.Dd March 22, 2013
.Os SQLite\ UDF
.Dt REGEX \&3s "SQLite User-defined Functions"
.Sh NAME
.Nm regex
.Nd Apply regular expression to a string or column
.Sh LIBRARY
SQLite User-defined function Library (regex.so)
.Sh SYNOPSIS
select
.Pf regex( Ar pattern , data Ns );
.Sh DESCRIPTION
The 
.Nm
function compiles 
.Ar pattern
as an extended regular expression using
.Xr regcomp 3
and executes
.Xr regexec 3
for 
.Ar data .
It returns 
.Ql T
or
.Ql F
to indicate a match (or nonmatch). 
.Sh EXAMPLES
.Bd -literal
sqlite> \f[CB].load /usr/local/lib/sqlite3/regex.so\f[]
sqlite> \f[CB]create virtual table t using readdir (/tmp/eg);\f[]
sqlite> \f[CB]select *, regex('^..$', name) from t where name like 'm%';\f[]
fileno      type        name        fullname     regex('^..$', name)
----------  ----------  ----------  -----------  -------------------
13630381    l           man         /tmp/eg/man  F                  
13630382    l           me          /tmp/eg/me   T                  
13630383    l           misc        /tmp/eg/mis  F                  
13630384    l           mk          /tmp/eg/mk   T                  
13630385    l           ms          /tmp/eg/ms   T                  
.Ed
.Sh IMPLEMENTATION NOTES
This implementation was written to use the regular expression functions provided in the NetBSD standard C library. With minor modifications it could be adapted to the GNU or PCRE versions.  
.Pp
To use 
.Nm
in the SQLite shell
.Ic sqlite3 ,
add the following to your 
.Pa ${HOME}/.sqliterc 
file:
.Bd -literal
\&.load /usr/local/lib/sqlite3/regex.so
.Ed
.Sh SEE ALSO
.Xr stat 3s
.Xr strmode 3s
.Pp
The above SQLite user-defined functions are intended for use with 
.Nm .
.Sh AUTHORS
.Nm
was contributed by James K. Lowden
.\" .Sh BUGS