1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--                                  S C N                                   --
6--                                                                          --
7--                                 S p e c                                  --
8--                                                                          --
9--          Copyright (C) 1992-2010, 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 the lexical analyzer routines. This is used by the
27--  compiler for scanning Ada source files.
28
29with Casing; use Casing;
30with Errout; use Errout;
31with Scng;
32with Style;  use Style;
33with Types;  use Types;
34
35package Scn is
36
37   procedure Initialize_Scanner
38     (Unit  : Unit_Number_Type;
39      Index : Source_File_Index);
40   --  Initialize lexical scanner for scanning a new file. The caller has
41   --  completed the construction of the Units.Table entry for the specified
42   --  Unit and Index references the corresponding source file. A special
43   --  case is when Unit = No_Unit_Number, and Index corresponds to the
44   --  source index for reading the configuration pragma file.
45
46   function Determine_Token_Casing return Casing_Type;
47   --  Determines the casing style of the current token, which is
48   --  either a keyword or an identifier. See also package Casing.
49
50   procedure Post_Scan;
51   --  Create nodes for tokens: Char_Literal, Identifier, Real_Literal,
52   --  Integer_Literal, String_Literal and Operator_Symbol.
53
54   procedure Scan_Reserved_Identifier (Force_Msg : Boolean);
55   --  This procedure is called to convert the current token, which the caller
56   --  has checked is for a reserved word, to an equivalent identifier. This is
57   --  of course only used in error situations where the parser can detect that
58   --  a reserved word is being used as an identifier. An appropriate error
59   --  message, pointing to the token, is also issued if either this is the
60   --  first occurrence of misuse of this identifier, or if Force_Msg is True.
61
62   -------------
63   -- Scanner --
64   -------------
65
66   --  The scanner used by the compiler is an instantiation of the
67   --  generic package Scng with routines appropriate to the compiler
68
69   package Scanner is new Scng
70     (Post_Scan    => Post_Scan,
71      Error_Msg    => Error_Msg,
72      Error_Msg_S  => Error_Msg_S,
73      Error_Msg_SC => Error_Msg_SC,
74      Error_Msg_SP => Error_Msg_SP,
75      Style        => Style.Style_Inst);
76
77   procedure Scan renames Scanner.Scan;
78   --  Scan scans out the next token, and advances the scan state accordingly
79   --  (see package Scans for details). If the scan encounters an illegal
80   --  token, then an error message is issued pointing to the bad character,
81   --  and Scan returns a reasonable substitute token of some kind.
82
83end Scn;
84