push-when ( ..a elt quot: ( ..a elt -- ..b ? ) accum -- ..b )

Vocabulary

sequences

Inputs

elt	an object
quot	a quotation with stack effect ( ..a elt -- ..b ? )
accum	a resizable mutable sequence

Outputs

None

Word description

Adds the element at the end of the sequence if the quotation yields a true value.

Notes

This word is a factor of filter.

See also

push, push-either, pop, pop*, prefix, suffix, suffix!

Definition

USING: kernel ;

IN: sequences

: push-when
    ( ..a elt quot: ( ..a elt -- ..b ? ) accum -- ..b )
    [ keep ] dip rot [ push ] [ 2drop ] if ; inline