138 lines
6.6 KiB
Ada
138 lines
6.6 KiB
Ada
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------------------------------------------------------------------------------
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-- --
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-- GNAT COMPILER COMPONENTS --
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-- --
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-- S Y S T E M . R E G E X P --
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-- --
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-- S p e c --
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-- --
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-- Copyright (C) 1998-2010, AdaCore --
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-- --
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-- GNAT is free software; you can redistribute it and/or modify it under --
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-- terms of the GNU General Public License as published by the Free Soft- --
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-- ware Foundation; either version 3, or (at your option) any later ver- --
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-- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
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-- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
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-- or FITNESS FOR A PARTICULAR PURPOSE. --
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-- --
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-- As a special exception under Section 7 of GPL version 3, you are granted --
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-- additional permissions described in the GCC Runtime Library Exception, --
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-- version 3.1, as published by the Free Software Foundation. --
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-- --
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-- You should have received a copy of the GNU General Public License and --
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-- a copy of the GCC Runtime Library Exception along with this program; --
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-- see the files COPYING3 and COPYING.RUNTIME respectively. If not, see --
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-- <http://www.gnu.org/licenses/>. --
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-- --
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-- GNAT was originally developed by the GNAT team at New York University. --
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-- Extensive contributions were provided by Ada Core Technologies Inc. --
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-- --
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------------------------------------------------------------------------------
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-- Simple Regular expression matching
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-- This package provides a simple implementation of a regular expression
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-- pattern matching algorithm, using a subset of the syntax of regular
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-- expressions copied from familiar Unix style utilities.
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-- Note: this package is in the System hierarchy so that it can be directly
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-- be used by other predefined packages. User access to this package is via
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-- a renaming of this package in GNAT.Regexp (file g-regexp.ads).
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with Ada.Finalization;
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package System.Regexp is
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-- The regular expression must first be compiled, using the Compile
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-- function, which creates a finite state matching table, allowing
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-- very fast matching once the expression has been compiled.
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-- The following is the form of a regular expression, expressed in Ada
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-- reference manual style BNF is as follows
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-- regexp ::= term
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-- regexp ::= term | term -- alternation (term or term ...)
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-- term ::= item
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-- term ::= item item ... -- concatenation (item then item)
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-- item ::= elmt -- match elmt
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-- item ::= elmt * -- zero or more elmt's
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-- item ::= elmt + -- one or more elmt's
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-- item ::= elmt ? -- matches elmt or nothing
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-- elmt ::= nchr -- matches given character
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-- elmt ::= [nchr nchr ...] -- matches any character listed
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-- elmt ::= [^ nchr nchr ...] -- matches any character not listed
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-- elmt ::= [char - char] -- matches chars in given range
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-- elmt ::= . -- matches any single character
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-- elmt ::= ( regexp ) -- parens used for grouping
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-- char ::= any character, including special characters
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-- nchr ::= any character except \()[].*+?^ or \char to match char
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-- ... is used to indication repetition (one or more terms)
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-- See also regexp(1) man page on Unix systems for further details
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-- A second kind of regular expressions is provided. This one is more
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-- like the wild card patterns used in file names by the Unix shell (or
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-- DOS prompt) command lines. The grammar is the following:
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-- regexp ::= term
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-- term ::= elmt
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-- term ::= elmt elmt ... -- concatenation (elmt then elmt)
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-- term ::= * -- any string of 0 or more characters
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-- term ::= ? -- matches any character
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-- term ::= [char char ...] -- matches any character listed
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-- term ::= [char - char] -- matches any character in given range
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-- term ::= {elmt, elmt, ...} -- alternation (matches any of elmt)
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-- Important note : This package was mainly intended to match regular
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-- expressions against file names. The whole string has to match the
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-- regular expression. If only a substring matches, then the function
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-- Match will return False.
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type Regexp is private;
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-- Private type used to represent a regular expression
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Error_In_Regexp : exception;
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-- Exception raised when an error is found in the regular expression
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function Compile
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(Pattern : String;
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Glob : Boolean := False;
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Case_Sensitive : Boolean := True) return Regexp;
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-- Compiles a regular expression S. If the syntax of the given
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-- expression is invalid (does not match above grammar), Error_In_Regexp
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-- is raised. If Glob is True, the pattern is considered as a 'globbing
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-- pattern', that is a pattern as given by the second grammar above.
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-- As a special case, if Pattern is the empty string it will always
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-- match.
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function Match (S : String; R : Regexp) return Boolean;
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-- True if S matches R, otherwise False. Raises Constraint_Error if
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-- R is an uninitialized regular expression value.
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private
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type Regexp_Value;
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type Regexp_Access is access Regexp_Value;
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type Regexp is new Ada.Finalization.Controlled with record
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R : Regexp_Access := null;
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end record;
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pragma Finalize_Storage_Only (Regexp);
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procedure Finalize (R : in out Regexp);
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-- Free the memory occupied by R
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procedure Adjust (R : in out Regexp);
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-- Called after an assignment (do a copy of the Regexp_Access.all)
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end System.Regexp;
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