1unless ( ..a x pred: ( ..a x -- ..b ? ) false: ( ..b x -- ..b x ) -- ..b x )

Vocabulary

kernel

Inputs

x	an object
pred	a quotation
false	a quotation

Outputs

x

an object

Word description

A variant of when that takes a pred quotation. Calls 1check on the pred quotation to return a boolean and preserves x for both branches. The false branch is called conditionally.

See also

1if, 1when, 2if, 2when, 2unless, 3if, 3when, 3unless

Definition

IN: kernel

: 1unless
    ( ..a x pred: ( ..a x -- ..b ? ) false: ( ..b x -- ..b x ) -- ..b x )
    [ ] swap 1if ; inline