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   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                                 S C N G                                  --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --          Copyright (C) 1992-2007, Free Software Foundation, Inc.         --
  10 --                                                                          --
  11 -- GNAT is free software;  you can  redistribute it  and/or modify it under --
  12 -- terms of the  GNU General Public License as published  by the Free Soft- --
  13 -- ware  Foundation;  either version 3,  or (at your option) any later ver- --
  14 -- sion.  GNAT is distributed in the hope that it will be useful, but WITH- --
  15 -- OUT ANY WARRANTY;  without even the  implied warranty of MERCHANTABILITY --
  16 -- or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License --
  17 -- for  more details.  You should have  received  a copy of the GNU General --
  18 -- Public License  distributed with GNAT; see file COPYING3.  If not, go to --
  19 -- http://www.gnu.org/licenses for a complete copy of the license.          --
  20 --                                                                          --
  21 -- GNAT was originally developed  by the GNAT team at  New York University. --
  22 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  23 --                                                                          --
  24 ------------------------------------------------------------------------------
  25
  26 --  This package contains a generic lexical analyzer. This is used
  27 --  for scanning Ada source files or text files with an Ada-like syntax,
  28 --  such as project files. It is instantiated in Scn and Prj.Err.
  29
  30 with Casing; use Casing;
  31 with Styleg;
  32 with Types;  use Types;
  33
  34 generic
  35    with procedure Post_Scan;
  36    --  Procedure called by Scan for the following tokens:
  37    --  Tok_Char_Literal, Tok_Identifier, Tok_Real_Literal, Tok_Real_Literal,
  38    --  Tok_Integer_Literal, Tok_String_Literal, Tok_Operator_Symbol.
  39
  40    with procedure Error_Msg (Msg : String; Flag_Location : Source_Ptr);
  41    --  Output a message at specified location
  42
  43    with procedure Error_Msg_S (Msg : String);
  44    --  Output a message at current scan pointer location
  45
  46    with procedure Error_Msg_SC (Msg : String);
  47    --  Output a message at the start of the current token
  48
  49    with procedure Error_Msg_SP (Msg : String);
  50    --  Output a message at the start of the previous token
  51
  52    with procedure Obsolescent_Check (S : Source_Ptr);
  53    --  Called when one of the obsolescent character replacements is
  54    --  used with S pointing to the character in question.
  55
  56    with package Style is new Styleg
  57      (Error_Msg, Error_Msg_S, Error_Msg_SC, Error_Msg_SP);
  58    --  Instantiation of Styleg with the same error reporting routines
  59
  60 package Scng is
  61
  62    procedure Initialize_Scanner (Index : Source_File_Index);
  63    --  Initialize lexical scanner for scanning a new file referenced by Index.
  64    --  Initialize_Scanner does not call Scan.
  65
  66    procedure Scan;
  67    --  Scan scans out the next token, and advances the scan state accordingly
  68    --  (see package Scan_State for details). If the scan encounters an illegal
  69    --  token, then an error message is issued pointing to the bad character,
  70    --  and Scan returns a reasonable substitute token of some kind.
  71    --  For tokens Char_Literal, Identifier, Real_Literal, Integer_Literal,
  72    --  String_Literal and Operator_Symbol, Post_Scan is called after scanning.
  73
  74    function Determine_Token_Casing return Casing_Type;
  75    pragma Inline (Determine_Token_Casing);
  76    --  Determines the casing style of the current token, which is
  77    --  either a keyword or an identifier. See also package Casing.
  78
  79    procedure Set_Special_Character (C : Character);
  80    --  Indicate that one of the following character '#', '$', '?', '@', '`',
  81    --  '\', '^', '_' or '~', when found is a Special token.
  82
  83    procedure Reset_Special_Characters;
  84    --  Indicate that there is no characters that are Special tokens., which
  85    --  is the default.
  86
  87    procedure Set_End_Of_Line_As_Token (Value : Boolean);
  88    --  Indicate if End_Of_Line is a token or not.
  89    --  By default, End_Of_Line is not a token.
  90
  91    procedure Set_Comment_As_Token (Value : Boolean);
  92    --  Indicate if a comment is a token or not.
  93    --  By default, a comment is not a token.
  94
  95    function Set_Start_Column return Column_Number;
  96    --  This routine is called with Scan_Ptr pointing to the first character
  97    --  of a line. On exit, Scan_Ptr is advanced to the first non-blank
  98    --  character of this line (or to the terminating format effector if the
  99    --  line contains no non-blank characters), and the returned result is the
 100    --  column number of this non-blank character (zero origin), which is the
 101    --  value to be stored in the Start_Column scan variable.
 102
 103 end Scng;