How to extend effects?

[1/3] from: atruter::labyrinth::net::au at: 19-Mar-2003 9:28

Given the following: <code> REBOL [] img: to-image layout [origin 0 box 100x100 blue] my-effect: func [face] [ repeat pos (face/size/x * face/size/y) [ poke face pos either odd? pos [255.255.255.0][0.0.0.0] ] ] view layout [ image my-effect img ] </code> 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? If VID is a dialect, what are effects? Built-ins, properties, words? Are they something that "belongs" to VID or View? Regards, Ashley

[2/3] from: antonr:iinet:au at: 19-Mar-2003 14:19

Ashley, I believe that this is not possible now, but it has been discussed before, and it may be a future possibility. It would be very handy. VID is a dialect, the effect dialect is another, which is understood at the face (View) level (ie. below VID). Anton.

[3/3] from: rotenca:telvia:it at: 19-Mar-2003 16:31

Hi,

> 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] ] img ] 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. --- Ciao Romano