3guard ( ..a x y z quot: ( ..a x y z -- ..b ? ) -- ..b x/f y/f z/f )
Factor handbook » The language » Combinators » Conditional combinators

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Vocabulary
kernel

Inputs

x	an object
y	an object
z	an object
quot	a quotation

Outputs

x/f	an object
y/f	an object
z/f	an object

Word description
Calls quot on x, y, and z and either keeps x, y, and z or replaces them with f.

Examples
True case:

USING: kernel math prettyprint ; 3 4 5 [ + + even? ] 3guard [ . ] tri@
3 4 5

False case:

USING: kernel math prettyprint ; 3 4 5 [ + + odd? ] 3guard [ . ] tri@
f f f

See also
1check, 1guard, 2check, 2guard, 3check

Definition

IN: kernel

: 3guard
    ( ..a x y z quot: ( ..a x y z -- ..b ? ) -- ..b x/f y/f z/f )
    3check [ 3drop f f f ] unless ; inline