[REBOL] Re: How to extend effects?
From: rotenca:telvia:it at: 19-Mar-2003 16:31
> is it possible to simply have "view layout [image img effect [my-effect]]",
> in essence extending the effects available to VID?
> *If* this is possible, is it also possible to make the my-effect func
> generic such that "view layout [box blue effect [my-effect]]" works?
No, but in this case you could do:
my-effect: func [img] [
repeat pos (img/size/x * img/size/y) [
poke img pos either odd? pos [255.255.255.0][0.0.0.0]
view layout [image effect [draw [image 0x0 my-effect img]]]
> If VID is a dialect, what are effects? Built-ins, properties, words? Are
> they something that "belongs" to VID or View?
Effects are words of a dialect interpreted by View.
The effect word Draw handles a sub-dialect in a block: the advantage of Draw
sub-dialect is that it is reduced before interpreted, so it can contain Rebol
code, like in the example.