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MYR(REGEX)							      MYR(REGEX)

NAME
     regex myr-regex

LIBRARY
     regex

SYNOPSIS
     use  regex  const	compile  :  (re  : byte[:] -> std.error(regex#, status))
     const dbgcompile	  : (re : byte[:] ->  std.error(regex#,  status))  const
     free : (re : regex# -> void)
     const  exec     : (re : regex#, str : byte[:] -> bool) const search   : (re
     : regex#, str : byte[:] -> bool)

DESCRIPTION
     The regex library provides functions for compiling and  evaluating  regular
     expressions, as described later in this document, or in myr-regex(7).

     regex.compile  will  take	a string describing a regex, and will attempt to
     compile it, returing `std.Success regex# if the regex is valid,  and  there
     were no error conditions encountered during compilation. If the compilation
     failed, `std.Failure regex.status will be returned, where regex.status is a
     failure code.

     regex.dbgcompile  is identical to regex.compile, however, it will print de-
     bugging information as it compiles, and each time the regex is evaluated.

     regex.exec will take the regex passed to it, and evaluate it over the  text
     provided,	returning  the	`std.Some matches, or `std.None if there were no
     matches found. The matches must span the whole string.

     regex.search is similar to regex.exec, but it will attempt to find a  match
     somewhere within the string, instead of attempting to find a match spanning
     the whole string.

REGEX SYNTAX
     The grammar used by libregex is below:

	 regex	     : altexpr
	 altexpr     : catexpr ('|' altexpr)+
	 catexpr     : repexpr (catexpr)+
	 repexpr     : baseexpr[*+?]
	 baseexpr    : literal
		     | charclass
		     | charrange
		     | escaped
		     | '.'
		     | '^'
		     | '$'
		     | '(' regex ')'
	 charclass   : see below
	 charrange   : '[' (literal('-' literal)?)+']'

     The following metacharacters have the meanings listed below:

     Matches a single unicode character

     ^	    Matches the beginning of a line. Does not consume any characters.

     $	    Matches the end of a line. Does not consume any characters.

     *	    Matches any number of repetitions of the preceding regex fragment.

     *?     Reluctantly matches any number of repetitions of the preceding regex
	    fragment.

     +	    Matches one or more repetitions of the preceding regex fragment.

     +?     Reluctantly  matches  one or more repetitions of the preceding regex
	    fragment.

     ?	    Matches zero or one of the preceding regex fragment.

     In order to match a literal metacharacter, it needs to be preceded by a '\'
     character.

     The following character classes are supported:

     \d     ASCII digits

     \D     Negation of ASCII digits

     \x     ASCII Hex digits

     \X     Negation of ASCII Hex digits

     \s     ASCII spaces

     \S     Negation of ASCII spaces

     \w     ASCII word characters

     \W     Negation of ASCII word characters

     \h     ASCII whitespace characters

     \H     Negation of ASCII whitespace characters

     \pX, \p{X}
	    Characters with unicode property 'X'

     \PX, \P{X}
	    Negation of characters with unicode property 'X'

     Unicode properties that are supported are listed below:

     L, Letter
	    Unicode letter property

     Lu, Uppercase_Letter
	    Uppercase letter unicode property

     Ll, Lowercase_Letter
	    Lowercase letter unicode property

     Lt, Titlecase_Letter
	    Titlecase letter unicode property

     N, Number
	    Number unicode property

     Z, Separator
	    Any separator character unicode property

     Zs, Space_Separator
	    Space separator unicode property

EXAMPLE
	     use std
	     use regex

	     const main = {
		 var i

		 match regex.compile(pat)
		 | `std.Ok re:
			 match regex.exec(re, text)
			 | `std.Some matches:
				 for i = 0; i < matches.len; i++
				     std.put("Match {}: {}0, i, matches[i])
				 ;;
			 | `std.None: std.put("Text did not match0)
			 ;;
		 | `std.Err err:
			 std.put("failed to compile regex")
		 ;;
	     }

FILES
     The source code  for  this  compiler  is  available  from	git://git.eigen-
     state.org/git/ori/libregex.git

SEE ALSO
     6m(1)

BUGS
     This code is insufficiently tested.

     This code does not support all of the regex features that one would expect.

					1			      MYR(REGEX)
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