3if ( ..a x y z pred: ( ..a x y z -- ..b x y z ? ) true: ( ..b x y z -- ..c ) false: ( ..b x y z -- ..c ) -- ..c )
Factor handbook » The language » Combinators » Conditional combinators

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Vocabulary
kernel

Inputs

x	an object
y	an object
z	an object
pred	a quotation
true	a quotation
false	a quotation

Outputs
None

Word description
A variant of if that takes a pred quotation. Calls 3check on the pred quotation to return a boolean and preserves x, y, and z for the true or false branches, one of which is called.

See also
1if, 1when, 1unless, 2if, 2when, 2unless, 3when, 3unless

Definition

IN: kernel

: 3if
    ( ..a x y z pred: ( ..a x y z -- ..b x y z ? ) true: ( ..b x y z -- ..c ) false: ( ..b x y z -- ..c ) -- ..c )
    [ 3check ] 2dip if ; inline