1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2011, 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
30 with Sinfo.CN; use Sinfo.CN;
35 -- Local subprograms, used only in this chapter
37 function P_Defining_Designator return Node_Id;
38 function P_Defining_Operator_Symbol return Node_Id;
39 function P_Return_Object_Declaration return Node_Id;
41 procedure P_Return_Subtype_Indication (Decl_Node : Node_Id);
42 -- Decl_Node is a N_Object_Declaration.
43 -- Set the Null_Exclusion_Present and Object_Definition fields of
46 procedure Check_Junk_Semicolon_Before_Return;
48 -- Check for common error of junk semicolon before RETURN keyword of
49 -- function specification. If present, skip over it with appropriate
50 -- error message, leaving Scan_Ptr pointing to the RETURN after. This
51 -- routine also deals with a possibly misspelled version of Return.
53 ----------------------------------------
54 -- Check_Junk_Semicolon_Before_Return --
55 ----------------------------------------
57 procedure Check_Junk_Semicolon_Before_Return is
58 Scan_State : Saved_Scan_State;
61 if Token = Tok_Semicolon then
62 Save_Scan_State (Scan_State);
63 Scan; -- past the semicolon
65 if Token = Tok_Return then
66 Restore_Scan_State (Scan_State);
67 Error_Msg_SC -- CODEFIX
68 ("|extra "";"" ignored");
69 Scan; -- rescan past junk semicolon
71 Restore_Scan_State (Scan_State);
74 elsif Bad_Spelling_Of (Tok_Return) then
77 end Check_Junk_Semicolon_Before_Return;
79 -----------------------------------------------------
80 -- 6.1 Subprogram (Also 6.3, 8.5.4, 10.1.3, 12.3) --
81 -----------------------------------------------------
83 -- This routine scans out a subprogram declaration, subprogram body,
84 -- subprogram renaming declaration or subprogram generic instantiation.
85 -- It also handles the new Ada 2012 expression function form
87 -- SUBPROGRAM_DECLARATION ::=
88 -- SUBPROGRAM_SPECIFICATION
89 -- [ASPECT_SPECIFICATIONS];
91 -- ABSTRACT_SUBPROGRAM_DECLARATION ::=
92 -- SUBPROGRAM_SPECIFICATION is abstract
93 -- [ASPECT_SPECIFICATIONS];
95 -- SUBPROGRAM_SPECIFICATION ::=
96 -- procedure DEFINING_PROGRAM_UNIT_NAME PARAMETER_PROFILE
97 -- | function DEFINING_DESIGNATOR PARAMETER_AND_RESULT_PROFILE
99 -- PARAMETER_PROFILE ::= [FORMAL_PART]
101 -- PARAMETER_AND_RESULT_PROFILE ::= [FORMAL_PART] return SUBTYPE_MARK
103 -- SUBPROGRAM_BODY ::=
104 -- SUBPROGRAM_SPECIFICATION is
107 -- HANDLED_SEQUENCE_OF_STATEMENTS
110 -- SUBPROGRAM_RENAMING_DECLARATION ::=
111 -- SUBPROGRAM_SPECIFICATION renames callable_entity_NAME;
113 -- SUBPROGRAM_BODY_STUB ::=
114 -- SUBPROGRAM_SPECIFICATION is separate;
116 -- GENERIC_INSTANTIATION ::=
117 -- procedure DEFINING_PROGRAM_UNIT_NAME is
118 -- new generic_procedure_NAME [GENERIC_ACTUAL_PART];
119 -- | function DEFINING_DESIGNATOR is
120 -- new generic_function_NAME [GENERIC_ACTUAL_PART];
122 -- NULL_PROCEDURE_DECLARATION ::=
123 -- SUBPROGRAM_SPECIFICATION is null;
125 -- Null procedures are an Ada 2005 feature. A null procedure declaration
126 -- is classified as a basic declarative item, but it is parsed here, with
127 -- other subprogram constructs.
129 -- EXPRESSION_FUNCTION ::=
130 -- FUNCTION SPECIFICATION IS (EXPRESSION);
132 -- The value in Pf_Flags indicates which of these possible declarations
133 -- is acceptable to the caller:
135 -- Pf_Flags.Decl Set if declaration OK
136 -- Pf_Flags.Gins Set if generic instantiation OK
137 -- Pf_Flags.Pbod Set if proper body OK
138 -- Pf_Flags.Rnam Set if renaming declaration OK
139 -- Pf_Flags.Stub Set if body stub OK
140 -- Pf_Flags.Pexp Set if expression function OK
142 -- If an inappropriate form is encountered, it is scanned out but an
143 -- error message indicating that it is appearing in an inappropriate
144 -- context is issued. The only possible values for Pf_Flags are those
145 -- defined as constants in the Par package.
147 -- The caller has checked that the initial token is FUNCTION, PROCEDURE,
148 -- NOT or OVERRIDING.
150 -- Error recovery: cannot raise Error_Resync
152 function P_Subprogram (Pf_Flags : Pf_Rec) return Node_Id is
153 Specification_Node : Node_Id;
155 Fpart_List : List_Id;
156 Fpart_Sloc : Source_Ptr;
157 Result_Not_Null : Boolean := False;
158 Result_Node : Node_Id;
162 Rename_Node : Node_Id;
163 Absdec_Node : Node_Id;
165 Fproc_Sloc : Source_Ptr;
167 Scan_State : Saved_Scan_State;
169 -- Flags for optional overriding indication. Two flags are needed,
170 -- to distinguish positive and negative overriding indicators from
171 -- the absence of any indicator.
173 Is_Overriding : Boolean := False;
174 Not_Overriding : Boolean := False;
177 -- Set up scope stack entry. Note that the Labl field will be set later
179 SIS_Entry_Active := False;
180 SIS_Missing_Semicolon_Message := No_Error_Msg;
182 Scope.Table (Scope.Last).Sloc := Token_Ptr;
183 Scope.Table (Scope.Last).Etyp := E_Name;
184 Scope.Table (Scope.Last).Ecol := Start_Column;
185 Scope.Table (Scope.Last).Lreq := False;
187 -- Ada 2005: Scan leading NOT OVERRIDING indicator
189 if Token = Tok_Not then
192 if Token = Tok_Overriding then
193 Scan; -- past OVERRIDING
194 Not_Overriding := True;
196 -- Overriding keyword used in non Ada 2005 mode
198 elsif Token = Tok_Identifier
199 and then Token_Name = Name_Overriding
201 Error_Msg_SC ("overriding indicator is an Ada 2005 extension");
202 Error_Msg_SC ("\unit must be compiled with -gnat05 switch");
203 Scan; -- past Overriding
204 Not_Overriding := True;
207 Error_Msg_SC -- CODEFIX
208 ("OVERRIDING expected!");
211 -- Ada 2005: scan leading OVERRIDING indicator
213 -- Note: in the case of OVERRIDING keyword used in Ada 95 mode, the
214 -- declaration circuit already gave an error message and changed the
215 -- token to Tok_Overriding.
217 elsif Token = Tok_Overriding then
218 Scan; -- past OVERRIDING
219 Is_Overriding := True;
222 if Is_Overriding or else Not_Overriding then
224 -- Note that if we are not in Ada_2005 mode, error messages have
225 -- already been given, so no need to give another message here.
227 -- An overriding indicator is allowed for subprogram declarations,
228 -- bodies (including subunits), renamings, stubs, and instantiations.
229 -- The test against Pf_Decl_Pbod is added to account for the case of
230 -- subprograms declared in a protected type, where only subprogram
231 -- declarations and bodies can occur. The Pf_Pbod case is for
234 if Pf_Flags /= Pf_Decl_Gins_Pbod_Rnam_Stub_Pexp
236 Pf_Flags /= Pf_Decl_Pbod_Pexp
238 Pf_Flags /= Pf_Pbod_Pexp
240 Error_Msg_SC ("overriding indicator not allowed here!");
242 elsif Token /= Tok_Function and then Token /= Tok_Procedure then
243 Error_Msg_SC -- CODEFIX
244 ("FUNCTION or PROCEDURE expected!");
248 Func := (Token = Tok_Function);
249 Fproc_Sloc := Token_Ptr;
250 Scan; -- past FUNCTION or PROCEDURE
255 Name_Node := P_Defining_Designator;
257 if Nkind (Name_Node) = N_Defining_Operator_Symbol
258 and then Scope.Last = 1
260 Error_Msg_SP ("operator symbol not allowed at library level");
261 Name_Node := New_Entity (N_Defining_Identifier, Sloc (Name_Node));
263 -- Set name from file name, we need some junk name, and that's
264 -- as good as anything. This is only approximate, since we do
265 -- not do anything with non-standard name translations.
267 Get_Name_String (File_Name (Current_Source_File));
269 for J in 1 .. Name_Len loop
270 if Name_Buffer (J) = '.' then
276 Set_Chars (Name_Node, Name_Find);
277 Set_Error_Posted (Name_Node);
281 Name_Node := P_Defining_Program_Unit_Name;
284 Scope.Table (Scope.Last).Labl := Name_Node;
287 -- Deal with generic instantiation, the one case in which we do not
288 -- have a subprogram specification as part of whatever we are parsing
290 if Token = Tok_Is then
291 Save_Scan_State (Scan_State); -- at the IS
292 T_Is; -- checks for redundant IS
294 if Token = Tok_New then
295 if not Pf_Flags.Gins then
296 Error_Msg_SC ("generic instantiation not allowed here!");
302 Inst_Node := New_Node (N_Function_Instantiation, Fproc_Sloc);
303 Set_Name (Inst_Node, P_Function_Name);
305 Inst_Node := New_Node (N_Procedure_Instantiation, Fproc_Sloc);
306 Set_Name (Inst_Node, P_Qualified_Simple_Name);
309 Set_Defining_Unit_Name (Inst_Node, Name_Node);
310 Set_Generic_Associations (Inst_Node, P_Generic_Actual_Part_Opt);
311 P_Aspect_Specifications (Inst_Node);
312 Pop_Scope_Stack; -- Don't need scope stack entry in this case
314 if Is_Overriding then
315 Set_Must_Override (Inst_Node);
317 elsif Not_Overriding then
318 Set_Must_Not_Override (Inst_Node);
324 Restore_Scan_State (Scan_State); -- to the IS
328 -- If not a generic instantiation, then we definitely have a subprogram
329 -- specification (all possibilities at this stage include one here)
331 Fpart_Sloc := Token_Ptr;
333 Check_Misspelling_Of (Tok_Return);
335 -- Scan formal part. First a special error check. If we have an
336 -- identifier here, then we have a definite error. If this identifier
337 -- is on the same line as the designator, then we assume it is the
338 -- first formal after a missing left parenthesis
340 if Token = Tok_Identifier
341 and then not Token_Is_At_Start_Of_Line
343 T_Left_Paren; -- to generate message
344 Fpart_List := P_Formal_Part;
346 -- Otherwise scan out an optional formal part in the usual manner
349 Fpart_List := P_Parameter_Profile;
352 -- We treat what we have as a function specification if FUNCTION was
353 -- used, or if a RETURN is present. This gives better error recovery
354 -- since later RETURN statements will be valid in either case.
356 Check_Junk_Semicolon_Before_Return;
357 Result_Node := Error;
359 if Token = Tok_Return then
362 ("PROCEDURE should be FUNCTION", Fproc_Sloc);
368 Result_Not_Null := P_Null_Exclusion; -- Ada 2005 (AI-231)
370 -- Ada 2005 (AI-318-02)
372 if Token = Tok_Access then
373 if Ada_Version < Ada_2005 then
375 ("anonymous access result type is an Ada 2005 extension");
376 Error_Msg_SC ("\unit must be compiled with -gnat05 switch");
379 Result_Node := P_Access_Definition (Result_Not_Null);
382 Result_Node := P_Subtype_Mark;
387 -- Skip extra parenthesis at end of formal part
389 Ignore (Tok_Right_Paren);
391 -- For function, scan result subtype
396 if Prev_Token = Tok_Return then
397 Result_Node := P_Subtype_Mark;
403 Specification_Node :=
404 New_Node (N_Function_Specification, Fproc_Sloc);
406 Set_Null_Exclusion_Present (Specification_Node, Result_Not_Null);
407 Set_Result_Definition (Specification_Node, Result_Node);
410 Specification_Node :=
411 New_Node (N_Procedure_Specification, Fproc_Sloc);
414 Set_Defining_Unit_Name (Specification_Node, Name_Node);
415 Set_Parameter_Specifications (Specification_Node, Fpart_List);
417 if Is_Overriding then
418 Set_Must_Override (Specification_Node);
420 elsif Not_Overriding then
421 Set_Must_Not_Override (Specification_Node);
424 -- Error check: barriers not allowed on protected functions/procedures
426 if Token = Tok_When then
428 Error_Msg_SC ("barrier not allowed on function, only on entry");
430 Error_Msg_SC ("barrier not allowed on procedure, only on entry");
434 Discard_Junk_Node (P_Expression);
437 -- Deal with semicolon followed by IS. We want to treat this as IS
439 if Token = Tok_Semicolon then
440 Save_Scan_State (Scan_State);
441 Scan; -- past semicolon
443 if Token = Tok_Is then
444 Error_Msg_SP -- CODEFIX
445 ("extra "";"" ignored");
447 Restore_Scan_State (Scan_State);
451 -- Subprogram declaration ended by aspect specifications
453 if Aspect_Specifications_Present then
454 goto Subprogram_Declaration;
456 -- Deal with case of semicolon ending a subprogram declaration
458 elsif Token = Tok_Semicolon then
459 if not Pf_Flags.Decl then
463 Save_Scan_State (Scan_State);
464 Scan; -- past semicolon
466 -- If semicolon is immediately followed by IS, then ignore the
467 -- semicolon, and go process the body.
469 if Token = Tok_Is then
470 Error_Msg_SP -- CODEFIX
471 ("|extra "";"" ignored");
472 T_Is; -- scan past IS
473 goto Subprogram_Body;
475 -- If BEGIN follows in an appropriate column, we immediately
476 -- commence the error action of assuming that the previous
477 -- subprogram declaration should have been a subprogram body,
478 -- i.e. that the terminating semicolon should have been IS.
480 elsif Token = Tok_Begin
481 and then Start_Column >= Scope.Table (Scope.Last).Ecol
483 Error_Msg_SP -- CODEFIX
484 ("|"";"" should be IS!");
485 goto Subprogram_Body;
488 Restore_Scan_State (Scan_State);
489 goto Subprogram_Declaration;
492 -- Case of not followed by semicolon
495 -- Subprogram renaming declaration case
497 Check_Misspelling_Of (Tok_Renames);
499 if Token = Tok_Renames then
500 if not Pf_Flags.Rnam then
501 Error_Msg_SC ("renaming declaration not allowed here!");
505 New_Node (N_Subprogram_Renaming_Declaration, Token_Ptr);
506 Scan; -- past RENAMES
507 Set_Name (Rename_Node, P_Name);
508 Set_Specification (Rename_Node, Specification_Node);
513 -- Case of IS following subprogram specification
515 elsif Token = Tok_Is then
516 T_Is; -- ignore redundant Is's
518 if Token_Name = Name_Abstract then
519 Check_95_Keyword (Tok_Abstract, Tok_Semicolon);
522 -- Deal nicely with (now obsolete) use of <> in place of abstract
524 if Token = Tok_Box then
525 Error_Msg_SC -- CODEFIX
526 ("ABSTRACT expected");
527 Token := Tok_Abstract;
530 -- Abstract subprogram declaration case
532 if Token = Tok_Abstract then
534 New_Node (N_Abstract_Subprogram_Declaration, Token_Ptr);
535 Set_Specification (Absdec_Node, Specification_Node);
536 Pop_Scope_Stack; -- discard unneeded entry
537 Scan; -- past ABSTRACT
538 P_Aspect_Specifications (Absdec_Node);
541 -- Ada 2005 (AI-248): Parse a null procedure declaration
543 elsif Token = Tok_Null then
544 if Ada_Version < Ada_2005 then
545 Error_Msg_SP ("null procedures are an Ada 2005 extension");
546 Error_Msg_SP ("\unit must be compiled with -gnat05 switch");
552 Error_Msg_SP ("only procedures can be null");
554 Set_Null_Present (Specification_Node);
557 goto Subprogram_Declaration;
559 -- Check for IS NEW with Formal_Part present and handle nicely
561 elsif Token = Tok_New then
563 ("formal part not allowed in instantiation", Fpart_Sloc);
567 Inst_Node := New_Node (N_Function_Instantiation, Fproc_Sloc);
570 New_Node (N_Procedure_Instantiation, Fproc_Sloc);
573 Set_Defining_Unit_Name (Inst_Node, Name_Node);
574 Set_Name (Inst_Node, P_Name);
575 Set_Generic_Associations (Inst_Node, P_Generic_Actual_Part_Opt);
577 Pop_Scope_Stack; -- Don't need scope stack entry in this case
581 goto Subprogram_Body;
584 -- Aspect specifications present
586 elsif Aspect_Specifications_Present then
587 goto Subprogram_Declaration;
589 -- Here we have a missing IS or missing semicolon, we always guess
590 -- a missing semicolon, since we are pretty good at fixing up a
591 -- semicolon which should really be an IS
594 Error_Msg_AP -- CODEFIX
596 SIS_Missing_Semicolon_Message := Get_Msg_Id;
597 goto Subprogram_Declaration;
601 -- Processing for stub or subprogram body or expression function
605 -- Subprogram body stub case
607 if Separate_Present then
608 if not Pf_Flags.Stub then
609 Error_Msg_SC ("body stub not allowed here!");
612 if Nkind (Name_Node) = N_Defining_Operator_Symbol then
614 ("operator symbol cannot be used as subunit name",
619 New_Node (N_Subprogram_Body_Stub, Sloc (Specification_Node));
620 Set_Specification (Stub_Node, Specification_Node);
621 Scan; -- past SEPARATE
626 -- Subprogram body or expression function case
629 Scan_Body_Or_Expression_Function : declare
631 Body_Is_Hidden_In_SPARK : Boolean;
632 Hidden_Region_Start : Source_Ptr;
634 function Likely_Expression_Function return Boolean;
635 -- Returns True if we have a probable case of an expression
636 -- function omitting the parentheses, if so, returns True
637 -- and emits an appropriate error message, else returns False.
639 --------------------------------
640 -- Likely_Expression_Function --
641 --------------------------------
643 function Likely_Expression_Function return Boolean is
645 -- If currently pointing to BEGIN or a declaration keyword
646 -- or a pragma, then we definitely have a subprogram body.
647 -- This is a common case, so worth testing first.
650 or else Token in Token_Class_Declk
651 or else Token = Tok_Pragma
655 -- Test for tokens which could only start an expression and
656 -- thus signal the case of a expression function.
658 elsif Token in Token_Class_Literal
659 or else Token in Token_Class_Unary_Addop
660 or else Token = Tok_Left_Paren
661 or else Token = Tok_Abs
662 or else Token = Tok_Null
663 or else Token = Tok_New
664 or else Token = Tok_Not
668 -- Anything other than an identifier must be a body
670 elsif Token /= Tok_Identifier then
673 -- Here for an identifier
676 -- If the identifier is the first token on its line, then
677 -- let's assume that we have a missing begin and this is
678 -- intended as a subprogram body. However, if the context
679 -- is a function and the unit is a package declaration, a
680 -- body would be illegal, so try for an unparenthesized
681 -- expression function.
683 if Token_Is_At_Start_Of_Line then
685 -- The enclosing scope entry is a subprogram spec
687 Spec_Node : constant Node_Id :=
689 (Scope.Table (Scope.Last).Labl);
690 Lib_Node : Node_Id := Spec_Node;
693 -- Check whether there is an enclosing scope that
694 -- is a package declaration.
696 if Scope.Last > 1 then
698 Parent (Scope.Table (Scope.Last - 1).Labl);
701 if Ada_Version >= Ada_2012
703 Nkind (Lib_Node) = N_Package_Specification
705 Nkind (Spec_Node) = N_Function_Specification
713 -- Otherwise we have to scan ahead. If the identifier is
714 -- followed by a colon or a comma, it is a declaration
715 -- and hence we have a subprogram body. Otherwise assume
716 -- a expression function.
720 Scan_State : Saved_Scan_State;
724 Save_Scan_State (Scan_State);
725 Scan; -- past identifier
727 Restore_Scan_State (Scan_State);
729 if Tok = Tok_Colon or else Tok = Tok_Comma then
736 -- Fall through if we have a likely expression function
739 ("expression function must be enclosed in parentheses");
741 end Likely_Expression_Function;
743 -- Start of processing for Scan_Body_Or_Expression_Function
746 -- Expression_Function case
748 if Token = Tok_Left_Paren
749 or else Likely_Expression_Function
751 -- Check expression function allowed here
753 if not Pf_Flags.Pexp then
754 Error_Msg_SC ("expression function not allowed here!");
757 -- Check we are in Ada 2012 mode
759 if Ada_Version < Ada_2012 then
761 ("expression function is an Ada 2012 feature!");
763 ("\unit must be compiled with -gnat2012 switch!");
766 -- Parse out expression and build expression function
770 (N_Expression_Function, Sloc (Specification_Node));
771 Set_Specification (Body_Node, Specification_Node);
772 Set_Expression (Body_Node, P_Expression);
776 -- Subprogram body case
779 -- Check body allowed here
781 if not Pf_Flags.Pbod then
782 Error_Msg_SP ("subprogram body not allowed here!");
785 -- Here is the test for a suspicious IS (i.e. one that
786 -- looks like it might more properly be a semicolon).
787 -- See separate section describing use of IS instead
788 -- of semicolon in package Parse.
790 if (Token in Token_Class_Declk
792 Token = Tok_Identifier)
793 and then Start_Column <= Scope.Table (Scope.Last).Ecol
794 and then Scope.Last /= 1
796 Scope.Table (Scope.Last).Etyp := E_Suspicious_Is;
797 Scope.Table (Scope.Last).S_Is := Prev_Token_Ptr;
800 -- Build and return subprogram body, parsing declarations
801 -- and statement sequence that belong to the body.
804 New_Node (N_Subprogram_Body, Sloc (Specification_Node));
805 Set_Specification (Body_Node, Specification_Node);
807 -- In SPARK, a HIDE directive can be placed at the beginning
808 -- of a subprogram implementation, thus hiding the
809 -- subprogram body from SPARK tool-set. No violation of the
810 -- SPARK restriction should be issued on nodes in a hidden
811 -- part, which is obtained by marking such hidden parts.
813 if Token = Tok_SPARK_Hide then
814 Body_Is_Hidden_In_SPARK := True;
815 Hidden_Region_Start := Token_Ptr;
816 Scan; -- past HIDE directive
818 Body_Is_Hidden_In_SPARK := False;
821 Parse_Decls_Begin_End (Body_Node);
823 if Body_Is_Hidden_In_SPARK then
824 Set_Hidden_Part_In_SPARK (Hidden_Region_Start, Token_Ptr);
829 end Scan_Body_Or_Expression_Function;
832 -- Processing for subprogram declaration
834 <<Subprogram_Declaration>>
836 New_Node (N_Subprogram_Declaration, Sloc (Specification_Node));
837 Set_Specification (Decl_Node, Specification_Node);
838 P_Aspect_Specifications (Decl_Node);
840 -- If this is a context in which a subprogram body is permitted,
841 -- set active SIS entry in case (see section titled "Handling
842 -- Semicolon Used in Place of IS" in body of Parser package)
843 -- Note that SIS_Missing_Semicolon_Message is already set properly.
845 if Pf_Flags.Pbod then
846 SIS_Labl := Scope.Table (Scope.Last).Labl;
847 SIS_Sloc := Scope.Table (Scope.Last).Sloc;
848 SIS_Ecol := Scope.Table (Scope.Last).Ecol;
849 SIS_Declaration_Node := Decl_Node;
850 SIS_Semicolon_Sloc := Prev_Token_Ptr;
851 SIS_Entry_Active := True;
858 ---------------------------------
859 -- 6.1 Subprogram Declaration --
860 ---------------------------------
862 -- Parsed by P_Subprogram (6.1)
864 ------------------------------------------
865 -- 6.1 Abstract Subprogram Declaration --
866 ------------------------------------------
868 -- Parsed by P_Subprogram (6.1)
870 -----------------------------------
871 -- 6.1 Subprogram Specification --
872 -----------------------------------
874 -- SUBPROGRAM_SPECIFICATION ::=
875 -- procedure DEFINING_PROGRAM_UNIT_NAME PARAMETER_PROFILE
876 -- | function DEFINING_DESIGNATOR PARAMETER_AND_RESULT_PROFILE
878 -- PARAMETER_PROFILE ::= [FORMAL_PART]
880 -- PARAMETER_AND_RESULT_PROFILE ::= [FORMAL_PART] return SUBTYPE_MARK
882 -- Subprogram specifications that appear in subprogram declarations
883 -- are parsed by P_Subprogram (6.1). This routine is used in other
884 -- contexts where subprogram specifications occur.
886 -- Note: this routine does not affect the scope stack in any way
888 -- Error recovery: can raise Error_Resync
890 function P_Subprogram_Specification return Node_Id is
891 Specification_Node : Node_Id;
892 Result_Not_Null : Boolean;
893 Result_Node : Node_Id;
896 if Token = Tok_Function then
897 Specification_Node := New_Node (N_Function_Specification, Token_Ptr);
898 Scan; -- past FUNCTION
900 Set_Defining_Unit_Name (Specification_Node, P_Defining_Designator);
901 Set_Parameter_Specifications
902 (Specification_Node, P_Parameter_Profile);
903 Check_Junk_Semicolon_Before_Return;
906 Result_Not_Null := P_Null_Exclusion; -- Ada 2005 (AI-231)
908 -- Ada 2005 (AI-318-02)
910 if Token = Tok_Access then
911 if Ada_Version < Ada_2005 then
913 ("anonymous access result type is an Ada 2005 extension");
914 Error_Msg_SC ("\unit must be compiled with -gnat05 switch");
917 Result_Node := P_Access_Definition (Result_Not_Null);
920 Result_Node := P_Subtype_Mark;
924 Set_Null_Exclusion_Present (Specification_Node, Result_Not_Null);
925 Set_Result_Definition (Specification_Node, Result_Node);
926 return Specification_Node;
928 elsif Token = Tok_Procedure then
929 Specification_Node := New_Node (N_Procedure_Specification, Token_Ptr);
930 Scan; -- past PROCEDURE
932 Set_Defining_Unit_Name
933 (Specification_Node, P_Defining_Program_Unit_Name);
934 Set_Parameter_Specifications
935 (Specification_Node, P_Parameter_Profile);
936 return Specification_Node;
939 Error_Msg_SC ("subprogram specification expected");
942 end P_Subprogram_Specification;
944 ---------------------
946 ---------------------
949 -- [PARENT_UNIT_NAME .] IDENTIFIER | OPERATOR_SYMBOL
951 -- The caller has checked that the initial token is an identifier,
952 -- operator symbol, or string literal. Note that we don't bother to
953 -- do much error diagnosis in this routine, since it is only used for
954 -- the label on END lines, and the routines in package Par.Endh will
955 -- check that the label is appropriate.
957 -- Error recovery: cannot raise Error_Resync
959 function P_Designator return Node_Id is
960 Ident_Node : Node_Id;
962 Prefix_Node : Node_Id;
964 function Real_Dot return Boolean;
965 -- Tests if a current token is an interesting period, i.e. is followed
966 -- by an identifier or operator symbol or string literal. If not, it is
967 -- probably just incorrect punctuation to be caught by our caller. Note
968 -- that the case of an operator symbol or string literal is also an
969 -- error, but that is an error that we catch here. If the result is
970 -- True, a real dot has been scanned and we are positioned past it,
971 -- if the result is False, the scan position is unchanged.
977 function Real_Dot return Boolean is
978 Scan_State : Saved_Scan_State;
981 if Token /= Tok_Dot then
985 Save_Scan_State (Scan_State);
988 if Token = Tok_Identifier
989 or else Token = Tok_Operator_Symbol
990 or else Token = Tok_String_Literal
995 Restore_Scan_State (Scan_State);
1001 -- Start of processing for P_Designator
1004 Ident_Node := Token_Node;
1005 Scan; -- past initial token
1007 if Prev_Token = Tok_Operator_Symbol
1008 or else Prev_Token = Tok_String_Literal
1009 or else not Real_Dot
1016 Prefix_Node := Ident_Node;
1018 -- Loop through child names, on entry to this loop, Prefix contains
1019 -- the name scanned so far, and Ident_Node is the last identifier.
1022 Name_Node := New_Node (N_Selected_Component, Prev_Token_Ptr);
1023 Set_Prefix (Name_Node, Prefix_Node);
1024 Ident_Node := P_Identifier;
1025 Set_Selector_Name (Name_Node, Ident_Node);
1026 Prefix_Node := Name_Node;
1027 exit when not Real_Dot;
1030 -- On exit from the loop, Ident_Node is the last identifier scanned,
1031 -- i.e. the defining identifier, and Prefix_Node is a node for the
1032 -- entire name, structured (incorrectly!) as a selected component.
1034 Name_Node := Prefix (Prefix_Node);
1035 Change_Node (Prefix_Node, N_Designator);
1036 Set_Name (Prefix_Node, Name_Node);
1037 Set_Identifier (Prefix_Node, Ident_Node);
1042 when Error_Resync =>
1043 while Token = Tok_Dot or else Token = Tok_Identifier loop
1050 ------------------------------
1051 -- 6.1 Defining Designator --
1052 ------------------------------
1054 -- DEFINING_DESIGNATOR ::=
1055 -- DEFINING_PROGRAM_UNIT_NAME | DEFINING_OPERATOR_SYMBOL
1057 -- Error recovery: cannot raise Error_Resync
1059 function P_Defining_Designator return Node_Id is
1061 if Token = Tok_Operator_Symbol then
1062 return P_Defining_Operator_Symbol;
1064 elsif Token = Tok_String_Literal then
1065 Error_Msg_SC ("invalid operator name");
1066 Scan; -- past junk string
1070 return P_Defining_Program_Unit_Name;
1072 end P_Defining_Designator;
1074 -------------------------------------
1075 -- 6.1 Defining Program Unit Name --
1076 -------------------------------------
1078 -- DEFINING_PROGRAM_UNIT_NAME ::=
1079 -- [PARENT_UNIT_NAME .] DEFINING_IDENTIFIER
1081 -- Note: PARENT_UNIT_NAME may be present only in 95 mode at the outer level
1083 -- Error recovery: cannot raise Error_Resync
1085 function P_Defining_Program_Unit_Name return Node_Id is
1086 Ident_Node : Node_Id;
1087 Name_Node : Node_Id;
1088 Prefix_Node : Node_Id;
1091 -- Set identifier casing if not already set and scan initial identifier
1093 if Token = Tok_Identifier
1094 and then Identifier_Casing (Current_Source_File) = Unknown
1096 Set_Identifier_Casing (Current_Source_File, Determine_Token_Casing);
1099 Ident_Node := P_Identifier (C_Dot);
1100 Merge_Identifier (Ident_Node, Tok_Return);
1102 -- Normal case (not child library unit name)
1104 if Token /= Tok_Dot then
1105 Change_Identifier_To_Defining_Identifier (Ident_Node);
1108 -- Child library unit name case
1111 if Scope.Last > 1 then
1112 Error_Msg_SP ("child unit allowed only at library level");
1115 elsif Ada_Version = Ada_83 then
1116 Error_Msg_SP ("(Ada 83) child unit not allowed!");
1120 Prefix_Node := Ident_Node;
1122 -- Loop through child names, on entry to this loop, Prefix contains
1123 -- the name scanned so far, and Ident_Node is the last identifier.
1126 exit when Token /= Tok_Dot;
1127 Name_Node := New_Node (N_Selected_Component, Token_Ptr);
1128 Scan; -- past period
1129 Set_Prefix (Name_Node, Prefix_Node);
1130 Ident_Node := P_Identifier (C_Dot);
1131 Set_Selector_Name (Name_Node, Ident_Node);
1132 Prefix_Node := Name_Node;
1135 -- On exit from the loop, Ident_Node is the last identifier scanned,
1136 -- i.e. the defining identifier, and Prefix_Node is a node for the
1137 -- entire name, structured (incorrectly!) as a selected component.
1139 Name_Node := Prefix (Prefix_Node);
1140 Change_Node (Prefix_Node, N_Defining_Program_Unit_Name);
1141 Set_Name (Prefix_Node, Name_Node);
1142 Change_Identifier_To_Defining_Identifier (Ident_Node);
1143 Set_Defining_Identifier (Prefix_Node, Ident_Node);
1145 -- All set with unit name parsed
1151 when Error_Resync =>
1152 while Token = Tok_Dot or else Token = Tok_Identifier loop
1157 end P_Defining_Program_Unit_Name;
1159 --------------------------
1160 -- 6.1 Operator Symbol --
1161 --------------------------
1163 -- OPERATOR_SYMBOL ::= STRING_LITERAL
1165 -- Operator symbol is returned by the scanner as Tok_Operator_Symbol
1167 -----------------------------------
1168 -- 6.1 Defining Operator Symbol --
1169 -----------------------------------
1171 -- DEFINING_OPERATOR_SYMBOL ::= OPERATOR_SYMBOL
1173 -- The caller has checked that the initial symbol is an operator symbol
1175 function P_Defining_Operator_Symbol return Node_Id is
1179 Op_Node := Token_Node;
1180 Change_Operator_Symbol_To_Defining_Operator_Symbol (Op_Node);
1181 Scan; -- past operator symbol
1183 end P_Defining_Operator_Symbol;
1185 ----------------------------
1186 -- 6.1 Parameter_Profile --
1187 ----------------------------
1189 -- PARAMETER_PROFILE ::= [FORMAL_PART]
1191 -- Empty is returned if no formal part is present
1193 -- Error recovery: cannot raise Error_Resync
1195 function P_Parameter_Profile return List_Id is
1197 if Token = Tok_Left_Paren then
1198 Scan; -- part left paren
1199 return P_Formal_Part;
1203 end P_Parameter_Profile;
1205 ---------------------------------------
1206 -- 6.1 Parameter And Result Profile --
1207 ---------------------------------------
1209 -- Parsed by its parent construct, which uses P_Parameter_Profile to
1210 -- parse the parameters, and P_Subtype_Mark to parse the return type.
1212 ----------------------
1213 -- 6.1 Formal part --
1214 ----------------------
1216 -- FORMAL_PART ::= (PARAMETER_SPECIFICATION {; PARAMETER_SPECIFICATION})
1218 -- PARAMETER_SPECIFICATION ::=
1219 -- DEFINING_IDENTIFIER_LIST : [ALIASED] MODE [NULL_EXCLUSION]
1220 -- SUBTYPE_MARK [:= DEFAULT_EXPRESSION]
1221 -- | DEFINING_IDENTIFIER_LIST : ACCESS_DEFINITION
1222 -- [:= DEFAULT_EXPRESSION]
1224 -- This scans the construct Formal_Part. The caller has already checked
1225 -- that the initial token is a left parenthesis, and skipped past it, so
1226 -- that on entry Token is the first token following the left parenthesis.
1228 -- Note: The ALIASED keyword is allowed only in Ada 2012 mode (AI 142)
1230 -- Error recovery: cannot raise Error_Resync
1232 function P_Formal_Part return List_Id is
1233 Specification_List : List_Id;
1234 Specification_Node : Node_Id;
1235 Scan_State : Saved_Scan_State;
1238 Ident_Sloc : Source_Ptr;
1239 Not_Null_Present : Boolean := False;
1240 Not_Null_Sloc : Source_Ptr;
1242 Idents : array (Int range 1 .. 4096) of Entity_Id;
1243 -- This array holds the list of defining identifiers. The upper bound
1244 -- of 4096 is intended to be essentially infinite, and we do not even
1245 -- bother to check for it being exceeded.
1248 Specification_List := New_List;
1249 Specification_Loop : loop
1251 if Token = Tok_Pragma then
1252 Error_Msg_SC ("pragma not allowed in formal part");
1253 Discard_Junk_Node (P_Pragma (Skipping => True));
1256 Ignore (Tok_Left_Paren);
1257 Ident_Sloc := Token_Ptr;
1258 Idents (1) := P_Defining_Identifier (C_Comma_Colon);
1262 exit Ident_Loop when Token = Tok_Colon;
1264 -- The only valid tokens are colon and comma, so if we have
1265 -- neither do a bit of investigation to see which is the
1266 -- better choice for insertion.
1268 if Token /= Tok_Comma then
1270 -- Assume colon if ALIASED, IN or OUT keyword found
1272 exit Ident_Loop when Token = Tok_Aliased or else
1273 Token = Tok_In or else
1276 -- Otherwise scan ahead
1278 Save_Scan_State (Scan_State);
1281 -- If we run into a semicolon, then assume that a
1282 -- colon was missing, e.g. Parms (X Y; ...). Also
1283 -- assume missing colon on EOF (a real disaster!)
1284 -- and on a right paren, e.g. Parms (X Y), and also
1285 -- on an assignment symbol, e.g. Parms (X Y := ..)
1287 if Token = Tok_Semicolon
1288 or else Token = Tok_Right_Paren
1289 or else Token = Tok_EOF
1290 or else Token = Tok_Colon_Equal
1292 Restore_Scan_State (Scan_State);
1295 -- If we run into a colon, assume that we had a missing
1296 -- comma, e.g. Parms (A B : ...). Also assume a missing
1297 -- comma if we hit another comma, e.g. Parms (A B, C ..)
1299 elsif Token = Tok_Colon
1300 or else Token = Tok_Comma
1302 Restore_Scan_State (Scan_State);
1307 end loop Look_Ahead;
1310 -- Here if a comma is present, or to be assumed
1313 Num_Idents := Num_Idents + 1;
1314 Idents (Num_Idents) := P_Defining_Identifier (C_Comma_Colon);
1315 end loop Ident_Loop;
1317 -- Fall through the loop on encountering a colon, or deciding
1318 -- that there is a missing colon.
1322 -- If there are multiple identifiers, we repeatedly scan the
1323 -- type and initialization expression information by resetting
1324 -- the scan pointer (so that we get completely separate trees
1325 -- for each occurrence).
1327 if Num_Idents > 1 then
1328 Save_Scan_State (Scan_State);
1331 -- Loop through defining identifiers in list
1335 Ident_List_Loop : loop
1336 Specification_Node :=
1337 New_Node (N_Parameter_Specification, Ident_Sloc);
1338 Set_Defining_Identifier (Specification_Node, Idents (Ident));
1340 -- Scan possible ALIASED for Ada 2012 (AI-142)
1342 if Token = Tok_Aliased then
1343 if Ada_Version < Ada_2012 then
1344 Error_Msg_SC ("ALIASED parameter is an Ada 2012 feature");
1346 Set_Aliased_Present (Specification_Node);
1349 Scan; -- past ALIASED
1352 -- Scan possible NOT NULL for Ada 2005 (AI-231, AI-447)
1354 Not_Null_Sloc := Token_Ptr;
1356 P_Null_Exclusion (Allow_Anonymous_In_95 => True);
1358 -- Case of ACCESS keyword present
1360 if Token = Tok_Access then
1361 Set_Null_Exclusion_Present
1362 (Specification_Node, Not_Null_Present);
1364 if Ada_Version = Ada_83 then
1365 Error_Msg_SC ("(Ada 83) access parameters not allowed");
1369 (Specification_Node,
1370 P_Access_Definition (Not_Null_Present));
1372 -- Case of IN or OUT present
1375 if Token = Tok_In or else Token = Tok_Out then
1376 if Not_Null_Present then
1378 ("`NOT NULL` can only be used with `ACCESS`",
1381 if Token = Tok_In then
1383 ("\`IN` not allowed together with `ACCESS`",
1387 ("\`OUT` not allowed together with `ACCESS`",
1392 P_Mode (Specification_Node);
1393 Not_Null_Present := P_Null_Exclusion; -- Ada 2005 (AI-231)
1396 Set_Null_Exclusion_Present
1397 (Specification_Node, Not_Null_Present);
1399 if Token = Tok_Procedure
1401 Token = Tok_Function
1403 Error_Msg_SC ("formal subprogram parameter not allowed");
1406 if Token = Tok_Left_Paren then
1407 Discard_Junk_List (P_Formal_Part);
1410 if Token = Tok_Return then
1412 Discard_Junk_Node (P_Subtype_Mark);
1415 Set_Parameter_Type (Specification_Node, Error);
1418 Set_Parameter_Type (Specification_Node, P_Subtype_Mark);
1423 Set_Expression (Specification_Node, Init_Expr_Opt (True));
1426 Set_Prev_Ids (Specification_Node, True);
1429 if Ident < Num_Idents then
1430 Set_More_Ids (Specification_Node, True);
1433 Append (Specification_Node, Specification_List);
1434 exit Ident_List_Loop when Ident = Num_Idents;
1436 Restore_Scan_State (Scan_State);
1437 end loop Ident_List_Loop;
1440 when Error_Resync =>
1441 Resync_Semicolon_List;
1444 if Token = Tok_Semicolon then
1445 Save_Scan_State (Scan_State);
1446 Scan; -- past semicolon
1448 -- If we have RETURN or IS after the semicolon, then assume
1449 -- that semicolon should have been a right parenthesis and exit
1451 if Token = Tok_Is or else Token = Tok_Return then
1452 Error_Msg_SP -- CODEFIX
1453 ("|"";"" should be "")""");
1454 exit Specification_Loop;
1457 -- If we have a declaration keyword after the semicolon, then
1458 -- assume we had a missing right parenthesis and terminate list
1460 if Token in Token_Class_Declk then
1461 Error_Msg_AP -- CODEFIX
1463 Restore_Scan_State (Scan_State);
1464 exit Specification_Loop;
1467 elsif Token = Tok_Right_Paren then
1468 Scan; -- past right paren
1469 exit Specification_Loop;
1471 -- Special check for common error of using comma instead of semicolon
1473 elsif Token = Tok_Comma then
1477 -- Special check for omitted separator
1479 elsif Token = Tok_Identifier then
1482 -- If nothing sensible, skip to next semicolon or right paren
1486 Resync_Semicolon_List;
1488 if Token = Tok_Semicolon then
1489 Scan; -- past semicolon
1492 exit Specification_Loop;
1495 end loop Specification_Loop;
1497 return Specification_List;
1500 ----------------------------------
1501 -- 6.1 Parameter Specification --
1502 ----------------------------------
1504 -- Parsed by P_Formal_Part (6.1)
1510 -- MODE ::= [in] | in out | out
1512 -- There is no explicit node in the tree for the Mode. Instead the
1513 -- In_Present and Out_Present flags are set in the parent node to
1514 -- record the presence of keywords specifying the mode.
1516 -- Error_Recovery: cannot raise Error_Resync
1518 procedure P_Mode (Node : Node_Id) is
1520 if Token = Tok_In then
1522 Set_In_Present (Node, True);
1524 if Style.Mode_In_Check and then Token /= Tok_Out then
1525 Error_Msg_SP -- CODEFIX
1526 ("(style) IN should be omitted");
1529 if Token = Tok_Access then
1530 Error_Msg_SP ("IN not allowed together with ACCESS");
1531 Scan; -- past ACCESS
1535 if Token = Tok_Out then
1537 Set_Out_Present (Node, True);
1540 if Token = Tok_In then
1541 Error_Msg_SC ("IN must precede OUT in parameter mode");
1543 Set_In_Present (Node, True);
1547 --------------------------
1548 -- 6.3 Subprogram Body --
1549 --------------------------
1551 -- Parsed by P_Subprogram (6.1)
1553 -----------------------------------
1554 -- 6.4 Procedure Call Statement --
1555 -----------------------------------
1557 -- Parsed by P_Sequence_Of_Statements (5.1)
1559 ------------------------
1560 -- 6.4 Function Call --
1561 ------------------------
1563 -- Parsed by P_Name (4.1)
1565 --------------------------------
1566 -- 6.4 Actual Parameter Part --
1567 --------------------------------
1569 -- Parsed by P_Name (4.1)
1571 --------------------------------
1572 -- 6.4 Parameter Association --
1573 --------------------------------
1575 -- Parsed by P_Name (4.1)
1577 ------------------------------------
1578 -- 6.4 Explicit Actual Parameter --
1579 ------------------------------------
1581 -- Parsed by P_Name (4.1)
1583 ---------------------------
1584 -- 6.5 Return Statement --
1585 ---------------------------
1587 -- SIMPLE_RETURN_STATEMENT ::= return [EXPRESSION];
1589 -- EXTENDED_RETURN_STATEMENT ::=
1590 -- return DEFINING_IDENTIFIER : [aliased] RETURN_SUBTYPE_INDICATION
1591 -- [:= EXPRESSION] [do
1592 -- HANDLED_SEQUENCE_OF_STATEMENTS
1595 -- RETURN_SUBTYPE_INDICATION ::= SUBTYPE_INDICATION | ACCESS_DEFINITION
1597 -- RETURN_STATEMENT ::= return [EXPRESSION];
1599 -- Error recovery: can raise Error_Resync
1601 procedure P_Return_Subtype_Indication (Decl_Node : Node_Id) is
1603 -- Note: We don't need to check Ada_Version here, because this is
1604 -- only called in >= Ada 2005 cases anyway.
1606 Not_Null_Present : constant Boolean := P_Null_Exclusion;
1609 Set_Null_Exclusion_Present (Decl_Node, Not_Null_Present);
1611 if Token = Tok_Access then
1612 Set_Object_Definition
1613 (Decl_Node, P_Access_Definition (Not_Null_Present));
1615 Set_Object_Definition
1616 (Decl_Node, P_Subtype_Indication (Not_Null_Present));
1618 end P_Return_Subtype_Indication;
1620 -- Error recovery: can raise Error_Resync
1622 function P_Return_Object_Declaration return Node_Id is
1623 Return_Obj : Node_Id;
1624 Decl_Node : Node_Id;
1627 Return_Obj := Token_Node;
1628 Change_Identifier_To_Defining_Identifier (Return_Obj);
1629 Decl_Node := New_Node (N_Object_Declaration, Token_Ptr);
1630 Set_Defining_Identifier (Decl_Node, Return_Obj);
1632 Scan; -- past identifier
1635 -- First an error check, if we have two identifiers in a row, a likely
1636 -- possibility is that the first of the identifiers is an incorrectly
1637 -- spelled keyword. See similar check in P_Identifier_Declarations.
1639 if Token = Tok_Identifier then
1641 SS : Saved_Scan_State;
1645 Save_Scan_State (SS);
1646 Scan; -- past initial identifier
1647 I2 := (Token = Tok_Identifier);
1648 Restore_Scan_State (SS);
1652 (Bad_Spelling_Of (Tok_Access) or else
1653 Bad_Spelling_Of (Tok_Aliased) or else
1654 Bad_Spelling_Of (Tok_Constant))
1661 -- We allow "constant" here (as in "return Result : constant
1662 -- T..."). This is not in the latest RM, but the ARG is considering an
1663 -- AI on the subject (see AI05-0015-1), which we expect to be approved.
1665 if Token = Tok_Constant then
1666 Scan; -- past CONSTANT
1667 Set_Constant_Present (Decl_Node);
1669 if Token = Tok_Aliased then
1670 Error_Msg_SC -- CODEFIX
1671 ("ALIASED should be before CONSTANT");
1672 Scan; -- past ALIASED
1673 Set_Aliased_Present (Decl_Node);
1676 elsif Token = Tok_Aliased then
1677 Scan; -- past ALIASED
1678 Set_Aliased_Present (Decl_Node);
1680 if Ada_Version < Ada_2012 then
1681 Error_Msg_SC -- CODEFIX
1682 ("ALIASED not allowed in extended return in Ada2012?");
1684 Error_Msg_SC -- CODEFIX
1685 ("ALIASED not allowed in extended return");
1688 if Token = Tok_Constant then
1689 Scan; -- past CONSTANT
1690 Set_Constant_Present (Decl_Node);
1694 P_Return_Subtype_Indication (Decl_Node);
1696 if Token = Tok_Colon_Equal then
1698 Set_Expression (Decl_Node, P_Expression_No_Right_Paren);
1702 end P_Return_Object_Declaration;
1704 -- Error recovery: can raise Error_Resync
1706 function P_Return_Statement return Node_Id is
1707 -- The caller has checked that the initial token is RETURN
1709 function Is_Simple return Boolean;
1710 -- Scan state is just after RETURN (and is left that way).
1711 -- Determine whether this is a simple or extended return statement
1712 -- by looking ahead for "identifier :", which implies extended.
1718 function Is_Simple return Boolean is
1719 Scan_State : Saved_Scan_State;
1720 Result : Boolean := True;
1723 if Token = Tok_Identifier then
1724 Save_Scan_State (Scan_State); -- at identifier
1725 Scan; -- past identifier
1727 if Token = Tok_Colon then
1728 Result := False; -- It's an extended_return_statement.
1731 Restore_Scan_State (Scan_State); -- to identifier
1737 Return_Sloc : constant Source_Ptr := Token_Ptr;
1738 Return_Node : Node_Id;
1740 -- Start of processing for P_Return_Statement
1743 Scan; -- past RETURN
1745 -- Simple_return_statement, no expression, return an
1746 -- N_Simple_Return_Statement node with the expression field left Empty.
1748 if Token = Tok_Semicolon then
1750 Return_Node := New_Node (N_Simple_Return_Statement, Return_Sloc);
1755 -- Simple_return_statement with expression
1757 -- We avoid trying to scan an expression if we are at an
1758 -- expression terminator since in that case the best error
1759 -- message is probably that we have a missing semicolon.
1762 Return_Node := New_Node (N_Simple_Return_Statement, Return_Sloc);
1764 if Token not in Token_Class_Eterm then
1765 Set_Expression (Return_Node, P_Expression_No_Right_Paren);
1768 -- Extended_return_statement (Ada 2005 only -- AI-318):
1771 if Ada_Version < Ada_2005 then
1773 (" extended_return_statement is an Ada 2005 extension");
1774 Error_Msg_SP ("\unit must be compiled with -gnat05 switch");
1777 Return_Node := New_Node (N_Extended_Return_Statement, Return_Sloc);
1778 Set_Return_Object_Declarations
1779 (Return_Node, New_List (P_Return_Object_Declaration));
1781 if Token = Tok_Do then
1783 Scope.Table (Scope.Last).Etyp := E_Return;
1784 Scope.Table (Scope.Last).Ecol := Start_Column;
1785 Scope.Table (Scope.Last).Sloc := Return_Sloc;
1788 Set_Handled_Statement_Sequence
1789 (Return_Node, P_Handled_Sequence_Of_Statements);
1792 -- Do we need to handle Error_Resync here???
1800 end P_Return_Statement;