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1 ------------------------------------------------------------------------------
2 -- --
3 -- GNAT COMPILER COMPONENTS --
4 -- --
5 -- P A R . C H 5 --
6 -- --
7 -- B o d y --
8 -- --
9 -- Copyright (C) 1992-2020, 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 by RM
28 -- section rather than alphabetical.
29
30 with Sinfo.CN; use Sinfo.CN;
31
32 separate (Par)
33 package body Ch5 is
34
35 -- Local functions, used only in this chapter
36
37 function P_Case_Statement return Node_Id;
38 function P_Case_Statement_Alternative return Node_Id;
39 function P_Exit_Statement return Node_Id;
40 function P_Goto_Statement return Node_Id;
41 function P_If_Statement return Node_Id;
42 function P_Label return Node_Id;
43 function P_Null_Statement return Node_Id;
44
45 function P_Assignment_Statement (LHS : Node_Id) return Node_Id;
46 -- Parse assignment statement. On entry, the caller has scanned the left
47 -- hand side (passed in as Lhs), and the colon-equal (or some symbol
48 -- taken to be an error equivalent such as equal).
49
50 function P_Begin_Statement (Block_Name : Node_Id := Empty) return Node_Id;
51 -- Parse begin-end statement. If Block_Name is non-Empty on entry, it is
52 -- the N_Identifier node for the label on the block. If Block_Name is
53 -- Empty on entry (the default), then the block statement is unlabeled.
54
55 function P_Declare_Statement (Block_Name : Node_Id := Empty) return Node_Id;
56 -- Parse declare block. If Block_Name is non-Empty on entry, it is
57 -- the N_Identifier node for the label on the block. If Block_Name is
58 -- Empty on entry (the default), then the block statement is unlabeled.
59
60 function P_For_Statement (Loop_Name : Node_Id := Empty) return Node_Id;
61 -- Parse for statement. If Loop_Name is non-Empty on entry, it is
62 -- the N_Identifier node for the label on the loop. If Loop_Name is
63 -- Empty on entry (the default), then the for statement is unlabeled.
64
65 function P_Iterator_Specification (Def_Id : Node_Id) return Node_Id;
66 -- Parse an iterator specification. The defining identifier has already
67 -- been scanned, as it is the common prefix between loop and iterator
68 -- specification.
69
70 function P_Loop_Statement (Loop_Name : Node_Id := Empty) return Node_Id;
71 -- Parse loop statement. If Loop_Name is non-Empty on entry, it is
72 -- the N_Identifier node for the label on the loop. If Loop_Name is
73 -- Empty on entry (the default), then the loop statement is unlabeled.
74
75 function P_While_Statement (Loop_Name : Node_Id := Empty) return Node_Id;
76 -- Parse while statement. If Loop_Name is non-Empty on entry, it is
77 -- the N_Identifier node for the label on the loop. If Loop_Name is
78 -- Empty on entry (the default), then the while statement is unlabeled.
79
80 function Set_Loop_Block_Name (L : Character) return Name_Id;
81 -- Given a letter 'L' for a loop or 'B' for a block, returns a name
82 -- of the form L_nn or B_nn where nn is a serial number obtained by
83 -- incrementing the variable Loop_Block_Count.
84
85 procedure Then_Scan;
86 -- Scan past THEN token, testing for illegal junk after it
87
88 ---------------------------------
89 -- 5.1 Sequence of Statements --
90 ---------------------------------
91
92 -- SEQUENCE_OF_STATEMENTS ::= STATEMENT {STATEMENT} {LABEL}
93 -- Note: the final label is an Ada 2012 addition.
94
95 -- STATEMENT ::=
96 -- {LABEL} SIMPLE_STATEMENT | {LABEL} COMPOUND_STATEMENT
97
98 -- SIMPLE_STATEMENT ::= NULL_STATEMENT
99 -- | ASSIGNMENT_STATEMENT | EXIT_STATEMENT
100 -- | GOTO_STATEMENT | PROCEDURE_CALL_STATEMENT
101 -- | RETURN_STATEMENT | ENTRY_CALL_STATEMENT
102 -- | REQUEUE_STATEMENT | DELAY_STATEMENT
103 -- | ABORT_STATEMENT | RAISE_STATEMENT
104 -- | CODE_STATEMENT
105
106 -- COMPOUND_STATEMENT ::=
107 -- IF_STATEMENT | CASE_STATEMENT
108 -- | LOOP_STATEMENT | BLOCK_STATEMENT
109 -- | ACCEPT_STATEMENT | SELECT_STATEMENT
110
111 -- This procedure scans a sequence of statements. The caller sets SS_Flags
112 -- to indicate acceptable termination conditions for the sequence:
113
114 -- SS_Flags.Eftm Terminate on ELSIF
115 -- SS_Flags.Eltm Terminate on ELSE
116 -- SS_Flags.Extm Terminate on EXCEPTION
117 -- SS_Flags.Ortm Terminate on OR
118 -- SS_Flags.Tatm Terminate on THEN ABORT (Token = ABORT on return)
119 -- SS_Flags.Whtm Terminate on WHEN
120 -- SS_Flags.Unco Unconditional terminate after scanning one statement
121
122 -- In addition, the scan is always terminated by encountering END or the
123 -- end of file (EOF) condition. If one of the six above terminators is
124 -- encountered with the corresponding SS_Flags flag not set, then the
125 -- action taken is as follows:
126
127 -- If the keyword occurs to the left of the expected column of the end
128 -- for the current sequence (as recorded in the current end context),
129 -- then it is assumed to belong to an outer context, and is considered
130 -- to terminate the sequence of statements.
131
132 -- If the keyword occurs to the right of, or in the expected column of
133 -- the end for the current sequence, then an error message is output,
134 -- the keyword together with its associated context is skipped, and
135 -- the statement scan continues until another terminator is found.
136
137 -- Note that the first action means that control can return to the caller
138 -- with Token set to a terminator other than one of those specified by the
139 -- SS parameter. The caller should treat such a case as equivalent to END.
140
141 -- In addition, the flag SS_Flags.Sreq is set to True to indicate that at
142 -- least one real statement (other than a pragma) is required in the
143 -- statement sequence. During the processing of the sequence, this
144 -- flag is manipulated to indicate the current status of the requirement
145 -- for a statement. For example, it is turned off by the occurrence of a
146 -- statement, and back on by a label (which requires a following statement)
147
148 -- Error recovery: cannot raise Error_Resync. If an error occurs during
149 -- parsing a statement, then the scan pointer is advanced past the next
150 -- semicolon and the parse continues.
151
152 function P_Sequence_Of_Statements (SS_Flags : SS_Rec) return List_Id is
153
154 Statement_Required : Boolean;
155 -- This flag indicates if a subsequent statement (other than a pragma)
156 -- is required. It is initialized from the Sreq flag, and modified as
157 -- statements are scanned (a statement turns it off, and a label turns
158 -- it back on again since a statement must follow a label).
159 -- Note : this final requirement is lifted in Ada 2012.
160
161 Statement_Seen : Boolean;
162 -- In Ada 2012, a label can end a sequence of statements, but the
163 -- sequence cannot contain only labels. This flag is set whenever a
164 -- label is encountered, to enforce this rule at the end of a sequence.
165
166 Declaration_Found : Boolean := False;
167 -- This flag is set True if a declaration is encountered, so that the
168 -- error message about declarations in the statement part is only
169 -- given once for a given sequence of statements.
170
171 Scan_State_Label : Saved_Scan_State;
172 Scan_State : Saved_Scan_State;
173
174 Statement_List : List_Id;
175 Block_Label : Name_Id;
176 Id_Node : Node_Id;
177 Name_Node : Node_Id;
178
179 procedure Junk_Declaration;
180 -- Procedure called to handle error of declaration encountered in
181 -- statement sequence.
182
183 procedure Test_Statement_Required;
184 -- Flag error if Statement_Required flag set
185
186 ----------------------
187 -- Junk_Declaration --
188 ----------------------
189
190 procedure Junk_Declaration is
191 begin
192 if (not Declaration_Found) or All_Errors_Mode then
193 Error_Msg_SC -- CODEFIX
194 ("declarations must come before BEGIN");
195 Declaration_Found := True;
196 end if;
197
198 Skip_Declaration (Statement_List);
199 end Junk_Declaration;
200
201 -----------------------------
202 -- Test_Statement_Required --
203 -----------------------------
204
205 procedure Test_Statement_Required is
206 function All_Pragmas return Boolean;
207 -- Return True if statement list is all pragmas
208
209 -----------------
210 -- All_Pragmas --
211 -----------------
212
213 function All_Pragmas return Boolean is
214 S : Node_Id;
215 begin
216 S := First (Statement_List);
217 while Present (S) loop
218 if Nkind (S) /= N_Pragma then
219 return False;
220 else
221 Next (S);
222 end if;
223 end loop;
224
225 return True;
226 end All_Pragmas;
227
228 -- Start of processing for Test_Statement_Required
229
230 begin
231 if Statement_Required then
232
233 -- Check no statement required after label in Ada 2012, and that
234 -- it is OK to have nothing but pragmas in a statement sequence.
235
236 if Ada_Version >= Ada_2012
237 and then not Is_Empty_List (Statement_List)
238 and then
239 ((Nkind (Last (Statement_List)) = N_Label
240 and then Statement_Seen)
241 or else All_Pragmas)
242 then
243 -- This Ada 2012 construct not allowed in a compiler unit
244
245 Check_Compiler_Unit ("null statement list", Token_Ptr);
246
247 declare
248 Null_Stm : constant Node_Id :=
249 Make_Null_Statement (Token_Ptr);
250 begin
251 Set_Comes_From_Source (Null_Stm, False);
252 Append_To (Statement_List, Null_Stm);
253 end;
254
255 -- If not Ada 2012, or not special case above, give error message
256
257 else
258 Error_Msg_BC -- CODEFIX
259 ("statement expected");
260 end if;
261 end if;
262 end Test_Statement_Required;
263
264 -- Start of processing for P_Sequence_Of_Statements
265
266 begin
267 Statement_List := New_List;
268 Statement_Required := SS_Flags.Sreq;
269 Statement_Seen := False;
270
271 loop
272 Ignore (Tok_Semicolon);
273
274 begin
275 if Style_Check then
276 Style.Check_Indentation;
277 end if;
278
279 -- Deal with reserved identifier (in assignment or call)
280
281 if Is_Reserved_Identifier then
282 Save_Scan_State (Scan_State); -- at possible bad identifier
283 Scan; -- and scan past it
284
285 -- We have an reserved word which is spelled in identifier
286 -- style, so the question is whether it really is intended
287 -- to be an identifier.
288
289 if
290 -- If followed by a semicolon, then it is an identifier,
291 -- with the exception of the cases tested for below.
292
293 (Token = Tok_Semicolon
294 and then Prev_Token /= Tok_Return
295 and then Prev_Token /= Tok_Null
296 and then Prev_Token /= Tok_Raise
297 and then Prev_Token /= Tok_End
298 and then Prev_Token /= Tok_Exit)
299
300 -- If followed by colon, colon-equal, or dot, then we
301 -- definitely have an identifier (could not be reserved)
302
303 or else Token = Tok_Colon
304 or else Token = Tok_Colon_Equal
305 or else Token = Tok_Dot
306
307 -- Left paren means we have an identifier except for those
308 -- reserved words that can legitimately be followed by a
309 -- left paren.
310
311 or else
312 (Token = Tok_Left_Paren
313 and then Prev_Token /= Tok_Case
314 and then Prev_Token /= Tok_Delay
315 and then Prev_Token /= Tok_If
316 and then Prev_Token /= Tok_Elsif
317 and then Prev_Token /= Tok_Return
318 and then Prev_Token /= Tok_When
319 and then Prev_Token /= Tok_While
320 and then Prev_Token /= Tok_Separate)
321 then
322 -- Here we have an apparent reserved identifier and the
323 -- token past it is appropriate to this usage (and would
324 -- be a definite error if this is not an identifier). What
325 -- we do is to use P_Identifier to fix up the identifier,
326 -- and then fall into the normal processing.
327
328 Restore_Scan_State (Scan_State); -- back to the ID
329 Scan_Reserved_Identifier (Force_Msg => False);
330
331 -- Not a reserved identifier after all (or at least we can't
332 -- be sure that it is), so reset the scan and continue.
333
334 else
335 Restore_Scan_State (Scan_State); -- back to the reserved word
336 end if;
337 end if;
338
339 -- Now look to see what kind of statement we have
340
341 case Token is
342
343 -- Case of end or EOF
344
345 when Tok_End
346 | Tok_EOF
347 =>
348 -- These tokens always terminate the statement sequence
349
350 Test_Statement_Required;
351 exit;
352
353 -- Case of ELSIF
354
355 when Tok_Elsif =>
356
357 -- Terminate if Eftm set or if the ELSIF is to the left
358 -- of the expected column of the end for this sequence
359
360 if SS_Flags.Eftm
361 or else Start_Column < Scopes (Scope.Last).Ecol
362 then
363 Test_Statement_Required;
364 exit;
365
366 -- Otherwise complain and skip past ELSIF Condition then
367
368 else
369 Error_Msg_SC ("ELSIF not allowed here");
370 Scan; -- past ELSIF
371 Discard_Junk_Node (P_Expression_No_Right_Paren);
372 Then_Scan;
373 Statement_Required := False;
374 end if;
375
376 -- Case of ELSE
377
378 when Tok_Else =>
379
380 -- Terminate if Eltm set or if the else is to the left
381 -- of the expected column of the end for this sequence
382
383 if SS_Flags.Eltm
384 or else Start_Column < Scopes (Scope.Last).Ecol
385 then
386 Test_Statement_Required;
387 exit;
388
389 -- Otherwise complain and skip past else
390
391 else
392 Error_Msg_SC ("ELSE not allowed here");
393 Scan; -- past ELSE
394 Statement_Required := False;
395 end if;
396
397 -- Case of exception
398
399 when Tok_Exception =>
400 Test_Statement_Required;
401
402 -- If Extm not set and the exception is not to the left of
403 -- the expected column of the end for this sequence, then we
404 -- assume it belongs to the current sequence, even though it
405 -- is not permitted.
406
407 if not SS_Flags.Extm and then
408 Start_Column >= Scopes (Scope.Last).Ecol
409
410 then
411 Error_Msg_SC ("exception handler not permitted here");
412 Scan; -- past EXCEPTION
413 Discard_Junk_List (Parse_Exception_Handlers);
414 end if;
415
416 -- Always return, in the case where we scanned out handlers
417 -- that we did not expect, Parse_Exception_Handlers returned
418 -- with Token being either end or EOF, so we are OK.
419
420 exit;
421
422 -- Case of OR
423
424 when Tok_Or =>
425
426 -- Terminate if Ortm set or if the or is to the left of the
427 -- expected column of the end for this sequence.
428
429 if SS_Flags.Ortm
430 or else Start_Column < Scopes (Scope.Last).Ecol
431 then
432 Test_Statement_Required;
433 exit;
434
435 -- Otherwise complain and skip past or
436
437 else
438 Error_Msg_SC ("OR not allowed here");
439 Scan; -- past or
440 Statement_Required := False;
441 end if;
442
443 -- Case of THEN (deal also with THEN ABORT)
444
445 when Tok_Then =>
446 Save_Scan_State (Scan_State); -- at THEN
447 Scan; -- past THEN
448
449 -- Terminate if THEN ABORT allowed (ATC case)
450
451 exit when SS_Flags.Tatm and then Token = Tok_Abort;
452
453 -- Otherwise we treat THEN as some kind of mess where we did
454 -- not see the associated IF, but we pick up assuming it had
455 -- been there.
456
457 Restore_Scan_State (Scan_State); -- to THEN
458 Append_To (Statement_List, P_If_Statement);
459 Statement_Required := False;
460
461 -- Case of WHEN (error because we are not in a case)
462
463 when Tok_Others
464 | Tok_When
465 =>
466 -- Terminate if Whtm set or if the WHEN is to the left of
467 -- the expected column of the end for this sequence.
468
469 if SS_Flags.Whtm
470 or else Start_Column < Scopes (Scope.Last).Ecol
471 then
472 Test_Statement_Required;
473 exit;
474
475 -- Otherwise complain and skip when Choice {| Choice} =>
476
477 else
478 Error_Msg_SC ("WHEN not allowed here");
479 Scan; -- past when
480 Discard_Junk_List (P_Discrete_Choice_List);
481 TF_Arrow;
482 Statement_Required := False;
483 end if;
484
485 -- Cases of statements starting with an identifier
486
487 when Tok_Identifier =>
488 Check_Bad_Layout;
489
490 -- Save scan pointers and line number in case block label
491
492 Id_Node := Token_Node;
493 Block_Label := Token_Name;
494 Save_Scan_State (Scan_State_Label); -- at possible label
495 Scan; -- past Id
496
497 -- Check for common case of assignment, since it occurs
498 -- frequently, and we want to process it efficiently.
499
500 if Token = Tok_Colon_Equal then
501 Scan; -- past the colon-equal
502 Append_To (Statement_List,
503 P_Assignment_Statement (Id_Node));
504 Statement_Required := False;
505
506 -- Check common case of procedure call, another case that
507 -- we want to speed up as much as possible.
508
509 elsif Token = Tok_Semicolon then
510 Change_Name_To_Procedure_Call_Statement (Id_Node);
511 Append_To (Statement_List, Id_Node);
512 Scan; -- past semicolon
513 Statement_Required := False;
514
515 -- Here is the special test for a suspicious label, more
516 -- accurately a suspicious name, which we think perhaps
517 -- should have been a label. If next token is one of
518 -- LOOP, FOR, WHILE, DECLARE, BEGIN, then make an entry
519 -- in the suspicious label table.
520
521 if Token = Tok_Loop or else
522 Token = Tok_For or else
523 Token = Tok_While or else
524 Token = Tok_Declare or else
525 Token = Tok_Begin
526 then
527 Suspicious_Labels.Append
528 ((Proc_Call => Id_Node,
529 Semicolon_Loc => Prev_Token_Ptr,
530 Start_Token => Token_Ptr));
531 end if;
532
533 -- Check for case of "go to" in place of "goto"
534
535 elsif Token = Tok_Identifier
536 and then Block_Label = Name_Go
537 and then Token_Name = Name_To
538 then
539 Error_Msg_SP -- CODEFIX
540 ("goto is one word");
541 Append_To (Statement_List, P_Goto_Statement);
542 Statement_Required := False;
543
544 -- Check common case of = used instead of :=, just so we
545 -- give a better error message for this special misuse.
546
547 elsif Token = Tok_Equal then
548 T_Colon_Equal; -- give := expected message
549 Append_To (Statement_List,
550 P_Assignment_Statement (Id_Node));
551 Statement_Required := False;
552
553 -- Check case of loop label or block label
554
555 elsif Token = Tok_Colon
556 or else (Token in Token_Class_Labeled_Stmt
557 and then not Token_Is_At_Start_Of_Line)
558 then
559 T_Colon; -- past colon (if there, or msg for missing one)
560
561 -- Test for more than one label
562
563 loop
564 exit when Token /= Tok_Identifier;
565 Save_Scan_State (Scan_State); -- at second Id
566 Scan; -- past Id
567
568 if Token = Tok_Colon then
569 Error_Msg_SP
570 ("only one label allowed on block or loop");
571 Scan; -- past colon on extra label
572
573 -- Use the second label as the "real" label
574
575 Scan_State_Label := Scan_State;
576
577 -- We will set Error_name as the Block_Label since
578 -- we really don't know which of the labels might
579 -- be used at the end of the loop or block.
580
581 Block_Label := Error_Name;
582
583 -- If Id with no colon, then backup to point to the
584 -- Id and we will issue the message below when we try
585 -- to scan out the statement as some other form.
586
587 else
588 Restore_Scan_State (Scan_State); -- to second Id
589 exit;
590 end if;
591 end loop;
592
593 -- Loop_Statement (labeled Loop_Statement)
594
595 if Token = Tok_Loop then
596 Append_To (Statement_List,
597 P_Loop_Statement (Id_Node));
598
599 -- While statement (labeled loop statement with WHILE)
600
601 elsif Token = Tok_While then
602 Append_To (Statement_List,
603 P_While_Statement (Id_Node));
604
605 -- Declare statement (labeled block statement with
606 -- DECLARE part)
607
608 elsif Token = Tok_Declare then
609 Append_To (Statement_List,
610 P_Declare_Statement (Id_Node));
611
612 -- Begin statement (labeled block statement with no
613 -- DECLARE part)
614
615 elsif Token = Tok_Begin then
616 Append_To (Statement_List,
617 P_Begin_Statement (Id_Node));
618
619 -- For statement (labeled loop statement with FOR)
620
621 elsif Token = Tok_For then
622 Append_To (Statement_List,
623 P_For_Statement (Id_Node));
624
625 -- Improper statement follows label. If we have an
626 -- expression token, then assume the colon was part
627 -- of a misplaced declaration.
628
629 elsif Token not in Token_Class_Eterm then
630 Restore_Scan_State (Scan_State_Label);
631 Junk_Declaration;
632
633 -- Otherwise complain we have inappropriate statement
634
635 else
636 Error_Msg_AP
637 ("loop or block statement must follow label");
638 end if;
639
640 Statement_Required := False;
641
642 -- Here we have an identifier followed by something
643 -- other than a colon, semicolon or assignment symbol.
644 -- The only valid possibility is a name extension symbol
645
646 elsif Token in Token_Class_Namext then
647 Restore_Scan_State (Scan_State_Label); -- to Id
648 Name_Node := P_Name;
649
650 -- Skip junk right parens in this context
651
652 Ignore (Tok_Right_Paren);
653
654 -- Check context following call
655
656 if Token = Tok_Colon_Equal then
657 Scan; -- past colon equal
658 Append_To (Statement_List,
659 P_Assignment_Statement (Name_Node));
660 Statement_Required := False;
661
662 -- Check common case of = used instead of :=
663
664 elsif Token = Tok_Equal then
665 T_Colon_Equal; -- give := expected message
666 Append_To (Statement_List,
667 P_Assignment_Statement (Name_Node));
668 Statement_Required := False;
669
670 -- Check apostrophe cases
671
672 elsif Token = Tok_Apostrophe then
673 Append_To (Statement_List,
674 P_Code_Statement (Name_Node));
675 Statement_Required := False;
676
677 -- The only other valid item after a name is ; which
678 -- means that the item we just scanned was a call.
679
680 elsif Token = Tok_Semicolon then
681 Change_Name_To_Procedure_Call_Statement (Name_Node);
682 Append_To (Statement_List, Name_Node);
683 Scan; -- past semicolon
684 Statement_Required := False;
685
686 -- A slash following an identifier or a selected
687 -- component in this situation is most likely a period
688 -- (see location of keys on keyboard).
689
690 elsif Token = Tok_Slash
691 and then (Nkind (Name_Node) = N_Identifier
692 or else
693 Nkind (Name_Node) = N_Selected_Component)
694 then
695 Error_Msg_SC -- CODEFIX
696 ("""/"" should be "".""");
697 Statement_Required := False;
698 raise Error_Resync;
699
700 -- Else we have a missing semicolon
701
702 else
703 TF_Semicolon;
704
705 -- Normal processing as though semicolon were present
706
707 Change_Name_To_Procedure_Call_Statement (Name_Node);
708 Append_To (Statement_List, Name_Node);
709 Statement_Required := False;
710 end if;
711
712 -- If junk after identifier, check if identifier is an
713 -- instance of an incorrectly spelled keyword. If so, we
714 -- do nothing. The Bad_Spelling_Of will have reset Token
715 -- to the appropriate keyword, so the next time round the
716 -- loop we will process the modified token. Note that we
717 -- check for ELSIF before ELSE here. That's not accidental.
718 -- We don't want to identify a misspelling of ELSE as
719 -- ELSIF, and in particular we do not want to treat ELSEIF
720 -- as ELSE IF.
721
722 else
723 Restore_Scan_State (Scan_State_Label); -- to identifier
724
725 if Bad_Spelling_Of (Tok_Abort)
726 or else Bad_Spelling_Of (Tok_Accept)
727 or else Bad_Spelling_Of (Tok_Case)
728 or else Bad_Spelling_Of (Tok_Declare)
729 or else Bad_Spelling_Of (Tok_Delay)
730 or else Bad_Spelling_Of (Tok_Elsif)
731 or else Bad_Spelling_Of (Tok_Else)
732 or else Bad_Spelling_Of (Tok_End)
733 or else Bad_Spelling_Of (Tok_Exception)
734 or else Bad_Spelling_Of (Tok_Exit)
735 or else Bad_Spelling_Of (Tok_For)
736 or else Bad_Spelling_Of (Tok_Goto)
737 or else Bad_Spelling_Of (Tok_If)
738 or else Bad_Spelling_Of (Tok_Loop)
739 or else Bad_Spelling_Of (Tok_Or)
740 or else Bad_Spelling_Of (Tok_Pragma)
741 or else Bad_Spelling_Of (Tok_Raise)
742 or else Bad_Spelling_Of (Tok_Requeue)
743 or else Bad_Spelling_Of (Tok_Return)
744 or else Bad_Spelling_Of (Tok_Select)
745 or else Bad_Spelling_Of (Tok_When)
746 or else Bad_Spelling_Of (Tok_While)
747 then
748 null;
749
750 -- If not a bad spelling, then we really have junk
751
752 else
753 Scan; -- past identifier again
754
755 -- If next token is first token on line, then we
756 -- consider that we were missing a semicolon after
757 -- the identifier, and process it as a procedure
758 -- call with no parameters.
759
760 if Token_Is_At_Start_Of_Line then
761 Change_Name_To_Procedure_Call_Statement (Id_Node);
762 Append_To (Statement_List, Id_Node);
763 T_Semicolon; -- to give error message
764 Statement_Required := False;
765
766 -- Otherwise we give a missing := message and
767 -- simply abandon the junk that is there now.
768
769 else
770 T_Colon_Equal; -- give := expected message
771 raise Error_Resync;
772 end if;
773
774 end if;
775 end if;
776
777 -- Statement starting with operator symbol. This could be
778 -- a call, a name starting an assignment, or a qualified
779 -- expression.
780
781 when Tok_Operator_Symbol =>
782 Check_Bad_Layout;
783 Name_Node := P_Name;
784
785 -- An attempt at a range attribute or a qualified expression
786 -- must be illegal here (a code statement cannot possibly
787 -- allow qualification by a function name).
788
789 if Token = Tok_Apostrophe then
790 Error_Msg_SC ("apostrophe illegal here");
791 raise Error_Resync;
792 end if;
793
794 -- Scan possible assignment if we have a name
795
796 if Expr_Form = EF_Name
797 and then Token = Tok_Colon_Equal
798 then
799 Scan; -- past colon equal
800 Append_To (Statement_List,
801 P_Assignment_Statement (Name_Node));
802 else
803 Change_Name_To_Procedure_Call_Statement (Name_Node);
804 Append_To (Statement_List, Name_Node);
805 end if;
806
807 TF_Semicolon;
808 Statement_Required := False;
809
810 -- Label starting with << which must precede real statement
811 -- Note: in Ada 2012, the label may end the sequence.
812
813 when Tok_Less_Less =>
814 if Present (Last (Statement_List))
815 and then Nkind (Last (Statement_List)) /= N_Label
816 then
817 Statement_Seen := True;
818 end if;
819
820 Append_To (Statement_List, P_Label);
821 Statement_Required := True;
822
823 -- Pragma appearing as a statement in a statement sequence
824
825 when Tok_Pragma =>
826 Check_Bad_Layout;
827 Append_To (Statement_List, P_Pragma);
828
829 -- Abort_Statement
830
831 when Tok_Abort =>
832 Check_Bad_Layout;
833 Append_To (Statement_List, P_Abort_Statement);
834 Statement_Required := False;
835
836 -- Accept_Statement
837
838 when Tok_Accept =>
839 Check_Bad_Layout;
840 Append_To (Statement_List, P_Accept_Statement);
841 Statement_Required := False;
842
843 -- Begin_Statement (Block_Statement with no declare, no label)
844
845 when Tok_Begin =>
846 Check_Bad_Layout;
847 Append_To (Statement_List, P_Begin_Statement);
848 Statement_Required := False;
849
850 -- Case_Statement
851
852 when Tok_Case =>
853 Check_Bad_Layout;
854 Append_To (Statement_List, P_Case_Statement);
855 Statement_Required := False;
856
857 -- Block_Statement with DECLARE and no label
858
859 when Tok_Declare =>
860 Check_Bad_Layout;
861 Append_To (Statement_List, P_Declare_Statement);
862 Statement_Required := False;
863
864 -- Delay_Statement
865
866 when Tok_Delay =>
867 Check_Bad_Layout;
868 Append_To (Statement_List, P_Delay_Statement);
869 Statement_Required := False;
870
871 -- Exit_Statement
872
873 when Tok_Exit =>
874 Check_Bad_Layout;
875 Append_To (Statement_List, P_Exit_Statement);
876 Statement_Required := False;
877
878 -- Loop_Statement with FOR and no label
879
880 when Tok_For =>
881 Check_Bad_Layout;
882 Append_To (Statement_List, P_For_Statement);
883 Statement_Required := False;
884
885 -- Goto_Statement
886
887 when Tok_Goto =>
888 Check_Bad_Layout;
889 Append_To (Statement_List, P_Goto_Statement);
890 Statement_Required := False;
891
892 -- If_Statement
893
894 when Tok_If =>
895 Check_Bad_Layout;
896 Append_To (Statement_List, P_If_Statement);
897 Statement_Required := False;
898
899 -- Loop_Statement
900
901 when Tok_Loop =>
902 Check_Bad_Layout;
903 Append_To (Statement_List, P_Loop_Statement);
904 Statement_Required := False;
905
906 -- Null_Statement
907
908 when Tok_Null =>
909 Check_Bad_Layout;
910 Append_To (Statement_List, P_Null_Statement);
911 Statement_Required := False;
912
913 -- Raise_Statement
914
915 when Tok_Raise =>
916 Check_Bad_Layout;
917 Append_To (Statement_List, P_Raise_Statement);
918 Statement_Required := False;
919
920 -- Requeue_Statement
921
922 when Tok_Requeue =>
923 Check_Bad_Layout;
924 Append_To (Statement_List, P_Requeue_Statement);
925 Statement_Required := False;
926
927 -- Return_Statement
928
929 when Tok_Return =>
930 Check_Bad_Layout;
931 Append_To (Statement_List, P_Return_Statement);
932 Statement_Required := False;
933
934 -- Select_Statement
935
936 when Tok_Select =>
937 Check_Bad_Layout;
938 Append_To (Statement_List, P_Select_Statement);
939 Statement_Required := False;
940
941 -- While_Statement (Block_Statement with while and no loop)
942
943 when Tok_While =>
944 Check_Bad_Layout;
945 Append_To (Statement_List, P_While_Statement);
946 Statement_Required := False;
947
948 -- Anything else is some kind of junk, signal an error message
949 -- and then raise Error_Resync, to merge with the normal
950 -- handling of a bad statement.
951
952 when others =>
953 if Token in Token_Class_Declk then
954 Junk_Declaration;
955
956 else
957 Error_Msg_BC -- CODEFIX
958 ("statement expected");
959 raise Error_Resync;
960 end if;
961 end case;
962
963 -- On error resynchronization, skip past next semicolon, and, since
964 -- we are still in the statement loop, look for next statement. We
965 -- set Statement_Required False to avoid an unnecessary error message
966 -- complaining that no statement was found (i.e. we consider the
967 -- junk to satisfy the requirement for a statement being present).
968
969 exception
970 when Error_Resync =>
971 Resync_Past_Semicolon_Or_To_Loop_Or_Then;
972 Statement_Required := False;
973 end;
974
975 exit when SS_Flags.Unco;
976 end loop;
977
978 return Statement_List;
979 end P_Sequence_Of_Statements;
980
981 --------------------
982 -- 5.1 Statement --
983 --------------------
984
985 ---------------------------
986 -- 5.1 Simple Statement --
987 ---------------------------
988
989 -- Parsed by P_Sequence_Of_Statements (5.1)
990
991 -----------------------------
992 -- 5.1 Compound Statement --
993 -----------------------------
994
995 -- Parsed by P_Sequence_Of_Statements (5.1)
996
997 -------------------------
998 -- 5.1 Null Statement --
999 -------------------------
1000
1001 -- NULL_STATEMENT ::= null;
1002
1003 -- The caller has already checked that the current token is null
1004
1005 -- Error recovery: cannot raise Error_Resync
1006
1007 function P_Null_Statement return Node_Id is
1008 Null_Stmt_Node : Node_Id;
1009
1010 begin
1011 Null_Stmt_Node := New_Node (N_Null_Statement, Token_Ptr);
1012 Scan; -- past NULL
1013 TF_Semicolon;
1014 return Null_Stmt_Node;
1015 end P_Null_Statement;
1016
1017 ----------------
1018 -- 5.1 Label --
1019 ----------------
1020
1021 -- LABEL ::= <<label_STATEMENT_IDENTIFIER>>
1022
1023 -- STATEMENT_IDENTIFIER ::= DIRECT_NAME
1024
1025 -- The IDENTIFIER of a STATEMENT_IDENTIFIER shall be an identifier
1026 -- (not an OPERATOR_SYMBOL)
1027
1028 -- The caller has already checked that the current token is <<
1029
1030 -- Error recovery: can raise Error_Resync
1031
1032 function P_Label return Node_Id is
1033 Label_Node : Node_Id;
1034
1035 begin
1036 Label_Node := New_Node (N_Label, Token_Ptr);
1037 Scan; -- past <<
1038 Set_Identifier (Label_Node, P_Identifier (C_Greater_Greater));
1039 T_Greater_Greater;
1040 Append_Elmt (Label_Node, Label_List);
1041 return Label_Node;
1042 end P_Label;
1043
1044 -------------------------------
1045 -- 5.1 Statement Identifier --
1046 -------------------------------
1047
1048 -- Statement label is parsed by P_Label (5.1)
1049
1050 -- Loop label is parsed by P_Loop_Statement (5.5), P_For_Statement (5.5)
1051 -- or P_While_Statement (5.5)
1052
1053 -- Block label is parsed by P_Begin_Statement (5.6) or
1054 -- P_Declare_Statement (5.6)
1055
1056 -------------------------------
1057 -- 5.2 Assignment Statement --
1058 -------------------------------
1059
1060 -- ASSIGNMENT_STATEMENT ::=
1061 -- variable_NAME := EXPRESSION;
1062
1063 -- Error recovery: can raise Error_Resync
1064
1065 function P_Assignment_Statement (LHS : Node_Id) return Node_Id is
1066 Assign_Node : Node_Id;
1067
1068 begin
1069 Assign_Node := New_Node (N_Assignment_Statement, Prev_Token_Ptr);
1070 Current_Assign_Node := Assign_Node;
1071 Set_Name (Assign_Node, LHS);
1072 Set_Expression (Assign_Node, P_Expression_No_Right_Paren);
1073 TF_Semicolon;
1074 Current_Assign_Node := Empty;
1075 return Assign_Node;
1076 end P_Assignment_Statement;
1077
1078 -----------------------
1079 -- 5.3 If Statement --
1080 -----------------------
1081
1082 -- IF_STATEMENT ::=
1083 -- if CONDITION then
1084 -- SEQUENCE_OF_STATEMENTS
1085 -- {elsif CONDITION then
1086 -- SEQUENCE_OF_STATEMENTS}
1087 -- [else
1088 -- SEQUENCE_OF_STATEMENTS]
1089 -- end if;
1090
1091 -- The caller has checked that the initial token is IF (or in the error
1092 -- case of a mysterious THEN, the initial token may simply be THEN, in
1093 -- which case, no condition (or IF) was scanned).
1094
1095 -- Error recovery: can raise Error_Resync
1096
1097 function P_If_Statement return Node_Id is
1098 If_Node : Node_Id;
1099 Elsif_Node : Node_Id;
1100 Loc : Source_Ptr;
1101
1102 procedure Add_Elsif_Part;
1103 -- An internal procedure used to scan out a single ELSIF part. On entry
1104 -- the ELSIF (or an ELSE which has been determined should be ELSIF) is
1105 -- scanned out and is in Prev_Token.
1106
1107 procedure Check_If_Column;
1108 -- An internal procedure used to check that THEN, ELSE, or ELSIF
1109 -- appear in the right place if column checking is enabled (i.e. if
1110 -- they are the first token on the line, then they must appear in
1111 -- the same column as the opening IF).
1112
1113 procedure Check_Then_Column;
1114 -- This procedure carries out the style checks for a THEN token
1115 -- Note that the caller has set Loc to the Source_Ptr value for
1116 -- the previous IF or ELSIF token.
1117
1118 function Else_Should_Be_Elsif return Boolean;
1119 -- An internal routine used to do a special error recovery check when
1120 -- an ELSE is encountered. It determines if the ELSE should be treated
1121 -- as an ELSIF. A positive decision (TRUE returned, is made if the ELSE
1122 -- is followed by a sequence of tokens, starting on the same line as
1123 -- the ELSE, which are not expression terminators, followed by a THEN.
1124 -- On entry, the ELSE has been scanned out.
1125
1126 procedure Add_Elsif_Part is
1127 begin
1128 if No (Elsif_Parts (If_Node)) then
1129 Set_Elsif_Parts (If_Node, New_List);
1130 end if;
1131
1132 Elsif_Node := New_Node (N_Elsif_Part, Prev_Token_Ptr);
1133 Loc := Prev_Token_Ptr;
1134 Set_Condition (Elsif_Node, P_Condition);
1135 Check_Then_Column;
1136 Then_Scan;
1137 Set_Then_Statements
1138 (Elsif_Node, P_Sequence_Of_Statements (SS_Eftm_Eltm_Sreq));
1139 Append (Elsif_Node, Elsif_Parts (If_Node));
1140 end Add_Elsif_Part;
1141
1142 procedure Check_If_Column is
1143 begin
1144 if RM_Column_Check and then Token_Is_At_Start_Of_Line
1145 and then Start_Column /= Scopes (Scope.Last).Ecol
1146 then
1147 Error_Msg_Col := Scopes (Scope.Last).Ecol;
1148 Error_Msg_SC ("(style) this token should be@");
1149 end if;
1150 end Check_If_Column;
1151
1152 procedure Check_Then_Column is
1153 begin
1154 if Token = Tok_Then then
1155 Check_If_Column;
1156
1157 if Style_Check then
1158 Style.Check_Then (Loc);
1159 end if;
1160 end if;
1161 end Check_Then_Column;
1162
1163 function Else_Should_Be_Elsif return Boolean is
1164 Scan_State : Saved_Scan_State;
1165
1166 begin
1167 if Token_Is_At_Start_Of_Line then
1168 return False;
1169
1170 else
1171 Save_Scan_State (Scan_State);
1172
1173 loop
1174 if Token in Token_Class_Eterm then
1175 Restore_Scan_State (Scan_State);
1176 return False;
1177 else
1178 Scan; -- past non-expression terminating token
1179
1180 if Token = Tok_Then then
1181 Restore_Scan_State (Scan_State);
1182 return True;
1183 end if;
1184 end if;
1185 end loop;
1186 end if;
1187 end Else_Should_Be_Elsif;
1188
1189 -- Start of processing for P_If_Statement
1190
1191 begin
1192 If_Node := New_Node (N_If_Statement, Token_Ptr);
1193
1194 Push_Scope_Stack;
1195 Scopes (Scope.Last).Etyp := E_If;
1196 Scopes (Scope.Last).Ecol := Start_Column;
1197 Scopes (Scope.Last).Sloc := Token_Ptr;
1198 Scopes (Scope.Last).Labl := Error;
1199 Scopes (Scope.Last).Node := If_Node;
1200
1201 if Token = Tok_If then
1202 Loc := Token_Ptr;
1203 Scan; -- past IF
1204 Set_Condition (If_Node, P_Condition);
1205
1206 -- Deal with misuse of IF expression => used instead
1207 -- of WHEN expression =>
1208
1209 if Token = Tok_Arrow then
1210 Error_Msg_SC -- CODEFIX
1211 ("THEN expected");
1212 Scan; -- past the arrow
1213 Pop_Scope_Stack; -- remove unneeded entry
1214 raise Error_Resync;
1215 end if;
1216
1217 Check_Then_Column;
1218
1219 else
1220 Error_Msg_SC ("no IF for this THEN");
1221 Set_Condition (If_Node, Error);
1222 end if;
1223
1224 Then_Scan;
1225
1226 Set_Then_Statements
1227 (If_Node, P_Sequence_Of_Statements (SS_Eftm_Eltm_Sreq));
1228
1229 -- This loop scans out else and elsif parts
1230
1231 loop
1232 if Token = Tok_Elsif then
1233 Check_If_Column;
1234
1235 if Present (Else_Statements (If_Node)) then
1236 Error_Msg_SP ("ELSIF cannot appear after ELSE");
1237 end if;
1238
1239 Scan; -- past ELSIF
1240 Add_Elsif_Part;
1241
1242 elsif Token = Tok_Else then
1243 Check_If_Column;
1244 Scan; -- past ELSE
1245
1246 if Else_Should_Be_Elsif then
1247 Error_Msg_SP -- CODEFIX
1248 ("ELSE should be ELSIF");
1249 Add_Elsif_Part;
1250
1251 else
1252 -- Here we have an else that really is an else
1253
1254 if Present (Else_Statements (If_Node)) then
1255 Error_Msg_SP ("only one ELSE part allowed");
1256 Append_List
1257 (P_Sequence_Of_Statements (SS_Eftm_Eltm_Sreq),
1258 Else_Statements (If_Node));
1259 else
1260 Set_Else_Statements
1261 (If_Node, P_Sequence_Of_Statements (SS_Eftm_Eltm_Sreq));
1262 end if;
1263 end if;
1264
1265 -- If anything other than ELSE or ELSIF, exit the loop. The token
1266 -- had better be END (and in fact it had better be END IF), but
1267 -- we will let End_Statements take care of checking that.
1268
1269 else
1270 exit;
1271 end if;
1272 end loop;
1273
1274 End_Statements;
1275 return If_Node;
1276
1277 end P_If_Statement;
1278
1279 --------------------
1280 -- 5.3 Condition --
1281 --------------------
1282
1283 -- CONDITION ::= boolean_EXPRESSION
1284
1285 function P_Condition return Node_Id is
1286 begin
1287 return P_Condition (P_Expression_No_Right_Paren);
1288 end P_Condition;
1289
1290 function P_Condition (Cond : Node_Id) return Node_Id is
1291 begin
1292 -- It is never possible for := to follow a condition, so if we get
1293 -- a := we assume it is a mistyped equality. Note that we do not try
1294 -- to reconstruct the tree correctly in this case, but we do at least
1295 -- give an accurate error message.
1296
1297 if Token = Tok_Colon_Equal then
1298 while Token = Tok_Colon_Equal loop
1299 Error_Msg_SC -- CODEFIX
1300 (""":="" should be ""=""");
1301 Scan; -- past junk :=
1302 Discard_Junk_Node (P_Expression_No_Right_Paren);
1303 end loop;
1304
1305 return Cond;
1306
1307 -- Otherwise check for redundant parentheses
1308
1309 -- If the condition is a conditional or a quantified expression, it is
1310 -- parenthesized in the context of a condition, because of a separate
1311 -- syntax rule.
1312
1313 else
1314 if Style_Check and then Paren_Count (Cond) > 0 then
1315 if not Nkind_In (Cond, N_If_Expression,
1316 N_Case_Expression,
1317 N_Quantified_Expression)
1318 or else Paren_Count (Cond) > 1
1319 then
1320 Style.Check_Xtra_Parens (First_Sloc (Cond));
1321 end if;
1322 end if;
1323
1324 -- And return the result
1325
1326 return Cond;
1327 end if;
1328 end P_Condition;
1329
1330 -------------------------
1331 -- 5.4 Case Statement --
1332 -------------------------
1333
1334 -- CASE_STATEMENT ::=
1335 -- case EXPRESSION is
1336 -- CASE_STATEMENT_ALTERNATIVE
1337 -- {CASE_STATEMENT_ALTERNATIVE}
1338 -- end case;
1339
1340 -- The caller has checked that the first token is CASE
1341
1342 -- Can raise Error_Resync
1343
1344 function P_Case_Statement return Node_Id is
1345 Case_Node : Node_Id;
1346 Alternatives_List : List_Id;
1347 First_When_Loc : Source_Ptr;
1348
1349 begin
1350 Case_Node := New_Node (N_Case_Statement, Token_Ptr);
1351
1352 Push_Scope_Stack;
1353 Scopes (Scope.Last).Etyp := E_Case;
1354 Scopes (Scope.Last).Ecol := Start_Column;
1355 Scopes (Scope.Last).Sloc := Token_Ptr;
1356 Scopes (Scope.Last).Labl := Error;
1357 Scopes (Scope.Last).Node := Case_Node;
1358
1359 Scan; -- past CASE
1360 Set_Expression (Case_Node, P_Expression_No_Right_Paren);
1361 TF_Is;
1362
1363 -- Prepare to parse case statement alternatives
1364
1365 Alternatives_List := New_List;
1366 P_Pragmas_Opt (Alternatives_List);
1367 First_When_Loc := Token_Ptr;
1368
1369 -- Loop through case statement alternatives
1370
1371 loop
1372 -- If we have a WHEN or OTHERS, then that's fine keep going. Note
1373 -- that it is a semantic check to ensure the proper use of OTHERS
1374
1375 if Token = Tok_When or else Token = Tok_Others then
1376 Append (P_Case_Statement_Alternative, Alternatives_List);
1377
1378 -- If we have an END, then probably we are at the end of the case
1379 -- but we only exit if Check_End thinks the END was reasonable.
1380
1381 elsif Token = Tok_End then
1382 exit when Check_End;
1383
1384 -- Here if token is other than WHEN, OTHERS or END. We definitely
1385 -- have an error, but the question is whether or not to get out of
1386 -- the case statement. We don't want to get out early, or we will
1387 -- get a slew of junk error messages for subsequent when tokens.
1388
1389 -- If the token is not at the start of the line, or if it is indented
1390 -- with respect to the current case statement, then the best guess is
1391 -- that we are still supposed to be inside the case statement. We
1392 -- complain about the missing WHEN, and discard the junk statements.
1393
1394 elsif not Token_Is_At_Start_Of_Line
1395 or else Start_Column > Scopes (Scope.Last).Ecol
1396 then
1397 Error_Msg_BC ("WHEN (case statement alternative) expected");
1398
1399 -- Here is a possibility for infinite looping if we don't make
1400 -- progress. So try to process statements, otherwise exit
1401
1402 declare
1403 Error_Ptr : constant Source_Ptr := Scan_Ptr;
1404 begin
1405 Discard_Junk_List (P_Sequence_Of_Statements (SS_Whtm));
1406 exit when Scan_Ptr = Error_Ptr and then Check_End;
1407 end;
1408
1409 -- Here we have a junk token at the start of the line and it is
1410 -- not indented. If Check_End thinks there is a missing END, then
1411 -- we will get out of the case, otherwise we keep going.
1412
1413 else
1414 exit when Check_End;
1415 end if;
1416 end loop;
1417
1418 -- Make sure we have at least one alternative
1419
1420 if No (First_Non_Pragma (Alternatives_List)) then
1421 Error_Msg
1422 ("WHEN expected, must have at least one alternative in case",
1423 First_When_Loc);
1424 return Error;
1425
1426 else
1427 Set_Alternatives (Case_Node, Alternatives_List);
1428 return Case_Node;
1429 end if;
1430 end P_Case_Statement;
1431
1432 -------------------------------------
1433 -- 5.4 Case Statement Alternative --
1434 -------------------------------------
1435
1436 -- CASE_STATEMENT_ALTERNATIVE ::=
1437 -- when DISCRETE_CHOICE_LIST =>
1438 -- SEQUENCE_OF_STATEMENTS
1439
1440 -- The caller has checked that the initial token is WHEN or OTHERS
1441 -- Error recovery: can raise Error_Resync
1442
1443 function P_Case_Statement_Alternative return Node_Id is
1444 Case_Alt_Node : Node_Id;
1445
1446 begin
1447 if Style_Check then
1448 Style.Check_Indentation;
1449 end if;
1450
1451 Case_Alt_Node := New_Node (N_Case_Statement_Alternative, Token_Ptr);
1452 T_When; -- past WHEN (or give error in OTHERS case)
1453 Set_Discrete_Choices (Case_Alt_Node, P_Discrete_Choice_List);
1454 TF_Arrow;
1455 Set_Statements (Case_Alt_Node, P_Sequence_Of_Statements (SS_Sreq_Whtm));
1456 return Case_Alt_Node;
1457 end P_Case_Statement_Alternative;
1458
1459 -------------------------
1460 -- 5.5 Loop Statement --
1461 -------------------------
1462
1463 -- LOOP_STATEMENT ::=
1464 -- [LOOP_STATEMENT_IDENTIFIER:]
1465 -- [ITERATION_SCHEME] loop
1466 -- SEQUENCE_OF_STATEMENTS
1467 -- end loop [loop_IDENTIFIER];
1468
1469 -- ITERATION_SCHEME ::=
1470 -- while CONDITION
1471 -- | for LOOP_PARAMETER_SPECIFICATION
1472
1473 -- The parsing of loop statements is handled by one of three functions
1474 -- P_Loop_Statement, P_For_Statement or P_While_Statement depending
1475 -- on the initial keyword in the construct (excluding the identifier)
1476
1477 -- P_Loop_Statement
1478
1479 -- This function parses the case where no iteration scheme is present
1480
1481 -- The caller has checked that the initial token is LOOP. The parameter
1482 -- is the node identifiers for the loop label if any (or is set to Empty
1483 -- if there is no loop label).
1484
1485 -- Error recovery : cannot raise Error_Resync
1486
1487 function P_Loop_Statement (Loop_Name : Node_Id := Empty) return Node_Id is
1488 Loop_Node : Node_Id;
1489 Created_Name : Node_Id;
1490
1491 begin
1492 Push_Scope_Stack;
1493 Scopes (Scope.Last).Labl := Loop_Name;
1494 Scopes (Scope.Last).Ecol := Start_Column;
1495 Scopes (Scope.Last).Sloc := Token_Ptr;
1496 Scopes (Scope.Last).Etyp := E_Loop;
1497
1498 Loop_Node := New_Node (N_Loop_Statement, Token_Ptr);
1499 TF_Loop;
1500
1501 if No (Loop_Name) then
1502 Created_Name :=
1503 Make_Identifier (Sloc (Loop_Node), Set_Loop_Block_Name ('L'));
1504 Set_Comes_From_Source (Created_Name, False);
1505 Set_Has_Created_Identifier (Loop_Node, True);
1506 Set_Identifier (Loop_Node, Created_Name);
1507 Scopes (Scope.Last).Labl := Created_Name;
1508 else
1509 Set_Identifier (Loop_Node, Loop_Name);
1510 end if;
1511
1512 Append_Elmt (Loop_Node, Label_List);
1513 Set_Statements (Loop_Node, P_Sequence_Of_Statements (SS_Sreq));
1514 End_Statements (Loop_Node);
1515 return Loop_Node;
1516 end P_Loop_Statement;
1517
1518 -- P_For_Statement
1519
1520 -- This function parses a loop statement with a FOR iteration scheme
1521
1522 -- The caller has checked that the initial token is FOR. The parameter
1523 -- is the node identifier for the block label if any (or is set to Empty
1524 -- if there is no block label).
1525
1526 -- Note: the caller fills in the Identifier field if a label was present
1527
1528 -- Error recovery: can raise Error_Resync
1529
1530 function P_For_Statement (Loop_Name : Node_Id := Empty) return Node_Id is
1531 Loop_Node : Node_Id;
1532 Iter_Scheme_Node : Node_Id;
1533 Loop_For_Flag : Boolean;
1534 Created_Name : Node_Id;
1535 Spec : Node_Id;
1536
1537 begin
1538 Push_Scope_Stack;
1539 Scopes (Scope.Last).Labl := Loop_Name;
1540 Scopes (Scope.Last).Ecol := Start_Column;
1541 Scopes (Scope.Last).Sloc := Token_Ptr;
1542 Scopes (Scope.Last).Etyp := E_Loop;
1543
1544 Loop_For_Flag := (Prev_Token = Tok_Loop);
1545 Scan; -- past FOR
1546 Iter_Scheme_Node := New_Node (N_Iteration_Scheme, Token_Ptr);
1547 Spec := P_Loop_Parameter_Specification;
1548
1549 if Nkind (Spec) = N_Loop_Parameter_Specification then
1550 Set_Loop_Parameter_Specification (Iter_Scheme_Node, Spec);
1551 else
1552 Set_Iterator_Specification (Iter_Scheme_Node, Spec);
1553 end if;
1554
1555 -- The following is a special test so that a miswritten for loop such
1556 -- as "loop for I in 1..10;" is handled nicely, without making an extra
1557 -- entry in the scope stack. We don't bother to actually fix up the
1558 -- tree in this case since it's not worth the effort. Instead we just
1559 -- eat up the loop junk, leaving the entry for what now looks like an
1560 -- unmodified loop intact.
1561
1562 if Loop_For_Flag and then Token = Tok_Semicolon then
1563 Error_Msg_SC ("LOOP belongs here, not before FOR");
1564 Pop_Scope_Stack;
1565 return Error;
1566
1567 -- Normal case
1568
1569 else
1570 Loop_Node := New_Node (N_Loop_Statement, Token_Ptr);
1571
1572 if No (Loop_Name) then
1573 Created_Name :=
1574 Make_Identifier (Sloc (Loop_Node), Set_Loop_Block_Name ('L'));
1575 Set_Comes_From_Source (Created_Name, False);
1576 Set_Has_Created_Identifier (Loop_Node, True);
1577 Set_Identifier (Loop_Node, Created_Name);
1578 Scopes (Scope.Last).Labl := Created_Name;
1579 else
1580 Set_Identifier (Loop_Node, Loop_Name);
1581 end if;
1582
1583 TF_Loop;
1584 Set_Statements (Loop_Node, P_Sequence_Of_Statements (SS_Sreq));
1585 End_Statements (Loop_Node);
1586 Set_Iteration_Scheme (Loop_Node, Iter_Scheme_Node);
1587 Append_Elmt (Loop_Node, Label_List);
1588 return Loop_Node;
1589 end if;
1590 end P_For_Statement;
1591
1592 -- P_While_Statement
1593
1594 -- This procedure scans a loop statement with a WHILE iteration scheme
1595
1596 -- The caller has checked that the initial token is WHILE. The parameter
1597 -- is the node identifier for the block label if any (or is set to Empty
1598 -- if there is no block label).
1599
1600 -- Error recovery: cannot raise Error_Resync
1601
1602 function P_While_Statement (Loop_Name : Node_Id := Empty) return Node_Id is
1603 Loop_Node : Node_Id;
1604 Iter_Scheme_Node : Node_Id;
1605 Loop_While_Flag : Boolean;
1606 Created_Name : Node_Id;
1607
1608 begin
1609 Push_Scope_Stack;
1610 Scopes (Scope.Last).Labl := Loop_Name;
1611 Scopes (Scope.Last).Ecol := Start_Column;
1612 Scopes (Scope.Last).Sloc := Token_Ptr;
1613 Scopes (Scope.Last).Etyp := E_Loop;
1614
1615 Loop_While_Flag := (Prev_Token = Tok_Loop);
1616 Iter_Scheme_Node := New_Node (N_Iteration_Scheme, Token_Ptr);
1617 Scan; -- past WHILE
1618 Set_Condition (Iter_Scheme_Node, P_Condition);
1619
1620 -- The following is a special test so that a miswritten for loop such
1621 -- as "loop while I > 10;" is handled nicely, without making an extra
1622 -- entry in the scope stack. We don't bother to actually fix up the
1623 -- tree in this case since it's not worth the effort. Instead we just
1624 -- eat up the loop junk, leaving the entry for what now looks like an
1625 -- unmodified loop intact.
1626
1627 if Loop_While_Flag and then Token = Tok_Semicolon then
1628 Error_Msg_SC ("LOOP belongs here, not before WHILE");
1629 Pop_Scope_Stack;
1630 return Error;
1631
1632 -- Normal case
1633
1634 else
1635 Loop_Node := New_Node (N_Loop_Statement, Token_Ptr);
1636 TF_Loop;
1637
1638 if No (Loop_Name) then
1639 Created_Name :=
1640 Make_Identifier (Sloc (Loop_Node), Set_Loop_Block_Name ('L'));
1641 Set_Comes_From_Source (Created_Name, False);
1642 Set_Has_Created_Identifier (Loop_Node, True);
1643 Set_Identifier (Loop_Node, Created_Name);
1644 Scopes (Scope.Last).Labl := Created_Name;
1645 else
1646 Set_Identifier (Loop_Node, Loop_Name);
1647 end if;
1648
1649 Set_Statements (Loop_Node, P_Sequence_Of_Statements (SS_Sreq));
1650 End_Statements (Loop_Node);
1651 Set_Iteration_Scheme (Loop_Node, Iter_Scheme_Node);
1652 Append_Elmt (Loop_Node, Label_List);
1653 return Loop_Node;
1654 end if;
1655 end P_While_Statement;
1656
1657 ---------------------------------------
1658 -- 5.5 Loop Parameter Specification --
1659 ---------------------------------------
1660
1661 -- LOOP_PARAMETER_SPECIFICATION ::=
1662 -- DEFINING_IDENTIFIER in [reverse] DISCRETE_SUBTYPE_DEFINITION
1663
1664 -- Error recovery: cannot raise Error_Resync
1665
1666 function P_Loop_Parameter_Specification return Node_Id is
1667 Loop_Param_Specification_Node : Node_Id;
1668
1669 ID_Node : Node_Id;
1670 Scan_State : Saved_Scan_State;
1671
1672 begin
1673
1674 Save_Scan_State (Scan_State);
1675 ID_Node := P_Defining_Identifier (C_In);
1676
1677 -- If the next token is OF, it indicates an Ada 2012 iterator. If the
1678 -- next token is a colon, this is also an Ada 2012 iterator, including
1679 -- a subtype indication for the loop parameter. Otherwise we parse the
1680 -- construct as a loop parameter specification. Note that the form
1681 -- "for A in B" is ambiguous, and must be resolved semantically: if B
1682 -- is a discrete subtype this is a loop specification, but if it is an
1683 -- expression it is an iterator specification. Ambiguity is resolved
1684 -- during analysis of the loop parameter specification.
1685
1686 if Token = Tok_Of or else Token = Tok_Colon then
1687 Error_Msg_Ada_2012_Feature ("iterator", Token_Ptr);
1688 return P_Iterator_Specification (ID_Node);
1689 end if;
1690
1691 -- The span of the Loop_Parameter_Specification starts at the
1692 -- defining identifier.
1693
1694 Loop_Param_Specification_Node :=
1695 New_Node (N_Loop_Parameter_Specification, Sloc (ID_Node));
1696 Set_Defining_Identifier (Loop_Param_Specification_Node, ID_Node);
1697
1698 if Token = Tok_Left_Paren then
1699 Error_Msg_SC ("subscripted loop parameter not allowed");
1700 Restore_Scan_State (Scan_State);
1701 Discard_Junk_Node (P_Name);
1702
1703 elsif Token = Tok_Dot then
1704 Error_Msg_SC ("selected loop parameter not allowed");
1705 Restore_Scan_State (Scan_State);
1706 Discard_Junk_Node (P_Name);
1707 end if;
1708
1709 T_In;
1710
1711 if Token = Tok_Reverse then
1712 Scan; -- past REVERSE
1713 Set_Reverse_Present (Loop_Param_Specification_Node, True);
1714 end if;
1715
1716 Set_Discrete_Subtype_Definition
1717 (Loop_Param_Specification_Node, P_Discrete_Subtype_Definition);
1718 return Loop_Param_Specification_Node;
1719
1720 exception
1721 when Error_Resync =>
1722 return Error;
1723 end P_Loop_Parameter_Specification;
1724
1725 ----------------------------------
1726 -- 5.5.1 Iterator_Specification --
1727 ----------------------------------
1728
1729 function P_Iterator_Specification (Def_Id : Node_Id) return Node_Id is
1730 Node1 : Node_Id;
1731
1732 begin
1733 Node1 := New_Node (N_Iterator_Specification, Sloc (Def_Id));
1734 Set_Defining_Identifier (Node1, Def_Id);
1735
1736 if Token = Tok_Colon then
1737 Scan; -- past :
1738 Set_Subtype_Indication (Node1, P_Subtype_Indication);
1739 end if;
1740
1741 if Token = Tok_Of then
1742 Set_Of_Present (Node1);
1743 Scan; -- past OF
1744
1745 elsif Token = Tok_In then
1746 Scan; -- past IN
1747
1748 elsif Prev_Token = Tok_In
1749 and then Present (Subtype_Indication (Node1))
1750 then
1751 -- Simplest recovery is to transform it into an element iterator.
1752 -- Error message on 'in" has already been emitted when parsing the
1753 -- optional constraint.
1754
1755 Set_Of_Present (Node1);
1756 Error_Msg_N
1757 ("subtype indication is only legal on an element iterator",
1758 Subtype_Indication (Node1));
1759
1760 else
1761 return Error;
1762 end if;
1763
1764 if Token = Tok_Reverse then
1765 Scan; -- past REVERSE
1766 Set_Reverse_Present (Node1, True);
1767 end if;
1768
1769 Set_Name (Node1, P_Name);
1770 return Node1;
1771 end P_Iterator_Specification;
1772
1773 --------------------------
1774 -- 5.6 Block Statement --
1775 --------------------------
1776
1777 -- BLOCK_STATEMENT ::=
1778 -- [block_STATEMENT_IDENTIFIER:]
1779 -- [declare
1780 -- DECLARATIVE_PART]
1781 -- begin
1782 -- HANDLED_SEQUENCE_OF_STATEMENTS
1783 -- end [block_IDENTIFIER];
1784
1785 -- The parsing of block statements is handled by one of the two functions
1786 -- P_Declare_Statement or P_Begin_Statement depending on whether or not
1787 -- a declare section is present
1788
1789 -- P_Declare_Statement
1790
1791 -- This function parses a block statement with DECLARE present
1792
1793 -- The caller has checked that the initial token is DECLARE
1794
1795 -- Error recovery: cannot raise Error_Resync
1796
1797 function P_Declare_Statement
1798 (Block_Name : Node_Id := Empty)
1799 return Node_Id
1800 is
1801 Block_Node : Node_Id;
1802 Created_Name : Node_Id;
1803
1804 begin
1805 Block_Node := New_Node (N_Block_Statement, Token_Ptr);
1806
1807 Push_Scope_Stack;
1808 Scopes (Scope.Last).Etyp := E_Name;
1809 Scopes (Scope.Last).Lreq := Present (Block_Name);
1810 Scopes (Scope.Last).Ecol := Start_Column;
1811 Scopes (Scope.Last).Labl := Block_Name;
1812 Scopes (Scope.Last).Sloc := Token_Ptr;
1813
1814 Scan; -- past DECLARE
1815
1816 if No (Block_Name) then
1817 Created_Name :=
1818 Make_Identifier (Sloc (Block_Node), Set_Loop_Block_Name ('B'));
1819 Set_Comes_From_Source (Created_Name, False);
1820 Set_Has_Created_Identifier (Block_Node, True);
1821 Set_Identifier (Block_Node, Created_Name);
1822 Scopes (Scope.Last).Labl := Created_Name;
1823 else
1824 Set_Identifier (Block_Node, Block_Name);
1825 end if;
1826
1827 Append_Elmt (Block_Node, Label_List);
1828 Parse_Decls_Begin_End (Block_Node);
1829 return Block_Node;
1830 end P_Declare_Statement;
1831
1832 -- P_Begin_Statement
1833
1834 -- This function parses a block statement with no DECLARE present
1835
1836 -- The caller has checked that the initial token is BEGIN
1837
1838 -- Error recovery: cannot raise Error_Resync
1839
1840 function P_Begin_Statement
1841 (Block_Name : Node_Id := Empty)
1842 return Node_Id
1843 is
1844 Block_Node : Node_Id;
1845 Created_Name : Node_Id;
1846
1847 begin
1848 Block_Node := New_Node (N_Block_Statement, Token_Ptr);
1849
1850 Push_Scope_Stack;
1851 Scopes (Scope.Last).Etyp := E_Name;
1852 Scopes (Scope.Last).Lreq := Present (Block_Name);
1853 Scopes (Scope.Last).Ecol := Start_Column;
1854 Scopes (Scope.Last).Labl := Block_Name;
1855 Scopes (Scope.Last).Sloc := Token_Ptr;
1856
1857 if No (Block_Name) then
1858 Created_Name :=
1859 Make_Identifier (Sloc (Block_Node), Set_Loop_Block_Name ('B'));
1860 Set_Comes_From_Source (Created_Name, False);
1861 Set_Has_Created_Identifier (Block_Node, True);
1862 Set_Identifier (Block_Node, Created_Name);
1863 Scopes (Scope.Last).Labl := Created_Name;
1864 else
1865 Set_Identifier (Block_Node, Block_Name);
1866 end if;
1867
1868 Append_Elmt (Block_Node, Label_List);
1869
1870 Scopes (Scope.Last).Ecol := Start_Column;
1871 Scopes (Scope.Last).Sloc := Token_Ptr;
1872 Scan; -- past BEGIN
1873 Set_Handled_Statement_Sequence
1874 (Block_Node, P_Handled_Sequence_Of_Statements);
1875 End_Statements (Handled_Statement_Sequence (Block_Node));
1876 return Block_Node;
1877 end P_Begin_Statement;
1878
1879 -------------------------
1880 -- 5.7 Exit Statement --
1881 -------------------------
1882
1883 -- EXIT_STATEMENT ::=
1884 -- exit [loop_NAME] [when CONDITION];
1885
1886 -- The caller has checked that the initial token is EXIT
1887
1888 -- Error recovery: can raise Error_Resync
1889
1890 function P_Exit_Statement return Node_Id is
1891 Exit_Node : Node_Id;
1892
1893 function Missing_Semicolon_On_Exit return Boolean;
1894 -- This function deals with the following specialized situation
1895 --
1896 -- when 'x' =>
1897 -- exit [identifier]
1898 -- when 'y' =>
1899 --
1900 -- This looks like a messed up EXIT WHEN, when in fact the problem
1901 -- is a missing semicolon. It is called with Token pointing to the
1902 -- WHEN token, and returns True if a semicolon is missing before
1903 -- the WHEN as in the above example.
1904
1905 -------------------------------
1906 -- Missing_Semicolon_On_Exit --
1907 -------------------------------
1908
1909 function Missing_Semicolon_On_Exit return Boolean is
1910 State : Saved_Scan_State;
1911
1912 begin
1913 if not Token_Is_At_Start_Of_Line then
1914 return False;
1915
1916 elsif Scopes (Scope.Last).Etyp /= E_Case then
1917 return False;
1918
1919 else
1920 Save_Scan_State (State);
1921 Scan; -- past WHEN
1922 Scan; -- past token after WHEN
1923
1924 if Token = Tok_Arrow then
1925 Restore_Scan_State (State);
1926 return True;
1927 else
1928 Restore_Scan_State (State);
1929 return False;
1930 end if;
1931 end if;
1932 end Missing_Semicolon_On_Exit;
1933
1934 -- Start of processing for P_Exit_Statement
1935
1936 begin
1937 Exit_Node := New_Node (N_Exit_Statement, Token_Ptr);
1938 Scan; -- past EXIT
1939
1940 if Token = Tok_Identifier then
1941 Set_Name (Exit_Node, P_Qualified_Simple_Name);
1942
1943 elsif Style_Check then
1944 -- This EXIT has no name, so check that
1945 -- the innermost loop is unnamed too.
1946
1947 Check_No_Exit_Name :
1948 for J in reverse 1 .. Scope.Last loop
1949 if Scopes (J).Etyp = E_Loop then
1950 if Present (Scopes (J).Labl)
1951 and then Comes_From_Source (Scopes (J).Labl)
1952 then
1953 -- Innermost loop in fact had a name, style check fails
1954
1955 Style.No_Exit_Name (Scopes (J).Labl);
1956 end if;
1957
1958 exit Check_No_Exit_Name;
1959 end if;
1960 end loop Check_No_Exit_Name;
1961 end if;
1962
1963 if Token = Tok_When and then not Missing_Semicolon_On_Exit then
1964 Scan; -- past WHEN
1965 Set_Condition (Exit_Node, P_Condition);
1966
1967 -- Allow IF instead of WHEN, giving error message
1968
1969 elsif Token = Tok_If then
1970 T_When;
1971 Scan; -- past IF used in place of WHEN
1972 Set_Condition (Exit_Node, P_Expression_No_Right_Paren);
1973 end if;
1974
1975 TF_Semicolon;
1976 return Exit_Node;
1977 end P_Exit_Statement;
1978
1979 -------------------------
1980 -- 5.8 Goto Statement --
1981 -------------------------
1982
1983 -- GOTO_STATEMENT ::= goto label_NAME;
1984
1985 -- The caller has checked that the initial token is GOTO (or TO in the
1986 -- error case where GO and TO were incorrectly separated).
1987
1988 -- Error recovery: can raise Error_Resync
1989
1990 function P_Goto_Statement return Node_Id is
1991 Goto_Node : Node_Id;
1992
1993 begin
1994 Goto_Node := New_Node (N_Goto_Statement, Token_Ptr);
1995 Scan; -- past GOTO (or TO)
1996 Set_Name (Goto_Node, P_Qualified_Simple_Name_Resync);
1997 Append_Elmt (Goto_Node, Goto_List);
1998 No_Constraint;
1999 TF_Semicolon;
2000 return Goto_Node;
2001 end P_Goto_Statement;
2002
2003 ---------------------------
2004 -- Parse_Decls_Begin_End --
2005 ---------------------------
2006
2007 -- This function parses the construct:
2008
2009 -- DECLARATIVE_PART
2010 -- begin
2011 -- HANDLED_SEQUENCE_OF_STATEMENTS
2012 -- end [NAME];
2013
2014 -- The caller has built the scope stack entry, and created the node to
2015 -- whose Declarations and Handled_Statement_Sequence fields are to be
2016 -- set. On return these fields are filled in (except in the case of a
2017 -- task body, where the handled statement sequence is optional, and may
2018 -- thus be Empty), and the scan is positioned past the End sequence.
2019
2020 -- If the BEGIN is missing, then the parent node is used to help construct
2021 -- an appropriate missing BEGIN message. Possibilities for the parent are:
2022
2023 -- N_Block_Statement declare block
2024 -- N_Entry_Body entry body
2025 -- N_Package_Body package body (begin part optional)
2026 -- N_Subprogram_Body procedure or function body
2027 -- N_Task_Body task body
2028
2029 -- Note: in the case of a block statement, there is definitely a DECLARE
2030 -- present (because a Begin statement without a DECLARE is handled by the
2031 -- P_Begin_Statement procedure, which does not call Parse_Decls_Begin_End.
2032
2033 -- Error recovery: cannot raise Error_Resync
2034
2035 procedure Parse_Decls_Begin_End (Parent : Node_Id) is
2036 Body_Decl : Node_Id;
2037 Decls : List_Id;
2038 Parent_Nkind : Node_Kind;
2039 Spec_Node : Node_Id;
2040 HSS : Node_Id;
2041
2042 procedure Missing_Begin (Msg : String);
2043 -- Called to post a missing begin message. In the normal case this is
2044 -- posted at the start of the current token. A special case arises when
2045 -- P_Declarative_Items has previously found a missing begin, in which
2046 -- case we replace the original error message.
2047
2048 procedure Set_Null_HSS (Parent : Node_Id);
2049 -- Construct an empty handled statement sequence and install in Parent
2050 -- Leaves HSS set to reference the newly constructed statement sequence.
2051
2052 -------------------
2053 -- Missing_Begin --
2054 -------------------
2055
2056 procedure Missing_Begin (Msg : String) is
2057 begin
2058 if Missing_Begin_Msg = No_Error_Msg then
2059 Error_Msg_BC (Msg);
2060 else
2061 Change_Error_Text (Missing_Begin_Msg, Msg);
2062
2063 -- Purge any messages issued after than, since a missing begin
2064 -- can cause a lot of havoc, and it is better not to dump these
2065 -- cascaded messages on the user.
2066
2067 Purge_Messages (Get_Location (Missing_Begin_Msg), Prev_Token_Ptr);
2068 end if;
2069 end Missing_Begin;
2070
2071 ------------------
2072 -- Set_Null_HSS --
2073 ------------------
2074
2075 procedure Set_Null_HSS (Parent : Node_Id) is
2076 Null_Stm : Node_Id;
2077
2078 begin
2079 Null_Stm :=
2080 Make_Null_Statement (Token_Ptr);
2081 Set_Comes_From_Source (Null_Stm, False);
2082
2083 HSS :=
2084 Make_Handled_Sequence_Of_Statements (Token_Ptr,
2085 Statements => New_List (Null_Stm));
2086 Set_Comes_From_Source (HSS, False);
2087
2088 Set_Handled_Statement_Sequence (Parent, HSS);
2089 end Set_Null_HSS;
2090
2091 -- Start of processing for Parse_Decls_Begin_End
2092
2093 begin
2094 Decls := P_Declarative_Part;
2095
2096 if Ada_Version = Ada_83 then
2097 Check_Later_Vs_Basic_Declarations (Decls, During_Parsing => True);
2098 end if;
2099
2100 -- Here is where we deal with the case of IS used instead of semicolon.
2101 -- Specifically, if the last declaration in the declarative part is a
2102 -- subprogram body still marked as having a bad IS, then this is where
2103 -- we decide that the IS should really have been a semicolon and that
2104 -- the body should have been a declaration. Note that if the bad IS
2105 -- had turned out to be OK (i.e. a decent begin/end was found for it),
2106 -- then the Bad_Is_Detected flag would have been reset by now.
2107
2108 Body_Decl := Last (Decls);
2109
2110 if Present (Body_Decl)
2111 and then Nkind (Body_Decl) = N_Subprogram_Body
2112 and then Bad_Is_Detected (Body_Decl)
2113 then
2114 -- OK, we have the case of a bad IS, so we need to fix up the tree.
2115 -- What we have now is a subprogram body with attached declarations
2116 -- and a possible statement sequence.
2117
2118 -- First step is to take the declarations that were part of the bogus
2119 -- subprogram body and append them to the outer declaration chain.
2120 -- In other words we append them past the body (which we will later
2121 -- convert into a declaration).
2122
2123 Append_List (Declarations (Body_Decl), Decls);
2124
2125 -- Now take the handled statement sequence of the bogus body and
2126 -- set it as the statement sequence for the outer construct. Note
2127 -- that it may be empty (we specially allowed a missing BEGIN for
2128 -- a subprogram body marked as having a bad IS -- see below).
2129
2130 Set_Handled_Statement_Sequence (Parent,
2131 Handled_Statement_Sequence (Body_Decl));
2132
2133 -- Next step is to convert the old body node to a declaration node
2134
2135 Spec_Node := Specification (Body_Decl);
2136 Change_Node (Body_Decl, N_Subprogram_Declaration);
2137 Set_Specification (Body_Decl, Spec_Node);
2138
2139 -- Final step is to put the declarations for the parent where
2140 -- they belong, and then fall through the IF to scan out the
2141 -- END statements.
2142
2143 Set_Declarations (Parent, Decls);
2144
2145 -- This is the normal case (i.e. any case except the bad IS case)
2146 -- If we have a BEGIN, then scan out the sequence of statements, and
2147 -- also reset the expected column for the END to match the BEGIN.
2148
2149 else
2150 Set_Declarations (Parent, Decls);
2151
2152 if Token = Tok_Begin then
2153 if Style_Check then
2154 Style.Check_Indentation;
2155 end if;
2156
2157 Error_Msg_Col := Scopes (Scope.Last).Ecol;
2158
2159 if RM_Column_Check
2160 and then Token_Is_At_Start_Of_Line
2161 and then Start_Column /= Error_Msg_Col
2162 then
2163 Error_Msg_SC ("(style) BEGIN in wrong column, should be@");
2164
2165 else
2166 Scopes (Scope.Last).Ecol := Start_Column;
2167 end if;
2168
2169 Scopes (Scope.Last).Sloc := Token_Ptr;
2170 Scan; -- past BEGIN
2171 Set_Handled_Statement_Sequence (Parent,
2172 P_Handled_Sequence_Of_Statements);
2173
2174 -- No BEGIN present
2175
2176 else
2177 Parent_Nkind := Nkind (Parent);
2178
2179 -- A special check for the missing IS case. If we have a
2180 -- subprogram body that was marked as having a suspicious
2181 -- IS, and the current token is END, then we simply confirm
2182 -- the suspicion, and do not require a BEGIN to be present
2183
2184 if Parent_Nkind = N_Subprogram_Body
2185 and then Token = Tok_End
2186 and then Scopes (Scope.Last).Etyp = E_Suspicious_Is
2187 then
2188 Scopes (Scope.Last).Etyp := E_Bad_Is;
2189
2190 -- Otherwise BEGIN is not required for a package body, so we
2191 -- don't mind if it is missing, but we do construct a dummy
2192 -- one (so that we have somewhere to set End_Label).
2193
2194 -- However if we have something other than a BEGIN which
2195 -- looks like it might be statements, then we signal a missing
2196 -- BEGIN for these cases as well. We define "something which
2197 -- looks like it might be statements" as a token other than
2198 -- END, EOF, or a token which starts declarations.
2199
2200 elsif Parent_Nkind = N_Package_Body
2201 and then (Token = Tok_End
2202 or else Token = Tok_EOF
2203 or else Token in Token_Class_Declk)
2204 then
2205 Set_Null_HSS (Parent);
2206
2207 -- These are cases in which a BEGIN is required and not present
2208
2209 else
2210 Set_Null_HSS (Parent);
2211
2212 -- Prepare to issue error message
2213
2214 Error_Msg_Sloc := Scopes (Scope.Last).Sloc;
2215 Error_Msg_Node_1 := Scopes (Scope.Last).Labl;
2216
2217 -- Now issue appropriate message
2218
2219 if Parent_Nkind = N_Block_Statement then
2220 Missing_Begin ("missing BEGIN for DECLARE#!");
2221
2222 elsif Parent_Nkind = N_Entry_Body then
2223 Missing_Begin ("missing BEGIN for ENTRY#!");
2224
2225 elsif Parent_Nkind = N_Subprogram_Body then
2226 if Nkind (Specification (Parent))
2227 = N_Function_Specification
2228 then
2229 Missing_Begin ("missing BEGIN for function&#!");
2230 else
2231 Missing_Begin ("missing BEGIN for procedure&#!");
2232 end if;
2233
2234 -- The case for package body arises only when
2235 -- we have possible statement junk present.
2236
2237 elsif Parent_Nkind = N_Package_Body then
2238 Missing_Begin ("missing BEGIN for package body&#!");
2239
2240 else
2241 pragma Assert (Parent_Nkind = N_Task_Body);
2242 Missing_Begin ("missing BEGIN for task body&#!");
2243 end if;
2244
2245 -- Here we pick up the statements after the BEGIN that
2246 -- should have been present but was not. We don't insist
2247 -- on statements being present if P_Declarative_Part had
2248 -- already found a missing BEGIN, since it might have
2249 -- swallowed a lone statement into the declarative part.
2250
2251 if Missing_Begin_Msg /= No_Error_Msg
2252 and then Token = Tok_End
2253 then
2254 null;
2255 else
2256 Set_Handled_Statement_Sequence (Parent,
2257 P_Handled_Sequence_Of_Statements);
2258 end if;
2259 end if;
2260 end if;
2261 end if;
2262
2263 -- Here with declarations and handled statement sequence scanned
2264
2265 if Present (Handled_Statement_Sequence (Parent)) then
2266 End_Statements (Handled_Statement_Sequence (Parent));
2267 else
2268 End_Statements;
2269 end if;
2270
2271 -- We know that End_Statements removed an entry from the scope stack
2272 -- (because it is required to do so under all circumstances). We can
2273 -- therefore reference the entry it removed one past the stack top.
2274 -- What we are interested in is whether it was a case of a bad IS.
2275 -- We can't call Scopes here.
2276
2277 if Scope.Table (Scope.Last + 1).Etyp = E_Bad_Is then
2278 Error_Msg -- CODEFIX
2279 ("|IS should be "";""", Scope.Table (Scope.Last + 1).S_Is);
2280 Set_Bad_Is_Detected (Parent, True);
2281 end if;
2282
2283 end Parse_Decls_Begin_End;
2284
2285 -------------------------
2286 -- Set_Loop_Block_Name --
2287 -------------------------
2288
2289 function Set_Loop_Block_Name (L : Character) return Name_Id is
2290 begin
2291 Name_Buffer (1) := L;
2292 Name_Buffer (2) := '_';
2293 Name_Len := 2;
2294 Loop_Block_Count := Loop_Block_Count + 1;
2295 Add_Nat_To_Name_Buffer (Loop_Block_Count);
2296 return Name_Find;
2297 end Set_Loop_Block_Name;
2298
2299 ---------------
2300 -- Then_Scan --
2301 ---------------
2302
2303 procedure Then_Scan is
2304 begin
2305 TF_Then;
2306
2307 while Token = Tok_Then loop
2308 Error_Msg_SC -- CODEFIX
2309 ("redundant THEN");
2310 TF_Then;
2311 end loop;
2312
2313 if Token = Tok_And or else Token = Tok_Or then
2314 Error_Msg_SC ("unexpected logical operator");
2315 Scan; -- past logical operator
2316
2317 if (Prev_Token = Tok_And and then Token = Tok_Then)
2318 or else
2319 (Prev_Token = Tok_Or and then Token = Tok_Else)
2320 then
2321 Scan;
2322 end if;
2323
2324 Discard_Junk_Node (P_Expression);
2325 end if;
2326
2327 if Token = Tok_Then then
2328 Scan;
2329 end if;
2330 end Then_Scan;
2331
2332 end Ch5;