dlist-find ( ... dlist quot: ( ... value -- ... ? ) -- ... obj/f ? )
Factor handbook » The language » Collections » Double-linked lists

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Vocabulary
dlists

Inputs

dlist	dlist
quot	a quotation

Outputs

obj/f	an object or f
?	a boolean

Word description
Applies the quotation to each element of the dlist in turn, until it outputs a true value or the end of the dlist is reached. Outputs either the object it found or f, and a boolean which is true if an object is found.

Notes
Returns a boolean to allow dlists to store f.

This operation is O(n).

Definition

USING: accessors kernel ;

IN: dlists

: dlist-find
    ( ... dlist quot: ( ... value -- ... ? ) -- ... obj/f ? )
    [ [ obj>> ] ] dip compose dlist-find-node
    [ obj>> t ] [ f f ] if* ; inline