# $EPIC: unshift_function.txt,v 1.2 2006/08/20 17:37:08 sthalik Exp $
======Synopsis:======
$__unshift__(<variable name> <word list>)

======Technical:======
   * If the <variable name> argument is omitted the empty string is returned.
   * If the <word list> argument is omitted the rvalue of $<variable name> is returned.
   * If the value of $<variable name> is the empty string, then the value of $<variable name> is set to <word list>.
   * If the value of $<variable name> is not the empty string, then the value of $<variable name> is set to <word list> plus a space plus the old value of $<variable name>.
   * The new value of $<variable name> is returned.
   * <variable name> must not be prefixed with a $.

======Practical:======
Whereas the "shift" operation removes the first word from a word list
(or variable), the "unshift" operation prepends words to the beginning
of a word list in a variable and assigns the result back to the variable.

======Returns:======
The new value of $<variable name> after the unshift.

======Examples:======
<file>
assign -foo
$unshift(foo blah)      assigns "blah" to $foo and returns "blah"
$unshift(foo booya)     prepends "booya " to $foo and returns "booya blah"
</file>