+++ /dev/null
-------------------------------------------------------------------------------
--- --
--- GNAT COMPILER COMPONENTS --
--- --
--- P A R . C H 6 --
--- --
--- B o d y --
--- --
--- $Revision: 1.2.10.1 $
--- --
--- Copyright (C) 1992-2001 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 2, 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 COPYING. If not, write --
--- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
--- MA 02111-1307, USA. --
--- --
--- 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;
-
- 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 ("Unexpected semicolon 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.
-
- -- SUBPROGRAM_DECLARATION ::= SUBPROGRAM_SPECIFICATION;
-
- -- ABSTRACT_SUBPROGRAM_DECLARATION ::=
- -- SUBPROGRAM_SPECIFICATION is abstract;
-
- -- 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];
-
- -- 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
-
- -- 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 or PROCEDURE
-
- -- 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;
- Return_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;
-
- 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;
-
- 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;
-
- if Token = Tok_Colon then
- Error_Msg_SC ("redundant colon ignored");
- Scan; -- past colon
- end if;
-
- -- 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's
-
- 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);
- TF_Semicolon;
- Pop_Scope_Stack; -- Don't need scope stack entry in this case
- 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;
- Return_Node := Error;
-
- if Token = Tok_Return then
- if not Func then
- Error_Msg ("PROCEDURE should be FUNCTION", Fproc_Sloc);
- Func := True;
- end if;
-
- Scan; -- past RETURN
- Return_Node := P_Subtype_Mark;
- No_Constraint;
-
- else
- if Func then
- Ignore (Tok_Right_Paren);
- TF_Return;
- end if;
- end if;
-
- if Func then
- Specification_Node :=
- New_Node (N_Function_Specification, Fproc_Sloc);
- Set_Subtype_Mark (Specification_Node, Return_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);
-
- -- 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 case of semicolon ending a subprogram declaration
-
- if Token = Tok_Semicolon then
- if not Pf_Flags.Decl then
- T_Is;
- end if;
-
- 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 ("unexpected semicolon ignored");
- T_Is; -- ignroe redundant IS's
- 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 (""";"" should be IS!");
- goto Subprogram_Body;
-
- else
- 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 ("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
- TF_Semicolon;
- return Absdec_Node;
-
- -- 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;
-
- -- 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 ("missing "";""");
- SIS_Missing_Semicolon_Message := Get_Msg_Id;
- goto Subprogram_Declaration;
- end if;
- end if;
-
- -- Processing for subprogram body
-
- <<Subprogram_Body>>
- if not Pf_Flags.Pbod then
- Error_Msg_SP ("subprogram body not allowed here!");
- end if;
-
- -- 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 case
-
- else
- -- Here is the test for a suspicious IS (i.e. one that looks
- -- like it might more properly be a semicolon). See separate
- -- section discussing 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;
-
- Body_Node :=
- New_Node (N_Subprogram_Body, Sloc (Specification_Node));
- Set_Specification (Body_Node, Specification_Node);
- Parse_Decls_Begin_End (Body_Node);
- return Body_Node;
- end if;
-
- -- Processing for subprogram declaration
-
- <<Subprogram_Declaration>>
- Decl_Node :=
- New_Node (N_Subprogram_Declaration, Sloc (Specification_Node));
- Set_Specification (Decl_Node, Specification_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;
-
- 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;
- Set_Subtype_Mark (Specification_Node, P_Subtype_Mark);
- No_Constraint;
- 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.
-
- 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;
- 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_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;
- 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 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;
-
- 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
- P_Pragmas_Misplaced;
- end if;
-
- Ignore (Tok_Left_Paren);
- Ident_Sloc := Token_Ptr;
- Idents (1) := P_Defining_Identifier;
- 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;
- 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));
-
- if Token = Tok_Access then
- if Ada_83 then
- Error_Msg_SC ("(Ada 83) access parameters not allowed");
- end if;
-
- Set_Parameter_Type
- (Specification_Node, P_Access_Definition);
-
- else
- P_Mode (Specification_Node);
-
- 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
- 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 ("expected "")"" in place of "";""");
- 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);
- 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 --
- ---------------------------
-
- -- RETURN_STATEMENT ::= return [EXPRESSION];
-
- -- The caller has checked that the initial token is RETURN
-
- -- Error recovery: can raise Error_Resync
-
- function P_Return_Statement return Node_Id is
- Return_Node : Node_Id;
-
- begin
- Return_Node := New_Node (N_Return_Statement, Token_Ptr);
-
- -- Sloc points to RETURN
- -- Expression (Op3)
-
- Scan; -- past RETURN
-
- if Token /= Tok_Semicolon then
-
- -- If no semicolon, then scan an expression, except that
- -- 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 Token not in Token_Class_Eterm then
- Set_Expression (Return_Node, P_Expression_No_Right_Paren);
- end if;
- end if;
-
- TF_Semicolon;
- return Return_Node;
- end P_Return_Statement;
-
-end Ch6;
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