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{{Short description|Pattern matching library developed by Rich Salz}}
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'''wildmat''' is a [[pattern matching]] library developed by [[Rich Salz]].  Based on the [[wildcard character|wildcard syntax]] already used in the [[Bourne shell]], wildmat provides a uniform mechanism for matching patterns across applications with simpler syntax than that typically offered by [[regular expression]]s.  Patterns are implicitly anchored at the beginning and end of each string when testing for a match.

In June 2019, Rich Salz released the original version of the now-defunct library on [[GitHub]] under a [[public domain]] dedication.<ref>{{cite web |last1=Salz |first1=Rich |title=wildmat: The hoary classic wildmat pattern matcher; public domain |website=[[GitHub]] |url=https://github.com/richsalz/wildmat |accessdate=25 November 2019 |date=25 June 2019}}</ref>

==Pattern matching operations==
There are five pattern matching operations other than a strict one-to-one match between the pattern and the source to be checked for a match.
* Asterisk ([[*]]) to match any sequence of zero or more characters.
* Question mark ([[?]]) to match any single character.
* [[Set (computer science)|Set]] of specified characters. It is specified as a list of characters, or as a range of characters where the beginning and end of the range are separated by a minus (or dash) character, or as any combination of lists and ranges.  The dash can also be included in the set as a character if it is the beginning or end of the set.  This set is enclosed in square brackets.  The close square bracket (<nowiki>]</nowiki>) may be used in a set if it is the first character in the set.
* [[Negation]] of a set. It is specified the same way as the set with the addition of a caret character (^) at the beginning of the test string just inside the open square bracket. (NNTP specifies an alternative !. The implementation can be configured to do either.)
* Backslash ([[\]]) character to invalidate the special meaning of the open square bracket (<nowiki>[</nowiki>), the asterisk, backslash or the question mark. Two backslashes in sequence will result in the evaluation of the backslash as a character with no special meaning.

===Examples===
* ''*foo*''  	  matches string containing "foo".
* ''mini*''       matches anything that begins with "mini" (including the string "mini" itself).
* ''???*''        matches any string of three and more letters.
* ''[0-9a-zA-Z]'' matches every single [[alphanumeric]] [[ASCII]] character.
* ''[^]-]''       matches a character other than a close square bracket or a dash.

==Usage==
wildmat is most commonly seen in [[Network News Transfer Protocol|NNTP]] implementations such as Salz's own [[InterNetNews|INN]], also in unrelated software such as [[GNU]] tar and [[Transmission (BitTorrent client)|Transmission]]. GNU tar replaced wildmat with the POSIX fnmatch glob matcher in September 1992. The early version contained a potential out-of-bound access on unclosed {{mono|[}}.<ref>{{cite web |last1=Salz |first1=Rich |title=wildmat.c |website=[[GitHub]] |url=https://github.com/richsalz/wildmat/blob/master/wildmat.c |date=25 June 2019 |quote=Might not be robust in face of malformed patterns; e.g., "foo[a-" could cause a segmentation violation.}}</ref>

The original byte oriented wildmat implementation is unable to handle [[Variable-width encoding|multibyte character sets]], and poses problems when the text being searched may contain multiple incompatible character sets.  A simplified version of wildmat oriented toward [[UTF-8]] encoding has been developed by the [[Internet Engineering Task Force|IETF]] NNTP working group. It is a part of {{IETF RFC|3977}} (section 4), the 2006 standard for NNTP.

In the newer INN which supports UTF-8, a "uwildmat" was added which supports all the features of wildmat. This 2000 rewrite, performed by Russ Allbery, fixes the OOB in the original implementation. Tightly-wound C loops were written out into smaller statements.<ref>{{man|3|uwildmat|ManKier}}</ref><ref name=uwildmat>{{cite web |title=uwildmat.c in trunk/lib – INN |url=https://inn.eyrie.org/trac/browser/trunk/lib/uwildmat.c |website=inn.eyrie.org |accessdate=27 November 2019}}</ref>

[[Rsync]] includes a GPLv3-licensed wildmat descendant known as wildmatch, modified by Wayne Davison. The [[Git]] version control system imports and makes use of it. It does not support UTF-8, but has the OOB fixed and has additional support for character classes and star globs (** for arbitrary-depth).<ref>{{cite web |title=git/git: wildmatch.c |url=https://github.com/git/git/blob/master/wildmatch.c |website=GitHub|date=16 February 2022 }}</ref>

==See also==
* [[glob (programming)]]
* [[Kleene star]]
* [[Matching wildcards]]

==References==
{{reflist}}

==External links==
* {{cite newsgroup|author=Rich Salz|newsgroup=comp.sources.misc|title=v17i079: wildmat-1.4 - a /bin/sh-style pattern matcher, Part01/01|message-id=1991Apr4.034350.3923@sparky.IMD.Sterling.COM|date=April 4, 1991|url=https://groups.google.com/forum/#!msg/comp.sources.misc/x0svep80riU/zbveOTOa8esJ}}
* {{cite newsgroup|author=Rich Salz|newsgroup=comp.sources.misc|title=v17i034: wildmat - a /bin/sh-style pattern matcher, Part01/01|date=March 9, 1991|message-id=1991Mar9.044016.2409@sparky.IMD.Sterling.COM|url=https://groups.google.com/forum/#!topic/comp.sources.misc/ZzYKqnKCpf4}}

[[Category:Pattern matching]]