------------------------------------------------------------------------------
--                                                                          --
--                         GNAT COMPILER COMPONENTS                         --
--                                                                          --
--                                 S C N G                                  --
--                                                                          --
--                                 S p e c                                  --
--                                                                          --
--          Copyright (C) 1992-2022, 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.      --
--                                                                          --
------------------------------------------------------------------------------

--  This is a generic lexical analyzer, used for scanning Ada source files, and
--  also for preprocessor files.

with Casing; use Casing;
with Scans;  use Scans;
with Styleg;
with Types;  use Types;

generic
   with procedure Post_Scan;
   --  Procedure called by Scan for the following tokens: Tok_Char_Literal,
   --  Tok_Identifier, Tok_Real_Literal, Tok_Real_Literal, Tok_Integer_Literal,
   --  Tok_String_Literal, Tok_Operator_Symbol, and Tok_Vertical_Bar. Used to
   --  build Token_Node and also check for obsolescent features.

   with procedure Error_Msg (Msg : String; Flag_Location : Source_Ptr);
   --  Output a message at specified location

   with procedure Error_Msg_S (Msg : String);
   --  Output a message at current scan pointer location

   with procedure Error_Msg_SC (Msg : String);
   --  Output a message at the start of the current token

   with procedure Error_Msg_SP (Msg : String);
   --  Output a message at the start of the previous token

   with package Style is new Styleg
     (Error_Msg, Error_Msg_S, Error_Msg_SC, Error_Msg_SP);
   --  Instantiation of Styleg with the same error reporting routines

package Scng is

   procedure Check_End_Of_Line;
   --  Called when end of line encountered. Checks that line is not too long,
   --  and that other style checks for the end of line are met.

   procedure Initialize_Scanner (Index : Source_File_Index);
   --  Initialize lexical scanner for scanning a new file referenced by Index.
   --  Initialize_Scanner does not call Scan.

   procedure Scan;
   --  Scan scans out the next token, and advances the scan state accordingly
   --  (see package Scan_State for details). If the scan encounters an illegal
   --  token, then an error message is issued pointing to the bad character,
   --  and Scan returns a reasonable substitute token. For tokens Char_Literal,
   --  Identifier, Real_Literal, Integer_Literal, String_Literal and
   --  Operator_Symbol, Post_Scan is called after scanning.

   function Determine_Token_Casing return Casing_Type;
   pragma Inline (Determine_Token_Casing);
   --  Determines the casing style of the current token, which is
   --  either a keyword or an identifier. See also package Casing.

   procedure Set_Special_Character (C : Special_Preprocessor_Character);
   --  Called when the preprocessor is active to indicate that Scan should
   --  return a Special token for C.

   procedure Reset_Special_Characters;
   --  Indicate that there are no characters that are Special tokens, which
   --  is the default.

   procedure Set_End_Of_Line_As_Token (Value : Boolean);
   --  Indicate if End_Of_Line is a token or not.
   --  By default, End_Of_Line is not a token.

   function Set_Start_Column return Column_Number;
   --  This routine is called with Scan_Ptr pointing to the first character
   --  of a line. On exit, Scan_Ptr is advanced to the first non-blank
   --  character of this line (or to the terminating format effector if the
   --  line contains no non-blank characters), and the returned result is the
   --  column number of this non-blank character (zero origin), which is the
   --  value to be stored in the Start_Column scan variable.

end Scng;