On Oct 29, 2010, at 11:20 AM, Tim Edwards wrote: > Kuba, > >> If you could give me a tutorial on how parameters are implemented, that'd be >> great. >> I have a vague feel for oparam and eparam, but what I don't get is exactly >> how propagation >> is supposed to work, and how can you modify the parameters. I can trivially >> parametrize, >> say, object's position -- the object then shows up with a little circle on >> it (that's the parameter >> indicator), so of course I can't move it anymore. Now how do I specify the >> value of the >> parameter? > > If you understand the difference between the "eparams" (element parameters) > and the "oparams" (object parameters), then you're 90% of the way toward > understanding the whole thing. > > For the element parameters, let's take your example of an element's position > (note that in xcircuit I have arbitrarily made the definitions "element" and > "object", but they are very specific, and most of the time I use the terms > correctly. In your case, you can't parameterize the position of an "object", > only the position of an "object instance", which is a type of "element".
You're right of course. Thanks for nitpicking, in this discussion the details are important! > Since I just made up all these designations 17 years ago, hopefully I am not > working against the standard etymology of computer science (if there is such > a thing)). The designations are fine. So, to recap: an object is simply a bunch of elements. It'd make no sense to parametrize its position, since it doesn't have one -- only an instance does. In an object, the constituent elements have positions. A position of something is always in relation to something else; as an object is merely a canvas for elements it doesn't have a position, but its constituents do. I'm going through the rest of your writeup -- thank you again for spending the time. I can't express my appreciation in any other way but learning from your description and putting it to use, so I'll try and see what I come up with the next few nights. Cheers, Kuba _______________________________________________ Xcircuit-dev mailing list [email protected] http://www.opencircuitdesign.com/mailman/listinfo/xcircuit-dev
