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Remove old autovect-branch by moving to "dead" directory.
[official-gcc.git] / old-autovect-branch / gcc / ada / par-ch6.adb
blob72855f90e7af5b40bffacebe67bfd8f08ed49667
1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- P A R . C H 6 --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2005, 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 2, 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 COPYING. If not, write --
19 -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, USA. --
21 -- --
22 -- GNAT was originally developed by the GNAT team at New York University. --
23 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 -- --
25 ------------------------------------------------------------------------------
26
27 pragma Style_Checks (All_Checks);
28 -- Turn off subprogram body ordering check. Subprograms are in order
29 -- by RM section rather than alphabetical
30
31 with Sinfo.CN; use Sinfo.CN;
32
33 separate (Par)
34 package body Ch6 is
35
36 -- Local subprograms, used only in this chapter
37
38 function P_Defining_Designator return Node_Id;
39 function P_Defining_Operator_Symbol return Node_Id;
40
41 procedure Check_Junk_Semicolon_Before_Return;
42
43 -- Check for common error of junk semicolon before RETURN keyword of
44 -- function specification. If present, skip over it with appropriate
45 -- error message, leaving Scan_Ptr pointing to the RETURN after. This
46 -- routine also deals with a possibly misspelled version of Return.
47
48 ----------------------------------------
49 -- Check_Junk_Semicolon_Before_Return --
50 ----------------------------------------
51
52 procedure Check_Junk_Semicolon_Before_Return is
53 Scan_State : Saved_Scan_State;
54
55 begin
56 if Token = Tok_Semicolon then
57 Save_Scan_State (Scan_State);
58 Scan; -- past the semicolon
59
60 if Token = Tok_Return then
61 Restore_Scan_State (Scan_State);
62 Error_Msg_SC ("unexpected semicolon ignored");
63 Scan; -- rescan past junk semicolon
64
65 else
66 Restore_Scan_State (Scan_State);
67 end if;
68
69 elsif Bad_Spelling_Of (Tok_Return) then
70 null;
71 end if;
72 end Check_Junk_Semicolon_Before_Return;
73
74 -----------------------------------------------------
75 -- 6.1 Subprogram (Also 6.3, 8.5.4, 10.1.3, 12.3) --
76 -----------------------------------------------------
77
78 -- This routine scans out a subprogram declaration, subprogram body,
79 -- subprogram renaming declaration or subprogram generic instantiation.
80
81 -- SUBPROGRAM_DECLARATION ::= SUBPROGRAM_SPECIFICATION;
82
83 -- ABSTRACT_SUBPROGRAM_DECLARATION ::=
84 -- SUBPROGRAM_SPECIFICATION is abstract;
85
86 -- SUBPROGRAM_SPECIFICATION ::=
87 -- procedure DEFINING_PROGRAM_UNIT_NAME PARAMETER_PROFILE
88 -- | function DEFINING_DESIGNATOR PARAMETER_AND_RESULT_PROFILE
89
90 -- PARAMETER_PROFILE ::= [FORMAL_PART]
91
92 -- PARAMETER_AND_RESULT_PROFILE ::= [FORMAL_PART] return SUBTYPE_MARK
93
94 -- SUBPROGRAM_BODY ::=
95 -- SUBPROGRAM_SPECIFICATION is
96 -- DECLARATIVE_PART
97 -- begin
98 -- HANDLED_SEQUENCE_OF_STATEMENTS
99 -- end [DESIGNATOR];
100
101 -- SUBPROGRAM_RENAMING_DECLARATION ::=
102 -- SUBPROGRAM_SPECIFICATION renames callable_entity_NAME;
103
104 -- SUBPROGRAM_BODY_STUB ::=
105 -- SUBPROGRAM_SPECIFICATION is separate;
106
107 -- GENERIC_INSTANTIATION ::=
108 -- procedure DEFINING_PROGRAM_UNIT_NAME is
109 -- new generic_procedure_NAME [GENERIC_ACTUAL_PART];
110 -- | function DEFINING_DESIGNATOR is
111 -- new generic_function_NAME [GENERIC_ACTUAL_PART];
112
113 -- NULL_PROCEDURE_DECLARATION ::=
114 -- SUBPROGRAM_SPECIFICATION is null;
115
116 -- Null procedures are an Ada 2005 feature. A null procedure declaration
117 -- is classified as a basic declarative item, but it is parsed here, with
118 -- other subprogram constructs.
119
120 -- The value in Pf_Flags indicates which of these possible declarations
121 -- is acceptable to the caller:
122
123 -- Pf_Flags.Decl Set if declaration OK
124 -- Pf_Flags.Gins Set if generic instantiation OK
125 -- Pf_Flags.Pbod Set if proper body OK
126 -- Pf_Flags.Rnam Set if renaming declaration OK
127 -- Pf_Flags.Stub Set if body stub OK
128
129 -- If an inappropriate form is encountered, it is scanned out but an
130 -- error message indicating that it is appearing in an inappropriate
131 -- context is issued. The only possible values for Pf_Flags are those
132 -- defined as constants in the Par package.
133
134 -- The caller has checked that the initial token is FUNCTION, PROCEDURE,
135 -- NOT or OVERRIDING.
136
137 -- Error recovery: cannot raise Error_Resync
138
139 function P_Subprogram (Pf_Flags : Pf_Rec) return Node_Id is
140 Specification_Node : Node_Id;
141 Name_Node : Node_Id;
142 Fpart_List : List_Id;
143 Fpart_Sloc : Source_Ptr;
144 Result_Not_Null : Boolean := False;
145 Result_Node : Node_Id;
146 Inst_Node : Node_Id;
147 Body_Node : Node_Id;
148 Decl_Node : Node_Id;
149 Rename_Node : Node_Id;
150 Absdec_Node : Node_Id;
151 Stub_Node : Node_Id;
152 Fproc_Sloc : Source_Ptr;
153 Func : Boolean;
154 Scan_State : Saved_Scan_State;
155
156 -- Flags for optional overriding indication. Two flags are needed,
157 -- to distinguish positive and negative overriding indicators from
158 -- the absence of any indicator.
159
160 Is_Overriding : Boolean := False;
161 Not_Overriding : Boolean := False;
162
163 begin
164 -- Set up scope stack entry. Note that the Labl field will be set later
165
166 SIS_Entry_Active := False;
167 SIS_Missing_Semicolon_Message := No_Error_Msg;
168 Push_Scope_Stack;
169 Scope.Table (Scope.Last).Sloc := Token_Ptr;
170 Scope.Table (Scope.Last).Etyp := E_Name;
171 Scope.Table (Scope.Last).Ecol := Start_Column;
172 Scope.Table (Scope.Last).Lreq := False;
173
174 -- Ada2005: scan leading overriding indicator
175
176 if Token = Tok_Not then
177 Scan; -- past NOT
178
179 if Token = Tok_Overriding then
180 Scan; -- past OVERRIDING
181 Not_Overriding := True;
182 else
183 Error_Msg_SC ("OVERRIDING expected!");
184 end if;
185
186 elsif Token = Tok_Overriding then
187 Scan; -- past OVERRIDING
188 Is_Overriding := True;
189 end if;
190
191 if (Is_Overriding or else Not_Overriding) then
192 if Ada_Version < Ada_05 then
193 Error_Msg_SP (" overriding indicator is an Ada 2005 extension");
194 Error_Msg_SP ("\unit must be compiled with -gnat05 switch");
195
196 -- An overriding indicator is allowed for subprogram declarations,
197 -- bodies, renamings, stubs, and instantiations.
198
199 elsif Pf_Flags /= Pf_Decl_Gins_Pbod_Rnam_Stub then
200 Error_Msg_SC ("overriding indicator not allowed here!");
201
202 elsif Token /= Tok_Function
203 and then Token /= Tok_Procedure
204 then
205 Error_Msg_SC ("FUNCTION or PROCEDURE expected!");
206 end if;
207 end if;
208
209 Func := (Token = Tok_Function);
210 Fproc_Sloc := Token_Ptr;
211 Scan; -- past FUNCTION or PROCEDURE
212 Ignore (Tok_Type);
213 Ignore (Tok_Body);
214
215 if Func then
216 Name_Node := P_Defining_Designator;
217
218 if Nkind (Name_Node) = N_Defining_Operator_Symbol
219 and then Scope.Last = 1
220 then
221 Error_Msg_SP ("operator symbol not allowed at library level");
222 Name_Node := New_Entity (N_Defining_Identifier, Sloc (Name_Node));
223
224 -- Set name from file name, we need some junk name, and that's
225 -- as good as anything. This is only approximate, since we do
226 -- not do anything with non-standard name translations.
227
228 Get_Name_String (File_Name (Current_Source_File));
229
230 for J in 1 .. Name_Len loop
231 if Name_Buffer (J) = '.' then
232 Name_Len := J - 1;
233 exit;
234 end if;
235 end loop;
236
237 Set_Chars (Name_Node, Name_Find);
238 Set_Error_Posted (Name_Node);
239 end if;
240
241 else
242 Name_Node := P_Defining_Program_Unit_Name;
243 end if;
244
245 Scope.Table (Scope.Last).Labl := Name_Node;
246
247 if Token = Tok_Colon then
248 Error_Msg_SC ("redundant colon ignored");
249 Scan; -- past colon
250 end if;
251
252 -- Deal with generic instantiation, the one case in which we do not
253 -- have a subprogram specification as part of whatever we are parsing
254
255 if Token = Tok_Is then
256 Save_Scan_State (Scan_State); -- at the IS
257 T_Is; -- checks for redundant IS
258
259 if Token = Tok_New then
260 if not Pf_Flags.Gins then
261 Error_Msg_SC ("generic instantation not allowed here!");
262 end if;
263
264 Scan; -- past NEW
265
266 if Func then
267 Inst_Node := New_Node (N_Function_Instantiation, Fproc_Sloc);
268 Set_Name (Inst_Node, P_Function_Name);
269 else
270 Inst_Node := New_Node (N_Procedure_Instantiation, Fproc_Sloc);
271 Set_Name (Inst_Node, P_Qualified_Simple_Name);
272 end if;
273
274 Set_Defining_Unit_Name (Inst_Node, Name_Node);
275 Set_Generic_Associations (Inst_Node, P_Generic_Actual_Part_Opt);
276 TF_Semicolon;
277 Pop_Scope_Stack; -- Don't need scope stack entry in this case
278
279 if Is_Overriding then
280 Set_Must_Override (Inst_Node);
281
282 elsif Not_Overriding then
283 Set_Must_Not_Override (Inst_Node);
284 end if;
285
286 return Inst_Node;
287
288 else
289 Restore_Scan_State (Scan_State); -- to the IS
290 end if;
291 end if;
292
293 -- If not a generic instantiation, then we definitely have a subprogram
294 -- specification (all possibilities at this stage include one here)
295
296 Fpart_Sloc := Token_Ptr;
297
298 Check_Misspelling_Of (Tok_Return);
299
300 -- Scan formal part. First a special error check. If we have an
301 -- identifier here, then we have a definite error. If this identifier
302 -- is on the same line as the designator, then we assume it is the
303 -- first formal after a missing left parenthesis
304
305 if Token = Tok_Identifier
306 and then not Token_Is_At_Start_Of_Line
307 then
308 T_Left_Paren; -- to generate message
309 Fpart_List := P_Formal_Part;
310
311 -- Otherwise scan out an optional formal part in the usual manner
312
313 else
314 Fpart_List := P_Parameter_Profile;
315 end if;
316
317 -- We treat what we have as a function specification if FUNCTION was
318 -- used, or if a RETURN is present. This gives better error recovery
319 -- since later RETURN statements will be valid in either case.
320
321 Check_Junk_Semicolon_Before_Return;
322 Result_Node := Error;
323
324 if Token = Tok_Return then
325 if not Func then
326 Error_Msg ("PROCEDURE should be FUNCTION", Fproc_Sloc);
327 Func := True;
328 end if;
329
330 Scan; -- past RETURN
331
332 Result_Not_Null := P_Null_Exclusion; -- Ada 2005 (AI-231)
333
334 -- Ada 2005 (AI-318-02)
335
336 if Token = Tok_Access then
337 if Ada_Version < Ada_05 then
338 Error_Msg_SC
339 ("anonymous access result type is an Ada 2005 extension");
340 Error_Msg_SC ("\unit must be compiled with -gnat05 switch");
341 end if;
342
343 Result_Node := P_Access_Definition (Result_Not_Null);
344
345 else
346 Result_Node := P_Subtype_Mark;
347 No_Constraint;
348 end if;
349
350 else
351 if Func then
352 Ignore (Tok_Right_Paren);
353 TF_Return;
354 end if;
355 end if;
356
357 if Func then
358 Specification_Node :=
359 New_Node (N_Function_Specification, Fproc_Sloc);
360
361 Set_Null_Exclusion_Present (Specification_Node, Result_Not_Null);
362 Set_Result_Definition (Specification_Node, Result_Node);
363
364 else
365 Specification_Node :=
366 New_Node (N_Procedure_Specification, Fproc_Sloc);
367 end if;
368
369 Set_Defining_Unit_Name (Specification_Node, Name_Node);
370 Set_Parameter_Specifications (Specification_Node, Fpart_List);
371
372 if Is_Overriding then
373 Set_Must_Override (Specification_Node);
374
375 elsif Not_Overriding then
376 Set_Must_Not_Override (Specification_Node);
377 end if;
378
379 -- Error check: barriers not allowed on protected functions/procedures
380
381 if Token = Tok_When then
382 if Func then
383 Error_Msg_SC ("barrier not allowed on function, only on entry");
384 else
385 Error_Msg_SC ("barrier not allowed on procedure, only on entry");
386 end if;
387
388 Scan; -- past WHEN
389 Discard_Junk_Node (P_Expression);
390 end if;
391
392 -- Deal with case of semicolon ending a subprogram declaration
393
394 if Token = Tok_Semicolon then
395 if not Pf_Flags.Decl then
396 T_Is;
397 end if;
398
399 Scan; -- past semicolon
400
401 -- If semicolon is immediately followed by IS, then ignore the
402 -- semicolon, and go process the body.
403
404 if Token = Tok_Is then
405 Error_Msg_SP ("unexpected semicolon ignored");
406 T_Is; -- ignroe redundant IS's
407 goto Subprogram_Body;
408
409 -- If BEGIN follows in an appropriate column, we immediately
410 -- commence the error action of assuming that the previous
411 -- subprogram declaration should have been a subprogram body,
412 -- i.e. that the terminating semicolon should have been IS.
413
414 elsif Token = Tok_Begin
415 and then Start_Column >= Scope.Table (Scope.Last).Ecol
416 then
417 Error_Msg_SP (""";"" should be IS!");
418 goto Subprogram_Body;
419
420 else
421 goto Subprogram_Declaration;
422 end if;
423
424 -- Case of not followed by semicolon
425
426 else
427 -- Subprogram renaming declaration case
428
429 Check_Misspelling_Of (Tok_Renames);
430
431 if Token = Tok_Renames then
432 if not Pf_Flags.Rnam then
433 Error_Msg_SC ("renaming declaration not allowed here!");
434 end if;
435
436 Rename_Node :=
437 New_Node (N_Subprogram_Renaming_Declaration, Token_Ptr);
438 Scan; -- past RENAMES
439 Set_Name (Rename_Node, P_Name);
440 Set_Specification (Rename_Node, Specification_Node);
441 TF_Semicolon;
442 Pop_Scope_Stack;
443 return Rename_Node;
444
445 -- Case of IS following subprogram specification
446
447 elsif Token = Tok_Is then
448 T_Is; -- ignore redundant Is's
449
450 if Token_Name = Name_Abstract then
451 Check_95_Keyword (Tok_Abstract, Tok_Semicolon);
452 end if;
453
454 -- Deal nicely with (now obsolete) use of <> in place of abstract
455
456 if Token = Tok_Box then
457 Error_Msg_SC ("ABSTRACT expected");
458 Token := Tok_Abstract;
459 end if;
460
461 -- Abstract subprogram declaration case
462
463 if Token = Tok_Abstract then
464 Absdec_Node :=
465 New_Node (N_Abstract_Subprogram_Declaration, Token_Ptr);
466 Set_Specification (Absdec_Node, Specification_Node);
467 Pop_Scope_Stack; -- discard unneeded entry
468 Scan; -- past ABSTRACT
469 TF_Semicolon;
470 return Absdec_Node;
471
472 -- Ada 2005 (AI-248): Parse a null procedure declaration
473
474 elsif Token = Tok_Null then
475 if Ada_Version < Ada_05 then
476 Error_Msg_SP ("null procedures are an Ada 2005 extension");
477 Error_Msg_SP ("\unit must be compiled with -gnat05 switch");
478 end if;
479
480 Scan; -- past NULL
481
482 if Func then
483 Error_Msg_SP ("only procedures can be null");
484 else
485 Set_Null_Present (Specification_Node);
486 end if;
487
488 TF_Semicolon;
489 goto Subprogram_Declaration;
490
491 -- Check for IS NEW with Formal_Part present and handle nicely
492
493 elsif Token = Tok_New then
494 Error_Msg
495 ("formal part not allowed in instantiation", Fpart_Sloc);
496 Scan; -- past NEW
497
498 if Func then
499 Inst_Node := New_Node (N_Function_Instantiation, Fproc_Sloc);
500 else
501 Inst_Node :=
502 New_Node (N_Procedure_Instantiation, Fproc_Sloc);
503 end if;
504
505 Set_Defining_Unit_Name (Inst_Node, Name_Node);
506 Set_Name (Inst_Node, P_Name);
507 Set_Generic_Associations (Inst_Node, P_Generic_Actual_Part_Opt);
508 TF_Semicolon;
509 Pop_Scope_Stack; -- Don't need scope stack entry in this case
510 return Inst_Node;
511
512 else
513 goto Subprogram_Body;
514 end if;
515
516 -- Here we have a missing IS or missing semicolon, we always guess
517 -- a missing semicolon, since we are pretty good at fixing up a
518 -- semicolon which should really be an IS
519
520 else
521 Error_Msg_AP ("missing "";""");
522 SIS_Missing_Semicolon_Message := Get_Msg_Id;
523 goto Subprogram_Declaration;
524 end if;
525 end if;
526
527 -- Processing for subprogram body
528
529 <<Subprogram_Body>>
530 if not Pf_Flags.Pbod then
531 Error_Msg_SP ("subprogram body not allowed here!");
532 end if;
533
534 -- Subprogram body stub case
535
536 if Separate_Present then
537 if not Pf_Flags.Stub then
538 Error_Msg_SC ("body stub not allowed here!");
539 end if;
540
541 if Nkind (Name_Node) = N_Defining_Operator_Symbol then
542 Error_Msg
543 ("operator symbol cannot be used as subunit name",
544 Sloc (Name_Node));
545 end if;
546
547 Stub_Node :=
548 New_Node (N_Subprogram_Body_Stub, Sloc (Specification_Node));
549 Set_Specification (Stub_Node, Specification_Node);
550 Scan; -- past SEPARATE
551 Pop_Scope_Stack;
552 TF_Semicolon;
553 return Stub_Node;
554
555 -- Subprogram body case
556
557 else
558 -- Here is the test for a suspicious IS (i.e. one that looks
559 -- like it might more properly be a semicolon). See separate
560 -- section discussing use of IS instead of semicolon in
561 -- package Parse.
562
563 if (Token in Token_Class_Declk
564 or else
565 Token = Tok_Identifier)
566 and then Start_Column <= Scope.Table (Scope.Last).Ecol
567 and then Scope.Last /= 1
568 then
569 Scope.Table (Scope.Last).Etyp := E_Suspicious_Is;
570 Scope.Table (Scope.Last).S_Is := Prev_Token_Ptr;
571 end if;
572
573 Body_Node :=
574 New_Node (N_Subprogram_Body, Sloc (Specification_Node));
575 Set_Specification (Body_Node, Specification_Node);
576 Parse_Decls_Begin_End (Body_Node);
577 return Body_Node;
578 end if;
579
580 -- Processing for subprogram declaration
581
582 <<Subprogram_Declaration>>
583 Decl_Node :=
584 New_Node (N_Subprogram_Declaration, Sloc (Specification_Node));
585 Set_Specification (Decl_Node, Specification_Node);
586
587 -- If this is a context in which a subprogram body is permitted,
588 -- set active SIS entry in case (see section titled "Handling
589 -- Semicolon Used in Place of IS" in body of Parser package)
590 -- Note that SIS_Missing_Semicolon_Message is already set properly.
591
592 if Pf_Flags.Pbod then
593 SIS_Labl := Scope.Table (Scope.Last).Labl;
594 SIS_Sloc := Scope.Table (Scope.Last).Sloc;
595 SIS_Ecol := Scope.Table (Scope.Last).Ecol;
596 SIS_Declaration_Node := Decl_Node;
597 SIS_Semicolon_Sloc := Prev_Token_Ptr;
598 SIS_Entry_Active := True;
599 end if;
600
601 Pop_Scope_Stack;
602 return Decl_Node;
603
604 end P_Subprogram;
605
606 ---------------------------------
607 -- 6.1 Subprogram Declaration --
608 ---------------------------------
609
610 -- Parsed by P_Subprogram (6.1)
611
612 ------------------------------------------
613 -- 6.1 Abstract Subprogram Declaration --
614 ------------------------------------------
615
616 -- Parsed by P_Subprogram (6.1)
617
618 -----------------------------------
619 -- 6.1 Subprogram Specification --
620 -----------------------------------
621
622 -- SUBPROGRAM_SPECIFICATION ::=
623 -- procedure DEFINING_PROGRAM_UNIT_NAME PARAMETER_PROFILE
624 -- | function DEFINING_DESIGNATOR PARAMETER_AND_RESULT_PROFILE
625
626 -- PARAMETER_PROFILE ::= [FORMAL_PART]
627
628 -- PARAMETER_AND_RESULT_PROFILE ::= [FORMAL_PART] return SUBTYPE_MARK
629
630 -- Subprogram specifications that appear in subprogram declarations
631 -- are parsed by P_Subprogram (6.1). This routine is used in other
632 -- contexts where subprogram specifications occur.
633
634 -- Note: this routine does not affect the scope stack in any way
635
636 -- Error recovery: can raise Error_Resync
637
638 function P_Subprogram_Specification return Node_Id is
639 Specification_Node : Node_Id;
640 Result_Not_Null : Boolean;
641 Result_Node : Node_Id;
642
643 begin
644 if Token = Tok_Function then
645 Specification_Node := New_Node (N_Function_Specification, Token_Ptr);
646 Scan; -- past FUNCTION
647 Ignore (Tok_Body);
648 Set_Defining_Unit_Name (Specification_Node, P_Defining_Designator);
649 Set_Parameter_Specifications
650 (Specification_Node, P_Parameter_Profile);
651 Check_Junk_Semicolon_Before_Return;
652 TF_Return;
653
654 Result_Not_Null := P_Null_Exclusion; -- Ada 2005 (AI-231)
655
656 -- Ada 2005 (AI-318-02)
657
658 if Token = Tok_Access then
659 if Ada_Version < Ada_05 then
660 Error_Msg_SC
661 ("anonymous access result type is an Ada 2005 extension");
662 Error_Msg_SC ("\unit must be compiled with -gnat05 switch");
663 end if;
664
665 Result_Node := P_Access_Definition (Result_Not_Null);
666
667 else
668 Result_Node := P_Subtype_Mark;
669 No_Constraint;
670 end if;
671
672 Set_Null_Exclusion_Present (Specification_Node, Result_Not_Null);
673 Set_Result_Definition (Specification_Node, Result_Node);
674 return Specification_Node;
675
676 elsif Token = Tok_Procedure then
677 Specification_Node := New_Node (N_Procedure_Specification, Token_Ptr);
678 Scan; -- past PROCEDURE
679 Ignore (Tok_Body);
680 Set_Defining_Unit_Name
681 (Specification_Node, P_Defining_Program_Unit_Name);
682 Set_Parameter_Specifications
683 (Specification_Node, P_Parameter_Profile);
684 return Specification_Node;
685
686 else
687 Error_Msg_SC ("subprogram specification expected");
688 raise Error_Resync;
689 end if;
690 end P_Subprogram_Specification;
691
692 ---------------------
693 -- 6.1 Designator --
694 ---------------------
695
696 -- DESIGNATOR ::=
697 -- [PARENT_UNIT_NAME .] IDENTIFIER | OPERATOR_SYMBOL
698
699 -- The caller has checked that the initial token is an identifier,
700 -- operator symbol, or string literal. Note that we don't bother to
701 -- do much error diagnosis in this routine, since it is only used for
702 -- the label on END lines, and the routines in package Par.Endh will
703 -- check that the label is appropriate.
704
705 -- Error recovery: cannot raise Error_Resync
706
707 function P_Designator return Node_Id is
708 Ident_Node : Node_Id;
709 Name_Node : Node_Id;
710 Prefix_Node : Node_Id;
711
712 function Real_Dot return Boolean;
713 -- Tests if a current token is an interesting period, i.e. is followed
714 -- by an identifier or operator symbol or string literal. If not, it is
715 -- probably just incorrect punctuation to be caught by our caller. Note
716 -- that the case of an operator symbol or string literal is also an
717 -- error, but that is an error that we catch here. If the result is
718 -- True, a real dot has been scanned and we are positioned past it,
719 -- if the result is False, the scan position is unchanged.
720
721 --------------
722 -- Real_Dot --
723 --------------
724
725 function Real_Dot return Boolean is
726 Scan_State : Saved_Scan_State;
727
728 begin
729 if Token /= Tok_Dot then
730 return False;
731
732 else
733 Save_Scan_State (Scan_State);
734 Scan; -- past dot
735
736 if Token = Tok_Identifier
737 or else Token = Tok_Operator_Symbol
738 or else Token = Tok_String_Literal
739 then
740 return True;
741
742 else
743 Restore_Scan_State (Scan_State);
744 return False;
745 end if;
746 end if;
747 end Real_Dot;
748
749 -- Start of processing for P_Designator
750
751 begin
752 Ident_Node := Token_Node;
753 Scan; -- past initial token
754
755 if Prev_Token = Tok_Operator_Symbol
756 or else Prev_Token = Tok_String_Literal
757 or else not Real_Dot
758 then
759 return Ident_Node;
760
761 -- Child name case
762
763 else
764 Prefix_Node := Ident_Node;
765
766 -- Loop through child names, on entry to this loop, Prefix contains
767 -- the name scanned so far, and Ident_Node is the last identifier.
768
769 loop
770 Name_Node := New_Node (N_Selected_Component, Prev_Token_Ptr);
771 Set_Prefix (Name_Node, Prefix_Node);
772 Ident_Node := P_Identifier;
773 Set_Selector_Name (Name_Node, Ident_Node);
774 Prefix_Node := Name_Node;
775 exit when not Real_Dot;
776 end loop;
777
778 -- On exit from the loop, Ident_Node is the last identifier scanned,
779 -- i.e. the defining identifier, and Prefix_Node is a node for the
780 -- entire name, structured (incorrectly!) as a selected component.
781
782 Name_Node := Prefix (Prefix_Node);
783 Change_Node (Prefix_Node, N_Designator);
784 Set_Name (Prefix_Node, Name_Node);
785 Set_Identifier (Prefix_Node, Ident_Node);
786 return Prefix_Node;
787 end if;
788
789 exception
790 when Error_Resync =>
791 while Token = Tok_Dot or else Token = Tok_Identifier loop
792 Scan;
793 end loop;
794
795 return Error;
796 end P_Designator;
797
798 ------------------------------
799 -- 6.1 Defining Designator --
800 ------------------------------
801
802 -- DEFINING_DESIGNATOR ::=
803 -- DEFINING_PROGRAM_UNIT_NAME | DEFINING_OPERATOR_SYMBOL
804
805 -- Error recovery: cannot raise Error_Resync
806
807 function P_Defining_Designator return Node_Id is
808 begin
809 if Token = Tok_Operator_Symbol then
810 return P_Defining_Operator_Symbol;
811
812 elsif Token = Tok_String_Literal then
813 Error_Msg_SC ("invalid operator name");
814 Scan; -- past junk string
815 return Error;
816
817 else
818 return P_Defining_Program_Unit_Name;
819 end if;
820 end P_Defining_Designator;
821
822 -------------------------------------
823 -- 6.1 Defining Program Unit Name --
824 -------------------------------------
825
826 -- DEFINING_PROGRAM_UNIT_NAME ::=
827 -- [PARENT_UNIT_NAME .] DEFINING_IDENTIFIER
828
829 -- Note: PARENT_UNIT_NAME may be present only in 95 mode at the outer level
830
831 -- Error recovery: cannot raise Error_Resync
832
833 function P_Defining_Program_Unit_Name return Node_Id is
834 Ident_Node : Node_Id;
835 Name_Node : Node_Id;
836 Prefix_Node : Node_Id;
837
838 begin
839 -- Set identifier casing if not already set and scan initial identifier
840
841 if Token = Tok_Identifier
842 and then Identifier_Casing (Current_Source_File) = Unknown
843 then
844 Set_Identifier_Casing (Current_Source_File, Determine_Token_Casing);
845 end if;
846
847 Ident_Node := P_Identifier (C_Dot);
848 Merge_Identifier (Ident_Node, Tok_Return);
849
850 -- Normal case (not child library unit name)
851
852 if Token /= Tok_Dot then
853 Change_Identifier_To_Defining_Identifier (Ident_Node);
854 return Ident_Node;
855
856 -- Child library unit name case
857
858 else
859 if Scope.Last > 1 then
860 Error_Msg_SP ("child unit allowed only at library level");
861 raise Error_Resync;
862
863 elsif Ada_Version = Ada_83 then
864 Error_Msg_SP ("(Ada 83) child unit not allowed!");
865
866 end if;
867
868 Prefix_Node := Ident_Node;
869
870 -- Loop through child names, on entry to this loop, Prefix contains
871 -- the name scanned so far, and Ident_Node is the last identifier.
872
873 loop
874 exit when Token /= Tok_Dot;
875 Name_Node := New_Node (N_Selected_Component, Token_Ptr);
876 Scan; -- past period
877 Set_Prefix (Name_Node, Prefix_Node);
878 Ident_Node := P_Identifier (C_Dot);
879 Set_Selector_Name (Name_Node, Ident_Node);
880 Prefix_Node := Name_Node;
881 end loop;
882
883 -- On exit from the loop, Ident_Node is the last identifier scanned,
884 -- i.e. the defining identifier, and Prefix_Node is a node for the
885 -- entire name, structured (incorrectly!) as a selected component.
886
887 Name_Node := Prefix (Prefix_Node);
888 Change_Node (Prefix_Node, N_Defining_Program_Unit_Name);
889 Set_Name (Prefix_Node, Name_Node);
890 Change_Identifier_To_Defining_Identifier (Ident_Node);
891 Set_Defining_Identifier (Prefix_Node, Ident_Node);
892
893 -- All set with unit name parsed
894
895 return Prefix_Node;
896 end if;
897
898 exception
899 when Error_Resync =>
900 while Token = Tok_Dot or else Token = Tok_Identifier loop
901 Scan;
902 end loop;
903
904 return Error;
905 end P_Defining_Program_Unit_Name;
906
907 --------------------------
908 -- 6.1 Operator Symbol --
909 --------------------------
910
911 -- OPERATOR_SYMBOL ::= STRING_LITERAL
912
913 -- Operator symbol is returned by the scanner as Tok_Operator_Symbol
914
915 -----------------------------------
916 -- 6.1 Defining Operator Symbol --
917 -----------------------------------
918
919 -- DEFINING_OPERATOR_SYMBOL ::= OPERATOR_SYMBOL
920
921 -- The caller has checked that the initial symbol is an operator symbol
922
923 function P_Defining_Operator_Symbol return Node_Id is
924 Op_Node : Node_Id;
925
926 begin
927 Op_Node := Token_Node;
928 Change_Operator_Symbol_To_Defining_Operator_Symbol (Op_Node);
929 Scan; -- past operator symbol
930 return Op_Node;
931 end P_Defining_Operator_Symbol;
932
933 ----------------------------
934 -- 6.1 Parameter_Profile --
935 ----------------------------
936
937 -- PARAMETER_PROFILE ::= [FORMAL_PART]
938
939 -- Empty is returned if no formal part is present
940
941 -- Error recovery: cannot raise Error_Resync
942
943 function P_Parameter_Profile return List_Id is
944 begin
945 if Token = Tok_Left_Paren then
946 Scan; -- part left paren
947 return P_Formal_Part;
948 else
949 return No_List;
950 end if;
951 end P_Parameter_Profile;
952
953 ---------------------------------------
954 -- 6.1 Parameter And Result Profile --
955 ---------------------------------------
956
957 -- Parsed by its parent construct, which uses P_Parameter_Profile to
958 -- parse the parameters, and P_Subtype_Mark to parse the return type.
959
960 ----------------------
961 -- 6.1 Formal part --
962 ----------------------
963
964 -- FORMAL_PART ::= (PARAMETER_SPECIFICATION {; PARAMETER_SPECIFICATION})
965
966 -- PARAMETER_SPECIFICATION ::=
967 -- DEFINING_IDENTIFIER_LIST : MODE [NULL_EXCLUSION] SUBTYPE_MARK
968 -- [:= DEFAULT_EXPRESSION]
969 -- | DEFINING_IDENTIFIER_LIST : ACCESS_DEFINITION
970 -- [:= DEFAULT_EXPRESSION]
971
972 -- This scans the construct Formal_Part. The caller has already checked
973 -- that the initial token is a left parenthesis, and skipped past it, so
974 -- that on entry Token is the first token following the left parenthesis.
975
976 -- Error recovery: cannot raise Error_Resync
977
978 function P_Formal_Part return List_Id is
979 Specification_List : List_Id;
980 Specification_Node : Node_Id;
981 Scan_State : Saved_Scan_State;
982 Num_Idents : Nat;
983 Ident : Nat;
984 Ident_Sloc : Source_Ptr;
985 Not_Null_Present : Boolean := False;
986
987 Idents : array (Int range 1 .. 4096) of Entity_Id;
988 -- This array holds the list of defining identifiers. The upper bound
989 -- of 4096 is intended to be essentially infinite, and we do not even
990 -- bother to check for it being exceeded.
991
992 begin
993 Specification_List := New_List;
994 Specification_Loop : loop
995 begin
996 if Token = Tok_Pragma then
997 P_Pragmas_Misplaced;
998 end if;
999
1000 Ignore (Tok_Left_Paren);
1001 Ident_Sloc := Token_Ptr;
1002 Idents (1) := P_Defining_Identifier (C_Comma_Colon);
1003 Num_Idents := 1;
1004
1005 Ident_Loop : loop
1006 exit Ident_Loop when Token = Tok_Colon;
1007
1008 -- The only valid tokens are colon and comma, so if we have
1009 -- neither do a bit of investigation to see which is the
1010 -- better choice for insertion.
1011
1012 if Token /= Tok_Comma then
1013
1014 -- Assume colon if IN or OUT keyword found
1015
1016 exit Ident_Loop when Token = Tok_In or else Token = Tok_Out;
1017
1018 -- Otherwise scan ahead
1019
1020 Save_Scan_State (Scan_State);
1021 Look_Ahead : loop
1022
1023 -- If we run into a semicolon, then assume that a
1024 -- colon was missing, e.g. Parms (X Y; ...). Also
1025 -- assume missing colon on EOF (a real disaster!)
1026 -- and on a right paren, e.g. Parms (X Y), and also
1027 -- on an assignment symbol, e.g. Parms (X Y := ..)
1028
1029 if Token = Tok_Semicolon
1030 or else Token = Tok_Right_Paren
1031 or else Token = Tok_EOF
1032 or else Token = Tok_Colon_Equal
1033 then
1034 Restore_Scan_State (Scan_State);
1035 exit Ident_Loop;
1036
1037 -- If we run into a colon, assume that we had a missing
1038 -- comma, e.g. Parms (A B : ...). Also assume a missing
1039 -- comma if we hit another comma, e.g. Parms (A B, C ..)
1040
1041 elsif Token = Tok_Colon
1042 or else Token = Tok_Comma
1043 then
1044 Restore_Scan_State (Scan_State);
1045 exit Look_Ahead;
1046 end if;
1047
1048 Scan;
1049 end loop Look_Ahead;
1050 end if;
1051
1052 -- Here if a comma is present, or to be assumed
1053
1054 T_Comma;
1055 Num_Idents := Num_Idents + 1;
1056 Idents (Num_Idents) := P_Defining_Identifier (C_Comma_Colon);
1057 end loop Ident_Loop;
1058
1059 -- Fall through the loop on encountering a colon, or deciding
1060 -- that there is a missing colon.
1061
1062 T_Colon;
1063
1064 -- If there are multiple identifiers, we repeatedly scan the
1065 -- type and initialization expression information by resetting
1066 -- the scan pointer (so that we get completely separate trees
1067 -- for each occurrence).
1068
1069 if Num_Idents > 1 then
1070 Save_Scan_State (Scan_State);
1071 end if;
1072
1073 -- Loop through defining identifiers in list
1074
1075 Ident := 1;
1076
1077 Ident_List_Loop : loop
1078 Specification_Node :=
1079 New_Node (N_Parameter_Specification, Ident_Sloc);
1080 Set_Defining_Identifier (Specification_Node, Idents (Ident));
1081 Not_Null_Present := P_Null_Exclusion; -- Ada 2005 (AI-231)
1082
1083 if Token = Tok_Access then
1084 Set_Null_Exclusion_Present
1085 (Specification_Node, Not_Null_Present);
1086
1087 if Ada_Version = Ada_83 then
1088 Error_Msg_SC ("(Ada 83) access parameters not allowed");
1089 end if;
1090
1091 Set_Parameter_Type (Specification_Node,
1092 P_Access_Definition (Not_Null_Present));
1093
1094 else
1095 if Token = Tok_In or else Token = Tok_Out then
1096 if Not_Null_Present then
1097 Error_Msg_SC
1098 ("ACCESS must be placed after the parameter mode");
1099 end if;
1100
1101 P_Mode (Specification_Node);
1102 Not_Null_Present := P_Null_Exclusion; -- Ada 2005 (AI-231)
1103 end if;
1104
1105 Set_Null_Exclusion_Present
1106 (Specification_Node, Not_Null_Present);
1107
1108 if Token = Tok_Procedure
1109 or else
1110 Token = Tok_Function
1111 then
1112 Error_Msg_SC ("formal subprogram parameter not allowed");
1113 Scan;
1114
1115 if Token = Tok_Left_Paren then
1116 Discard_Junk_List (P_Formal_Part);
1117 end if;
1118
1119 if Token = Tok_Return then
1120 Scan;
1121 Discard_Junk_Node (P_Subtype_Mark);
1122 end if;
1123
1124 Set_Parameter_Type (Specification_Node, Error);
1125
1126 else
1127 Set_Parameter_Type (Specification_Node, P_Subtype_Mark);
1128 No_Constraint;
1129 end if;
1130 end if;
1131
1132 Set_Expression (Specification_Node, Init_Expr_Opt (True));
1133
1134 if Ident > 1 then
1135 Set_Prev_Ids (Specification_Node, True);
1136 end if;
1137
1138 if Ident < Num_Idents then
1139 Set_More_Ids (Specification_Node, True);
1140 end if;
1141
1142 Append (Specification_Node, Specification_List);
1143 exit Ident_List_Loop when Ident = Num_Idents;
1144 Ident := Ident + 1;
1145 Restore_Scan_State (Scan_State);
1146 end loop Ident_List_Loop;
1147
1148 exception
1149 when Error_Resync =>
1150 Resync_Semicolon_List;
1151 end;
1152
1153 if Token = Tok_Semicolon then
1154 Save_Scan_State (Scan_State);
1155 Scan; -- past semicolon
1156
1157 -- If we have RETURN or IS after the semicolon, then assume
1158 -- that semicolon should have been a right parenthesis and exit
1159
1160 if Token = Tok_Is or else Token = Tok_Return then
1161 Error_Msg_SP ("expected "")"" in place of "";""");
1162 exit Specification_Loop;
1163 end if;
1164
1165 -- If we have a declaration keyword after the semicolon, then
1166 -- assume we had a missing right parenthesis and terminate list
1167
1168 if Token in Token_Class_Declk then
1169 Error_Msg_AP ("missing "")""");
1170 Restore_Scan_State (Scan_State);
1171 exit Specification_Loop;
1172 end if;
1173
1174 elsif Token = Tok_Right_Paren then
1175 Scan; -- past right paren
1176 exit Specification_Loop;
1177
1178 -- Special check for common error of using comma instead of semicolon
1179
1180 elsif Token = Tok_Comma then
1181 T_Semicolon;
1182 Scan; -- past comma
1183
1184 -- Special check for omitted separator
1185
1186 elsif Token = Tok_Identifier then
1187 T_Semicolon;
1188
1189 -- If nothing sensible, skip to next semicolon or right paren
1190
1191 else
1192 T_Semicolon;
1193 Resync_Semicolon_List;
1194
1195 if Token = Tok_Semicolon then
1196 Scan; -- past semicolon
1197 else
1198 T_Right_Paren;
1199 exit Specification_Loop;
1200 end if;
1201 end if;
1202 end loop Specification_Loop;
1203
1204 return Specification_List;
1205 end P_Formal_Part;
1206
1207 ----------------------------------
1208 -- 6.1 Parameter Specification --
1209 ----------------------------------
1210
1211 -- Parsed by P_Formal_Part (6.1)
1212
1213 ---------------
1214 -- 6.1 Mode --
1215 ---------------
1216
1217 -- MODE ::= [in] | in out | out
1218
1219 -- There is no explicit node in the tree for the Mode. Instead the
1220 -- In_Present and Out_Present flags are set in the parent node to
1221 -- record the presence of keywords specifying the mode.
1222
1223 -- Error_Recovery: cannot raise Error_Resync
1224
1225 procedure P_Mode (Node : Node_Id) is
1226 begin
1227 if Token = Tok_In then
1228 Scan; -- past IN
1229 Set_In_Present (Node, True);
1230 end if;
1231
1232 if Token = Tok_Out then
1233 Scan; -- past OUT
1234 Set_Out_Present (Node, True);
1235 end if;
1236
1237 if Token = Tok_In then
1238 Error_Msg_SC ("IN must preceed OUT in parameter mode");
1239 Scan; -- past IN
1240 Set_In_Present (Node, True);
1241 end if;
1242 end P_Mode;
1243
1244 --------------------------
1245 -- 6.3 Subprogram Body --
1246 --------------------------
1247
1248 -- Parsed by P_Subprogram (6.1)
1249
1250 -----------------------------------
1251 -- 6.4 Procedure Call Statement --
1252 -----------------------------------
1253
1254 -- Parsed by P_Sequence_Of_Statements (5.1)
1255
1256 ------------------------
1257 -- 6.4 Function Call --
1258 ------------------------
1259
1260 -- Parsed by P_Call_Or_Name (4.1)
1261
1262 --------------------------------
1263 -- 6.4 Actual Parameter Part --
1264 --------------------------------
1265
1266 -- Parsed by P_Call_Or_Name (4.1)
1267
1268 --------------------------------
1269 -- 6.4 Parameter Association --
1270 --------------------------------
1271
1272 -- Parsed by P_Call_Or_Name (4.1)
1273
1274 ------------------------------------
1275 -- 6.4 Explicit Actual Parameter --
1276 ------------------------------------
1277
1278 -- Parsed by P_Call_Or_Name (4.1)
1279
1280 ---------------------------
1281 -- 6.5 Return Statement --
1282 ---------------------------
1283
1284 -- RETURN_STATEMENT ::= return [EXPRESSION];
1285
1286 -- The caller has checked that the initial token is RETURN
1287
1288 -- Error recovery: can raise Error_Resync
1289
1290 function P_Return_Statement return Node_Id is
1291 Return_Node : Node_Id;
1292
1293 begin
1294 Return_Node := New_Node (N_Return_Statement, Token_Ptr);
1295
1296 -- Sloc points to RETURN
1297 -- Expression (Op3)
1298
1299 Scan; -- past RETURN
1300
1301 if Token /= Tok_Semicolon then
1302
1303 -- If no semicolon, then scan an expression, except that
1304 -- we avoid trying to scan an expression if we are at an
1305 -- expression terminator since in that case the best error
1306 -- message is probably that we have a missing semicolon.
1307
1308 if Token not in Token_Class_Eterm then
1309 Set_Expression (Return_Node, P_Expression_No_Right_Paren);
1310 end if;
1311 end if;
1312
1313 TF_Semicolon;
1314 return Return_Node;
1315 end P_Return_Statement;
1316
1317 end Ch6;
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