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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) 1992-2018, 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 for scanning
  27 --  Ada source files or text files with an Ada-like syntax, such as project
  28 --  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: Tok_Char_Literal,
  37    --  Tok_Identifier, Tok_Real_Literal, Tok_Real_Literal, Tok_Integer_Literal,
  38    --  Tok_String_Literal, Tok_Operator_Symbol, and Tok_Vertical_Bar. Used to
  39    --  build Token_Node and also check for obsolescent features.
  40
  41    with procedure Error_Msg (Msg : String; Flag_Location : Source_Ptr);
  42    --  Output a message at specified location
  43
  44    with procedure Error_Msg_S (Msg : String);
  45    --  Output a message at current scan pointer location
  46
  47    with procedure Error_Msg_SC (Msg : String);
  48    --  Output a message at the start of the current token
  49
  50    with procedure Error_Msg_SP (Msg : String);
  51    --  Output a message at the start of the previous token
  52
  53    with package Style is new Styleg
  54      (Error_Msg, Error_Msg_S, Error_Msg_SC, Error_Msg_SP);
  55    --  Instantiation of Styleg with the same error reporting routines
  56
  57 package Scng is
  58
  59    procedure Check_End_Of_Line;
  60    --  Called when end of line encountered. Checks that line is not too long,
  61    --  and that other style checks for the end of line are met.
  62
  63    procedure Initialize_Scanner (Index : Source_File_Index);
  64    --  Initialize lexical scanner for scanning a new file referenced by Index.
  65    --  Initialize_Scanner does not call Scan.
  66
  67    procedure Scan;
  68    --  Scan scans out the next token, and advances the scan state accordingly
  69    --  (see package Scan_State for details). If the scan encounters an illegal
  70    --  token, then an error message is issued pointing to the bad character,
  71    --  and Scan returns a reasonable substitute token of some kind.
  72    --  For tokens Char_Literal, Identifier, Real_Literal, Integer_Literal,
  73    --  String_Literal and Operator_Symbol, Post_Scan is called after scanning.
  74
  75    function Determine_Token_Casing return Casing_Type;
  76    pragma Inline (Determine_Token_Casing);
  77    --  Determines the casing style of the current token, which is
  78    --  either a keyword or an identifier. See also package Casing.
  79
  80    procedure Set_Special_Character (C : Character);
  81    --  Indicate that one of the following character '#', '$', '?',  '`',
  82    --  '\', '^', '_' or '~', when found is a Special token.
  83    --  AI12-0125-03 : target name (ES) is not in this list because '@' is
  84    --  handled as a special token as abbreviation of LHS of assignment.
  85
  86    procedure Reset_Special_Characters;
  87    --  Indicate that there is no characters that are Special tokens., which
  88    --  is the default.
  89
  90    procedure Set_End_Of_Line_As_Token (Value : Boolean);
  91    --  Indicate if End_Of_Line is a token or not.
  92    --  By default, End_Of_Line is not a token.
  93
  94    procedure Set_Comment_As_Token (Value : Boolean);
  95    --  Indicate if a comment is a token or not.
  96    --  By default, a comment is not a token.
  97
  98    function Set_Start_Column return Column_Number;
  99    --  This routine is called with Scan_Ptr pointing to the first character
 100    --  of a line. On exit, Scan_Ptr is advanced to the first non-blank
 101    --  character of this line (or to the terminating format effector if the
 102    --  line contains no non-blank characters), and the returned result is the
 103    --  column number of this non-blank character (zero origin), which is the
 104    --  value to be stored in the Start_Column scan variable.
 105
 106 end Scng;