User Tools

Site Tools


unshift_function

# $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:

assign -foo
$unshift(foo blah)      assigns "blah" to $foo and returns "blah"
$unshift(foo booya)     prepends "booya " to $foo and returns "booya blah"
unshift_function.txt · Last modified: 2006/08/29 16:08 (external edit)