# $EPIC: pattern.txt,v 1.3 2007/05/15 01:28:58 jnelson Exp $
======Synopsis:======
$__pattern__(<pattern> <word list>)

======Technical:======
   * If the <pattern> argument is omitted the empty string is returned.
   * This function returns a space separated word list of all of the words in <word list> that are matched by <pattern>.
   * This is the complement to $[[filter]](), and the inverse of $[[rpattern]]().
   * Remember that the words in <word list> are [[what is a word|words]], so double quoted words are not honored unless you turn [[xdebug]] dword on.
   * The <pattern> is also a [[what is a word|word]], so you should not put double quotes around it unless you have turned [[xdebug]] dword on.  This is an important difference from epic4.
   * Double quotes around words are not lost if you have [[xdebug]] dword turned on.  This is an important difference from epic4.
   * There is no reasonable way to support matching a <pattern> that has spaces (a dword) against a word list that does not have spaces (a uword list), since by rule a uword can **never** contain a space, so it can't match.  It has to be all one way or the other.

======Practical:======
This function lets you "filter" <word list> through a pattern, keeping all
of the words that match the pattern and discarding all of the words that
do not match the pattern.  By appending * to a string and using this
function, you can quickly find all words in a word list that start with
a particular substring.

======Returns:======
The list of words from <word list> that are matched by <pattern>.

======History:======
This function first appeared in "plus-2" (post-ircII, pre-EPIC)

======Examples:======
<file>
$pattern(*oo* foobar blah booya) returns "foobar booya"
$pattern(*a* hello there bob)    returns nothing
$pattern(irc* $myservers())      returns all servers you are connected to
                                 that start with the string "irc".
</file>