1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2010, Free Software Foundation, Inc. --
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. --
21 -- GNAT was originally developed by the GNAT team at New York University. --
22 -- Extensive contributions were provided by Ada Core Technologies Inc. --
24 ------------------------------------------------------------------------------
26 pragma Style_Checks (All_Checks);
27 -- Turn off subprogram body ordering check. Subprograms are in order
28 -- by RM section rather than alphabetical
33 -- Local functions, used only in this chapter
35 function P_Case_Statement return Node_Id;
36 function P_Case_Statement_Alternative return Node_Id;
37 function P_Exit_Statement return Node_Id;
38 function P_Goto_Statement return Node_Id;
39 function P_If_Statement return Node_Id;
40 function P_Label return Node_Id;
41 function P_Loop_Parameter_Specification return Node_Id;
42 function P_Null_Statement return Node_Id;
44 function P_Assignment_Statement (LHS : Node_Id) return Node_Id;
45 -- Parse assignment statement. On entry, the caller has scanned the left
46 -- hand side (passed in as Lhs), and the colon-equal (or some symbol
47 -- taken to be an error equivalent such as equal).
49 function P_Begin_Statement (Block_Name : Node_Id := Empty) return Node_Id;
50 -- Parse begin-end statement. If Block_Name is non-Empty on entry, it is
51 -- the N_Identifier node for the label on the block. If Block_Name is
52 -- Empty on entry (the default), then the block statement is unlabeled.
54 function P_Declare_Statement (Block_Name : Node_Id := Empty) return Node_Id;
55 -- Parse declare block. If Block_Name is non-Empty on entry, it is
56 -- the N_Identifier node for the label on the block. If Block_Name is
57 -- Empty on entry (the default), then the block statement is unlabeled.
59 function P_For_Statement (Loop_Name : Node_Id := Empty) return Node_Id;
60 -- Parse for statement. If Loop_Name is non-Empty on entry, it is
61 -- the N_Identifier node for the label on the loop. If Loop_Name is
62 -- Empty on entry (the default), then the for statement is unlabeled.
64 function P_Loop_Statement (Loop_Name : Node_Id := Empty) return Node_Id;
65 -- Parse loop statement. If Loop_Name is non-Empty on entry, it is
66 -- the N_Identifier node for the label on the loop. If Loop_Name is
67 -- Empty on entry (the default), then the loop statement is unlabeled.
69 function P_While_Statement (Loop_Name : Node_Id := Empty) return Node_Id;
70 -- Parse while statement. If Loop_Name is non-Empty on entry, it is
71 -- the N_Identifier node for the label on the loop. If Loop_Name is
72 -- Empty on entry (the default), then the while statement is unlabeled.
74 function Set_Loop_Block_Name (L : Character) return Name_Id;
75 -- Given a letter 'L' for a loop or 'B' for a block, returns a name
76 -- of the form L_nn or B_nn where nn is a serial number obtained by
77 -- incrementing the variable Loop_Block_Count.
80 -- Scan past THEN token, testing for illegal junk after it
82 ---------------------------------
83 -- 5.1 Sequence of Statements --
84 ---------------------------------
86 -- SEQUENCE_OF_STATEMENTS ::= STATEMENT {STATEMENT} {LABEL}
87 -- Note: the final label is an Ada 2012 addition.
90 -- {LABEL} SIMPLE_STATEMENT | {LABEL} COMPOUND_STATEMENT
92 -- SIMPLE_STATEMENT ::= NULL_STATEMENT
93 -- | ASSIGNMENT_STATEMENT | EXIT_STATEMENT
94 -- | GOTO_STATEMENT | PROCEDURE_CALL_STATEMENT
95 -- | RETURN_STATEMENT | ENTRY_CALL_STATEMENT
96 -- | REQUEUE_STATEMENT | DELAY_STATEMENT
97 -- | ABORT_STATEMENT | RAISE_STATEMENT
100 -- COMPOUND_STATEMENT ::=
101 -- IF_STATEMENT | CASE_STATEMENT
102 -- | LOOP_STATEMENT | BLOCK_STATEMENT
103 -- | ACCEPT_STATEMENT | SELECT_STATEMENT
105 -- This procedure scans a sequence of statements. The caller sets SS_Flags
106 -- to indicate acceptable termination conditions for the sequence:
108 -- SS_Flags.Eftm Terminate on ELSIF
109 -- SS_Flags.Eltm Terminate on ELSE
110 -- SS_Flags.Extm Terminate on EXCEPTION
111 -- SS_Flags.Ortm Terminate on OR
112 -- SS_Flags.Tatm Terminate on THEN ABORT (Token = ABORT on return)
113 -- SS_Flags.Whtm Terminate on WHEN
114 -- SS_Flags.Unco Unconditional terminate after scanning one statement
116 -- In addition, the scan is always terminated by encountering END or the
117 -- end of file (EOF) condition. If one of the six above terminators is
118 -- encountered with the corresponding SS_Flags flag not set, then the
119 -- action taken is as follows:
121 -- If the keyword occurs to the left of the expected column of the end
122 -- for the current sequence (as recorded in the current end context),
123 -- then it is assumed to belong to an outer context, and is considered
124 -- to terminate the sequence of statements.
126 -- If the keyword occurs to the right of, or in the expected column of
127 -- the end for the current sequence, then an error message is output,
128 -- the keyword together with its associated context is skipped, and
129 -- the statement scan continues until another terminator is found.
131 -- Note that the first action means that control can return to the caller
132 -- with Token set to a terminator other than one of those specified by the
133 -- SS parameter. The caller should treat such a case as equivalent to END.
135 -- In addition, the flag SS_Flags.Sreq is set to True to indicate that at
136 -- least one real statement (other than a pragma) is required in the
137 -- statement sequence. During the processing of the sequence, this
138 -- flag is manipulated to indicate the current status of the requirement
139 -- for a statement. For example, it is turned off by the occurrence of a
140 -- statement, and back on by a label (which requires a following statement)
142 -- Error recovery: cannot raise Error_Resync. If an error occurs during
143 -- parsing a statement, then the scan pointer is advanced past the next
144 -- semicolon and the parse continues.
146 function P_Sequence_Of_Statements (SS_Flags : SS_Rec) return List_Id is
148 Statement_Required : Boolean;
149 -- This flag indicates if a subsequent statement (other than a pragma)
150 -- is required. It is initialized from the Sreq flag, and modified as
151 -- statements are scanned (a statement turns it off, and a label turns
152 -- it back on again since a statement must follow a label).
153 -- Note : this final requirement is lifted in Ada 2012.
155 Statement_Seen : Boolean;
156 -- In Ada 2012, a label can end a sequence of statements, but the
157 -- sequence cannot contain only labels. This flag is set whenever a
158 -- label is encountered, to enforce this rule at the end of a sequence.
160 Declaration_Found : Boolean := False;
161 -- This flag is set True if a declaration is encountered, so that the
162 -- error message about declarations in the statement part is only
163 -- given once for a given sequence of statements.
165 Scan_State_Label : Saved_Scan_State;
166 Scan_State : Saved_Scan_State;
168 Statement_List : List_Id;
169 Block_Label : Name_Id;
173 procedure Junk_Declaration;
174 -- Procedure called to handle error of declaration encountered in
175 -- statement sequence.
177 procedure Test_Statement_Required;
178 -- Flag error if Statement_Required flag set
180 ----------------------
181 -- Junk_Declaration --
182 ----------------------
184 procedure Junk_Declaration is
186 if (not Declaration_Found) or All_Errors_Mode then
187 Error_Msg_SC -- CODEFIX
188 ("declarations must come before BEGIN");
189 Declaration_Found := True;
192 Skip_Declaration (Statement_List);
193 end Junk_Declaration;
195 -----------------------------
196 -- Test_Statement_Required --
197 -----------------------------
199 procedure Test_Statement_Required is
200 function All_Pragmas return Boolean;
201 -- Return True if statement list is all pragmas
207 function All_Pragmas return Boolean is
210 S := First (Statement_List);
211 while Present (S) loop
212 if Nkind (S) /= N_Pragma then
222 -- Start of processing for Test_Statement_Required
225 if Statement_Required then
227 -- Check no statement required after label in Ada 2012, and that
228 -- it is OK to have nothing but pragmas in a statement sequence.
230 if Ada_Version >= Ada_2012
231 and then not Is_Empty_List (Statement_List)
233 ((Nkind (Last (Statement_List)) = N_Label
234 and then Statement_Seen)
238 Null_Stm : constant Node_Id :=
239 Make_Null_Statement (Token_Ptr);
241 Set_Comes_From_Source (Null_Stm, False);
242 Append_To (Statement_List, Null_Stm);
245 -- If not Ada 2012, or not special case above, give error message
248 Error_Msg_BC -- CODEFIX
249 ("statement expected");
252 end Test_Statement_Required;
254 -- Start of processing for P_Sequence_Of_Statements
257 Statement_List := New_List;
258 Statement_Required := SS_Flags.Sreq;
259 Statement_Seen := False;
262 Ignore (Tok_Semicolon);
266 Style.Check_Indentation;
269 -- Deal with reserved identifier (in assignment or call)
271 if Is_Reserved_Identifier then
272 Save_Scan_State (Scan_State); -- at possible bad identifier
273 Scan; -- and scan past it
275 -- We have an reserved word which is spelled in identifier
276 -- style, so the question is whether it really is intended
277 -- to be an identifier.
280 -- If followed by a semicolon, then it is an identifier,
281 -- with the exception of the cases tested for below.
283 (Token = Tok_Semicolon
284 and then Prev_Token /= Tok_Return
285 and then Prev_Token /= Tok_Null
286 and then Prev_Token /= Tok_Raise
287 and then Prev_Token /= Tok_End
288 and then Prev_Token /= Tok_Exit)
290 -- If followed by colon, colon-equal, or dot, then we
291 -- definitely have an identifier (could not be reserved)
293 or else Token = Tok_Colon
294 or else Token = Tok_Colon_Equal
295 or else Token = Tok_Dot
297 -- Left paren means we have an identifier except for those
298 -- reserved words that can legitimately be followed by a
302 (Token = Tok_Left_Paren
303 and then Prev_Token /= Tok_Case
304 and then Prev_Token /= Tok_Delay
305 and then Prev_Token /= Tok_If
306 and then Prev_Token /= Tok_Elsif
307 and then Prev_Token /= Tok_Return
308 and then Prev_Token /= Tok_When
309 and then Prev_Token /= Tok_While
310 and then Prev_Token /= Tok_Separate)
312 -- Here we have an apparent reserved identifier and the
313 -- token past it is appropriate to this usage (and would
314 -- be a definite error if this is not an identifier). What
315 -- we do is to use P_Identifier to fix up the identifier,
316 -- and then fall into the normal processing.
318 Restore_Scan_State (Scan_State); -- back to the ID
319 Scan_Reserved_Identifier (Force_Msg => False);
321 -- Not a reserved identifier after all (or at least we can't
322 -- be sure that it is), so reset the scan and continue.
325 Restore_Scan_State (Scan_State); -- back to the reserved word
329 -- Now look to see what kind of statement we have
333 -- Case of end or EOF
335 when Tok_End | Tok_EOF =>
337 -- These tokens always terminate the statement sequence
339 Test_Statement_Required;
346 -- Terminate if Eftm set or if the ELSIF is to the left
347 -- of the expected column of the end for this sequence
350 or else Start_Column < Scope.Table (Scope.Last).Ecol
352 Test_Statement_Required;
355 -- Otherwise complain and skip past ELSIF Condition then
358 Error_Msg_SC ("ELSIF not allowed here");
360 Discard_Junk_Node (P_Expression_No_Right_Paren);
362 Statement_Required := False;
369 -- Terminate if Eltm set or if the else is to the left
370 -- of the expected column of the end for this sequence
373 or else Start_Column < Scope.Table (Scope.Last).Ecol
375 Test_Statement_Required;
378 -- Otherwise complain and skip past else
381 Error_Msg_SC ("ELSE not allowed here");
383 Statement_Required := False;
388 when Tok_Exception =>
389 Test_Statement_Required;
391 -- If Extm not set and the exception is not to the left of
392 -- the expected column of the end for this sequence, then we
393 -- assume it belongs to the current sequence, even though it
396 if not SS_Flags.Extm and then
397 Start_Column >= Scope.Table (Scope.Last).Ecol
400 Error_Msg_SC ("exception handler not permitted here");
401 Scan; -- past EXCEPTION
402 Discard_Junk_List (Parse_Exception_Handlers);
405 -- Always return, in the case where we scanned out handlers
406 -- that we did not expect, Parse_Exception_Handlers returned
407 -- with Token being either end or EOF, so we are OK.
415 -- Terminate if Ortm set or if the or is to the left of the
416 -- expected column of the end for this sequence.
419 or else Start_Column < Scope.Table (Scope.Last).Ecol
421 Test_Statement_Required;
424 -- Otherwise complain and skip past or
427 Error_Msg_SC ("OR not allowed here");
429 Statement_Required := False;
432 -- Case of THEN (deal also with THEN ABORT)
435 Save_Scan_State (Scan_State); -- at THEN
438 -- Terminate if THEN ABORT allowed (ATC case)
440 exit when SS_Flags.Tatm and then Token = Tok_Abort;
442 -- Otherwise we treat THEN as some kind of mess where we did
443 -- not see the associated IF, but we pick up assuming it had
446 Restore_Scan_State (Scan_State); -- to THEN
447 Append_To (Statement_List, P_If_Statement);
448 Statement_Required := False;
450 -- Case of WHEN (error because we are not in a case)
452 when Tok_When | Tok_Others =>
454 -- Terminate if Whtm set or if the WHEN is to the left of
455 -- the expected column of the end for this sequence.
458 or else Start_Column < Scope.Table (Scope.Last).Ecol
460 Test_Statement_Required;
463 -- Otherwise complain and skip when Choice {| Choice} =>
466 Error_Msg_SC ("WHEN not allowed here");
468 Discard_Junk_List (P_Discrete_Choice_List);
470 Statement_Required := False;
473 -- Cases of statements starting with an identifier
475 when Tok_Identifier =>
478 -- Save scan pointers and line number in case block label
480 Id_Node := Token_Node;
481 Block_Label := Token_Name;
482 Save_Scan_State (Scan_State_Label); -- at possible label
485 -- Check for common case of assignment, since it occurs
486 -- frequently, and we want to process it efficiently.
488 if Token = Tok_Colon_Equal then
489 Scan; -- past the colon-equal
490 Append_To (Statement_List,
491 P_Assignment_Statement (Id_Node));
492 Statement_Required := False;
494 -- Check common case of procedure call, another case that
495 -- we want to speed up as much as possible.
497 elsif Token = Tok_Semicolon then
498 Append_To (Statement_List,
499 P_Statement_Name (Id_Node));
500 Scan; -- past semicolon
501 Statement_Required := False;
503 -- Check for case of "go to" in place of "goto"
505 elsif Token = Tok_Identifier
506 and then Block_Label = Name_Go
507 and then Token_Name = Name_To
509 Error_Msg_SP -- CODEFIX
510 ("goto is one word");
511 Append_To (Statement_List, P_Goto_Statement);
512 Statement_Required := False;
514 -- Check common case of = used instead of :=, just so we
515 -- give a better error message for this special misuse.
517 elsif Token = Tok_Equal then
518 T_Colon_Equal; -- give := expected message
519 Append_To (Statement_List,
520 P_Assignment_Statement (Id_Node));
521 Statement_Required := False;
523 -- Check case of loop label or block label
525 elsif Token = Tok_Colon
526 or else (Token in Token_Class_Labeled_Stmt
527 and then not Token_Is_At_Start_Of_Line)
529 T_Colon; -- past colon (if there, or msg for missing one)
531 -- Test for more than one label
534 exit when Token /= Tok_Identifier;
535 Save_Scan_State (Scan_State); -- at second Id
538 if Token = Tok_Colon then
540 ("only one label allowed on block or loop");
541 Scan; -- past colon on extra label
543 -- Use the second label as the "real" label
545 Scan_State_Label := Scan_State;
547 -- We will set Error_name as the Block_Label since
548 -- we really don't know which of the labels might
549 -- be used at the end of the loop or block!
551 Block_Label := Error_Name;
553 -- If Id with no colon, then backup to point to the
554 -- Id and we will issue the message below when we try
555 -- to scan out the statement as some other form.
558 Restore_Scan_State (Scan_State); -- to second Id
563 -- Loop_Statement (labeled Loop_Statement)
565 if Token = Tok_Loop then
566 Append_To (Statement_List,
567 P_Loop_Statement (Id_Node));
569 -- While statement (labeled loop statement with WHILE)
571 elsif Token = Tok_While then
572 Append_To (Statement_List,
573 P_While_Statement (Id_Node));
575 -- Declare statement (labeled block statement with
578 elsif Token = Tok_Declare then
579 Append_To (Statement_List,
580 P_Declare_Statement (Id_Node));
582 -- Begin statement (labeled block statement with no
585 elsif Token = Tok_Begin then
586 Append_To (Statement_List,
587 P_Begin_Statement (Id_Node));
589 -- For statement (labeled loop statement with FOR)
591 elsif Token = Tok_For then
592 Append_To (Statement_List,
593 P_For_Statement (Id_Node));
595 -- Improper statement follows label. If we have an
596 -- expression token, then assume the colon was part
597 -- of a misplaced declaration.
599 elsif Token not in Token_Class_Eterm then
600 Restore_Scan_State (Scan_State_Label);
603 -- Otherwise complain we have inappropriate statement
607 ("loop or block statement must follow label");
610 Statement_Required := False;
612 -- Here we have an identifier followed by something
613 -- other than a colon, semicolon or assignment symbol.
614 -- The only valid possibility is a name extension symbol
616 elsif Token in Token_Class_Namext then
617 Restore_Scan_State (Scan_State_Label); -- to Id
620 -- Skip junk right parens in this context
622 Ignore (Tok_Right_Paren);
624 -- Check context following call
626 if Token = Tok_Colon_Equal then
627 Scan; -- past colon equal
628 Append_To (Statement_List,
629 P_Assignment_Statement (Name_Node));
630 Statement_Required := False;
632 -- Check common case of = used instead of :=
634 elsif Token = Tok_Equal then
635 T_Colon_Equal; -- give := expected message
636 Append_To (Statement_List,
637 P_Assignment_Statement (Name_Node));
638 Statement_Required := False;
640 -- Check apostrophe cases
642 elsif Token = Tok_Apostrophe then
643 Append_To (Statement_List,
644 P_Code_Statement (Name_Node));
645 Statement_Required := False;
647 -- The only other valid item after a name is ; which
648 -- means that the item we just scanned was a call.
650 elsif Token = Tok_Semicolon then
651 Append_To (Statement_List,
652 P_Statement_Name (Name_Node));
653 Scan; -- past semicolon
654 Statement_Required := False;
656 -- A slash following an identifier or a selected
657 -- component in this situation is most likely a period
658 -- (see location of keys on keyboard).
660 elsif Token = Tok_Slash
661 and then (Nkind (Name_Node) = N_Identifier
663 Nkind (Name_Node) = N_Selected_Component)
665 Error_Msg_SC -- CODEFIX
666 ("""/"" should be "".""");
667 Statement_Required := False;
670 -- Else we have a missing semicolon
674 Statement_Required := False;
677 -- If junk after identifier, check if identifier is an
678 -- instance of an incorrectly spelled keyword. If so, we
679 -- do nothing. The Bad_Spelling_Of will have reset Token
680 -- to the appropriate keyword, so the next time round the
681 -- loop we will process the modified token. Note that we
682 -- check for ELSIF before ELSE here. That's not accidental.
683 -- We don't want to identify a misspelling of ELSE as
684 -- ELSIF, and in particular we do not want to treat ELSEIF
688 Restore_Scan_State (Scan_State_Label); -- to identifier
690 if Bad_Spelling_Of (Tok_Abort)
691 or else Bad_Spelling_Of (Tok_Accept)
692 or else Bad_Spelling_Of (Tok_Case)
693 or else Bad_Spelling_Of (Tok_Declare)
694 or else Bad_Spelling_Of (Tok_Delay)
695 or else Bad_Spelling_Of (Tok_Elsif)
696 or else Bad_Spelling_Of (Tok_Else)
697 or else Bad_Spelling_Of (Tok_End)
698 or else Bad_Spelling_Of (Tok_Exception)
699 or else Bad_Spelling_Of (Tok_Exit)
700 or else Bad_Spelling_Of (Tok_For)
701 or else Bad_Spelling_Of (Tok_Goto)
702 or else Bad_Spelling_Of (Tok_If)
703 or else Bad_Spelling_Of (Tok_Loop)
704 or else Bad_Spelling_Of (Tok_Or)
705 or else Bad_Spelling_Of (Tok_Pragma)
706 or else Bad_Spelling_Of (Tok_Raise)
707 or else Bad_Spelling_Of (Tok_Requeue)
708 or else Bad_Spelling_Of (Tok_Return)
709 or else Bad_Spelling_Of (Tok_Select)
710 or else Bad_Spelling_Of (Tok_When)
711 or else Bad_Spelling_Of (Tok_While)
715 -- If not a bad spelling, then we really have junk
718 Scan; -- past identifier again
720 -- If next token is first token on line, then we
721 -- consider that we were missing a semicolon after
722 -- the identifier, and process it as a procedure
723 -- call with no parameters.
725 if Token_Is_At_Start_Of_Line then
726 Append_To (Statement_List,
727 P_Statement_Name (Id_Node));
728 T_Semicolon; -- to give error message
729 Statement_Required := False;
731 -- Otherwise we give a missing := message and
732 -- simply abandon the junk that is there now.
735 T_Colon_Equal; -- give := expected message
742 -- Statement starting with operator symbol. This could be
743 -- a call, a name starting an assignment, or a qualified
746 when Tok_Operator_Symbol =>
750 -- An attempt at a range attribute or a qualified expression
751 -- must be illegal here (a code statement cannot possibly
752 -- allow qualification by a function name).
754 if Token = Tok_Apostrophe then
755 Error_Msg_SC ("apostrophe illegal here");
759 -- Scan possible assignment if we have a name
761 if Expr_Form = EF_Name
762 and then Token = Tok_Colon_Equal
764 Scan; -- past colon equal
765 Append_To (Statement_List,
766 P_Assignment_Statement (Name_Node));
768 Append_To (Statement_List,
769 P_Statement_Name (Name_Node));
773 Statement_Required := False;
775 -- Label starting with << which must precede real statement
776 -- Note: in Ada 2012, the label may end the sequence.
778 when Tok_Less_Less =>
779 if Present (Last (Statement_List))
780 and then Nkind (Last (Statement_List)) /= N_Label
782 Statement_Seen := True;
785 Append_To (Statement_List, P_Label);
786 Statement_Required := True;
788 -- Pragma appearing as a statement in a statement sequence
792 Append_To (Statement_List, P_Pragma);
798 Append_To (Statement_List, P_Abort_Statement);
799 Statement_Required := False;
805 Append_To (Statement_List, P_Accept_Statement);
806 Statement_Required := False;
808 -- Begin_Statement (Block_Statement with no declare, no label)
812 Append_To (Statement_List, P_Begin_Statement);
813 Statement_Required := False;
819 Append_To (Statement_List, P_Case_Statement);
820 Statement_Required := False;
822 -- Block_Statement with DECLARE and no label
826 Append_To (Statement_List, P_Declare_Statement);
827 Statement_Required := False;
833 Append_To (Statement_List, P_Delay_Statement);
834 Statement_Required := False;
840 Append_To (Statement_List, P_Exit_Statement);
841 Statement_Required := False;
843 -- Loop_Statement with FOR and no label
847 Append_To (Statement_List, P_For_Statement);
848 Statement_Required := False;
854 Append_To (Statement_List, P_Goto_Statement);
855 Statement_Required := False;
861 Append_To (Statement_List, P_If_Statement);
862 Statement_Required := False;
868 Append_To (Statement_List, P_Loop_Statement);
869 Statement_Required := False;
875 Append_To (Statement_List, P_Null_Statement);
876 Statement_Required := False;
882 Append_To (Statement_List, P_Raise_Statement);
883 Statement_Required := False;
889 Append_To (Statement_List, P_Requeue_Statement);
890 Statement_Required := False;
896 Append_To (Statement_List, P_Return_Statement);
897 Statement_Required := False;
903 Append_To (Statement_List, P_Select_Statement);
904 Statement_Required := False;
906 -- While_Statement (Block_Statement with while and no loop)
910 Append_To (Statement_List, P_While_Statement);
911 Statement_Required := False;
913 -- Anything else is some kind of junk, signal an error message
914 -- and then raise Error_Resync, to merge with the normal
915 -- handling of a bad statement.
919 if Token in Token_Class_Declk then
923 Error_Msg_BC -- CODEFIX
924 ("statement expected");
929 -- On error resynchronization, skip past next semicolon, and, since
930 -- we are still in the statement loop, look for next statement. We
931 -- set Statement_Required False to avoid an unnecessary error message
932 -- complaining that no statement was found (i.e. we consider the
933 -- junk to satisfy the requirement for a statement being present).
937 Resync_Past_Semicolon_Or_To_Loop_Or_Then;
938 Statement_Required := False;
941 exit when SS_Flags.Unco;
945 return Statement_List;
947 end P_Sequence_Of_Statements;
953 -- Parsed by P_Sequence_Of_Statements (5.1), except for the case
954 -- of a statement of the form of a name, which is handled here. The
955 -- argument passed in is the tree for the name which has been scanned
956 -- The returned value is the corresponding statement form.
958 -- This routine is also used by Par.Prag for processing the procedure
959 -- call that appears as the second argument of a pragma Assert.
961 -- Error recovery: cannot raise Error_Resync
963 function P_Statement_Name (Name_Node : Node_Id) return Node_Id is
967 -- Case of Indexed component, which is a procedure call with arguments
969 if Nkind (Name_Node) = N_Indexed_Component then
971 Prefix_Node : constant Node_Id := Prefix (Name_Node);
972 Exprs_Node : constant List_Id := Expressions (Name_Node);
975 Change_Node (Name_Node, N_Procedure_Call_Statement);
976 Set_Name (Name_Node, Prefix_Node);
977 Set_Parameter_Associations (Name_Node, Exprs_Node);
981 -- Case of function call node, which is a really a procedure call
983 elsif Nkind (Name_Node) = N_Function_Call then
985 Fname_Node : constant Node_Id := Name (Name_Node);
986 Params_List : constant List_Id :=
987 Parameter_Associations (Name_Node);
990 Change_Node (Name_Node, N_Procedure_Call_Statement);
991 Set_Name (Name_Node, Fname_Node);
992 Set_Parameter_Associations (Name_Node, Params_List);
996 -- Case of call to attribute that denotes a procedure. Here we
997 -- just leave the attribute reference unchanged.
999 elsif Nkind (Name_Node) = N_Attribute_Reference
1000 and then Is_Procedure_Attribute_Name (Attribute_Name (Name_Node))
1004 -- All other cases of names are parameterless procedure calls
1008 New_Node (N_Procedure_Call_Statement, Sloc (Name_Node));
1009 Set_Name (Stmt_Node, Name_Node);
1013 end P_Statement_Name;
1015 ---------------------------
1016 -- 5.1 Simple Statement --
1017 ---------------------------
1019 -- Parsed by P_Sequence_Of_Statements (5.1)
1021 -----------------------------
1022 -- 5.1 Compound Statement --
1023 -----------------------------
1025 -- Parsed by P_Sequence_Of_Statements (5.1)
1027 -------------------------
1028 -- 5.1 Null Statement --
1029 -------------------------
1031 -- NULL_STATEMENT ::= null;
1033 -- The caller has already checked that the current token is null
1035 -- Error recovery: cannot raise Error_Resync
1037 function P_Null_Statement return Node_Id is
1038 Null_Stmt_Node : Node_Id;
1041 Null_Stmt_Node := New_Node (N_Null_Statement, Token_Ptr);
1044 return Null_Stmt_Node;
1045 end P_Null_Statement;
1051 -- LABEL ::= <<label_STATEMENT_IDENTIFIER>>
1053 -- STATEMENT_IDENTIFIER ::= DIRECT_NAME
1055 -- The IDENTIFIER of a STATEMENT_IDENTIFIER shall be an identifier
1056 -- (not an OPERATOR_SYMBOL)
1058 -- The caller has already checked that the current token is <<
1060 -- Error recovery: can raise Error_Resync
1062 function P_Label return Node_Id is
1063 Label_Node : Node_Id;
1066 Label_Node := New_Node (N_Label, Token_Ptr);
1068 Set_Identifier (Label_Node, P_Identifier (C_Greater_Greater));
1070 Append_Elmt (Label_Node, Label_List);
1074 -------------------------------
1075 -- 5.1 Statement Identifier --
1076 -------------------------------
1078 -- Statement label is parsed by P_Label (5.1)
1080 -- Loop label is parsed by P_Loop_Statement (5.5), P_For_Statement (5.5)
1081 -- or P_While_Statement (5.5)
1083 -- Block label is parsed by P_Begin_Statement (5.6) or
1084 -- P_Declare_Statement (5.6)
1086 -------------------------------
1087 -- 5.2 Assignment Statement --
1088 -------------------------------
1090 -- ASSIGNMENT_STATEMENT ::=
1091 -- variable_NAME := EXPRESSION;
1093 -- Error recovery: can raise Error_Resync
1095 function P_Assignment_Statement (LHS : Node_Id) return Node_Id is
1096 Assign_Node : Node_Id;
1099 Assign_Node := New_Node (N_Assignment_Statement, Prev_Token_Ptr);
1100 Set_Name (Assign_Node, LHS);
1101 Set_Expression (Assign_Node, P_Expression_No_Right_Paren);
1104 end P_Assignment_Statement;
1106 -----------------------
1107 -- 5.3 If Statement --
1108 -----------------------
1111 -- if CONDITION then
1112 -- SEQUENCE_OF_STATEMENTS
1113 -- {elsif CONDITION then
1114 -- SEQUENCE_OF_STATEMENTS}
1116 -- SEQUENCE_OF_STATEMENTS]
1119 -- The caller has checked that the initial token is IF (or in the error
1120 -- case of a mysterious THEN, the initial token may simply be THEN, in
1121 -- which case, no condition (or IF) was scanned).
1123 -- Error recovery: can raise Error_Resync
1125 function P_If_Statement return Node_Id is
1127 Elsif_Node : Node_Id;
1130 procedure Add_Elsif_Part;
1131 -- An internal procedure used to scan out a single ELSIF part. On entry
1132 -- the ELSIF (or an ELSE which has been determined should be ELSIF) is
1133 -- scanned out and is in Prev_Token.
1135 procedure Check_If_Column;
1136 -- An internal procedure used to check that THEN, ELSE, or ELSIF
1137 -- appear in the right place if column checking is enabled (i.e. if
1138 -- they are the first token on the line, then they must appear in
1139 -- the same column as the opening IF).
1141 procedure Check_Then_Column;
1142 -- This procedure carries out the style checks for a THEN token
1143 -- Note that the caller has set Loc to the Source_Ptr value for
1144 -- the previous IF or ELSIF token. These checks apply only to a
1145 -- THEN at the start of a line.
1147 function Else_Should_Be_Elsif return Boolean;
1148 -- An internal routine used to do a special error recovery check when
1149 -- an ELSE is encountered. It determines if the ELSE should be treated
1150 -- as an ELSIF. A positive decision (TRUE returned, is made if the ELSE
1151 -- is followed by a sequence of tokens, starting on the same line as
1152 -- the ELSE, which are not expression terminators, followed by a THEN.
1153 -- On entry, the ELSE has been scanned out.
1155 procedure Add_Elsif_Part is
1157 if No (Elsif_Parts (If_Node)) then
1158 Set_Elsif_Parts (If_Node, New_List);
1161 Elsif_Node := New_Node (N_Elsif_Part, Prev_Token_Ptr);
1162 Loc := Prev_Token_Ptr;
1163 Set_Condition (Elsif_Node, P_Condition);
1167 (Elsif_Node, P_Sequence_Of_Statements (SS_Eftm_Eltm_Sreq));
1168 Append (Elsif_Node, Elsif_Parts (If_Node));
1171 procedure Check_If_Column is
1173 if RM_Column_Check and then Token_Is_At_Start_Of_Line
1174 and then Start_Column /= Scope.Table (Scope.Last).Ecol
1176 Error_Msg_Col := Scope.Table (Scope.Last).Ecol;
1177 Error_Msg_SC ("(style) this token should be@");
1179 end Check_If_Column;
1181 procedure Check_Then_Column is
1183 if Token_Is_At_Start_Of_Line and then Token = Tok_Then then
1187 Style.Check_Then (Loc);
1190 end Check_Then_Column;
1192 function Else_Should_Be_Elsif return Boolean is
1193 Scan_State : Saved_Scan_State;
1196 if Token_Is_At_Start_Of_Line then
1200 Save_Scan_State (Scan_State);
1203 if Token in Token_Class_Eterm then
1204 Restore_Scan_State (Scan_State);
1207 Scan; -- past non-expression terminating token
1209 if Token = Tok_Then then
1210 Restore_Scan_State (Scan_State);
1216 end Else_Should_Be_Elsif;
1218 -- Start of processing for P_If_Statement
1221 If_Node := New_Node (N_If_Statement, Token_Ptr);
1224 Scope.Table (Scope.Last).Etyp := E_If;
1225 Scope.Table (Scope.Last).Ecol := Start_Column;
1226 Scope.Table (Scope.Last).Sloc := Token_Ptr;
1227 Scope.Table (Scope.Last).Labl := Error;
1228 Scope.Table (Scope.Last).Node := If_Node;
1230 if Token = Tok_If then
1233 Set_Condition (If_Node, P_Condition);
1235 -- Deal with misuse of IF expression => used instead
1236 -- of WHEN expression =>
1238 if Token = Tok_Arrow then
1239 Error_Msg_SC -- CODEFIX
1241 Scan; -- past the arrow
1242 Pop_Scope_Stack; -- remove unneeded entry
1249 Error_Msg_SC ("no IF for this THEN");
1250 Set_Condition (If_Node, Error);
1256 (If_Node, P_Sequence_Of_Statements (SS_Eftm_Eltm_Sreq));
1258 -- This loop scans out else and elsif parts
1261 if Token = Tok_Elsif then
1264 if Present (Else_Statements (If_Node)) then
1265 Error_Msg_SP ("ELSIF cannot appear after ELSE");
1271 elsif Token = Tok_Else then
1275 if Else_Should_Be_Elsif then
1276 Error_Msg_SP -- CODEFIX
1277 ("ELSE should be ELSIF");
1281 -- Here we have an else that really is an else
1283 if Present (Else_Statements (If_Node)) then
1284 Error_Msg_SP ("only one ELSE part allowed");
1286 (P_Sequence_Of_Statements (SS_Eftm_Eltm_Sreq),
1287 Else_Statements (If_Node));
1290 (If_Node, P_Sequence_Of_Statements (SS_Eftm_Eltm_Sreq));
1294 -- If anything other than ELSE or ELSIF, exit the loop. The token
1295 -- had better be END (and in fact it had better be END IF), but
1296 -- we will let End_Statements take care of checking that.
1308 --------------------
1310 --------------------
1312 -- CONDITION ::= boolean_EXPRESSION
1314 function P_Condition return Node_Id is
1318 Cond := P_Expression_No_Right_Paren;
1320 -- It is never possible for := to follow a condition, so if we get
1321 -- a := we assume it is a mistyped equality. Note that we do not try
1322 -- to reconstruct the tree correctly in this case, but we do at least
1323 -- give an accurate error message.
1325 if Token = Tok_Colon_Equal then
1326 while Token = Tok_Colon_Equal loop
1327 Error_Msg_SC -- CODEFIX
1328 (""":="" should be ""=""");
1329 Scan; -- past junk :=
1330 Discard_Junk_Node (P_Expression_No_Right_Paren);
1335 -- Otherwise check for redundant parens
1339 and then Paren_Count (Cond) > 0
1341 Style.Check_Xtra_Parens (First_Sloc (Cond));
1344 -- And return the result
1350 -------------------------
1351 -- 5.4 Case Statement --
1352 -------------------------
1354 -- CASE_STATEMENT ::=
1355 -- case EXPRESSION is
1356 -- CASE_STATEMENT_ALTERNATIVE
1357 -- {CASE_STATEMENT_ALTERNATIVE}
1360 -- The caller has checked that the first token is CASE
1362 -- Can raise Error_Resync
1364 function P_Case_Statement return Node_Id is
1365 Case_Node : Node_Id;
1366 Alternatives_List : List_Id;
1367 First_When_Loc : Source_Ptr;
1370 Case_Node := New_Node (N_Case_Statement, Token_Ptr);
1373 Scope.Table (Scope.Last).Etyp := E_Case;
1374 Scope.Table (Scope.Last).Ecol := Start_Column;
1375 Scope.Table (Scope.Last).Sloc := Token_Ptr;
1376 Scope.Table (Scope.Last).Labl := Error;
1377 Scope.Table (Scope.Last).Node := Case_Node;
1380 Set_Expression (Case_Node, P_Expression_No_Right_Paren);
1383 -- Prepare to parse case statement alternatives
1385 Alternatives_List := New_List;
1386 P_Pragmas_Opt (Alternatives_List);
1387 First_When_Loc := Token_Ptr;
1389 -- Loop through case statement alternatives
1392 -- If we have a WHEN or OTHERS, then that's fine keep going. Note
1393 -- that it is a semantic check to ensure the proper use of OTHERS
1395 if Token = Tok_When or else Token = Tok_Others then
1396 Append (P_Case_Statement_Alternative, Alternatives_List);
1398 -- If we have an END, then probably we are at the end of the case
1399 -- but we only exit if Check_End thinks the END was reasonable.
1401 elsif Token = Tok_End then
1402 exit when Check_End;
1404 -- Here if token is other than WHEN, OTHERS or END. We definitely
1405 -- have an error, but the question is whether or not to get out of
1406 -- the case statement. We don't want to get out early, or we will
1407 -- get a slew of junk error messages for subsequent when tokens.
1409 -- If the token is not at the start of the line, or if it is indented
1410 -- with respect to the current case statement, then the best guess is
1411 -- that we are still supposed to be inside the case statement. We
1412 -- complain about the missing WHEN, and discard the junk statements.
1414 elsif not Token_Is_At_Start_Of_Line
1415 or else Start_Column > Scope.Table (Scope.Last).Ecol
1417 Error_Msg_BC ("WHEN (case statement alternative) expected");
1419 -- Here is a possibility for infinite looping if we don't make
1420 -- progress. So try to process statements, otherwise exit
1423 Error_Ptr : constant Source_Ptr := Scan_Ptr;
1425 Discard_Junk_List (P_Sequence_Of_Statements (SS_Whtm));
1426 exit when Scan_Ptr = Error_Ptr and then Check_End;
1429 -- Here we have a junk token at the start of the line and it is
1430 -- not indented. If Check_End thinks there is a missing END, then
1431 -- we will get out of the case, otherwise we keep going.
1434 exit when Check_End;
1438 -- Make sure we have at least one alternative
1440 if No (First_Non_Pragma (Alternatives_List)) then
1442 ("WHEN expected, must have at least one alternative in case",
1447 Set_Alternatives (Case_Node, Alternatives_List);
1450 end P_Case_Statement;
1452 -------------------------------------
1453 -- 5.4 Case Statement Alternative --
1454 -------------------------------------
1456 -- CASE_STATEMENT_ALTERNATIVE ::=
1457 -- when DISCRETE_CHOICE_LIST =>
1458 -- SEQUENCE_OF_STATEMENTS
1460 -- The caller has checked that the initial token is WHEN or OTHERS
1461 -- Error recovery: can raise Error_Resync
1463 function P_Case_Statement_Alternative return Node_Id is
1464 Case_Alt_Node : Node_Id;
1468 Style.Check_Indentation;
1471 Case_Alt_Node := New_Node (N_Case_Statement_Alternative, Token_Ptr);
1472 T_When; -- past WHEN (or give error in OTHERS case)
1473 Set_Discrete_Choices (Case_Alt_Node, P_Discrete_Choice_List);
1475 Set_Statements (Case_Alt_Node, P_Sequence_Of_Statements (SS_Sreq_Whtm));
1476 return Case_Alt_Node;
1477 end P_Case_Statement_Alternative;
1479 -------------------------
1480 -- 5.5 Loop Statement --
1481 -------------------------
1483 -- LOOP_STATEMENT ::=
1484 -- [LOOP_STATEMENT_IDENTIFIER:]
1485 -- [ITERATION_SCHEME] loop
1486 -- SEQUENCE_OF_STATEMENTS
1487 -- end loop [loop_IDENTIFIER];
1489 -- ITERATION_SCHEME ::=
1491 -- | for LOOP_PARAMETER_SPECIFICATION
1493 -- The parsing of loop statements is handled by one of three functions
1494 -- P_Loop_Statement, P_For_Statement or P_While_Statement depending
1495 -- on the initial keyword in the construct (excluding the identifier)
1499 -- This function parses the case where no iteration scheme is present
1501 -- The caller has checked that the initial token is LOOP. The parameter
1502 -- is the node identifiers for the loop label if any (or is set to Empty
1503 -- if there is no loop label).
1505 -- Error recovery : cannot raise Error_Resync
1507 function P_Loop_Statement (Loop_Name : Node_Id := Empty) return Node_Id is
1508 Loop_Node : Node_Id;
1509 Created_Name : Node_Id;
1513 Scope.Table (Scope.Last).Labl := Loop_Name;
1514 Scope.Table (Scope.Last).Ecol := Start_Column;
1515 Scope.Table (Scope.Last).Sloc := Token_Ptr;
1516 Scope.Table (Scope.Last).Etyp := E_Loop;
1518 Loop_Node := New_Node (N_Loop_Statement, Token_Ptr);
1521 if No (Loop_Name) then
1523 Make_Identifier (Sloc (Loop_Node),
1524 Chars => Set_Loop_Block_Name ('L'));
1525 Set_Comes_From_Source (Created_Name, False);
1526 Set_Has_Created_Identifier (Loop_Node, True);
1527 Set_Identifier (Loop_Node, Created_Name);
1528 Scope.Table (Scope.Last).Labl := Created_Name;
1530 Set_Identifier (Loop_Node, Loop_Name);
1533 Append_Elmt (Loop_Node, Label_List);
1534 Set_Statements (Loop_Node, P_Sequence_Of_Statements (SS_Sreq));
1535 End_Statements (Loop_Node);
1537 end P_Loop_Statement;
1541 -- This function parses a loop statement with a FOR iteration scheme
1543 -- The caller has checked that the initial token is FOR. The parameter
1544 -- is the node identifier for the block label if any (or is set to Empty
1545 -- if there is no block label).
1547 -- Note: the caller fills in the Identifier field if a label was present
1549 -- Error recovery: can raise Error_Resync
1551 function P_For_Statement (Loop_Name : Node_Id := Empty) return Node_Id is
1552 Loop_Node : Node_Id;
1553 Iter_Scheme_Node : Node_Id;
1554 Loop_For_Flag : Boolean;
1555 Created_Name : Node_Id;
1559 Scope.Table (Scope.Last).Labl := Loop_Name;
1560 Scope.Table (Scope.Last).Ecol := Start_Column;
1561 Scope.Table (Scope.Last).Sloc := Token_Ptr;
1562 Scope.Table (Scope.Last).Etyp := E_Loop;
1564 Loop_For_Flag := (Prev_Token = Tok_Loop);
1566 Iter_Scheme_Node := New_Node (N_Iteration_Scheme, Token_Ptr);
1567 Set_Loop_Parameter_Specification
1568 (Iter_Scheme_Node, P_Loop_Parameter_Specification);
1570 -- The following is a special test so that a miswritten for loop such
1571 -- as "loop for I in 1..10;" is handled nicely, without making an extra
1572 -- entry in the scope stack. We don't bother to actually fix up the
1573 -- tree in this case since it's not worth the effort. Instead we just
1574 -- eat up the loop junk, leaving the entry for what now looks like an
1575 -- unmodified loop intact.
1577 if Loop_For_Flag and then Token = Tok_Semicolon then
1578 Error_Msg_SC ("LOOP belongs here, not before FOR");
1585 Loop_Node := New_Node (N_Loop_Statement, Token_Ptr);
1587 if No (Loop_Name) then
1589 Make_Identifier (Sloc (Loop_Node),
1590 Chars => Set_Loop_Block_Name ('L'));
1591 Set_Comes_From_Source (Created_Name, False);
1592 Set_Has_Created_Identifier (Loop_Node, True);
1593 Set_Identifier (Loop_Node, Created_Name);
1594 Scope.Table (Scope.Last).Labl := Created_Name;
1596 Set_Identifier (Loop_Node, Loop_Name);
1600 Set_Statements (Loop_Node, P_Sequence_Of_Statements (SS_Sreq));
1601 End_Statements (Loop_Node);
1602 Set_Iteration_Scheme (Loop_Node, Iter_Scheme_Node);
1603 Append_Elmt (Loop_Node, Label_List);
1606 end P_For_Statement;
1608 -- P_While_Statement
1610 -- This procedure scans a loop statement with a WHILE iteration scheme
1612 -- The caller has checked that the initial token is WHILE. The parameter
1613 -- is the node identifier for the block label if any (or is set to Empty
1614 -- if there is no block label).
1616 -- Error recovery: cannot raise Error_Resync
1618 function P_While_Statement (Loop_Name : Node_Id := Empty) return Node_Id is
1619 Loop_Node : Node_Id;
1620 Iter_Scheme_Node : Node_Id;
1621 Loop_While_Flag : Boolean;
1622 Created_Name : Node_Id;
1626 Scope.Table (Scope.Last).Labl := Loop_Name;
1627 Scope.Table (Scope.Last).Ecol := Start_Column;
1628 Scope.Table (Scope.Last).Sloc := Token_Ptr;
1629 Scope.Table (Scope.Last).Etyp := E_Loop;
1631 Loop_While_Flag := (Prev_Token = Tok_Loop);
1632 Iter_Scheme_Node := New_Node (N_Iteration_Scheme, Token_Ptr);
1634 Set_Condition (Iter_Scheme_Node, P_Condition);
1636 -- The following is a special test so that a miswritten for loop such
1637 -- as "loop while I > 10;" is handled nicely, without making an extra
1638 -- entry in the scope stack. We don't bother to actually fix up the
1639 -- tree in this case since it's not worth the effort. Instead we just
1640 -- eat up the loop junk, leaving the entry for what now looks like an
1641 -- unmodified loop intact.
1643 if Loop_While_Flag and then Token = Tok_Semicolon then
1644 Error_Msg_SC ("LOOP belongs here, not before WHILE");
1651 Loop_Node := New_Node (N_Loop_Statement, Token_Ptr);
1654 if No (Loop_Name) then
1656 Make_Identifier (Sloc (Loop_Node),
1657 Chars => Set_Loop_Block_Name ('L'));
1658 Set_Comes_From_Source (Created_Name, False);
1659 Set_Has_Created_Identifier (Loop_Node, True);
1660 Set_Identifier (Loop_Node, Created_Name);
1661 Scope.Table (Scope.Last).Labl := Created_Name;
1663 Set_Identifier (Loop_Node, Loop_Name);
1666 Set_Statements (Loop_Node, P_Sequence_Of_Statements (SS_Sreq));
1667 End_Statements (Loop_Node);
1668 Set_Iteration_Scheme (Loop_Node, Iter_Scheme_Node);
1669 Append_Elmt (Loop_Node, Label_List);
1672 end P_While_Statement;
1674 ---------------------------------------
1675 -- 5.5 Loop Parameter Specification --
1676 ---------------------------------------
1678 -- LOOP_PARAMETER_SPECIFICATION ::=
1679 -- DEFINING_IDENTIFIER in [reverse] DISCRETE_SUBTYPE_DEFINITION
1681 -- Error recovery: cannot raise Error_Resync
1683 function P_Loop_Parameter_Specification return Node_Id is
1684 Loop_Param_Specification_Node : Node_Id;
1687 Scan_State : Saved_Scan_State;
1690 Loop_Param_Specification_Node :=
1691 New_Node (N_Loop_Parameter_Specification, Token_Ptr);
1693 Save_Scan_State (Scan_State);
1694 ID_Node := P_Defining_Identifier (C_In);
1695 Set_Defining_Identifier (Loop_Param_Specification_Node, ID_Node);
1697 if Token = Tok_Left_Paren then
1698 Error_Msg_SC ("subscripted loop parameter not allowed");
1699 Restore_Scan_State (Scan_State);
1700 Discard_Junk_Node (P_Name);
1702 elsif Token = Tok_Dot then
1703 Error_Msg_SC ("selected loop parameter not allowed");
1704 Restore_Scan_State (Scan_State);
1705 Discard_Junk_Node (P_Name);
1710 if Token = Tok_Reverse then
1711 Scan; -- past REVERSE
1712 Set_Reverse_Present (Loop_Param_Specification_Node, True);
1715 Set_Discrete_Subtype_Definition
1716 (Loop_Param_Specification_Node, P_Discrete_Subtype_Definition);
1717 return Loop_Param_Specification_Node;
1720 when Error_Resync =>
1722 end P_Loop_Parameter_Specification;
1724 --------------------------
1725 -- 5.6 Block Statement --
1726 --------------------------
1728 -- BLOCK_STATEMENT ::=
1729 -- [block_STATEMENT_IDENTIFIER:]
1731 -- DECLARATIVE_PART]
1733 -- HANDLED_SEQUENCE_OF_STATEMENTS
1734 -- end [block_IDENTIFIER];
1736 -- The parsing of block statements is handled by one of the two functions
1737 -- P_Declare_Statement or P_Begin_Statement depending on whether or not
1738 -- a declare section is present
1740 -- P_Declare_Statement
1742 -- This function parses a block statement with DECLARE present
1744 -- The caller has checked that the initial token is DECLARE
1746 -- Error recovery: cannot raise Error_Resync
1748 function P_Declare_Statement
1749 (Block_Name : Node_Id := Empty)
1752 Block_Node : Node_Id;
1753 Created_Name : Node_Id;
1756 Block_Node := New_Node (N_Block_Statement, Token_Ptr);
1759 Scope.Table (Scope.Last).Etyp := E_Name;
1760 Scope.Table (Scope.Last).Lreq := Present (Block_Name);
1761 Scope.Table (Scope.Last).Ecol := Start_Column;
1762 Scope.Table (Scope.Last).Labl := Block_Name;
1763 Scope.Table (Scope.Last).Sloc := Token_Ptr;
1765 Scan; -- past DECLARE
1767 if No (Block_Name) then
1769 Make_Identifier (Sloc (Block_Node),
1770 Chars => Set_Loop_Block_Name ('B'));
1771 Set_Comes_From_Source (Created_Name, False);
1772 Set_Has_Created_Identifier (Block_Node, True);
1773 Set_Identifier (Block_Node, Created_Name);
1774 Scope.Table (Scope.Last).Labl := Created_Name;
1776 Set_Identifier (Block_Node, Block_Name);
1779 Append_Elmt (Block_Node, Label_List);
1780 Parse_Decls_Begin_End (Block_Node);
1782 end P_Declare_Statement;
1784 -- P_Begin_Statement
1786 -- This function parses a block statement with no DECLARE present
1788 -- The caller has checked that the initial token is BEGIN
1790 -- Error recovery: cannot raise Error_Resync
1792 function P_Begin_Statement
1793 (Block_Name : Node_Id := Empty)
1796 Block_Node : Node_Id;
1797 Created_Name : Node_Id;
1800 Block_Node := New_Node (N_Block_Statement, Token_Ptr);
1803 Scope.Table (Scope.Last).Etyp := E_Name;
1804 Scope.Table (Scope.Last).Lreq := Present (Block_Name);
1805 Scope.Table (Scope.Last).Ecol := Start_Column;
1806 Scope.Table (Scope.Last).Labl := Block_Name;
1807 Scope.Table (Scope.Last).Sloc := Token_Ptr;
1809 if No (Block_Name) then
1811 Make_Identifier (Sloc (Block_Node),
1812 Chars => Set_Loop_Block_Name ('B'));
1813 Set_Comes_From_Source (Created_Name, False);
1814 Set_Has_Created_Identifier (Block_Node, True);
1815 Set_Identifier (Block_Node, Created_Name);
1816 Scope.Table (Scope.Last).Labl := Created_Name;
1818 Set_Identifier (Block_Node, Block_Name);
1821 Append_Elmt (Block_Node, Label_List);
1823 Scope.Table (Scope.Last).Ecol := Start_Column;
1824 Scope.Table (Scope.Last).Sloc := Token_Ptr;
1826 Set_Handled_Statement_Sequence
1827 (Block_Node, P_Handled_Sequence_Of_Statements);
1828 End_Statements (Handled_Statement_Sequence (Block_Node));
1830 end P_Begin_Statement;
1832 -------------------------
1833 -- 5.7 Exit Statement --
1834 -------------------------
1836 -- EXIT_STATEMENT ::=
1837 -- exit [loop_NAME] [when CONDITION];
1839 -- The caller has checked that the initial token is EXIT
1841 -- Error recovery: can raise Error_Resync
1843 function P_Exit_Statement return Node_Id is
1844 Exit_Node : Node_Id;
1846 function Missing_Semicolon_On_Exit return Boolean;
1847 -- This function deals with the following specialized situation
1850 -- exit [identifier]
1853 -- This looks like a messed up EXIT WHEN, when in fact the problem
1854 -- is a missing semicolon. It is called with Token pointing to the
1855 -- WHEN token, and returns True if a semicolon is missing before
1856 -- the WHEN as in the above example.
1858 -------------------------------
1859 -- Missing_Semicolon_On_Exit --
1860 -------------------------------
1862 function Missing_Semicolon_On_Exit return Boolean is
1863 State : Saved_Scan_State;
1866 if not Token_Is_At_Start_Of_Line then
1869 elsif Scope.Table (Scope.Last).Etyp /= E_Case then
1873 Save_Scan_State (State);
1875 Scan; -- past token after WHEN
1877 if Token = Tok_Arrow then
1878 Restore_Scan_State (State);
1881 Restore_Scan_State (State);
1885 end Missing_Semicolon_On_Exit;
1887 -- Start of processing for P_Exit_Statement
1890 Exit_Node := New_Node (N_Exit_Statement, Token_Ptr);
1893 if Token = Tok_Identifier then
1894 Set_Name (Exit_Node, P_Qualified_Simple_Name);
1896 elsif Style_Check then
1897 -- This EXIT has no name, so check that
1898 -- the innermost loop is unnamed too.
1900 Check_No_Exit_Name :
1901 for J in reverse 1 .. Scope.Last loop
1902 if Scope.Table (J).Etyp = E_Loop then
1903 if Present (Scope.Table (J).Labl)
1904 and then Comes_From_Source (Scope.Table (J).Labl)
1906 -- Innermost loop in fact had a name, style check fails
1908 Style.No_Exit_Name (Scope.Table (J).Labl);
1911 exit Check_No_Exit_Name;
1913 end loop Check_No_Exit_Name;
1916 if Token = Tok_When and then not Missing_Semicolon_On_Exit then
1918 Set_Condition (Exit_Node, P_Condition);
1920 -- Allow IF instead of WHEN, giving error message
1922 elsif Token = Tok_If then
1924 Scan; -- past IF used in place of WHEN
1925 Set_Condition (Exit_Node, P_Expression_No_Right_Paren);
1930 end P_Exit_Statement;
1932 -------------------------
1933 -- 5.8 Goto Statement --
1934 -------------------------
1936 -- GOTO_STATEMENT ::= goto label_NAME;
1938 -- The caller has checked that the initial token is GOTO (or TO in the
1939 -- error case where GO and TO were incorrectly separated).
1941 -- Error recovery: can raise Error_Resync
1943 function P_Goto_Statement return Node_Id is
1944 Goto_Node : Node_Id;
1947 Goto_Node := New_Node (N_Goto_Statement, Token_Ptr);
1948 Scan; -- past GOTO (or TO)
1949 Set_Name (Goto_Node, P_Qualified_Simple_Name_Resync);
1950 Append_Elmt (Goto_Node, Goto_List);
1954 end P_Goto_Statement;
1956 ---------------------------
1957 -- Parse_Decls_Begin_End --
1958 ---------------------------
1960 -- This function parses the construct:
1964 -- HANDLED_SEQUENCE_OF_STATEMENTS
1967 -- The caller has built the scope stack entry, and created the node to
1968 -- whose Declarations and Handled_Statement_Sequence fields are to be
1969 -- set. On return these fields are filled in (except in the case of a
1970 -- task body, where the handled statement sequence is optional, and may
1971 -- thus be Empty), and the scan is positioned past the End sequence.
1973 -- If the BEGIN is missing, then the parent node is used to help construct
1974 -- an appropriate missing BEGIN message. Possibilities for the parent are:
1976 -- N_Block_Statement declare block
1977 -- N_Entry_Body entry body
1978 -- N_Package_Body package body (begin part optional)
1979 -- N_Subprogram_Body procedure or function body
1980 -- N_Task_Body task body
1982 -- Note: in the case of a block statement, there is definitely a DECLARE
1983 -- present (because a Begin statement without a DECLARE is handled by the
1984 -- P_Begin_Statement procedure, which does not call Parse_Decls_Begin_End.
1986 -- Error recovery: cannot raise Error_Resync
1988 procedure Parse_Decls_Begin_End (Parent : Node_Id) is
1989 Body_Decl : Node_Id;
1990 Body_Sloc : Source_Ptr;
1993 Parent_Nkind : Node_Kind;
1994 Spec_Node : Node_Id;
1997 procedure Missing_Begin (Msg : String);
1998 -- Called to post a missing begin message. In the normal case this is
1999 -- posted at the start of the current token. A special case arises when
2000 -- P_Declarative_Items has previously found a missing begin, in which
2001 -- case we replace the original error message.
2003 procedure Set_Null_HSS (Parent : Node_Id);
2004 -- Construct an empty handled statement sequence and install in Parent
2005 -- Leaves HSS set to reference the newly constructed statement sequence.
2011 procedure Missing_Begin (Msg : String) is
2013 if Missing_Begin_Msg = No_Error_Msg then
2016 Change_Error_Text (Missing_Begin_Msg, Msg);
2018 -- Purge any messages issued after than, since a missing begin
2019 -- can cause a lot of havoc, and it is better not to dump these
2020 -- cascaded messages on the user.
2022 Purge_Messages (Get_Location (Missing_Begin_Msg), Prev_Token_Ptr);
2030 procedure Set_Null_HSS (Parent : Node_Id) is
2035 Make_Null_Statement (Token_Ptr);
2036 Set_Comes_From_Source (Null_Stm, False);
2039 Make_Handled_Sequence_Of_Statements (Token_Ptr,
2040 Statements => New_List (Null_Stm));
2041 Set_Comes_From_Source (HSS, False);
2043 Set_Handled_Statement_Sequence (Parent, HSS);
2046 -- Start of processing for Parse_Decls_Begin_End
2049 Decls := P_Declarative_Part;
2051 -- Check for misplacement of later vs basic declarations in Ada 83
2053 if Ada_Version = Ada_83 then
2054 Decl := First (Decls);
2056 -- Loop through sequence of basic declarative items
2058 Outer : while Present (Decl) loop
2059 if Nkind (Decl) /= N_Subprogram_Body
2060 and then Nkind (Decl) /= N_Package_Body
2061 and then Nkind (Decl) /= N_Task_Body
2062 and then Nkind (Decl) not in N_Body_Stub
2066 -- Once a body is encountered, we only allow later declarative
2067 -- items. The inner loop checks the rest of the list.
2070 Body_Sloc := Sloc (Decl);
2072 Inner : while Present (Decl) loop
2073 if Nkind (Decl) not in N_Later_Decl_Item
2074 and then Nkind (Decl) /= N_Pragma
2076 if Ada_Version = Ada_83 then
2077 Error_Msg_Sloc := Body_Sloc;
2079 ("(Ada 83) decl cannot appear after body#", Decl);
2089 -- Here is where we deal with the case of IS used instead of semicolon.
2090 -- Specifically, if the last declaration in the declarative part is a
2091 -- subprogram body still marked as having a bad IS, then this is where
2092 -- we decide that the IS should really have been a semicolon and that
2093 -- the body should have been a declaration. Note that if the bad IS
2094 -- had turned out to be OK (i.e. a decent begin/end was found for it),
2095 -- then the Bad_Is_Detected flag would have been reset by now.
2097 Body_Decl := Last (Decls);
2099 if Present (Body_Decl)
2100 and then Nkind (Body_Decl) = N_Subprogram_Body
2101 and then Bad_Is_Detected (Body_Decl)
2103 -- OK, we have the case of a bad IS, so we need to fix up the tree.
2104 -- What we have now is a subprogram body with attached declarations
2105 -- and a possible statement sequence.
2107 -- First step is to take the declarations that were part of the bogus
2108 -- subprogram body and append them to the outer declaration chain.
2109 -- In other words we append them past the body (which we will later
2110 -- convert into a declaration).
2112 Append_List (Declarations (Body_Decl), Decls);
2114 -- Now take the handled statement sequence of the bogus body and
2115 -- set it as the statement sequence for the outer construct. Note
2116 -- that it may be empty (we specially allowed a missing BEGIN for
2117 -- a subprogram body marked as having a bad IS -- see below).
2119 Set_Handled_Statement_Sequence (Parent,
2120 Handled_Statement_Sequence (Body_Decl));
2122 -- Next step is to convert the old body node to a declaration node
2124 Spec_Node := Specification (Body_Decl);
2125 Change_Node (Body_Decl, N_Subprogram_Declaration);
2126 Set_Specification (Body_Decl, Spec_Node);
2128 -- Final step is to put the declarations for the parent where
2129 -- they belong, and then fall through the IF to scan out the
2132 Set_Declarations (Parent, Decls);
2134 -- This is the normal case (i.e. any case except the bad IS case)
2135 -- If we have a BEGIN, then scan out the sequence of statements, and
2136 -- also reset the expected column for the END to match the BEGIN.
2139 Set_Declarations (Parent, Decls);
2141 if Token = Tok_Begin then
2143 Style.Check_Indentation;
2146 Error_Msg_Col := Scope.Table (Scope.Last).Ecol;
2149 and then Token_Is_At_Start_Of_Line
2150 and then Start_Column /= Error_Msg_Col
2152 Error_Msg_SC ("(style) BEGIN in wrong column, should be@");
2155 Scope.Table (Scope.Last).Ecol := Start_Column;
2158 Scope.Table (Scope.Last).Sloc := Token_Ptr;
2160 Set_Handled_Statement_Sequence (Parent,
2161 P_Handled_Sequence_Of_Statements);
2166 Parent_Nkind := Nkind (Parent);
2168 -- A special check for the missing IS case. If we have a
2169 -- subprogram body that was marked as having a suspicious
2170 -- IS, and the current token is END, then we simply confirm
2171 -- the suspicion, and do not require a BEGIN to be present
2173 if Parent_Nkind = N_Subprogram_Body
2174 and then Token = Tok_End
2175 and then Scope.Table (Scope.Last).Etyp = E_Suspicious_Is
2177 Scope.Table (Scope.Last).Etyp := E_Bad_Is;
2179 -- Otherwise BEGIN is not required for a package body, so we
2180 -- don't mind if it is missing, but we do construct a dummy
2181 -- one (so that we have somewhere to set End_Label).
2183 -- However if we have something other than a BEGIN which
2184 -- looks like it might be statements, then we signal a missing
2185 -- BEGIN for these cases as well. We define "something which
2186 -- looks like it might be statements" as a token other than
2187 -- END, EOF, or a token which starts declarations.
2189 elsif Parent_Nkind = N_Package_Body
2190 and then (Token = Tok_End
2191 or else Token = Tok_EOF
2192 or else Token in Token_Class_Declk)
2194 Set_Null_HSS (Parent);
2196 -- These are cases in which a BEGIN is required and not present
2199 Set_Null_HSS (Parent);
2201 -- Prepare to issue error message
2203 Error_Msg_Sloc := Scope.Table (Scope.Last).Sloc;
2204 Error_Msg_Node_1 := Scope.Table (Scope.Last).Labl;
2206 -- Now issue appropriate message
2208 if Parent_Nkind = N_Block_Statement then
2209 Missing_Begin ("missing BEGIN for DECLARE#!");
2211 elsif Parent_Nkind = N_Entry_Body then
2212 Missing_Begin ("missing BEGIN for ENTRY#!");
2214 elsif Parent_Nkind = N_Subprogram_Body then
2215 if Nkind (Specification (Parent))
2216 = N_Function_Specification
2218 Missing_Begin ("missing BEGIN for function&#!");
2220 Missing_Begin ("missing BEGIN for procedure&#!");
2223 -- The case for package body arises only when
2224 -- we have possible statement junk present.
2226 elsif Parent_Nkind = N_Package_Body then
2227 Missing_Begin ("missing BEGIN for package body&#!");
2230 pragma Assert (Parent_Nkind = N_Task_Body);
2231 Missing_Begin ("missing BEGIN for task body&#!");
2234 -- Here we pick up the statements after the BEGIN that
2235 -- should have been present but was not. We don't insist
2236 -- on statements being present if P_Declarative_Part had
2237 -- already found a missing BEGIN, since it might have
2238 -- swallowed a lone statement into the declarative part.
2240 if Missing_Begin_Msg /= No_Error_Msg
2241 and then Token = Tok_End
2245 Set_Handled_Statement_Sequence (Parent,
2246 P_Handled_Sequence_Of_Statements);
2252 -- Here with declarations and handled statement sequence scanned
2254 if Present (Handled_Statement_Sequence (Parent)) then
2255 End_Statements (Handled_Statement_Sequence (Parent));
2260 -- We know that End_Statements removed an entry from the scope stack
2261 -- (because it is required to do so under all circumstances). We can
2262 -- therefore reference the entry it removed one past the stack top.
2263 -- What we are interested in is whether it was a case of a bad IS.
2265 if Scope.Table (Scope.Last + 1).Etyp = E_Bad_Is then
2266 Error_Msg -- CODEFIX
2267 ("|IS should be "";""", Scope.Table (Scope.Last + 1).S_Is);
2268 Set_Bad_Is_Detected (Parent, True);
2271 end Parse_Decls_Begin_End;
2273 -------------------------
2274 -- Set_Loop_Block_Name --
2275 -------------------------
2277 function Set_Loop_Block_Name (L : Character) return Name_Id is
2279 Name_Buffer (1) := L;
2280 Name_Buffer (2) := '_';
2282 Loop_Block_Count := Loop_Block_Count + 1;
2283 Add_Nat_To_Name_Buffer (Loop_Block_Count);
2285 end Set_Loop_Block_Name;
2291 procedure Then_Scan is
2295 while Token = Tok_Then loop
2296 Error_Msg_SC -- CODEFIX
2301 if Token = Tok_And or else Token = Tok_Or then
2302 Error_Msg_SC ("unexpected logical operator");
2303 Scan; -- past logical operator
2305 if (Prev_Token = Tok_And and then Token = Tok_Then)
2307 (Prev_Token = Tok_Or and then Token = Tok_Else)
2312 Discard_Junk_Node (P_Expression);
2315 if Token = Tok_Then then