Word description Calls cond on the default object and if cond outputs a new object then the true quotation is called with that new object. Otherwise, calls false with the old object.
Examples Look up an existing word or make an error pair:
USING: arrays definitions kernel math prettyprint sequences vocabs.parser ;
"+" [ search ] [ where first ] [ "not found" 2array ] ?if . "resource:core/math/math.factor"
Try to look up a word that doesn't exist:
USING: arrays definitions kernel math prettyprint sequences vocabs.parser ;
"+++++" [ search ] [ where first ] [ "not found" 2array ] ?if . { "+++++" "not found" }