?1guard ( ..a x quot: ( ..a x -- ..b ? ) -- ..b x/f ? )

Vocabulary

combinators.extras

Inputs

x	an object
quot	a quotation with stack effect ( ..a x -- ..b ? )

Outputs

x/f	an object
?	an object

Definition

USING: kernel ;

IN: combinators.extras

: ?1guard ( ..a x quot: ( ..a x -- ..b ? ) -- ..b x/f ? )
    1check [ t ] [ drop f f ] if ; inline