output-stream? ( object -- ? )

Vocabulary

io

Inputs and outputs

object	an object
?	a boolean

Word description

Tests if the object is an instance of the output-stream class.

Definition

USING: classes.tuple.private curses.listener growable
html.streams io.crlf io.ports io.streams.c io.streams.counting
io.streams.duplex io.streams.null io.streams.peek kernel
math.private slots.private ui.gadgets.panes ;

IN: io

: output-stream? ( object -- ? )
    dup dup tuple? [
        layout-of
        dup
        7
        slot
        dup
        \ counting-stream
        eq?
        [ drop t ]
        [
            dup \ peek-stream eq?
            [ drop t ] [
                dup \ crlf-stream eq?
                [ drop t ] [
                    dup \ pane-stream eq?
                    [ drop t ] [
                        dup \ duplex-stream eq?
                        ~quotation~ ~quotation~ if
                    ] if
                ] if
            ] if
        ]
        if
        [ drop t ]
        [
            dup dup 1 slot 15 fixnum>=
            [ 15 slot \ output-port eq? ] [ drop f ] if
            [ drop t ] [
                dup dup 1 slot 13 fixnum>=
                [ 13 slot \ c-writer eq? ] [ drop f ] if
                [ drop t ] [
                    dup dup 1 slot 11 fixnum>=
                    [ 11 slot \ html-writer eq? ] [ drop f ] if
                    [ drop t ] [
                        dup
                        1
                        slot
                        9
                        fixnum>=
                        ~composed~
                        ~quotation~
                        if
                    ] if
                ] if
            ] if
        ]
        if
    ] [ drop f ] if
    [ drop t ] [
        dup curses-listener-stream?
        [ drop t ]
        [ dup null-writer? [ drop t ] [ growable? ] if ] if
    ] if ;