1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--                                 S C N G                                  --
6--                                                                          --
7--                                 S p e c                                  --
8--                                                                          --
9--          Copyright (C) 1992-2020, 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
30with Casing; use Casing;
31with Styleg;
32with Types;  use Types;
33
34generic
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
57package 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
106end Scng;
107