# $EPIC: copattern,v 1.3 2001/07/23 17:53:03 jnelson Exp $
Synopsis:
   $copattern(<pattern> <var1> <var2>)

Technical:
   * If the <pattern> argument is omitted the empty string is returned.
   * If the <var1> argument is omitted the empty string is returned.
   * If the <var2> argument is omitted the empty string is returned.
   * <pattern> is taken to be a wildcard pattern
   * <var1> and <var2> are taken to be lvals (names of ASSIGNs)
   * <var1> and <var2> should each have the same number of words.
   * For each set of words, one from $<var1> and one from $<var2>, in order,
     if the word from $<var1> is matched by <pattern> then the corresponding
     word from $<var2> shall be included in the return value.  
   * Formally, the return value is a list of words from $<var2> that
     correspond in position to the words from $<var1> that are matched 
     by <pattern>.
   * The principle behind this is similar to $pattern(), but the return
     value is made up of the words from a different variable than the one 
     that you are matching against.
   * Parsing ends whenever $<var1> or $<var2> run out of words, whichever
     comes first.
   * Double quoted words are honored, but the double quotes will be lost
     in the return value.

Practical:
   When you have two variables, one that contains a list of control data,
   and another that contains a list of secondary data, and you wish to
   retrieve the secondary data, but you need to do it based on a query of
   the control data, you might use this function.  One possible use might
   be if one variable held your friends list, and another held their access
   levels.

Returns:
   The words from $<var2> that correspond to all of the words in $<var1> 
   that are matched by <pattern>.

Examples:
   @ friends = [bob@foo.com tom@bar.com]
   @ levels  = [20 10]
   $copattern(*@foo.com friends levels)       returns "20"
   $copattern(*@bar.com friends levels)       returns "10"
   $copattern(*@*.com friends levels)         returns "20 10"
   $copattern(*@*.net friends levels)         returns ""  (empty string)

See also:
   match(6); word(6)