1------------------------------------------------------------------------------
2--                                                                          --
3--                         GNAT COMPILER COMPONENTS                         --
4--                                                                          --
5--                        S Y S T E M . R E G E X P                         --
6--                                                                          --
7--                                 S p e c                                  --
8--                                                                          --
9--                     Copyright (C) 1998-2010, AdaCore                     --
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.                                     --
17--                                                                          --
18-- As a special exception under Section 7 of GPL version 3, you are granted --
19-- additional permissions described in the GCC Runtime Library Exception,   --
20-- version 3.1, as published by the Free Software Foundation.               --
21--                                                                          --
22-- You should have received a copy of the GNU General Public License and    --
23-- a copy of the GCC Runtime Library Exception along with this program;     --
24-- see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see    --
25-- <http://www.gnu.org/licenses/>.                                          --
26--                                                                          --
27-- GNAT was originally developed  by the GNAT team at  New York University. --
28-- Extensive contributions were provided by Ada Core Technologies Inc.      --
29--                                                                          --
30------------------------------------------------------------------------------
31
32--  Simple Regular expression matching
33
34--  This package provides a simple implementation of a regular expression
35--  pattern matching algorithm, using a subset of the syntax of regular
36--  expressions copied from familiar Unix style utilities.
37
38--  Note: this package is in the System hierarchy so that it can be directly
39--  be used by other predefined packages. User access to this package is via
40--  a renaming of this package in GNAT.Regexp (file g-regexp.ads).
41
42with Ada.Finalization;
43
44package System.Regexp is
45
46   --  The regular expression must first be compiled, using the Compile
47   --  function, which creates a finite state matching table, allowing
48   --  very fast matching once the expression has been compiled.
49
50   --  The following is the form of a regular expression, expressed in Ada
51   --  reference manual style BNF is as follows
52
53   --     regexp ::= term
54
55   --     regexp ::= term | term          -- alternation (term or term ...)
56
57   --     term ::= item
58
59   --     term ::= item item ...          -- concatenation (item then item)
60
61   --     item ::= elmt                   -- match elmt
62   --     item ::= elmt *                 -- zero or more elmt's
63   --     item ::= elmt +                 -- one or more elmt's
64   --     item ::= elmt ?                 -- matches elmt or nothing
65
66   --     elmt ::= nchr                   -- matches given character
67   --     elmt ::= [nchr nchr ...]        -- matches any character listed
68   --     elmt ::= [^ nchr nchr ...]      -- matches any character not listed
69   --     elmt ::= [char - char]          -- matches chars in given range
70   --     elmt ::= .                      -- matches any single character
71   --     elmt ::= ( regexp )             -- parens used for grouping
72
73   --     char ::= any character, including special characters
74   --     nchr ::= any character except \()[].*+?^ or \char to match char
75   --     ... is used to indication repetition (one or more terms)
76
77   --  See also regexp(1) man page on Unix systems for further details
78
79   --  A second kind of regular expressions is provided. This one is more
80   --  like the wild card patterns used in file names by the Unix shell (or
81   --  DOS prompt) command lines. The grammar is the following:
82
83   --     regexp ::= term
84
85   --     term   ::= elmt
86
87   --     term   ::= elmt elmt ...     -- concatenation (elmt then elmt)
88   --     term   ::= *                 -- any string of 0 or more characters
89   --     term   ::= ?                 -- matches any character
90   --     term   ::= [char char ...]   -- matches any character listed
91   --     term   ::= [char - char]     -- matches any character in given range
92   --     term   ::= {elmt, elmt, ...} -- alternation (matches any of elmt)
93
94   --  Important note : This package was mainly intended to match regular
95   --  expressions against file names. The whole string has to match the
96   --  regular expression. If only a substring matches, then the function
97   --  Match will return False.
98
99   type Regexp is private;
100   --  Private type used to represent a regular expression
101
102   Error_In_Regexp : exception;
103   --  Exception raised when an error is found in the regular expression
104
105   function Compile
106     (Pattern        : String;
107      Glob           : Boolean := False;
108      Case_Sensitive : Boolean := True) return Regexp;
109   --  Compiles a regular expression S. If the syntax of the given
110   --  expression is invalid (does not match above grammar), Error_In_Regexp
111   --  is raised. If Glob is True, the pattern is considered as a 'globbing
112   --  pattern', that is a pattern as given by the second grammar above.
113   --  As a special case, if Pattern is the empty string it will always
114   --  match.
115
116   function Match (S : String; R : Regexp) return Boolean;
117   --  True if S matches R, otherwise False. Raises Constraint_Error if
118   --  R is an uninitialized regular expression value.
119
120private
121   type Regexp_Value;
122
123   type Regexp_Access is access Regexp_Value;
124
125   type Regexp is new Ada.Finalization.Controlled with record
126      R : Regexp_Access := null;
127   end record;
128
129   pragma Finalize_Storage_Only (Regexp);
130
131   procedure Finalize (R : in out Regexp);
132   --  Free the memory occupied by R
133
134   procedure Adjust (R : in out Regexp);
135   --  Called after an assignment (do a copy of the Regexp_Access.all)
136
137end System.Regexp;
138