3guard ( ..a x y z quot: ( ..a x y z -- ..b ? ) -- ..b x/f y/f z/f ) (original) (raw)
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
: 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