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author | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
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committer | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
commit | 554fd8c5195424bdbcabf5de30fdc183aba391bd (patch) | |
tree | 976dc5ab7fddf506dadce60ae936f43f58787092 /gcc/ada/par-ch6.adb | |
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-rw-r--r-- | gcc/ada/par-ch6.adb | 1727 |
1 files changed, 1727 insertions, 0 deletions
diff --git a/gcc/ada/par-ch6.adb b/gcc/ada/par-ch6.adb new file mode 100644 index 000000000..6fe1dea14 --- /dev/null +++ b/gcc/ada/par-ch6.adb @@ -0,0 +1,1727 @@ +------------------------------------------------------------------------------ +-- -- +-- GNAT COMPILER COMPONENTS -- +-- -- +-- P A R . C H 6 -- +-- -- +-- B o d y -- +-- -- +-- Copyright (C) 1992-2010, Free Software Foundation, Inc. -- +-- -- +-- GNAT is free software; you can redistribute it and/or modify it under -- +-- terms of the GNU General Public License as published by the Free Soft- -- +-- ware Foundation; either version 3, or (at your option) any later ver- -- +-- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- +-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- +-- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- +-- for more details. You should have received a copy of the GNU General -- +-- Public License distributed with GNAT; see file COPYING3. If not, go to -- +-- http://www.gnu.org/licenses for a complete copy of the license. -- +-- -- +-- GNAT was originally developed by the GNAT team at New York University. -- +-- Extensive contributions were provided by Ada Core Technologies Inc. -- +-- -- +------------------------------------------------------------------------------ + +pragma Style_Checks (All_Checks); +-- Turn off subprogram body ordering check. Subprograms are in order +-- by RM section rather than alphabetical + +with Sinfo.CN; use Sinfo.CN; + +separate (Par) +package body Ch6 is + + -- Local subprograms, used only in this chapter + + function P_Defining_Designator return Node_Id; + function P_Defining_Operator_Symbol return Node_Id; + function P_Return_Object_Declaration return Node_Id; + + procedure P_Return_Subtype_Indication (Decl_Node : Node_Id); + -- Decl_Node is a N_Object_Declaration. + -- Set the Null_Exclusion_Present and Object_Definition fields of + -- Decl_Node. + + procedure Check_Junk_Semicolon_Before_Return; + + -- Check for common error of junk semicolon before RETURN keyword of + -- function specification. If present, skip over it with appropriate + -- error message, leaving Scan_Ptr pointing to the RETURN after. This + -- routine also deals with a possibly misspelled version of Return. + + ---------------------------------------- + -- Check_Junk_Semicolon_Before_Return -- + ---------------------------------------- + + procedure Check_Junk_Semicolon_Before_Return is + Scan_State : Saved_Scan_State; + + begin + if Token = Tok_Semicolon then + Save_Scan_State (Scan_State); + Scan; -- past the semicolon + + if Token = Tok_Return then + Restore_Scan_State (Scan_State); + Error_Msg_SC -- CODEFIX + ("|extra "";"" ignored"); + Scan; -- rescan past junk semicolon + else + Restore_Scan_State (Scan_State); + end if; + + elsif Bad_Spelling_Of (Tok_Return) then + null; + end if; + end Check_Junk_Semicolon_Before_Return; + + ----------------------------------------------------- + -- 6.1 Subprogram (Also 6.3, 8.5.4, 10.1.3, 12.3) -- + ----------------------------------------------------- + + -- This routine scans out a subprogram declaration, subprogram body, + -- subprogram renaming declaration or subprogram generic instantiation. + -- It also handles the new Ada 2012 parameterized expression form + + -- SUBPROGRAM_DECLARATION ::= + -- SUBPROGRAM_SPECIFICATION + -- [ASPECT_SPECIFICATIONS]; + + -- ABSTRACT_SUBPROGRAM_DECLARATION ::= + -- SUBPROGRAM_SPECIFICATION is abstract + -- [ASPECT_SPECIFICATIONS]; + + -- SUBPROGRAM_SPECIFICATION ::= + -- procedure DEFINING_PROGRAM_UNIT_NAME PARAMETER_PROFILE + -- | function DEFINING_DESIGNATOR PARAMETER_AND_RESULT_PROFILE + + -- PARAMETER_PROFILE ::= [FORMAL_PART] + + -- PARAMETER_AND_RESULT_PROFILE ::= [FORMAL_PART] return SUBTYPE_MARK + + -- SUBPROGRAM_BODY ::= + -- SUBPROGRAM_SPECIFICATION is + -- DECLARATIVE_PART + -- begin + -- HANDLED_SEQUENCE_OF_STATEMENTS + -- end [DESIGNATOR]; + + -- SUBPROGRAM_RENAMING_DECLARATION ::= + -- SUBPROGRAM_SPECIFICATION renames callable_entity_NAME; + + -- SUBPROGRAM_BODY_STUB ::= + -- SUBPROGRAM_SPECIFICATION is separate; + + -- GENERIC_INSTANTIATION ::= + -- procedure DEFINING_PROGRAM_UNIT_NAME is + -- new generic_procedure_NAME [GENERIC_ACTUAL_PART]; + -- | function DEFINING_DESIGNATOR is + -- new generic_function_NAME [GENERIC_ACTUAL_PART]; + + -- NULL_PROCEDURE_DECLARATION ::= + -- SUBPROGRAM_SPECIFICATION is null; + + -- Null procedures are an Ada 2005 feature. A null procedure declaration + -- is classified as a basic declarative item, but it is parsed here, with + -- other subprogram constructs. + + -- PARAMETERIZED_EXPRESSION ::= + -- FUNCTION SPECIFICATION IS (EXPRESSION); + + -- The value in Pf_Flags indicates which of these possible declarations + -- is acceptable to the caller: + + -- Pf_Flags.Decl Set if declaration OK + -- Pf_Flags.Gins Set if generic instantiation OK + -- Pf_Flags.Pbod Set if proper body OK + -- Pf_Flags.Rnam Set if renaming declaration OK + -- Pf_Flags.Stub Set if body stub OK + -- Pf_Flags.Pexp Set if parameterized expression OK + + -- If an inappropriate form is encountered, it is scanned out but an + -- error message indicating that it is appearing in an inappropriate + -- context is issued. The only possible values for Pf_Flags are those + -- defined as constants in the Par package. + + -- The caller has checked that the initial token is FUNCTION, PROCEDURE, + -- NOT or OVERRIDING. + + -- Error recovery: cannot raise Error_Resync + + function P_Subprogram (Pf_Flags : Pf_Rec) return Node_Id is + Specification_Node : Node_Id; + Name_Node : Node_Id; + Fpart_List : List_Id; + Fpart_Sloc : Source_Ptr; + Result_Not_Null : Boolean := False; + Result_Node : Node_Id; + Inst_Node : Node_Id; + Body_Node : Node_Id; + Decl_Node : Node_Id; + Rename_Node : Node_Id; + Absdec_Node : Node_Id; + Stub_Node : Node_Id; + Fproc_Sloc : Source_Ptr; + Func : Boolean; + Scan_State : Saved_Scan_State; + + -- Flags for optional overriding indication. Two flags are needed, + -- to distinguish positive and negative overriding indicators from + -- the absence of any indicator. + + Is_Overriding : Boolean := False; + Not_Overriding : Boolean := False; + + begin + -- Set up scope stack entry. Note that the Labl field will be set later + + SIS_Entry_Active := False; + SIS_Missing_Semicolon_Message := No_Error_Msg; + Push_Scope_Stack; + Scope.Table (Scope.Last).Sloc := Token_Ptr; + Scope.Table (Scope.Last).Etyp := E_Name; + Scope.Table (Scope.Last).Ecol := Start_Column; + Scope.Table (Scope.Last).Lreq := False; + + -- Ada2005: scan leading NOT OVERRIDING indicator + + if Token = Tok_Not then + Scan; -- past NOT + + if Token = Tok_Overriding then + Scan; -- past OVERRIDING + Not_Overriding := True; + + -- Overriding keyword used in non Ada 2005 mode + + elsif Token = Tok_Identifier + and then Token_Name = Name_Overriding + then + Error_Msg_SC ("overriding indicator is an Ada 2005 extension"); + Error_Msg_SC ("\unit must be compiled with -gnat05 switch"); + Scan; -- past Overriding + Not_Overriding := True; + + else + Error_Msg_SC -- CODEFIX + ("OVERRIDING expected!"); + end if; + + -- Ada 2005: scan leading OVERRIDING indicator + + -- Note: in the case of OVERRIDING keyword used in Ada 95 mode, the + -- declaration circuit already gave an error message and changed the + -- token to Tok_Overriding. + + elsif Token = Tok_Overriding then + Scan; -- past OVERRIDING + Is_Overriding := True; + end if; + + if Is_Overriding or else Not_Overriding then + + -- Note that if we are not in Ada_2005 mode, error messages have + -- already been given, so no need to give another message here. + + -- An overriding indicator is allowed for subprogram declarations, + -- bodies (including subunits), renamings, stubs, and instantiations. + -- The test against Pf_Decl_Pbod is added to account for the case of + -- subprograms declared in a protected type, where only subprogram + -- declarations and bodies can occur. The Pf_Pbod case is for + -- subunits. + + if Pf_Flags /= Pf_Decl_Gins_Pbod_Rnam_Stub_Pexp + and then + Pf_Flags /= Pf_Decl_Pbod_Pexp + and then + Pf_Flags /= Pf_Pbod_Pexp + then + Error_Msg_SC ("overriding indicator not allowed here!"); + + elsif Token /= Tok_Function and then Token /= Tok_Procedure then + Error_Msg_SC -- CODEFIX + ("FUNCTION or PROCEDURE expected!"); + end if; + end if; + + Func := (Token = Tok_Function); + Fproc_Sloc := Token_Ptr; + Scan; -- past FUNCTION or PROCEDURE + Ignore (Tok_Type); + Ignore (Tok_Body); + + if Func then + Name_Node := P_Defining_Designator; + + if Nkind (Name_Node) = N_Defining_Operator_Symbol + and then Scope.Last = 1 + then + Error_Msg_SP ("operator symbol not allowed at library level"); + Name_Node := New_Entity (N_Defining_Identifier, Sloc (Name_Node)); + + -- Set name from file name, we need some junk name, and that's + -- as good as anything. This is only approximate, since we do + -- not do anything with non-standard name translations. + + Get_Name_String (File_Name (Current_Source_File)); + + for J in 1 .. Name_Len loop + if Name_Buffer (J) = '.' then + Name_Len := J - 1; + exit; + end if; + end loop; + + Set_Chars (Name_Node, Name_Find); + Set_Error_Posted (Name_Node); + end if; + + else + Name_Node := P_Defining_Program_Unit_Name; + end if; + + Scope.Table (Scope.Last).Labl := Name_Node; + Ignore (Tok_Colon); + + -- Deal with generic instantiation, the one case in which we do not + -- have a subprogram specification as part of whatever we are parsing + + if Token = Tok_Is then + Save_Scan_State (Scan_State); -- at the IS + T_Is; -- checks for redundant IS + + if Token = Tok_New then + if not Pf_Flags.Gins then + Error_Msg_SC ("generic instantiation not allowed here!"); + end if; + + Scan; -- past NEW + + if Func then + Inst_Node := New_Node (N_Function_Instantiation, Fproc_Sloc); + Set_Name (Inst_Node, P_Function_Name); + else + Inst_Node := New_Node (N_Procedure_Instantiation, Fproc_Sloc); + Set_Name (Inst_Node, P_Qualified_Simple_Name); + end if; + + Set_Defining_Unit_Name (Inst_Node, Name_Node); + Set_Generic_Associations (Inst_Node, P_Generic_Actual_Part_Opt); + P_Aspect_Specifications (Inst_Node); + Pop_Scope_Stack; -- Don't need scope stack entry in this case + + if Is_Overriding then + Set_Must_Override (Inst_Node); + + elsif Not_Overriding then + Set_Must_Not_Override (Inst_Node); + end if; + + return Inst_Node; + + else + Restore_Scan_State (Scan_State); -- to the IS + end if; + end if; + + -- If not a generic instantiation, then we definitely have a subprogram + -- specification (all possibilities at this stage include one here) + + Fpart_Sloc := Token_Ptr; + + Check_Misspelling_Of (Tok_Return); + + -- Scan formal part. First a special error check. If we have an + -- identifier here, then we have a definite error. If this identifier + -- is on the same line as the designator, then we assume it is the + -- first formal after a missing left parenthesis + + if Token = Tok_Identifier + and then not Token_Is_At_Start_Of_Line + then + T_Left_Paren; -- to generate message + Fpart_List := P_Formal_Part; + + -- Otherwise scan out an optional formal part in the usual manner + + else + Fpart_List := P_Parameter_Profile; + end if; + + -- We treat what we have as a function specification if FUNCTION was + -- used, or if a RETURN is present. This gives better error recovery + -- since later RETURN statements will be valid in either case. + + Check_Junk_Semicolon_Before_Return; + Result_Node := Error; + + if Token = Tok_Return then + if not Func then + Error_Msg -- CODEFIX + ("PROCEDURE should be FUNCTION", Fproc_Sloc); + Func := True; + end if; + + Scan; -- past RETURN + + Result_Not_Null := P_Null_Exclusion; -- Ada 2005 (AI-231) + + -- Ada 2005 (AI-318-02) + + if Token = Tok_Access then + if Ada_Version < Ada_2005 then + Error_Msg_SC + ("anonymous access result type is an Ada 2005 extension"); + Error_Msg_SC ("\unit must be compiled with -gnat05 switch"); + end if; + + Result_Node := P_Access_Definition (Result_Not_Null); + + else + Result_Node := P_Subtype_Mark; + No_Constraint; + end if; + + else + -- Skip extra parenthesis at end of formal part + + Ignore (Tok_Right_Paren); + + -- For function, scan result subtype + + if Func then + TF_Return; + + if Prev_Token = Tok_Return then + Result_Node := P_Subtype_Mark; + end if; + end if; + end if; + + if Func then + Specification_Node := + New_Node (N_Function_Specification, Fproc_Sloc); + + Set_Null_Exclusion_Present (Specification_Node, Result_Not_Null); + Set_Result_Definition (Specification_Node, Result_Node); + + else + Specification_Node := + New_Node (N_Procedure_Specification, Fproc_Sloc); + end if; + + Set_Defining_Unit_Name (Specification_Node, Name_Node); + Set_Parameter_Specifications (Specification_Node, Fpart_List); + + if Is_Overriding then + Set_Must_Override (Specification_Node); + + elsif Not_Overriding then + Set_Must_Not_Override (Specification_Node); + end if; + + -- Error check: barriers not allowed on protected functions/procedures + + if Token = Tok_When then + if Func then + Error_Msg_SC ("barrier not allowed on function, only on entry"); + else + Error_Msg_SC ("barrier not allowed on procedure, only on entry"); + end if; + + Scan; -- past WHEN + Discard_Junk_Node (P_Expression); + end if; + + -- Deal with semicolon followed by IS. We want to treat this as IS + + if Token = Tok_Semicolon then + Save_Scan_State (Scan_State); + Scan; -- past semicolon + + if Token = Tok_Is then + Error_Msg_SP -- CODEFIX + ("extra "";"" ignored"); + else + Restore_Scan_State (Scan_State); + end if; + end if; + + -- Subprogram declaration ended by aspect specifications + + if Aspect_Specifications_Present then + goto Subprogram_Declaration; + + -- Deal with case of semicolon ending a subprogram declaration + + elsif Token = Tok_Semicolon then + if not Pf_Flags.Decl then + T_Is; + end if; + + Save_Scan_State (Scan_State); + Scan; -- past semicolon + + -- If semicolon is immediately followed by IS, then ignore the + -- semicolon, and go process the body. + + if Token = Tok_Is then + Error_Msg_SP -- CODEFIX + ("|extra "";"" ignored"); + T_Is; -- scan past IS + goto Subprogram_Body; + + -- If BEGIN follows in an appropriate column, we immediately + -- commence the error action of assuming that the previous + -- subprogram declaration should have been a subprogram body, + -- i.e. that the terminating semicolon should have been IS. + + elsif Token = Tok_Begin + and then Start_Column >= Scope.Table (Scope.Last).Ecol + then + Error_Msg_SP -- CODEFIX + ("|"";"" should be IS!"); + goto Subprogram_Body; + + else + Restore_Scan_State (Scan_State); + goto Subprogram_Declaration; + end if; + + -- Case of not followed by semicolon + + else + -- Subprogram renaming declaration case + + Check_Misspelling_Of (Tok_Renames); + + if Token = Tok_Renames then + if not Pf_Flags.Rnam then + Error_Msg_SC ("renaming declaration not allowed here!"); + end if; + + Rename_Node := + New_Node (N_Subprogram_Renaming_Declaration, Token_Ptr); + Scan; -- past RENAMES + Set_Name (Rename_Node, P_Name); + Set_Specification (Rename_Node, Specification_Node); + TF_Semicolon; + Pop_Scope_Stack; + return Rename_Node; + + -- Case of IS following subprogram specification + + elsif Token = Tok_Is then + T_Is; -- ignore redundant Is's + + if Token_Name = Name_Abstract then + Check_95_Keyword (Tok_Abstract, Tok_Semicolon); + end if; + + -- Deal nicely with (now obsolete) use of <> in place of abstract + + if Token = Tok_Box then + Error_Msg_SC -- CODEFIX + ("ABSTRACT expected"); + Token := Tok_Abstract; + end if; + + -- Abstract subprogram declaration case + + if Token = Tok_Abstract then + Absdec_Node := + New_Node (N_Abstract_Subprogram_Declaration, Token_Ptr); + Set_Specification (Absdec_Node, Specification_Node); + Pop_Scope_Stack; -- discard unneeded entry + Scan; -- past ABSTRACT + P_Aspect_Specifications (Absdec_Node); + return Absdec_Node; + + -- Ada 2005 (AI-248): Parse a null procedure declaration + + elsif Token = Tok_Null then + if Ada_Version < Ada_2005 then + Error_Msg_SP ("null procedures are an Ada 2005 extension"); + Error_Msg_SP ("\unit must be compiled with -gnat05 switch"); + end if; + + Scan; -- past NULL + + if Func then + Error_Msg_SP ("only procedures can be null"); + else + Set_Null_Present (Specification_Node); + end if; + + goto Subprogram_Declaration; + + -- Check for IS NEW with Formal_Part present and handle nicely + + elsif Token = Tok_New then + Error_Msg + ("formal part not allowed in instantiation", Fpart_Sloc); + Scan; -- past NEW + + if Func then + Inst_Node := New_Node (N_Function_Instantiation, Fproc_Sloc); + else + Inst_Node := + New_Node (N_Procedure_Instantiation, Fproc_Sloc); + end if; + + Set_Defining_Unit_Name (Inst_Node, Name_Node); + Set_Name (Inst_Node, P_Name); + Set_Generic_Associations (Inst_Node, P_Generic_Actual_Part_Opt); + TF_Semicolon; + Pop_Scope_Stack; -- Don't need scope stack entry in this case + return Inst_Node; + + else + goto Subprogram_Body; + end if; + + -- Aspect specifications present + + elsif Aspect_Specifications_Present then + goto Subprogram_Declaration; + + -- Here we have a missing IS or missing semicolon, we always guess + -- a missing semicolon, since we are pretty good at fixing up a + -- semicolon which should really be an IS + + else + Error_Msg_AP -- CODEFIX + ("|missing "";"""); + SIS_Missing_Semicolon_Message := Get_Msg_Id; + goto Subprogram_Declaration; + end if; + end if; + + -- Processing for stub or subprogram body or parameterized expression + + <<Subprogram_Body>> + + -- Subprogram body stub case + + if Separate_Present then + if not Pf_Flags.Stub then + Error_Msg_SC ("body stub not allowed here!"); + end if; + + if Nkind (Name_Node) = N_Defining_Operator_Symbol then + Error_Msg + ("operator symbol cannot be used as subunit name", + Sloc (Name_Node)); + end if; + + Stub_Node := + New_Node (N_Subprogram_Body_Stub, Sloc (Specification_Node)); + Set_Specification (Stub_Node, Specification_Node); + Scan; -- past SEPARATE + Pop_Scope_Stack; + TF_Semicolon; + return Stub_Node; + + -- Subprogram body or parameterized expression case + + else + Scan_Body_Or_Parameterized_Expression : declare + + function Likely_Parameterized_Expression return Boolean; + -- Returns True if we have a probably case of a parameterized + -- expression omitting the parentheses, if so, returns True + -- and emits an appropriate error message, else returns False. + + ------------------------------------- + -- Likely_Parameterized_Expression -- + ------------------------------------- + + function Likely_Parameterized_Expression return Boolean is + begin + -- If currently pointing to BEGIN or a declaration keyword + -- or a pragma, then we definitely have a subprogram body. + -- This is a common case, so worth testing first. + + if Token = Tok_Begin + or else Token in Token_Class_Declk + or else Token = Tok_Pragma + then + return False; + + -- Test for tokens which could only start an expression and + -- thus signal the case of a parameterized expression. + + elsif Token in Token_Class_Literal + or else Token in Token_Class_Unary_Addop + or else Token = Tok_Left_Paren + or else Token = Tok_Abs + or else Token = Tok_Null + or else Token = Tok_New + or else Token = Tok_Not + then + null; + + -- Anything other than an identifier must be a body + + elsif Token /= Tok_Identifier then + return False; + + -- Here for an identifier + + else + -- If the identifier is the first token on its line, then + -- let's assume that we have a missing begin and this is + -- intended as a subprogram body. + + if Token_Is_At_Start_Of_Line then + return False; + + -- Otherwise we have to scan ahead. If the identifier is + -- followed by a colon or a comma, it is a declaration + -- and hence we have a subprogram body. Otherwise assume + -- a parameterized expression. + + else + declare + Scan_State : Saved_Scan_State; + Tok : Token_Type; + begin + Save_Scan_State (Scan_State); + Scan; -- past identifier + Tok := Token; + Restore_Scan_State (Scan_State); + + if Tok = Tok_Colon or else Tok = Tok_Comma then + return False; + end if; + end; + end if; + end if; + + -- Fall through if we have a likely parameterized expression + + Error_Msg_SC + ("parameterized expression must be " + & "enclosed in parentheses"); + return True; + end Likely_Parameterized_Expression; + + -- Start of processing for Scan_Body_Or_Parameterized_Expression + + begin + -- Parameterized_Expression case + + if Token = Tok_Left_Paren + or else Likely_Parameterized_Expression + then + -- Check parameterized expression allowed here + + if not Pf_Flags.Pexp then + Error_Msg_SC + ("parameterized expression not allowed here!"); + end if; + + -- Check we are in Ada 2012 mode + + if Ada_Version < Ada_2012 then + Error_Msg_SC + ("parameterized expression is an Ada 2012 feature!"); + Error_Msg_SC + ("\unit must be compiled with -gnat2012 switch!"); + end if; + + -- Parse out expression and build parameterized expression + + Body_Node := + New_Node + (N_Parameterized_Expression, Sloc (Specification_Node)); + Set_Specification (Body_Node, Specification_Node); + Set_Expression (Body_Node, P_Expression); + T_Semicolon; + Pop_Scope_Stack; + + -- Subprogram body case + + else + -- Check body allowed here + + if not Pf_Flags.Pbod then + Error_Msg_SP ("subprogram body not allowed here!"); + end if; + + -- Here is the test for a suspicious IS (i.e. one that + -- looks like it might more properly be a semicolon). + -- See separate section describing use of IS instead + -- of semicolon in package Parse. + + if (Token in Token_Class_Declk + or else + Token = Tok_Identifier) + and then Start_Column <= Scope.Table (Scope.Last).Ecol + and then Scope.Last /= 1 + then + Scope.Table (Scope.Last).Etyp := E_Suspicious_Is; + Scope.Table (Scope.Last).S_Is := Prev_Token_Ptr; + end if; + + -- Build and return subprogram body, parsing declarations + -- and statement sequence that belong to the body. + + Body_Node := + New_Node (N_Subprogram_Body, Sloc (Specification_Node)); + Set_Specification (Body_Node, Specification_Node); + Parse_Decls_Begin_End (Body_Node); + end if; + + return Body_Node; + end Scan_Body_Or_Parameterized_Expression; + end if; + + -- Processing for subprogram declaration + + <<Subprogram_Declaration>> + Decl_Node := + New_Node (N_Subprogram_Declaration, Sloc (Specification_Node)); + Set_Specification (Decl_Node, Specification_Node); + P_Aspect_Specifications (Decl_Node); + + -- If this is a context in which a subprogram body is permitted, + -- set active SIS entry in case (see section titled "Handling + -- Semicolon Used in Place of IS" in body of Parser package) + -- Note that SIS_Missing_Semicolon_Message is already set properly. + + if Pf_Flags.Pbod then + SIS_Labl := Scope.Table (Scope.Last).Labl; + SIS_Sloc := Scope.Table (Scope.Last).Sloc; + SIS_Ecol := Scope.Table (Scope.Last).Ecol; + SIS_Declaration_Node := Decl_Node; + SIS_Semicolon_Sloc := Prev_Token_Ptr; + SIS_Entry_Active := True; + end if; + + Pop_Scope_Stack; + return Decl_Node; + end P_Subprogram; + + --------------------------------- + -- 6.1 Subprogram Declaration -- + --------------------------------- + + -- Parsed by P_Subprogram (6.1) + + ------------------------------------------ + -- 6.1 Abstract Subprogram Declaration -- + ------------------------------------------ + + -- Parsed by P_Subprogram (6.1) + + ----------------------------------- + -- 6.1 Subprogram Specification -- + ----------------------------------- + + -- SUBPROGRAM_SPECIFICATION ::= + -- procedure DEFINING_PROGRAM_UNIT_NAME PARAMETER_PROFILE + -- | function DEFINING_DESIGNATOR PARAMETER_AND_RESULT_PROFILE + + -- PARAMETER_PROFILE ::= [FORMAL_PART] + + -- PARAMETER_AND_RESULT_PROFILE ::= [FORMAL_PART] return SUBTYPE_MARK + + -- Subprogram specifications that appear in subprogram declarations + -- are parsed by P_Subprogram (6.1). This routine is used in other + -- contexts where subprogram specifications occur. + + -- Note: this routine does not affect the scope stack in any way + + -- Error recovery: can raise Error_Resync + + function P_Subprogram_Specification return Node_Id is + Specification_Node : Node_Id; + Result_Not_Null : Boolean; + Result_Node : Node_Id; + + begin + if Token = Tok_Function then + Specification_Node := New_Node (N_Function_Specification, Token_Ptr); + Scan; -- past FUNCTION + Ignore (Tok_Body); + Set_Defining_Unit_Name (Specification_Node, P_Defining_Designator); + Set_Parameter_Specifications + (Specification_Node, P_Parameter_Profile); + Check_Junk_Semicolon_Before_Return; + TF_Return; + + Result_Not_Null := P_Null_Exclusion; -- Ada 2005 (AI-231) + + -- Ada 2005 (AI-318-02) + + if Token = Tok_Access then + if Ada_Version < Ada_2005 then + Error_Msg_SC + ("anonymous access result type is an Ada 2005 extension"); + Error_Msg_SC ("\unit must be compiled with -gnat05 switch"); + end if; + + Result_Node := P_Access_Definition (Result_Not_Null); + + else + Result_Node := P_Subtype_Mark; + No_Constraint; + end if; + + Set_Null_Exclusion_Present (Specification_Node, Result_Not_Null); + Set_Result_Definition (Specification_Node, Result_Node); + return Specification_Node; + + elsif Token = Tok_Procedure then + Specification_Node := New_Node (N_Procedure_Specification, Token_Ptr); + Scan; -- past PROCEDURE + Ignore (Tok_Body); + Set_Defining_Unit_Name + (Specification_Node, P_Defining_Program_Unit_Name); + Set_Parameter_Specifications + (Specification_Node, P_Parameter_Profile); + return Specification_Node; + + else + Error_Msg_SC ("subprogram specification expected"); + raise Error_Resync; + end if; + end P_Subprogram_Specification; + + --------------------- + -- 6.1 Designator -- + --------------------- + + -- DESIGNATOR ::= + -- [PARENT_UNIT_NAME .] IDENTIFIER | OPERATOR_SYMBOL + + -- The caller has checked that the initial token is an identifier, + -- operator symbol, or string literal. Note that we don't bother to + -- do much error diagnosis in this routine, since it is only used for + -- the label on END lines, and the routines in package Par.Endh will + -- check that the label is appropriate. + + -- Error recovery: cannot raise Error_Resync + + function P_Designator return Node_Id is + Ident_Node : Node_Id; + Name_Node : Node_Id; + Prefix_Node : Node_Id; + + function Real_Dot return Boolean; + -- Tests if a current token is an interesting period, i.e. is followed + -- by an identifier or operator symbol or string literal. If not, it is + -- probably just incorrect punctuation to be caught by our caller. Note + -- that the case of an operator symbol or string literal is also an + -- error, but that is an error that we catch here. If the result is + -- True, a real dot has been scanned and we are positioned past it, + -- if the result is False, the scan position is unchanged. + + -------------- + -- Real_Dot -- + -------------- + + function Real_Dot return Boolean is + Scan_State : Saved_Scan_State; + + begin + if Token /= Tok_Dot then + return False; + + else + Save_Scan_State (Scan_State); + Scan; -- past dot + + if Token = Tok_Identifier + or else Token = Tok_Operator_Symbol + or else Token = Tok_String_Literal + then + return True; + + else + Restore_Scan_State (Scan_State); + return False; + end if; + end if; + end Real_Dot; + + -- Start of processing for P_Designator + + begin + Ident_Node := Token_Node; + Scan; -- past initial token + + if Prev_Token = Tok_Operator_Symbol + or else Prev_Token = Tok_String_Literal + or else not Real_Dot + then + return Ident_Node; + + -- Child name case + + else + Prefix_Node := Ident_Node; + + -- Loop through child names, on entry to this loop, Prefix contains + -- the name scanned so far, and Ident_Node is the last identifier. + + loop + Name_Node := New_Node (N_Selected_Component, Prev_Token_Ptr); + Set_Prefix (Name_Node, Prefix_Node); + Ident_Node := P_Identifier; + Set_Selector_Name (Name_Node, Ident_Node); + Prefix_Node := Name_Node; + exit when not Real_Dot; + end loop; + + -- On exit from the loop, Ident_Node is the last identifier scanned, + -- i.e. the defining identifier, and Prefix_Node is a node for the + -- entire name, structured (incorrectly!) as a selected component. + + Name_Node := Prefix (Prefix_Node); + Change_Node (Prefix_Node, N_Designator); + Set_Name (Prefix_Node, Name_Node); + Set_Identifier (Prefix_Node, Ident_Node); + return Prefix_Node; + end if; + + exception + when Error_Resync => + while Token = Tok_Dot or else Token = Tok_Identifier loop + Scan; + end loop; + + return Error; + end P_Designator; + + ------------------------------ + -- 6.1 Defining Designator -- + ------------------------------ + + -- DEFINING_DESIGNATOR ::= + -- DEFINING_PROGRAM_UNIT_NAME | DEFINING_OPERATOR_SYMBOL + + -- Error recovery: cannot raise Error_Resync + + function P_Defining_Designator return Node_Id is + begin + if Token = Tok_Operator_Symbol then + return P_Defining_Operator_Symbol; + + elsif Token = Tok_String_Literal then + Error_Msg_SC ("invalid operator name"); + Scan; -- past junk string + return Error; + + else + return P_Defining_Program_Unit_Name; + end if; + end P_Defining_Designator; + + ------------------------------------- + -- 6.1 Defining Program Unit Name -- + ------------------------------------- + + -- DEFINING_PROGRAM_UNIT_NAME ::= + -- [PARENT_UNIT_NAME .] DEFINING_IDENTIFIER + + -- Note: PARENT_UNIT_NAME may be present only in 95 mode at the outer level + + -- Error recovery: cannot raise Error_Resync + + function P_Defining_Program_Unit_Name return Node_Id is + Ident_Node : Node_Id; + Name_Node : Node_Id; + Prefix_Node : Node_Id; + + begin + -- Set identifier casing if not already set and scan initial identifier + + if Token = Tok_Identifier + and then Identifier_Casing (Current_Source_File) = Unknown + then + Set_Identifier_Casing (Current_Source_File, Determine_Token_Casing); + end if; + + Ident_Node := P_Identifier (C_Dot); + Merge_Identifier (Ident_Node, Tok_Return); + + -- Normal case (not child library unit name) + + if Token /= Tok_Dot then + Change_Identifier_To_Defining_Identifier (Ident_Node); + return Ident_Node; + + -- Child library unit name case + + else + if Scope.Last > 1 then + Error_Msg_SP ("child unit allowed only at library level"); + raise Error_Resync; + + elsif Ada_Version = Ada_83 then + Error_Msg_SP ("(Ada 83) child unit not allowed!"); + + end if; + + Prefix_Node := Ident_Node; + + -- Loop through child names, on entry to this loop, Prefix contains + -- the name scanned so far, and Ident_Node is the last identifier. + + loop + exit when Token /= Tok_Dot; + Name_Node := New_Node (N_Selected_Component, Token_Ptr); + Scan; -- past period + Set_Prefix (Name_Node, Prefix_Node); + Ident_Node := P_Identifier (C_Dot); + Set_Selector_Name (Name_Node, Ident_Node); + Prefix_Node := Name_Node; + end loop; + + -- On exit from the loop, Ident_Node is the last identifier scanned, + -- i.e. the defining identifier, and Prefix_Node is a node for the + -- entire name, structured (incorrectly!) as a selected component. + + Name_Node := Prefix (Prefix_Node); + Change_Node (Prefix_Node, N_Defining_Program_Unit_Name); + Set_Name (Prefix_Node, Name_Node); + Change_Identifier_To_Defining_Identifier (Ident_Node); + Set_Defining_Identifier (Prefix_Node, Ident_Node); + + -- All set with unit name parsed + + return Prefix_Node; + end if; + + exception + when Error_Resync => + while Token = Tok_Dot or else Token = Tok_Identifier loop + Scan; + end loop; + + return Error; + end P_Defining_Program_Unit_Name; + + -------------------------- + -- 6.1 Operator Symbol -- + -------------------------- + + -- OPERATOR_SYMBOL ::= STRING_LITERAL + + -- Operator symbol is returned by the scanner as Tok_Operator_Symbol + + ----------------------------------- + -- 6.1 Defining Operator Symbol -- + ----------------------------------- + + -- DEFINING_OPERATOR_SYMBOL ::= OPERATOR_SYMBOL + + -- The caller has checked that the initial symbol is an operator symbol + + function P_Defining_Operator_Symbol return Node_Id is + Op_Node : Node_Id; + + begin + Op_Node := Token_Node; + Change_Operator_Symbol_To_Defining_Operator_Symbol (Op_Node); + Scan; -- past operator symbol + return Op_Node; + end P_Defining_Operator_Symbol; + + ---------------------------- + -- 6.1 Parameter_Profile -- + ---------------------------- + + -- PARAMETER_PROFILE ::= [FORMAL_PART] + + -- Empty is returned if no formal part is present + + -- Error recovery: cannot raise Error_Resync + + function P_Parameter_Profile return List_Id is + begin + if Token = Tok_Left_Paren then + Scan; -- part left paren + return P_Formal_Part; + else + return No_List; + end if; + end P_Parameter_Profile; + + --------------------------------------- + -- 6.1 Parameter And Result Profile -- + --------------------------------------- + + -- Parsed by its parent construct, which uses P_Parameter_Profile to + -- parse the parameters, and P_Subtype_Mark to parse the return type. + + ---------------------- + -- 6.1 Formal part -- + ---------------------- + + -- FORMAL_PART ::= (PARAMETER_SPECIFICATION {; PARAMETER_SPECIFICATION}) + + -- PARAMETER_SPECIFICATION ::= + -- DEFINING_IDENTIFIER_LIST : MODE [NULL_EXCLUSION] SUBTYPE_MARK + -- [:= DEFAULT_EXPRESSION] + -- | DEFINING_IDENTIFIER_LIST : ACCESS_DEFINITION + -- [:= DEFAULT_EXPRESSION] + + -- This scans the construct Formal_Part. The caller has already checked + -- that the initial token is a left parenthesis, and skipped past it, so + -- that on entry Token is the first token following the left parenthesis. + + -- Error recovery: cannot raise Error_Resync + + function P_Formal_Part return List_Id is + Specification_List : List_Id; + Specification_Node : Node_Id; + Scan_State : Saved_Scan_State; + Num_Idents : Nat; + Ident : Nat; + Ident_Sloc : Source_Ptr; + Not_Null_Present : Boolean := False; + Not_Null_Sloc : Source_Ptr; + + Idents : array (Int range 1 .. 4096) of Entity_Id; + -- This array holds the list of defining identifiers. The upper bound + -- of 4096 is intended to be essentially infinite, and we do not even + -- bother to check for it being exceeded. + + begin + Specification_List := New_List; + Specification_Loop : loop + begin + if Token = Tok_Pragma then + Error_Msg_SC ("pragma not allowed in formal part"); + Discard_Junk_Node (P_Pragma (Skipping => True)); + end if; + + Ignore (Tok_Left_Paren); + Ident_Sloc := Token_Ptr; + Idents (1) := P_Defining_Identifier (C_Comma_Colon); + Num_Idents := 1; + + Ident_Loop : loop + exit Ident_Loop when Token = Tok_Colon; + + -- The only valid tokens are colon and comma, so if we have + -- neither do a bit of investigation to see which is the + -- better choice for insertion. + + if Token /= Tok_Comma then + + -- Assume colon if IN or OUT keyword found + + exit Ident_Loop when Token = Tok_In or else Token = Tok_Out; + + -- Otherwise scan ahead + + Save_Scan_State (Scan_State); + Look_Ahead : loop + + -- If we run into a semicolon, then assume that a + -- colon was missing, e.g. Parms (X Y; ...). Also + -- assume missing colon on EOF (a real disaster!) + -- and on a right paren, e.g. Parms (X Y), and also + -- on an assignment symbol, e.g. Parms (X Y := ..) + + if Token = Tok_Semicolon + or else Token = Tok_Right_Paren + or else Token = Tok_EOF + or else Token = Tok_Colon_Equal + then + Restore_Scan_State (Scan_State); + exit Ident_Loop; + + -- If we run into a colon, assume that we had a missing + -- comma, e.g. Parms (A B : ...). Also assume a missing + -- comma if we hit another comma, e.g. Parms (A B, C ..) + + elsif Token = Tok_Colon + or else Token = Tok_Comma + then + Restore_Scan_State (Scan_State); + exit Look_Ahead; + end if; + + Scan; + end loop Look_Ahead; + end if; + + -- Here if a comma is present, or to be assumed + + T_Comma; + Num_Idents := Num_Idents + 1; + Idents (Num_Idents) := P_Defining_Identifier (C_Comma_Colon); + end loop Ident_Loop; + + -- Fall through the loop on encountering a colon, or deciding + -- that there is a missing colon. + + T_Colon; + + -- If there are multiple identifiers, we repeatedly scan the + -- type and initialization expression information by resetting + -- the scan pointer (so that we get completely separate trees + -- for each occurrence). + + if Num_Idents > 1 then + Save_Scan_State (Scan_State); + end if; + + -- Loop through defining identifiers in list + + Ident := 1; + + Ident_List_Loop : loop + Specification_Node := + New_Node (N_Parameter_Specification, Ident_Sloc); + Set_Defining_Identifier (Specification_Node, Idents (Ident)); + + -- Scan possible NOT NULL for Ada 2005 (AI-231, AI-447) + + Not_Null_Sloc := Token_Ptr; + Not_Null_Present := + P_Null_Exclusion (Allow_Anonymous_In_95 => True); + + -- Case of ACCESS keyword present + + if Token = Tok_Access then + Set_Null_Exclusion_Present + (Specification_Node, Not_Null_Present); + + if Ada_Version = Ada_83 then + Error_Msg_SC ("(Ada 83) access parameters not allowed"); + end if; + + Set_Parameter_Type + (Specification_Node, + P_Access_Definition (Not_Null_Present)); + + -- Case of IN or OUT present + + else + if Token = Tok_In or else Token = Tok_Out then + if Not_Null_Present then + Error_Msg + ("`NOT NULL` can only be used with `ACCESS`", + Not_Null_Sloc); + + if Token = Tok_In then + Error_Msg + ("\`IN` not allowed together with `ACCESS`", + Not_Null_Sloc); + else + Error_Msg + ("\`OUT` not allowed together with `ACCESS`", + Not_Null_Sloc); + end if; + end if; + + P_Mode (Specification_Node); + Not_Null_Present := P_Null_Exclusion; -- Ada 2005 (AI-231) + end if; + + Set_Null_Exclusion_Present + (Specification_Node, Not_Null_Present); + + if Token = Tok_Procedure + or else + Token = Tok_Function + then + Error_Msg_SC ("formal subprogram parameter not allowed"); + Scan; + + if Token = Tok_Left_Paren then + Discard_Junk_List (P_Formal_Part); + end if; + + if Token = Tok_Return then + Scan; + Discard_Junk_Node (P_Subtype_Mark); + end if; + + Set_Parameter_Type (Specification_Node, Error); + + else + Set_Parameter_Type (Specification_Node, P_Subtype_Mark); + No_Constraint; + end if; + end if; + + Set_Expression (Specification_Node, Init_Expr_Opt (True)); + + if Ident > 1 then + Set_Prev_Ids (Specification_Node, True); + end if; + + if Ident < Num_Idents then + Set_More_Ids (Specification_Node, True); + end if; + + Append (Specification_Node, Specification_List); + exit Ident_List_Loop when Ident = Num_Idents; + Ident := Ident + 1; + Restore_Scan_State (Scan_State); + end loop Ident_List_Loop; + + exception + when Error_Resync => + Resync_Semicolon_List; + end; + + if Token = Tok_Semicolon then + Save_Scan_State (Scan_State); + Scan; -- past semicolon + + -- If we have RETURN or IS after the semicolon, then assume + -- that semicolon should have been a right parenthesis and exit + + if Token = Tok_Is or else Token = Tok_Return then + Error_Msg_SP -- CODEFIX + ("|"";"" should be "")"""); + exit Specification_Loop; + end if; + + -- If we have a declaration keyword after the semicolon, then + -- assume we had a missing right parenthesis and terminate list + + if Token in Token_Class_Declk then + Error_Msg_AP -- CODEFIX + ("missing "")"""); + Restore_Scan_State (Scan_State); + exit Specification_Loop; + end if; + + elsif Token = Tok_Right_Paren then + Scan; -- past right paren + exit Specification_Loop; + + -- Special check for common error of using comma instead of semicolon + + elsif Token = Tok_Comma then + T_Semicolon; + Scan; -- past comma + + -- Special check for omitted separator + + elsif Token = Tok_Identifier then + T_Semicolon; + + -- If nothing sensible, skip to next semicolon or right paren + + else + T_Semicolon; + Resync_Semicolon_List; + + if Token = Tok_Semicolon then + Scan; -- past semicolon + else + T_Right_Paren; + exit Specification_Loop; + end if; + end if; + end loop Specification_Loop; + + return Specification_List; + end P_Formal_Part; + + ---------------------------------- + -- 6.1 Parameter Specification -- + ---------------------------------- + + -- Parsed by P_Formal_Part (6.1) + + --------------- + -- 6.1 Mode -- + --------------- + + -- MODE ::= [in] | in out | out + + -- There is no explicit node in the tree for the Mode. Instead the + -- In_Present and Out_Present flags are set in the parent node to + -- record the presence of keywords specifying the mode. + + -- Error_Recovery: cannot raise Error_Resync + + procedure P_Mode (Node : Node_Id) is + begin + if Token = Tok_In then + Scan; -- past IN + Set_In_Present (Node, True); + + if Style.Mode_In_Check and then Token /= Tok_Out then + Error_Msg_SP -- CODEFIX + ("(style) IN should be omitted"); + end if; + + if Token = Tok_Access then + Error_Msg_SP ("IN not allowed together with ACCESS"); + Scan; -- past ACCESS + end if; + end if; + + if Token = Tok_Out then + Scan; -- past OUT + Set_Out_Present (Node, True); + end if; + + if Token = Tok_In then + Error_Msg_SC ("IN must precede OUT in parameter mode"); + Scan; -- past IN + Set_In_Present (Node, True); + end if; + end P_Mode; + + -------------------------- + -- 6.3 Subprogram Body -- + -------------------------- + + -- Parsed by P_Subprogram (6.1) + + ----------------------------------- + -- 6.4 Procedure Call Statement -- + ----------------------------------- + + -- Parsed by P_Sequence_Of_Statements (5.1) + + ------------------------ + -- 6.4 Function Call -- + ------------------------ + + -- Parsed by P_Call_Or_Name (4.1) + + -------------------------------- + -- 6.4 Actual Parameter Part -- + -------------------------------- + + -- Parsed by P_Call_Or_Name (4.1) + + -------------------------------- + -- 6.4 Parameter Association -- + -------------------------------- + + -- Parsed by P_Call_Or_Name (4.1) + + ------------------------------------ + -- 6.4 Explicit Actual Parameter -- + ------------------------------------ + + -- Parsed by P_Call_Or_Name (4.1) + + --------------------------- + -- 6.5 Return Statement -- + --------------------------- + + -- SIMPLE_RETURN_STATEMENT ::= return [EXPRESSION]; + -- + -- EXTENDED_RETURN_STATEMENT ::= + -- return DEFINING_IDENTIFIER : [aliased] RETURN_SUBTYPE_INDICATION + -- [:= EXPRESSION] [do + -- HANDLED_SEQUENCE_OF_STATEMENTS + -- end return]; + -- + -- RETURN_SUBTYPE_INDICATION ::= SUBTYPE_INDICATION | ACCESS_DEFINITION + + -- RETURN_STATEMENT ::= return [EXPRESSION]; + + -- Error recovery: can raise Error_Resync + + procedure P_Return_Subtype_Indication (Decl_Node : Node_Id) is + + -- Note: We don't need to check Ada_Version here, because this is + -- only called in >= Ada 2005 cases anyway. + + Not_Null_Present : constant Boolean := P_Null_Exclusion; + + begin + Set_Null_Exclusion_Present (Decl_Node, Not_Null_Present); + + if Token = Tok_Access then + Set_Object_Definition + (Decl_Node, P_Access_Definition (Not_Null_Present)); + else + Set_Object_Definition + (Decl_Node, P_Subtype_Indication (Not_Null_Present)); + end if; + end P_Return_Subtype_Indication; + + -- Error recovery: can raise Error_Resync + + function P_Return_Object_Declaration return Node_Id is + Return_Obj : Node_Id; + Decl_Node : Node_Id; + + begin + Return_Obj := Token_Node; + Change_Identifier_To_Defining_Identifier (Return_Obj); + Decl_Node := New_Node (N_Object_Declaration, Token_Ptr); + Set_Defining_Identifier (Decl_Node, Return_Obj); + + Scan; -- past identifier + Scan; -- past : + + -- First an error check, if we have two identifiers in a row, a likely + -- possibility is that the first of the identifiers is an incorrectly + -- spelled keyword. See similar check in P_Identifier_Declarations. + + if Token = Tok_Identifier then + declare + SS : Saved_Scan_State; + I2 : Boolean; + + begin + Save_Scan_State (SS); + Scan; -- past initial identifier + I2 := (Token = Tok_Identifier); + Restore_Scan_State (SS); + + if I2 + and then + (Bad_Spelling_Of (Tok_Access) or else + Bad_Spelling_Of (Tok_Aliased) or else + Bad_Spelling_Of (Tok_Constant)) + then + null; + end if; + end; + end if; + + -- We allow "constant" here (as in "return Result : constant + -- T..."). This is not in the latest RM, but the ARG is considering an + -- AI on the subject (see AI05-0015-1), which we expect to be approved. + + if Token = Tok_Constant then + Scan; -- past CONSTANT + Set_Constant_Present (Decl_Node); + + if Token = Tok_Aliased then + Error_Msg_SC -- CODEFIX + ("ALIASED should be before CONSTANT"); + Scan; -- past ALIASED + Set_Aliased_Present (Decl_Node); + end if; + + elsif Token = Tok_Aliased then + Scan; -- past ALIASED + Set_Aliased_Present (Decl_Node); + + if Token = Tok_Constant then + Scan; -- past CONSTANT + Set_Constant_Present (Decl_Node); + end if; + end if; + + P_Return_Subtype_Indication (Decl_Node); + + if Token = Tok_Colon_Equal then + Scan; -- past := + Set_Expression (Decl_Node, P_Expression_No_Right_Paren); + end if; + + return Decl_Node; + end P_Return_Object_Declaration; + + -- Error recovery: can raise Error_Resync + + function P_Return_Statement return Node_Id is + -- The caller has checked that the initial token is RETURN + + function Is_Simple return Boolean; + -- Scan state is just after RETURN (and is left that way). + -- Determine whether this is a simple or extended return statement + -- by looking ahead for "identifier :", which implies extended. + + --------------- + -- Is_Simple -- + --------------- + + function Is_Simple return Boolean is + Scan_State : Saved_Scan_State; + Result : Boolean := True; + + begin + if Token = Tok_Identifier then + Save_Scan_State (Scan_State); -- at identifier + Scan; -- past identifier + + if Token = Tok_Colon then + Result := False; -- It's an extended_return_statement. + end if; + + Restore_Scan_State (Scan_State); -- to identifier + end if; + + return Result; + end Is_Simple; + + Return_Sloc : constant Source_Ptr := Token_Ptr; + Return_Node : Node_Id; + + -- Start of processing for P_Return_Statement + + begin + Scan; -- past RETURN + + -- Simple_return_statement, no expression, return an + -- N_Simple_Return_Statement node with the expression field left Empty. + + if Token = Tok_Semicolon then + Scan; -- past ; + Return_Node := New_Node (N_Simple_Return_Statement, Return_Sloc); + + -- Non-trivial case + + else + -- Simple_return_statement with expression + + -- We avoid trying to scan an expression if we are at an + -- expression terminator since in that case the best error + -- message is probably that we have a missing semicolon. + + if Is_Simple then + Return_Node := New_Node (N_Simple_Return_Statement, Return_Sloc); + + if Token not in Token_Class_Eterm then + Set_Expression (Return_Node, P_Expression_No_Right_Paren); + end if; + + -- Extended_return_statement (Ada 2005 only -- AI-318): + + else + if Ada_Version < Ada_2005 then + Error_Msg_SP + (" extended_return_statement is an Ada 2005 extension"); + Error_Msg_SP ("\unit must be compiled with -gnat05 switch"); + end if; + + Return_Node := New_Node (N_Extended_Return_Statement, Return_Sloc); + Set_Return_Object_Declarations + (Return_Node, New_List (P_Return_Object_Declaration)); + + if Token = Tok_Do then + Push_Scope_Stack; + Scope.Table (Scope.Last).Etyp := E_Return; + Scope.Table (Scope.Last).Ecol := Start_Column; + Scope.Table (Scope.Last).Sloc := Return_Sloc; + + Scan; -- past DO + Set_Handled_Statement_Sequence + (Return_Node, P_Handled_Sequence_Of_Statements); + End_Statements; + + -- Do we need to handle Error_Resync here??? + end if; + end if; + + TF_Semicolon; + end if; + + return Return_Node; + end P_Return_Statement; + +end Ch6; |