product-find ( ... sequences quot: ( ... seq -- ... ? ) -- ... sequence )
Product sequences

Prev:

product-each ( ... sequences quot: ( ... seq -- ... ) -- ... )

Vocabulary
sequences.product

Inputs

sequences	a sequence
quot	a quotation with stack effect ( ... seq -- ... ? )

Outputs

sequence

a sequence

Word description
Calls quot for every element of the cartesian product of sequences, returning the first sequence where the quotation returns a true value.

Notes
[ ... ] product-find is equivalent to, but more efficient than, <product-sequence> [ ... ] find nip.

See also
product-map, product-each

Definition

USING: kernel sequences sequences.product.private ;

IN: sequences.product

:: product-find
    ( ... sequences quot: ( ... seq -- ... ? ) -- ... sequence )
    sequences start-product-iter :> ( ns lengths ) lengths
    [ 0 = ] any?
    [ f ] [
        f
        [ ns lengths end-product-iter? over or ] [
            drop ns sequences product-nths quot keep and
            ns lengths product-iter
        ] until
    ] if ; inline