bidirectional-cursor? ( object -- ? )

Vocabulary

cursors

Inputs and outputs

object	an object
?	a boolean

Word description

Tests if the object is an instance of the bidirectional-cursor class.

Definition

USING: classes.tuple.private kernel math.private slots.private ;

IN: cursors

: bidirectional-cursor? ( object -- ? )
    dup dup tuple? [
        layout-of
        dup
        1
        slot
        9
        fixnum>=
        [ 9 slot \ quadratic-cursor eq? ]
        [ drop f ]
        if
    ] [ drop f ] if [ drop t ] [ random-access-cursor? ] if ;