□? ( object -- ? )

Vocabulary

boolean-expr

Inputs and outputs

object	an object
?	a boolean

Word description

Tests if the object is an instance of the □ class.

Definition

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

IN: boolean-expr

: □? ( object -- ? )
    dup dup tuple? [
        layout-of
        7
        slot
        dup
        \ ¬
        eq?
        [ drop t ]
        [ dup \ ⋁ eq? [ drop t ] [ \ ⋀ eq? ] if ]
        if
    ] [ drop f ] if
    [ drop t ] [
        dup Z?
        [ drop t ] [
            dup Y?
            [ drop t ] [
                dup X?
                [ drop t ] [
                    dup W?
                    [ drop t ]
                    [ dup V? ~quotation~ ~quotation~ if ] if
                ] if
            ] if
        ] if
    ] if ;