aspect specifications present
640
641 elsif Aspect_Specifications_Present then
642 goto Subprogram_Declaration;
643
644 -- Here we have a missing IS or missing semicolon
645
646 else
647 -- If the next token is a left paren at the start of a line, then
648 -- this is almost certainly the start of the expression for an
649 -- expression function, so in this case guess a missing IS.
650
651 if Token = Tok_Left_Paren and then Token_Is_At_Start_Of_Line then
652 Error_Msg_AP -- CODEFIX
653 ("missing IS");
654
655 -- In all other cases, we guess a missing semicolon, since we are
656 -- good at fixing up a semicolon which should really be an IS.
657
658 else
659 Error_Msg_AP -- CODEFIX
660 ("|missing "";""");
661 SIS_Missing_Semicolon_Message := Get_Msg_Id;
662 goto Subprogram_Declaration;
663 end if;
664 end if;
665 end if;
666
667 -- Processing for stub or subprogram body or expression function
668
669 <<Subprogram_Body>>
670
671 -- Subprogram body stub case
672
673 if Separate_Present then
674 if not Pf_Flags.Stub then
675 Error_Msg_SC ("body stub not allowed here!");
676 end if;
677
678 if Nkind (Name_Node) = N_Defining_Operator_Symbol then
679 Error_Msg
680 ("operator symbol cannot be used as subunit name",
681 Sloc (Name_Node));
682 end if;
683
684 Stub_Node :=
685 New_Node (N_Subprogram_Body_Stub, Sloc (Specification_Node));
686 Set_Specification (Stub_Node, Specification_Node);
687 Scan; -- past SEPARATE
688 Pop_Scope_Stack;
689 TF_Semicolon;
690 return Stub_Node;
691
692 -- Subprogram body or expression function case
693
694 else
695 Scan_Body_Or_Expression_Function : declare
696
697 Body_Is_Hidden_In_SPARK : Boolean;
698 Hidden_Region_Start : Source_Ptr;
699
700 function Likely_Expression_Function return Boolean;
701 -- Returns True if we have a probable case of an expression
702 -- function omitting the parentheses, if so, returns True
703 -- and emits an appropriate error message, else returns False.
704
705 --------------------------------
706 -- Likely_Expression_Function --
707 --------------------------------
708
709 function Likely_Expression_Function return Boolean is
710 begin
711 -- If currently pointing to BEGIN or a declaration keyword
712 -- or a pragma, then we definitely have a subprogram body.
713 -- This is a common case, so worth testing first.
714
715 if Token = Tok_Begin
716 or else Token in Token_Class_Declk
717 or else Token = Tok_Pragma
718 then
719 return False;
720
721 -- Test for tokens which could only start an expression and
722 -- thus signal the case of a expression function.
723
724 elsif Token in Token_Class_Literal
725 or else Token in Token_Class_Unary_Addop
726 or else Token = Tok_Left_Paren
727 or else Token = Tok_Abs
728 or else Token = Tok_Null
729 or else Token = Tok_New
730 or else Token = Tok_Not
731 then
732 null;
733
734 -- Anything other than an identifier must be a body
735
736 elsif Token /= Tok_Identifier then
737 return False;
738
739 -- Here for an identifier
740
741 else
742 -- If the identifier is the first token on its line, then
743 -- let's assume that we have a missing begin and this is
744 -- intended as a subprogram body. However, if the context
745 -- is a function and the unit is a package declaration, a
746 -- body would be illegal, so try for an unparenthesized
747 -- expression function.
748
749 if Token_Is_At_Start_Of_Line then
750 declare
751 -- The enclosing scope entry is a subprogram spec
752
753 Spec_Node : constant Node_Id :=
754 Parent
755 (Scope.Table (Scope.Last).Labl);
756 Lib_Node : Node_Id := Spec_Node;
757
758 begin
759 -- Check whether there is an enclosing scope that
760 -- is a package declaration.
761
762 if Scope.Last > 1 then
763 Lib_Node :=
764 Parent (Scope.Table (Scope.Last - 1).Labl);
765 end if;
766
767 if Ada_Version >= Ada_2012
768 and then
769 Nkind (Lib_Node) = N_Package_Specification
770 and then
771 Nkind (Spec_Node) = N_Function_Specification
772 then
773 null;
774 else
775 return False;
776 end if;
777 end;
778
779 -- Otherwise we have to scan ahead. If the identifier is
780 -- followed by a colon or a comma, it is a declaration
781 -- and hence we have a subprogram body. Otherwise assume
782 -- a expression function.
783
784 else
785 declare
786 Scan_State : Saved_Scan_State;
787 Tok : Token_Type;
788
789 begin
790 Save_Scan_State (Scan_State);
791 Scan; -- past identifier
792 Tok := Token;
793 Restore_Scan_State (Scan_State);
794
795 if Tok = Tok_Colon or else Tok = Tok_Comma then
796 return False;
797 end if;
798 end;
799 end if;
800 end if;
801
802 -- Fall through if we have a likely expression function
803
804 Error_Msg_SC
805 ("expression function must be enclosed in parentheses");
806 return True;
807 end Likely_Expression_Function;
808
809 -- Start of processing for Scan_Body_Or_Expression_Function
810
811 begin
812 -- Expression_Function case
813
814 if Token = Tok_Left_Paren
815 or else Likely_Expression_Function
816 then
817 -- Check expression function allowed here
818
819 if not Pf_Flags.Pexp then
820 Error_Msg_SC ("expression function not allowed here!");
821 end if;
822
823 -- Check we are in Ada 2012 mode
824
825 if Ada_Version < Ada_2012 then
826 Error_Msg_SC
827 ("expression function is an Ada 2012 feature!");
828 Error_Msg_SC
829 ("\unit must be compiled with -gnat2012 switch!");
830 end if;
831
832 -- Parse out expression and build expression function
833
834 Body_Node :=
835 New_Node
836 (N_Expression_Function, Sloc (Specification_Node));
837 Set_Specification (Body_Node, Specification_Node);
838 Set_Expression (Body_Node, P_Expression);
839
840 -- Expression functions can carry pre/postconditions
841
842 P_Aspect_Specifications (Body_Node);
843 Pop_Scope_Stack;
844
845 -- Subprogram body case
846
847 else
848 -- Check body allowed here
849
850 if not Pf_Flags.Pbod then
851 Error_Msg_SP ("subprogram body not allowed here!");
852 end if;
853
854 -- Here is the test for a suspicious IS (i.e. one that
855 -- looks like it might more properly be a semicolon).
856 -- See separate section describing use of IS instead
857 -- of semicolon in package Parse.
858
859 if (Token in Token_Class_Declk
860 or else
861 Token = Tok_Identifier)
862 and then Start_Column <= Scope.Table (Scope.Last).Ecol
863 and then Scope.Last /= 1
864 then
865 Scope.Table (Scope.Last).Etyp := E_Suspicious_Is;
866 Scope.Table (Scope.Last).S_Is := Prev_Token_Ptr;
867 end if;
868
869 -- Build and return subprogram body, parsing declarations
870 -- and statement sequence that belong to the body.
871
872 Body_Node :=
873 New_Node (N_Subprogram_Body, Sloc (Specification_Node));
874 Set_Specification (Body_Node, Specification_Node);
875
876 -- If aspects are present, the specification is parsed as
877 -- a subprogram declaration, and we jump here after seeing
878 -- the keyword IS. Attach asspects previously collected to
879 -- the body.
880
881 if Is_Non_Empty_List (Aspects) then
882 Set_Parent (Aspects, Body_Node);
883 Set_Aspect_Specifications (Body_Node, Aspects);
884 end if;
885
886 -- In SPARK, a HIDE directive can be placed at the beginning
887 -- of a subprogram implementation, thus hiding the
888 -- subprogram body from SPARK tool-set. No violation of the
889 -- SPARK restriction should be issued on nodes in a hidden
890 -- part, which is obtained by marking such hidden parts.
891
892 if Token = Tok_SPARK_Hide then
893 Body_Is_Hidden_In_SPARK := True;
894 Hidden_Region_Start := Token_Ptr;
895 Scan; -- past HIDE directive
896 else
897 Body_Is_Hidden_In_SPARK := False;
898 end if;
899
900 Parse_Decls_Begin_End (Body_Node);
901
902 if Body_Is_Hidden_In_SPARK then
903 Set_Hidden_Part_In_SPARK (Hidden_Region_Start, Token_Ptr);
904 end if;
905 end if;
906
907 return Body_Node;
908 end Scan_Body_Or_Expression_Function;
909 end if;
910
911 -- Processing for subprogram declaration
912
913 <<Subprogram_Declaration>>
914 Decl_Node :=
915 New_Node (N_Subprogram_Declaration, Sloc (Specification_Node));
916 Set_Specification (Decl_Node, Specification_Node);
917 Aspects := Get_Aspect_Specifications (Semicolon => False);
918
919 -- Aspects may be present on a subprogram body. The source parsed
920 -- so far is that of its specification, go parse the body and attach
921 -- the collected aspects, if any, to the body.
922
923 if Token = Tok_Is then
924 Scan;
925 goto Subprogram_Body;
926
927 else
928 if Is_Non_Empty_List (Aspects) then
929 Set_Parent (Aspects, Decl_Node);
930 Set_Aspect_Specifications (Decl_Node, Aspects);
931 end if;
932
933 TF_Semicolon;
934 end if;
935
936 -- If this is a context in which a subprogram body is permitted,
937 -- set active SIS entry in case (see section titled "Handling
938 -- Semicolon Used in Place of IS" in body of Parser package)
939 -- Note that SIS_Missing_Semicolon_Message is already set properly.
940
941 if Pf_Flags.Pbod then
942 SIS_Labl := Scope.Table (Scope.Last).Labl;
943 SIS_Sloc := Scope.Table (Scope.Last).Sloc;
944 SIS_Ecol := Scope.Table (Scope.Last).Ecol;
945 SIS_Declaration_Node := Decl_Node;
946 SIS_Semicolon_Sloc := Prev_Token_Ptr;
947 SIS_Entry_Active := True;
948 end if;
949
950 Pop_Scope_Stack;
951 return Decl_Node;
952 end P_Subprogram;
953
954 ---------------------------------
955 -- 6.1 Subprogram Declaration --
956 ---------------------------------
957
958 -- Parsed by P_Subprogram (6.1)
959
960 ------------------------------------------
961 -- 6.1 Abstract Subprogram Declaration --
962 ------------------------------------------
963
964 -- Parsed by P_Subprogram (6.1)
965
966 -----------------------------------
967 -- 6.1 Subprogram Specification --
968 -----------------------------------
969
970 -- SUBPROGRAM_SPECIFICATION ::=
971 -- procedure DEFINING_PROGRAM_UNIT_NAME PARAMETER_PROFILE
972 -- | function DEFINING_DESIGNATOR PARAMETER_AND_RESULT_PROFILE
973
974 -- PARAMETER_PROFILE ::= [FORMAL_PART]
975
976 -- PARAMETER_AND_RESULT_PROFILE ::= [FORMAL_PART] return SUBTYPE_MARK
977
978 -- Subprogram specifications that appear in subprogram declarations
979 -- are parsed by P_Subprogram (6.1). This routine is used in other
980 -- contexts where subprogram specifications occur.
981
982 -- Note: this routine does not affect the scope stack in any way
983
984 -- Error recovery: can raise Error_Resync
985
986 function P_Subprogram_Specification return Node_Id is
987 Specification_Node : Node_Id;
988 Result_Not_Null : Boolean;
989 Result_Node : Node_Id;
990
991 begin
992 if Token = Tok_Function then
993 Specification_Node := New_Node (N_Function_Specification, Token_Ptr);
994 Scan; -- past FUNCTION
995 Ignore (Tok_Body);
996 Set_Defining_Unit_Name (Specification_Node, P_Defining_Designator);
997 Set_Parameter_Specifications
998 (Specification_Node, P_Parameter_Profile);
999 Check_Junk_Semicolon_Before_Return;
1000 TF_Return;
1001
1002 Result_Not_Null := P_Null_Exclusion; -- Ada 2005 (AI-231)
1003
1004 -- Ada 2005 (AI-318-02)
1005
1006 if Token = Tok_Access then
1007 if Ada_Version < Ada_2005 then
1008 Error_Msg_SC
1009 ("anonymous access result type is an Ada 2005 extension");
1010 Error_Msg_SC ("\unit must be compiled with -gnat05 switch");
1011 end if;
1012
1013 Result_Node := P_Access_Definition (Result_Not_Null);
1014
1015 else
1016 Result_Node := P_Subtype_Mark;
1017 No_Constraint_Maybe_Expr_Func;
1018 end if;
1019
1020 Set_Null_Exclusion_Present (Specification_Node, Result_Not_Null);
1021 Set_Result_Definition (Specification_Node, Result_Node);
1022 return Specification_Node;
1023
1024 elsif Token = Tok_Procedure then
1025 Specification_Node := New_Node (N_Procedure_Specification, Token_Ptr);
1026 Scan; -- past PROCEDURE
1027 Ignore (Tok_Body);
1028 Set_Defining_Unit_Name
1029 (Specification_Node, P_Defining_Program_Unit_Name);
1030 Set_Parameter_Specifications
1031 (Specification_Node, P_Parameter_Profile);
1032 return Specification_Node;
1033
1034 else
1035 Error_Msg_SC ("subprogram specification expected");
1036 raise Error_Resync;
1037 end if;
1038 end P_Subprogram_Specification;
1039
1040 ---------------------
1041 -- 6.1 Designator --
1042 ---------------------
1043
1044 -- DESIGNATOR ::=
1045 -- [PARENT_UNIT_NAME .] IDENTIFIER | OPERATOR_SYMBOL
1046
1047 -- The caller has checked that the initial token is an identifier,
1048 -- operator symbol, or string literal. Note that we don't bother to
1049 -- do much error diagnosis in this routine, since it is only used for
1050 -- the label on END lines, and the routines in package Par.Endh will
1051 -- check that the label is appropriate.
1052
1053 -- Error recovery: cannot raise Error_Resync
1054
1055 function P_Designator return Node_Id is
1056 Ident_Node : Node_Id;
1057 Name_Node : Node_Id;
1058 Prefix_Node : Node_Id;
1059
1060 function Real_Dot return Boolean;
1061 -- Tests if a current token is an interesting period, i.e. is followed
1062 -- by an identifier or operator symbol or string literal. If not, it is
1063 -- probably just incorrect punctuation to be caught by our caller. Note
1064 -- that the case of an operator symbol or string literal is also an
1065 -- error, but that is an error that we catch here. If the result is
1066 -- True, a real dot has been scanned and we are positioned past it,
1067 -- if the result is False, the scan position is unchanged.
1068
1069 --------------
1070 -- Real_Dot --
1071 --------------
1072
1073 function Real_Dot return Boolean is
1074 Scan_State : Saved_Scan_State;
1075
1076 begin
1077 if Token /= Tok_Dot then
1078 return False;
1079
1080 else
1081 Save_Scan_State (Scan_State);
1082 Scan; -- past dot
1083
1084 if Token = Tok_Identifier
1085 or else Token = Tok_Operator_Symbol
1086 or else Token = Tok_String_Literal
1087 then
1088 return True;
1089
1090 else
1091 Restore_Scan_State (Scan_State);
1092 return False;
1093 end if;
1094 end if;
1095 end Real_Dot;
1096
1097 -- Start of processing for P_Designator
1098
1099 begin
1100 Ident_Node := Token_Node;
1101 Scan; -- past initial token
1102
1103 if Prev_Token = Tok_Operator_Symbol
1104 or else Prev_Token = Tok_String_Literal
1105 or else not Real_Dot
1106 then
1107 return Ident_Node;
1108
1109 -- Child name case
1110
1111 else
1112 Prefix_Node := Ident_Node;
1113
1114 -- Loop through child names, on entry to this loop, Prefix contains
1115 -- the name scanned so far, and Ident_Node is the last identifier.
1116
1117 loop
1118 Name_Node := New_Node (N_Selected_Component, Prev_Token_Ptr);
1119 Set_Prefix (Name_Node, Prefix_Node);
1120 Ident_Node := P_Identifier;
1121 Set_Selector_Name (Name_Node, Ident_Node);
1122 Prefix_Node := Name_Node;
1123 exit when not Real_Dot;
1124 end loop;
1125
1126 -- On exit from the loop, Ident_Node is the last identifier scanned,
1127 -- i.e. the defining identifier, and Prefix_Node is a node for the
1128 -- entire name, structured (incorrectly!) as a selected component.
1129
1130 Name_Node := Prefix (Prefix_Node);
1131 Change_Node (Prefix_Node, N_Designator);
1132 Set_Name (Prefix_Node, Name_Node);
1133 Set_Identifier (Prefix_Node, Ident_Node);
1134 return Prefix_Node;
1135 end if;
1136
1137 exception
1138 when Error_Resync =>
1139 while Token = Tok_Dot or else Token = Tok_Identifier loop
1140 Scan;
1141 end loop;
1142
1143 return Error;
1144 end P_Designator;
1145
1146 ------------------------------
1147 -- 6.1 Defining Designator --
1148 ------------------------------
1149
1150 -- DEFINING_DESIGNATOR ::=
1151 -- DEFINING_PROGRAM_UNIT_NAME | DEFINING_OPERATOR_SYMBOL
1152
1153 -- Error recovery: cannot raise Error_Resync
1154
1155 function P_Defining_Designator return Node_Id is
1156 begin
1157 if Token = Tok_Operator_Symbol then
1158 return P_Defining_Operator_Symbol;
1159
1160 elsif Token = Tok_String_Literal then
1161 Error_Msg_SC ("invalid operator name");
1162 Scan; -- past junk string
1163 return Error;
1164
1165 else
1166 return P_Defining_Program_Unit_Name;
1167 end if;
1168 end P_Defining_Designator;
1169
1170 -------------------------------------
1171 -- 6.1 Defining Program Unit Name --
1172 -------------------------------------
1173
1174 -- DEFINING_PROGRAM_UNIT_NAME ::=
1175 -- [PARENT_UNIT_NAME .] DEFINING_IDENTIFIER
1176
1177 -- Note: PARENT_UNIT_NAME may be present only in 95 mode at the outer level
1178
1179 -- Error recovery: cannot raise Error_Resync
1180
1181 function P_Defining_Program_Unit_Name return Node_Id is
1182 Ident_Node : Node_Id;
1183 Name_Node : Node_Id;
1184 Prefix_Node : Node_Id;
1185
1186 begin
1187 -- Set identifier casing if not already set and scan initial identifier
1188
1189 if Token = Tok_Identifier
1190 and then Identifier_Casing (Current_Source_File) = Unknown
1191 then
1192 Set_Identifier_Casing (Current_Source_File, Determine_Token_Casing);
1193 end if;
1194
1195 Ident_Node := P_Identifier (C_Dot);
1196 Merge_Identifier (Ident_Node, Tok_Return);
1197
1198 -- Normal case (not child library unit name)
1199
1200 if Token /= Tok_Dot then
1201 Change_Identifier_To_Defining_Identifier (Ident_Node);
1202 Warn_If_Standard_Redefinition (Ident_Node);
1203 return Ident_Node;
1204
1205 -- Child library unit name case
1206
1207 else
1208 if Scope.Last > 1 then
1209 Error_Msg_SP ("child unit allowed only at library level");
1210 raise Error_Resync;
1211
1212 elsif Ada_Version = Ada_83 then
1213 Error_Msg_SP ("(Ada 83) child unit not allowed!");
1214
1215 end if;
1216
1217 Prefix_Node := Ident_Node;
1218
1219 -- Loop through child names, on entry to this loop, Prefix contains
1220 -- the name scanned so far, and Ident_Node is the last identifier.
1221
1222 loop
1223 exit when Token /= Tok_Dot;
1224 Name_Node := New_Node (N_Selected_Component, Token_Ptr);
1225 Scan; -- past period
1226 Set_Prefix (Name_Node, Prefix_Node);
1227 Ident_Node := P_Identifier (C_Dot);
1228 Set_Selector_Name (Name_Node, Ident_Node);
1229 Prefix_Node := Name_Node;
1230 end loop;
1231
1232 -- On exit from the loop, Ident_Node is the last identifier scanned,
1233 -- i.e. the defining identifier, and Prefix_Node is a node for the
1234 -- entire name, structured (incorrectly!) as a selected component.
1235
1236 Name_Node := Prefix (Prefix_Node);
1237 Change_Node (Prefix_Node, N_Defining_Program_Unit_Name);
1238 Set_Name (Prefix_Node, Name_Node);
1239 Change_Identifier_To_Defining_Identifier (Ident_Node);
1240 Warn_If_Standard_Redefinition (Ident_Node);
1241 Set_Defining_Identifier (Prefix_Node, Ident_Node);
1242
1243 -- All set with unit name parsed
1244
1245 return Prefix_Node;
1246 end if;
1247
1248 exception
1249 when Error_Resync =>
1250 while Token = Tok_Dot or else Token = Tok_Identifier loop
1251 Scan;
1252 end loop;
1253
1254 return Error;
1255 end P_Defining_Program_Unit_Name;
1256
1257 --------------------------
1258 -- 6.1 Operator Symbol --
1259 --------------------------
1260
1261 -- OPERATOR_SYMBOL ::= STRING_LITERAL
1262
1263 -- Operator symbol is returned by the scanner as Tok_Operator_Symbol
1264
1265 -----------------------------------
1266 -- 6.1 Defining Operator Symbol --
1267 -----------------------------------
1268
1269 -- DEFINING_OPERATOR_SYMBOL ::= OPERATOR_SYMBOL
1270
1271 -- The caller has checked that the initial symbol is an operator symbol
1272
1273 function P_Defining_Operator_Symbol return Node_Id is
1274 Op_Node : Node_Id;
1275
1276 begin
1277 Op_Node := Token_Node;
1278 Change_Operator_Symbol_To_Defining_Operator_Symbol (Op_Node);
1279 Scan; -- past operator symbol
1280 return Op_Node;
1281 end P_Defining_Operator_Symbol;
1282
1283 ----------------------------
1284 -- 6.1 Parameter_Profile --
1285 ----------------------------
1286
1287 -- PARAMETER_PROFILE ::= [FORMAL_PART]
1288
1289 -- Empty is returned if no formal part is present
1290
1291 -- Error recovery: cannot raise Error_Resync
1292
1293 function P_Parameter_Profile return List_Id is
1294 begin
1295 if Token = Tok_Left_Paren then
1296 Scan; -- part left paren
1297 return P_Formal_Part;
1298 else
1299 return No_List;
1300 end if;
1301 end P_Parameter_Profile;
1302
1303 ---------------------------------------
1304 -- 6.1 Parameter And Result Profile --
1305 ---------------------------------------
1306
1307 -- Parsed by its parent construct, which uses P_Parameter_Profile to
1308 -- parse the parameters, and P_Subtype_Mark to parse the return type.
1309
1310 ----------------------
1311 -- 6.1 Formal part --
1312 ----------------------
1313
1314 -- FORMAL_PART ::= (PARAMETER_SPECIFICATION {; PARAMETER_SPECIFICATION})
1315
1316 -- PARAMETER_SPECIFICATION ::=
1317 -- DEFINING_IDENTIFIER_LIST : [ALIASED] MODE [NULL_EXCLUSION]
1318 -- SUBTYPE_MARK [:= DEFAULT_EXPRESSION]
1319 -- | DEFINING_IDENTIFIER_LIST : ACCESS_DEFINITION
1320 -- [:= DEFAULT_EXPRESSION]
1321
1322 -- This scans the construct Formal_Part. The caller has already checked
1323 -- that the initial token is a left parenthesis, and skipped past it, so
1324 -- that on entry Token is the first token following the left parenthesis.
1325
1326 -- Note: The ALIASED keyword is allowed only in Ada 2012 mode (AI 142)
1327
1328 -- Error recovery: cannot raise Error_Resync
1329
1330 function P_Formal_Part return List_Id is
1331 Specification_List : List_Id;
1332 Specification_Node : Node_Id;
1333 Scan_State : Saved_Scan_State;
1334 Num_Idents : Nat;
1335 Ident : Nat;
1336 Ident_Sloc : Source_Ptr;
1337 Not_Null_Present : Boolean := False;
1338 Not_Null_Sloc : Source_Ptr;
1339
1340 Idents : array (Int range 1 .. 4096) of Entity_Id;
1341 -- This array holds the list of defining identifiers. The upper bound
1342 -- of 4096 is intended to be essentially infinite, and we do not even
1343 -- bother to check for it being exceeded.
1344
1345 begin
1346 Specification_List := New_List;
1347 Specification_Loop : loop
1348 begin
1349 if Token = Tok_Pragma then
1350 Error_Msg_SC ("pragma not allowed in formal part");
1351 Discard_Junk_Node (P_Pragma (Skipping => True));
1352 end if;
1353
1354 Ignore (Tok_Left_Paren);
1355 Ident_Sloc := Token_Ptr;
1356 Idents (1) := P_Defining_Identifier (C_Comma_Colon);
1357 Num_Idents := 1;
1358
1359 Ident_Loop : loop
1360 exit Ident_Loop when Token = Tok_Colon;
1361
1362 -- The only valid tokens are colon and comma, so if we have
1363 -- neither do a bit of investigation to see which is the
1364 -- better choice for insertion.
1365
1366 if Token /= Tok_Comma then
1367
1368 -- Assume colon if ALIASED, IN or OUT keyword found
1369
1370 exit Ident_Loop when Token = Tok_Aliased or else
1371 Token = Tok_In or else
1372 Token = Tok_Out;
1373
1374 -- Otherwise scan ahead
1375
1376 Save_Scan_State (Scan_State);
1377 Look_Ahead : loop
1378
1379 -- If we run into a semicolon, then assume that a
1380 -- colon was missing, e.g. Parms (X Y; ...). Also
1381 -- assume missing colon on EOF (a real disaster!)
1382 -- and on a right paren, e.g. Parms (X Y), and also
1383 -- on an assignment symbol, e.g. Parms (X Y := ..)
1384
1385 if Token = Tok_Semicolon
1386 or else Token = Tok_Right_Paren
1387 or else Token = Tok_EOF
1388 or else Token = Tok_Colon_Equal
1389 then
1390 Restore_Scan_State (Scan_State);
1391 exit Ident_Loop;
1392
1393 -- If we run into a colon, assume that we had a missing
1394 -- comma, e.g. Parms (A B : ...). Also assume a missing
1395 -- comma if we hit another comma, e.g. Parms (A B, C ..)
1396
1397 elsif Token = Tok_Colon
1398 or else Token = Tok_Comma
1399 then
1400 Restore_Scan_State (Scan_State);
1401 exit Look_Ahead;
1402 end if;
1403
1404 Scan;
1405 end loop Look_Ahead;
1406 end if;
1407
1408 -- Here if a comma is present, or to be assumed
1409
1410 T_Comma;
1411 Num_Idents := Num_Idents + 1;
1412 Idents (Num_Idents) := P_Defining_Identifier (C_Comma_Colon);
1413 end loop Ident_Loop;
1414
1415 -- Fall through the loop on encountering a colon, or deciding
1416 -- that there is a missing colon.
1417
1418 T_Colon;
1419
1420 -- If there are multiple identifiers, we repeatedly scan the
1421 -- type and initialization expression information by resetting
1422 -- the scan pointer (so that we get completely separate trees
1423 -- for each occurrence).
1424
1425 if Num_Idents > 1 then
1426 Save_Scan_State (Scan_State);
1427 end if;
1428
1429 -- Loop through defining identifiers in list
1430
1431 Ident := 1;
1432
1433 Ident_List_Loop : loop
1434 Specification_Node :=
1435 New_Node (N_Parameter_Specification, Ident_Sloc);
1436 Set_Defining_Identifier (Specification_Node, Idents (Ident));
1437
1438 -- Scan possible ALIASED for Ada 2012 (AI-142)
1439
1440 if Token = Tok_Aliased then
1441 if Ada_Version < Ada_2012 then
1442 Error_Msg_SC ("ALIASED parameter is an Ada 2012 feature");
1443 else
1444 Set_Aliased_Present (Specification_Node);
1445 end if;
1446
1447 Scan; -- past ALIASED
1448 end if;
1449
1450 -- Scan possible NOT NULL for Ada 2005 (AI-231, AI-447)
1451
1452 Not_Null_Sloc := Token_Ptr;
1453 Not_Null_Present :=
1454 P_Null_Exclusion (Allow_Anonymous_In_95 => True);
1455
1456 -- Case of ACCESS keyword present
1457
1458 if Token = Tok_Access then
1459 Set_Null_Exclusion_Present
1460 (Specification_Node, Not_Null_Present);
1461
1462 if Ada_Version = Ada_83 then
1463 Error_Msg_SC ("(Ada 83) access parameters not allowed");
1464 end if;
1465
1466 Set_Parameter_Type
1467 (Specification_Node,
1468 P_Access_Definition (Not_Null_Present));
1469
1470 -- Case of IN or OUT present
1471
1472 else
1473 if Token = Tok_In or else Token = Tok_Out then
1474 if Not_Null_Present then
1475 Error_Msg
1476 ("`NOT NULL` can only be used with `ACCESS`",
1477 Not_Null_Sloc);
1478
1479 if Token = Tok_In then
1480 Error_Msg
1481 ("\`IN` not allowed together with `ACCESS`",
1482 Not_Null_Sloc);
1483 else
1484 Error_Msg
1485 ("\`OUT` not allowed together with `ACCESS`",
1486 Not_Null_Sloc);
1487 end if;
1488 end if;
1489
1490 P_Mode (Specification_Node);
1491 Not_Null_Present := P_Null_Exclusion; -- Ada 2005 (AI-231)
1492 end if;
1493
1494 Set_Null_Exclusion_Present
1495 (Specification_Node, Not_Null_Present);
1496
1497 if Token = Tok_Procedure
1498 or else
1499 Token = Tok_Function
1500 then
1501 Error_Msg_SC ("formal subprogram parameter not allowed");
1502 Scan;
1503
1504 if Token = Tok_Left_Paren then
1505 Discard_Junk_List (P_Formal_Part);
1506 end if;
1507
1508 if Token = Tok_Return then
1509 Scan;
1510 Discard_Junk_Node (P_Subtype_Mark);
1511 end if;
1512
1513 Set_Parameter_Type (Specification_Node, Error);
1514
1515 else
1516 Set_Parameter_Type (Specification_Node, P_Subtype_Mark);
1517 No_Constraint;
1518 end if;
1519 end if;
1520
1521 Set_Expression (Specification_Node, Init_Expr_Opt (True));
1522
1523 if Ident > 1 then
1524 Set_Prev_Ids (Specification_Node, True);
1525 end if;
1526
1527 if Ident < Num_Idents then
1528 Set_More_Ids (Specification_Node, True);
1529 end if;
1530
1531 Append (Specification_Node, Specification_List);
1532 exit Ident_List_Loop when Ident = Num_Idents;
1533 Ident := Ident + 1;
1534 Restore_Scan_State (Scan_State);
1535 end loop Ident_List_Loop;
1536
1537 exception
1538 when Error_Resync =>
1539 Resync_Semicolon_List;
1540 end;
1541
1542 if Token = Tok_Semicolon then
1543 Save_Scan_State (Scan_State);
1544 Scan; -- past semicolon
1545
1546 -- If we have RETURN or IS after the semicolon, then assume
1547 -- that semicolon should have been a right parenthesis and exit
1548
1549 if Token = Tok_Is or else Token = Tok_Return then
1550 Error_Msg_SP -- CODEFIX
1551 ("|"";"" should be "")""");
1552 exit Specification_Loop;
1553 end if;
1554
1555 -- If we have a declaration keyword after the semicolon, then
1556 -- assume we had a missing right parenthesis and terminate list
1557
1558 if Token in Token_Class_Declk then
1559 Error_Msg_AP -- CODEFIX
1560 ("missing "")""");
1561 Restore_Scan_State (Scan_State);
1562 exit Specification_Loop;
1563 end if;
1564
1565 elsif Token = Tok_Right_Paren then
1566 Scan; -- past right paren
1567 exit Specification_Loop;
1568
1569 -- Special check for common error of using comma instead of semicolon
1570
1571 elsif Token = Tok_Comma then
1572 T_Semicolon;
1573 Scan; -- past comma
1574
1575 -- Special check for omitted separator
1576
1577 elsif Token = Tok_Identifier then
1578 T_Semicolon;
1579
1580 -- If nothing sensible, skip to next semicolon or right paren
1581
1582 else
1583 T_Semicolon;
1584 Resync_Semicolon_List;
1585
1586 if Token = Tok_Semicolon then
1587 Scan; -- past semicolon
1588 else
1589 T_Right_Paren;
1590 exit Specification_Loop;
1591 end if;
1592 end if;
1593 end loop Specification_Loop;
1594
1595 return Specification_List;
1596 end P_Formal_Part;
1597
1598 ----------------------------------
1599 -- 6.1 Parameter Specification --
1600 ----------------------------------
1601
1602 -- Parsed by P_Formal_Part (6.1)
1603
1604 ---------------
1605 -- 6.1 Mode --
1606 ---------------
1607
1608 -- MODE ::= [in] | in out | out
1609
1610 -- There is no explicit node in the tree for the Mode. Instead the
1611 -- In_Present and Out_Present flags are set in the parent node to
1612 -- record the presence of keywords specifying the mode.
1613
1614 -- Error_Recovery: cannot raise Error_Resync
1615
1616 procedure P_Mode (Node : Node_Id) is
1617 begin
1618 if Token = Tok_In then
1619 Scan; -- past IN
1620 Set_In_Present (Node, True);
1621
1622 if Style.Mode_In_Check and then Token /= Tok_Out then
1623 Error_Msg_SP -- CODEFIX
1624 ("(style) IN should be omitted");
1625 end if;
1626
1627 -- Since Ada 2005, formal objects can have an anonymous access type,
1628 -- and of course carry a mode indicator.
1629
1630 if Token = Tok_Access
1631 and then Nkind (Node) /= N_Formal_Object_Declaration
1632 then
1633 Error_Msg_SP ("IN not allowed together with ACCESS");
1634 Scan; -- past ACCESS
1635 end if;
1636 end if;
1637
1638 if Token = Tok_Out then
1639 Scan; -- past OUT
1640 Set_Out_Present (Node, True);
1641 end if;
1642
1643 if Token = Tok_In then
1644 Error_Msg_SC ("IN must precede OUT in parameter mode");
1645 Scan; -- past IN
1646 Set_In_Present (Node, True);
1647 end if;
1648 end P_Mode;
1649
1650 --------------------------
1651 -- 6.3 Subprogram Body --
1652 --------------------------
1653
1654 -- Parsed by P_Subprogram (6.1)
1655
1656 -----------------------------------
1657 -- 6.4 Procedure Call Statement --
1658 -----------------------------------
1659
1660 -- Parsed by P_Sequence_Of_Statements (5.1)
1661
1662 ------------------------
1663 -- 6.4 Function Call --
1664 ------------------------
1665
1666 -- Parsed by P_Name (4.1)
1667
1668 --------------------------------
1669 -- 6.4 Actual Parameter Part --
1670 --------------------------------
1671
1672 -- Parsed by P_Name (4.1)
1673
1674 --------------------------------
1675 -- 6.4 Parameter Association --
1676 --------------------------------
1677
1678 -- Parsed by P_Name (4.1)
1679
1680 ------------------------------------
1681 -- 6.4 Explicit Actual Parameter --
1682 ------------------------------------
1683
1684 -- Parsed by P_Name (4.1)
1685
1686 ---------------------------
1687 -- 6.5 Return Statement --
1688 ---------------------------
1689
1690 -- SIMPLE_RETURN_STATEMENT ::= return [EXPRESSION];
1691 --
1692 -- EXTENDED_RETURN_STATEMENT ::=
1693 -- return DEFINING_IDENTIFIER : [aliased] RETURN_SUBTYPE_INDICATION
1694 -- [:= EXPRESSION] [do
1695 -- HANDLED_SEQUENCE_OF_STATEMENTS
1696 -- end return];
1697 --
1698 -- RETURN_SUBTYPE_INDICATION ::= SUBTYPE_INDICATION | ACCESS_DEFINITION
1699
1700 -- RETURN_STATEMENT ::= return [EXPRESSION];
1701
1702 -- Error recovery: can raise Error_Resync
1703
1704 procedure P_Return_Subtype_Indication (Decl_Node : Node_Id) is
1705
1706 -- Note: We don't need to check Ada_Version here, because this is
1707 -- only called in >= Ada 2005 cases anyway.
1708
1709 Not_Null_Present : constant Boolean := P_Null_Exclusion;
1710
1711 begin
1712 Set_Null_Exclusion_Present (Decl_Node, Not_Null_Present);
1713
1714 if Token = Tok_Access then
1715 Set_Object_Definition
1716 (Decl_Node, P_Access_Definition (Not_Null_Present));
1717 else
1718 Set_Object_Definition
1719 (Decl_Node, P_Subtype_Indication (Not_Null_Present));
1720 end if;
1721 end P_Return_Subtype_Indication;
1722
1723 -- Error recovery: can raise Error_Resync
1724
1725 function P_Return_Object_Declaration return Node_Id is
1726 Return_Obj : Node_Id;
1727 Decl_Node : Node_Id;
1728
1729 begin
1730 Return_Obj := Token_Node;
1731 Change_Identifier_To_Defining_Identifier (Return_Obj);
1732 Warn_If_Standard_Redefinition (Return_Obj);
1733 Decl_Node := New_Node (N_Object_Declaration, Token_Ptr);
1734 Set_Defining_Identifier (Decl_Node, Return_Obj);
1735
1736 Scan; -- past identifier
1737 Scan; -- past :
1738
1739 -- First an error check, if we have two identifiers in a row, a likely
1740 -- possibility is that the first of the identifiers is an incorrectly
1741 -- spelled keyword. See similar check in P_Identifier_Declarations.
1742
1743 if Token = Tok_Identifier then
1744 declare
1745 SS : Saved_Scan_State;
1746 I2 : Boolean;
1747
1748 begin
1749 Save_Scan_State (SS);
1750 Scan; -- past initial identifier
1751 I2 := (Token = Tok_Identifier);
1752 Restore_Scan_State (SS);
1753
1754 if I2
1755 and then
1756 (Bad_Spelling_Of (Tok_Access) or else
1757 Bad_Spelling_Of (Tok_Aliased) or else
1758 Bad_Spelling_Of (Tok_Constant))
1759 then
1760 null;
1761 end if;
1762 end;
1763 end if;
1764
1765 -- We allow "constant" here (as in "return Result : constant
1766 -- T..."). This is not in the latest RM, but the ARG is considering an
1767 -- AI on the subject (see AI05-0015-1), which we expect to be approved.
1768
1769 if Token = Tok_Constant then
1770 Scan; -- past CONSTANT
1771 Set_Constant_Present (Decl_Node);
1772
1773 if Token = Tok_Aliased then
1774 Error_Msg_SC -- CODEFIX
1775 ("ALIASED should be before CONSTANT");
1776 Scan; -- past ALIASED
1777 Set_Aliased_Present (Decl_Node);
1778 end if;
1779
1780 elsif Token = Tok_Aliased then
1781 Scan; -- past ALIASED
1782 Set_Aliased_Present (Decl_Node);
1783
1784 -- The restrictions on the use of aliased in an extended return
1785 -- are semantic, not syntactic.
1786
1787 if Token = Tok_Constant then
1788 Scan; -- past CONSTANT
1789 Set_Constant_Present (Decl_Node);
1790 end if;
1791 end if;
1792
1793 P_Return_Subtype_Indication (Decl_Node);
1794
1795 if Token = Tok_Colon_Equal then
1796 Scan; -- past :=
1797 Set_Expression (Decl_Node, P_Expression_No_Right_Paren);
1798 end if;
1799
1800 return Decl_Node;
1801 end P_Return_Object_Declaration;
1802
1803 -- Error recovery: can raise Error_Resync
1804
1805 function P_Return_Statement return Node_Id is
1806 -- The caller has checked that the initial token is RETURN
1807
1808 function Is_Simple return Boolean;
1809 -- Scan state is just after RETURN (and is left that way).
1810 -- Determine whether this is a simple or extended return statement
1811 -- by looking ahead for "identifier :", which implies extended.
1812
1813 ---------------
1814 -- Is_Simple --
1815 ---------------
1816
1817 function Is_Simple return Boolean is
1818 Scan_State : Saved_Scan_State;
1819 Result : Boolean := True;
1820
1821 begin
1822 if Token = Tok_Identifier then
1823 Save_Scan_State (Scan_State); -- at identifier
1824 Scan; -- past identifier
1825
1826 if Token = Tok_Colon then
1827 Result := False; -- It's an extended_return_statement.
1828 end if;
1829
1830 Restore_Scan_State (Scan_State); -- to identifier
1831 end if;
1832
1833 return Result;
1834 end Is_Simple;
1835
1836 Return_Sloc : constant Source_Ptr := Token_Ptr;
1837 Return_Node : Node_Id;
1838
1839 -- Start of processing for P_Return_Statement
1840
1841 begin
1842 Scan; -- past RETURN
1843
1844 -- Simple_return_statement, no expression, return an
1845 -- N_Simple_Return_Statement node with the expression field left Empty.
1846
1847 if Token = Tok_Semicolon then
1848 Scan; -- past ;
1849 Return_Node := New_Node (N_Simple_Return_Statement, Return_Sloc);
1850
1851 -- Non-trivial case
1852
1853 else
1854 -- Simple_return_statement with expression
1855
1856 -- We avoid trying to scan an expression if we are at an
1857 -- expression terminator since in that case the best error
1858 -- message is probably that we have a missing semicolon.
1859
1860 if Is_Simple then
1861 Return_Node := New_Node (N_Simple_Return_Statement, Return_Sloc);
1862
1863 if Token not in Token_Class_Eterm then
1864 Set_Expression (Return_Node, P_Expression_No_Right_Paren);
1865 end if;
1866
1867 -- Extended_return_statement (Ada 2005 only -- AI-318):
1868
1869 else
1870 if Ada_Version < Ada_2005 then
1871 Error_Msg_SP
1872 (" extended_return_statement is an Ada 2005 extension");
1873 Error_Msg_SP ("\unit must be compiled with -gnat05 switch");
1874 end if;
1875
1876 Return_Node := New_Node (N_Extended_Return_Statement, Return_Sloc);
1877 Set_Return_Object_Declarations
1878 (Return_Node, New_List (P_Return_Object_Declaration));
1879
1880 if Token = Tok_Do then
1881 Push_Scope_Stack;
1882 Scope.Table (Scope.Last).Etyp := E_Return;
1883 Scope.Table (Scope.Last).Ecol := Start_Column;
1884 Scope.Table (Scope.Last).Sloc := Return_Sloc;
1885
1886 Scan; -- past DO
1887 Set_Handled_Statement_Sequence
1888 (Return_Node, P_Handled_Sequence_Of_Statements);
1889 End_Statements;
1890
1891 -- Do we need to handle Error_Resync here???
1892 end if;
1893 end if;
1894
1895 TF_Semicolon;
1896 end if;
1897
1898 return Return_Node;
1899 end P_Return_Statement;
1900
1901 end Ch6;
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