gcc/ada/g-regexp.ads

   1 ------------------------------------------------------------------------------
   2 --                                                                          --
   3 --                         GNAT COMPILER COMPONENTS                         --
   4 --                                                                          --
   5 --                          G N A T . R E G E X P                           --
   6 --                                                                          --
   7 --                                 S p e c                                  --
   8 --                                                                          --
   9 --           Copyright (C) 1998-2003 Ada Core Technologies, 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- --
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  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 COPYING.  If not, write --
  19 -- to  the Free Software Foundation,  59 Temple Place - Suite 330,  Boston, --
  20 -- MA 02111-1307, USA.                                                      --
  21 --                                                                          --
  22 -- As a special exception,  if other files  instantiate  generics from this --
  23 -- unit, or you link  this unit with other files  to produce an executable, --
  24 -- this  unit  does not  by itself cause  the resulting  executable  to  be --
  25 -- covered  by the  GNU  General  Public  License.  This exception does not --
  26 -- however invalidate  any other reasons why  the executable file  might be --
  27 -- covered by the  GNU Public License.                                      --
  28 --                                                                          --
  29 -- GNAT was originally developed  by the GNAT team at  New York University. --
  30 -- Extensive contributions were provided by Ada Core Technologies Inc.      --
  31 --                                                                          --
  32 ------------------------------------------------------------------------------
  33
  34 --  Simple Regular expression matching
  35
  36 --  This package provides a simple implementation of a regular expression
  37 --  pattern matching algorithm, using a subset of the syntax of regular
  38 --  expressions copied from familiar Unix style utilities.
  39
  40 ------------------------------------------------------------
  41 -- Summary of Pattern Matching Packages in GNAT Hierarchy --
  42 ------------------------------------------------------------
  43
  44 --  There are three related packages that perform pattern maching functions.
  45 --  the following is an outline of these packages, to help you determine
  46 --  which is best for your needs.
  47
  48 --     GNAT.Regexp (files g-regexp.ads/g-regexp.adb)
  49 --       This is a simple package providing Unix-style regular expression
  50 --       matching with the restriction that it matches entire strings. It
  51 --       is particularly useful for file name matching, and in particular
  52 --       it provides "globbing patterns" that are useful in implementing
  53 --       unix or DOS style wild card matching for file names.
  54
  55 --     GNAT.Regpat (files g-regpat.ads/g-regpat.adb)
  56 --       This is a more complete implementation of Unix-style regular
  57 --       expressions, copied from the original V7 style regular expression
  58 --       library written in C by Henry Spencer. It is functionally the
  59 --       same as this library, and uses the same internal data structures
  60 --       stored in a binary compatible manner.
  61
  62 --     GNAT.Spitbol.Patterns (files g-spipat.ads/g-spipat.adb)
  63 --       This is a completely general patterm matching package based on the
  64 --       pattern language of SNOBOL4, as implemented in SPITBOL. The pattern
  65 --       language is modeled on context free grammars, with context sensitive
  66 --       extensions that provide full (type 0) computational capabilities.
  67
  68 with Ada.Finalization;
  69
  70 package GNAT.Regexp is
  71
  72    --  The regular expression must first be compiled, using the Compile
  73    --  function, which creates a finite state matching table, allowing
  74    --  very fast matching once the expression has been compiled.
  75
  76    --  The following is the form of a regular expression, expressed in Ada
  77    --  reference manual style BNF is as follows
  78
  79    --     regexp ::= term
  80
  81    --     regexp ::= term | term          -- alternation (term or term ...)
  82
  83    --     term ::= item
  84
  85    --     term ::= item item ...          -- concatenation (item then item)
  86
  87    --     item ::= elmt                   -- match elmt
  88    --     item ::= elmt *                 -- zero or more elmt's
  89    --     item ::= elmt +                 -- one or more elmt's
  90    --     item ::= elmt ?                 -- matches elmt or nothing
  91
  92    --     elmt ::= nchr                   -- matches given character
  93    --     elmt ::= [nchr nchr ...]        -- matches any character listed
  94    --     elmt ::= [^ nchr nchr ...]      -- matches any character not listed
  95    --     elmt ::= [char - char]          -- matches chars in given range
  96    --     elmt ::= .                      -- matches any single character
  97    --     elmt ::= ( regexp )             -- parens used for grouping
  98
  99    --     char ::= any character, including special characters
 100    --     nchr ::= any character except \()[].*+?^ or \char to match char
 101    --     ... is used to indication repetition (one or more terms)
 102
 103    --  See also regexp(1) man page on Unix systems for further details
 104
 105    --  A second kind of regular expressions is provided. This one is more
 106    --  like the wild card patterns used in file names by the Unix shell (or
 107    --  DOS prompt) command lines. The grammar is the following:
 108
 109    --     regexp ::= term
 110
 111    --     term   ::= elmt
 112
 113    --     term   ::= elmt elmt ...     -- concatenation (elmt then elmt)
 114    --     term   ::= *                 -- any string of 0 or more characters
 115    --     term   ::= ?                 -- matches any character
 116    --     term   ::= [char char ...]   -- matches any character listed
 117    --     term   ::= [char - char]     -- matches any character in given range
 118    --     term   ::= {elmt, elmt, ...} -- alternation (matches any of elmt)
 119
 120    --  Important note : This package was mainly intended to match regular
 121    --  expressions against file names. The whole string has to match the
 122    --  regular expression. If only a substring matches, then the function
 123    --  Match will return False.
 124
 125    type Regexp is private;
 126    --  Private type used to represent a regular expression
 127
 128    Error_In_Regexp : exception;
 129    --  Exception raised when an error is found in the regular expression
 130
 131    function Compile
 132      (Pattern        : String;
 133       Glob           : Boolean := False;
 134       Case_Sensitive : Boolean := True)
 135       return           Regexp;
 136    --  Compiles a regular expression S. If the syntax of the given
 137    --  expression is invalid (does not match above grammar, Error_In_Regexp
 138    --  is raised. If Glob is True, the pattern is considered as a 'globbing
 139    --  pattern', that is a pattern as given by the second grammar above.
 140    --  As a special case, if Pattern is the empty string it will always
 141    --  match.
 142
 143    function Match (S : String; R : Regexp) return Boolean;
 144    --  True if S matches R, otherwise False. Raises Constraint_Error if
 145    --  R is an uninitialized regular expression value.
 146
 147 private
 148    type Regexp_Value;
 149
 150    type Regexp_Access is access Regexp_Value;
 151
 152    type Regexp is new Ada.Finalization.Controlled with record
 153       R : Regexp_Access := null;
 154    end record;
 155
 156    pragma Finalize_Storage_Only (Regexp);
 157
 158    procedure Finalize (R : in out Regexp);
 159    --  Free the memory occupied by R
 160
 161    procedure Adjust (R : in out Regexp);
 162    --  Called after an assignment (do a copy of the Regexp_Access.all)
 163
 164 end GNAT.Regexp;