ref: a9a7d5b32a9423f871311384af6260a3848291d1
dir: /lib/regex/myr-regex.3/
.TH MYR REGEX 1
.SH NAME
regex myr-regex
.SH LIBRARY
regex
.SH SYNOPSIS
.B use regex
.I const compile : (re : byte[:] -> std.error(regex#, status))
.I const dbgcompile : (re : byte[:] -> std.error(regex#, status))
.I const free : (re : regex# -> void)
.br
.I const exec : (re : regex#, str : byte[:] -> bool)
.I const search : (re : regex#, str : byte[:] -> bool)
.SH DESCRIPTION
.PP
The regex library provides functions for compiling and evaluating regular
expressions, as described later in this document, or in myr-regex(7).
.PP
.I regex.compile will take a string describing a regex, and will attempt
to compile it, returing
.I `std.Success regex#
if the regex is valid, and there were no error conditions encountered during
compilation. If the compilation failed,
.I `std.Failure regex.status
will be returned, where regex.status is a failure code.
.PP
.I regex.dbgcompile
is identical to
.I regex.compile,
however, it will print debugging information as it compiles, and each
time the regex is evaluated.
.PP
.I regex.exec
will take the regex passed to it, and evaluate it over the text provided,
returning the
.I `std.Some matches,
or
.I `std.None
if there were no matches found. The matches must span the whole string.
.PP
.I 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.
.SH REGEX SYNTAX
.PP
The grammar used by libregex is below:
.EX
regex : altexpr
altexpr : catexpr ('|' altexpr)+
catexpr : repexpr (catexpr)+
repexpr : baseexpr[*+?]
baseexpr : literal
| charclass
| charrange
| escaped
| '.'
| '^'
| '$'
| '(' regex ')'
charclass : see below
charrange : '[' (literal('-' literal)?)+']'
.EE
The following metacharacters have the meanings listed below:
.TP
.
Matches a single unicode character
.TP
^
Matches the beginning of a line. Does not consume any characters.
.TP
$
Matches the end of a line. Does not consume any characters.
.TP
*
Matches any number of repetitions of the preceding regex fragment.
.TP
*?
Reluctantly matches any number of repetitions of the preceding regex fragment.
.TP
+
Matches one or more repetitions of the preceding regex fragment.
.TP
+?
Reluctantly matches one or more repetitions of the preceding regex fragment.
.TP
?
Matches zero or one of the preceding regex fragment.
.PP
In order to match a literal metacharacter, it needs to be preceded by
a '\\' character.
The following character classes are supported:
.TP
\\d
ASCII digits
.TP
\\D
Negation of ASCII digits
.TP
\\x
ASCII Hex digits
.TP
\\X
Negation of ASCII Hex digits
.TP
\\s
ASCII spaces
.TP
\\S
Negation of ASCII spaces
.TP
\\w
ASCII word characters
.TP
\\W
Negation of ASCII word characters
.TP
\\h
ASCII whitespace characters
.TP
\\H
Negation of ASCII whitespace characters
.TP
\\pX, \\p{X}
Characters with unicode property 'X'
.TP
\\PX, \\P{X}
Negation of characters with unicode property 'X'
.PP
Unicode properties that are supported are listed below:
.TP
L, Letter
Unicode letter property
.TP
Lu, Uppercase_Letter
Uppercase letter unicode property
.TP
Ll, Lowercase_Letter
Lowercase letter unicode property
.TP
Lt, Titlecase_Letter
Titlecase letter unicode property
.TP
N, Number
Number unicode property
.TP
Z, Separator
Any separator character unicode property
.TP
Zs, Space_Separator
Space separator unicode property
.SH EXAMPLE
.EX
use std
use regex
const main = {
match regex.compile(pat)
var i
| `std.Success re:
match regex.exec(re, text)
| `std.Some matches:
for i = 0; i < matches.len; i++
std.put("Match %i: %s\n", i, match[i])
;;
| `std.None: std.put("Text did not match\n")
;;
| `std.Failure err:
std.put("failed to compile regex")
;;
}
.EE
.SH FILES
The source code for this compiler is available from
.B git://git.eigenstate.org/git/ori/libregex.git
.SH SEE ALSO
.IR 6m(1)
.SH BUGS
.PP
This code is insufficiently tested.
.PP
This code does not support all of the regex features that one would expect.