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------------------------------------------------------------------------------

--                                                                          --

--                         GNAT COMPILER COMPONENTS                         --

--                                                                          --

--                              P A R . C H 2                               --

--                                                                          --

--                                 B o d y                                  --

--                                                                          --

--          Copyright (C) 1992-2009, 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

separate (Par)

package body Ch2 is

   --  Local functions, used only in this chapter

   procedure Scan_Pragma_Argument_Association

     (Identifier_Seen : in out Boolean;

      Association     : out Node_Id);

   --  Scans out a pragma argument association. Identifier_Seen is true on

   --  entry if a previous association had an identifier, and gets set True if

   --  the scanned association has an identifier (this is used to check the

   --  rule that no associations without identifiers can follow an association

   --  which has an identifier). The result is returned in Association.

   ---------------------

   -- 2.3  Identifier --

   ---------------------

   --  IDENTIFIER ::= LETTER {[UNDERLINE] LETTER_OR_DIGIT}

   --  LETTER_OR_DIGIT ::= IDENTIFIER_LETTER | DIGIT

   --  An IDENTIFIER shall not be a reserved word

   --  Error recovery: can raise Error_Resync (cannot return Error)

   function P_Identifier (C : Id_Check := None) return Node_Id is

      Ident_Node : Node_Id;

   begin

      --  All set if we do indeed have an identifier

      if Token = Tok_Identifier then

         --  Ada 2005 (AI-284): Compiling in Ada95 mode we warn that INTERFACE,

         --  OVERRIDING, and SYNCHRONIZED are new reserved words.

         if Ada_Version = Ada_95

           and then Warn_On_Ada_2005_Compatibility

         then

            if Token_Name = Name_Overriding

              or else Token_Name = Name_Synchronized

              or else (Token_Name = Name_Interface

                        and then Prev_Token /= Tok_Pragma)

            then

               Error_Msg_N ("& is a reserved word in Ada 2005?", Token_Node);

            end if;

         end if;

         Ident_Node := Token_Node;

         Scan; -- past Identifier

         return Ident_Node;

      --  If we have a reserved identifier, manufacture an identifier with

      --  a corresponding name after posting an appropriate error message

      elsif Is_Reserved_Identifier (C) then

         Scan_Reserved_Identifier (Force_Msg => False);

         Ident_Node := Token_Node;

         Scan; -- past the node

         return Ident_Node;

      --  Otherwise we have junk that cannot be interpreted as an identifier

      else

         T_Identifier; -- to give message

         raise Error_Resync;

      end if;

   end P_Identifier;

   --------------------------

   -- 2.3  Letter Or Digit --

   --------------------------

   --  Parsed by P_Identifier (2.3)

   --------------------------

   -- 2.4  Numeric Literal --

   --------------------------

   --  NUMERIC_LITERAL ::= DECIMAL_LITERAL | BASED_LITERAL

   --  Numeric literal is returned by the scanner as either

   --  Tok_Integer_Literal or Tok_Real_Literal

   ----------------------------

   -- 2.4.1  Decimal Literal --

   ----------------------------

   --  DECIMAL_LITERAL ::= NUMERAL [.NUMERAL] [EXPONENT]

   --  Handled by scanner as part of numeric literal handing (see 2.4)

   --------------------

   -- 2.4.1  Numeral --

   --------------------

   --  NUMERAL ::= DIGIT {[UNDERLINE] DIGIT}

   --  Handled by scanner as part of numeric literal handling (see 2.4)

   ---------------------

   -- 2.4.1  Exponent --

   ---------------------

   --  EXPONENT ::= E [+] NUMERAL | E - NUMERAL

   --  Handled by scanner as part of numeric literal handling (see 2.4)

   --------------------------

   -- 2.4.2  Based Literal --

   --------------------------

   --  BASED_LITERAL ::=

   --   BASE # BASED_NUMERAL [.BASED_NUMERAL] # [EXPONENT]

   --  Handled by scanner as part of numeric literal handling (see 2.4)

   -----------------

   -- 2.4.2  Base --

   -----------------

   --  BASE ::= NUMERAL

   --  Handled by scanner as part of numeric literal handling (see 2.4)

   --------------------------

   -- 2.4.2  Based Numeral --

   --------------------------

   --  BASED_NUMERAL ::=

   --    EXTENDED_DIGIT {[UNDERLINE] EXTENDED_DIGIT}

   --  Handled by scanner as part of numeric literal handling (see 2.4)

   ---------------------------

   -- 2.4.2  Extended Digit --

   ---------------------------

   --  EXTENDED_DIGIT ::= DIGIT | A | B | C | D | E | F

   --  Handled by scanner as part of numeric literal handling (see 2.4)

   ----------------------------

   -- 2.5  Character Literal --

   ----------------------------

   --  CHARACTER_LITERAL ::= ' GRAPHIC_CHARACTER '

   --  Handled by the scanner and returned as Tok_Char_Literal

   -------------------------

   -- 2.6  String Literal --

   -------------------------

   --  STRING LITERAL ::= "{STRING_ELEMENT}"

   --  Handled by the scanner and returned as Tok_String_Literal

   --  or if the string looks like an operator as Tok_Operator_Symbol.

   -------------------------

   -- 2.6  String Element --

   -------------------------

   --  STRING_ELEMENT ::= "" | non-quotation_mark_GRAPHIC_CHARACTER

   --  A STRING_ELEMENT is either a pair of quotation marks ("),

   --  or a single GRAPHIC_CHARACTER other than a quotation mark.

   --  Handled by scanner as part of string literal handling (see 2.4)

   ------------------

   -- 2.7  Comment --

   ------------------

   --  A COMMENT starts with two adjacent hyphens and extends up to the

   --  end of the line. A COMMENT may appear on any line of a program.

   --  Handled by the scanner which simply skips past encountered comments

   -----------------

   -- 2.8  Pragma --

   -----------------

   --  PRAGMA ::= pragma IDENTIFIER

   --    [(PRAGMA_ARGUMENT_ASSOCIATION {, PRAGMA_ARGUMENT_ASSOCIATION})];

   --  The caller has checked that the initial token is PRAGMA

   --  Error recovery: cannot raise Error_Resync

   --  One special piece of processing is needed in this routine. As described

   --  in the section on "Handling semicolon used in place of IS" in module

   --  Parse, the parser detects the case of missing subprogram bodies to

   --  allow recovery from this syntactic error. Pragma INTERFACE (and, for

   --  Ada 95, pragma IMPORT) can appear in place of the body. The parser must

   --  recognize the use of these two pragmas in this context, otherwise it

   --  will think there are missing bodies, and try to change ; to IS, when

   --  in fact the bodies ARE present, supplied by these pragmas.

   function P_Pragma (Skipping : Boolean := False) return Node_Id is

      Interface_Check_Required : Boolean := False;

      --  Set True if check of pragma INTERFACE is required

      Import_Check_Required : Boolean := False;

      --  Set True if check of pragma IMPORT is required

      Arg_Count : Int := 0;

      --  Number of argument associations processed

      Identifier_Seen : Boolean := False;

      --  Set True if an identifier is encountered for a pragma argument. Used

      --  to check that there are no more arguments without identifiers.

      Prag_Node     : Node_Id;

      Prag_Name     : Name_Id;

      Semicolon_Loc : Source_Ptr;

      Ident_Node    : Node_Id;

      Assoc_Node    : Node_Id;

      Result        : Node_Id;

      procedure Skip_Pragma_Semicolon;

      --  Skip past semicolon at end of pragma

      ---------------------------

      -- Skip_Pragma_Semicolon --

      ---------------------------

      procedure Skip_Pragma_Semicolon is

      begin

         if Token /= Tok_Semicolon then

            --  If skipping the pragma, ignore a missing semicolon

            if Skipping then

               null;

            --  Otherwise demand a semicolon

            else

               T_Semicolon;

            end if;

         --  Scan past semicolon if present

         else

            Scan;

         end if;

      end Skip_Pragma_Semicolon;

   --  Start of processing for P_Pragma

   begin

      Prag_Node := New_Node (N_Pragma, Token_Ptr);

      Scan; -- past PRAGMA

      Prag_Name := Token_Name;

      if Style_Check then

         Style.Check_Pragma_Name;

      end if;

      --  Ada 2005 (AI-284): INTERFACE is a new reserved word but it is

      --  allowed as a pragma name.

      if Ada_Version >= Ada_05

        and then Token = Tok_Interface

      then

         Prag_Name := Name_Interface;

         Ident_Node  := Make_Identifier (Token_Ptr, Name_Interface);

         Scan; -- past INTERFACE

      else

         Ident_Node := P_Identifier;

      end if;

      Set_Pragma_Identifier (Prag_Node, Ident_Node);

      --  See if special INTERFACE/IMPORT check is required

      if SIS_Entry_Active then

         Interface_Check_Required := (Prag_Name = Name_Interface);

         Import_Check_Required    := (Prag_Name = Name_Import);

      else

         Interface_Check_Required := False;

         Import_Check_Required    := False;

      end if;

      --  Scan arguments. We assume that arguments are present if there is

      --  a left paren, or if a semicolon is missing and there is another

      --  token on the same line as the pragma name.

      if Token = Tok_Left_Paren

        or else (Token /= Tok_Semicolon

                   and then not Token_Is_At_Start_Of_Line)

      then

         Set_Pragma_Argument_Associations (Prag_Node, New_List);

         T_Left_Paren;

         loop

            Arg_Count := Arg_Count + 1;

            Scan_Pragma_Argument_Association (Identifier_Seen, Assoc_Node);

            if Arg_Count = 2

              and then (Interface_Check_Required or else Import_Check_Required)

            then

               --  Here is where we cancel the SIS active status if this pragma

               --  supplies a body for the currently active subprogram spec.

               if Nkind (Expression (Assoc_Node)) in N_Direct_Name

                 and then Chars (Expression (Assoc_Node)) = Chars (SIS_Labl)

               then

                  SIS_Entry_Active := False;

               end if;

            end if;

            Append (Assoc_Node, Pragma_Argument_Associations (Prag_Node));

            exit when Token /= Tok_Comma;

            Scan; -- past comma

         end loop;

         --  If we have := for pragma Debug, it is worth special casing the

         --  error message (it is easy to think of pragma Debug as taking a

         --  statement, and an assignment statement is the most likely

         --  candidate for this error)

         if Token = Tok_Colon_Equal and then Prag_Name = Name_Debug then

            Error_Msg_SC ("argument for pragma Debug must be procedure call");

            Resync_To_Semicolon;

         --  Normal case, we expect a right paren here

         else

            T_Right_Paren;

         end if;

      end if;

      Semicolon_Loc := Token_Ptr;

      --  Now we have two tasks left, we need to scan out the semicolon

      --  following the pragma, and we have to call Par.Prag to process

      --  the pragma. Normally we do them in this order, however, there

      --  is one exception namely pragma Style_Checks where we like to

      --  skip the semicolon after processing the pragma, since that way

      --  the style checks for the scanning of the semicolon follow the

      --  settings of the pragma.

      --  You might think we could just unconditionally do things in

      --  the opposite order, but there are other pragmas, notably the

      --  case of pragma Source_File_Name, which assume the semicolon

      --  is already scanned out.

      if Prag_Name = Name_Style_Checks then

         Result := Par.Prag (Prag_Node, Semicolon_Loc);

         Skip_Pragma_Semicolon;

         return Result;

      else

         Skip_Pragma_Semicolon;

         return Par.Prag (Prag_Node, Semicolon_Loc);

      end if;

   exception

      when Error_Resync =>

         Resync_Past_Semicolon;

         return Error;

   end P_Pragma;

   --  This routine is called if a pragma is encountered in an inappropriate

   --  position, the pragma is scanned out and control returns to continue.

   --  The caller has checked that the initial token is pragma

   --  Error recovery: cannot raise Error_Resync

   procedure P_Pragmas_Misplaced is

   begin

      while Token = Tok_Pragma loop

         Error_Msg_SC ("pragma not allowed here");

         Discard_Junk_Node (P_Pragma (Skipping => True));

      end loop;

   end P_Pragmas_Misplaced;

   --  This function is called to scan out an optional sequence of pragmas.

   --  If no pragmas are found, then No_List is returned.

   --  Error recovery: Cannot raise Error_Resync

   function P_Pragmas_Opt return List_Id is

      L : List_Id;

   begin

      if Token = Tok_Pragma then

         L := New_List;

         P_Pragmas_Opt (L);

         return L;

      else

         return No_List;

      end if;

   end P_Pragmas_Opt;

   --  This procedure is called to scan out an optional sequence of pragmas.

   --  Any pragmas found are appended to the list provided as an argument.

   --  Error recovery: Cannot raise Error_Resync

   procedure P_Pragmas_Opt (List : List_Id) is

      P     : Node_Id;

   begin

      while Token = Tok_Pragma loop

         P := P_Pragma;

         if Nkind (P) /= N_Error

          and then (Pragma_Name (P) = Name_Assert

                      or else

                    Pragma_Name (P) = Name_Debug)

         then

            Error_Msg_Name_1 := Pragma_Name (P);

            Error_Msg_N

              ("pragma% must be in declaration/statement context", P);

         else

            Append (P, List);

         end if;

      end loop;

   end P_Pragmas_Opt;

   --------------------------------------

   -- 2.8  Pragma_Argument Association --

   --------------------------------------

   --  PRAGMA_ARGUMENT_ASSOCIATION ::=

   --    [pragma_argument_IDENTIFIER =>] NAME

   --  | [pragma_argument_IDENTIFIER =>] EXPRESSION

   --  Error recovery: cannot raise Error_Resync

   procedure Scan_Pragma_Argument_Association

     (Identifier_Seen : in out Boolean;

      Association     : out Node_Id)

   is

      Scan_State      : Saved_Scan_State;

      Identifier_Node : Node_Id;

      Id_Present      : Boolean;

   begin

      Association := New_Node (N_Pragma_Argument_Association, Token_Ptr);

      Set_Chars (Association, No_Name);

      --  Argument starts with identifier

      if Token = Tok_Identifier then

         Identifier_Node := Token_Node;

         Save_Scan_State (Scan_State); -- at Identifier

         Scan; -- past Identifier

         if Token = Tok_Arrow then

            Identifier_Seen := True;

            Scan; -- past arrow

            Set_Chars (Association, Chars (Identifier_Node));

            Id_Present := True;

         --  Case of argument with no identifier

         else

            Restore_Scan_State (Scan_State); -- to Identifier

            Id_Present := False;

         end if;

      --  Argument does not start with identifier

      else

         Id_Present := False;

      end if;

      if Identifier_Seen and not Id_Present then

         Error_Msg_SC

           ("|pragma argument identifier required here (RM 2.8(4))");

      end if;

      if Id_Present then

         Set_Expression (Association, P_Expression);

      else

         Set_Expression (Association, P_Expression_If_OK);

      end if;

   end Scan_Pragma_Argument_Association;

end Ch2;