[Xy-pic] 'macros' with saved points
ross at ics.mq.edu.au
Fri Oct 31 14:56:39 CET 2003
On Thu, 30 Oct 2003, Scott Morrison wrote:
> I'm fairly new to xy-pic, please forgive my ignorance!
> I'd like to be able to do something like this:
This cannot work as it is, since it does not turn on the Xy-pic
But this works:
* is a non-active shorthand for \drop , when in the
appropriate parser context.
Another useful way to define a macro expansion is as:
where now the graphics state reverts to what it was before
the \dropblob macro is called.
> That is, have a new command which drops some stuff (generally much more
> complicated than just a circle), and names certain points in it according
> to passed arguments. This command would be for drawing certain complicated
> objects which I reuse many times. Being able to name certain points in
> this way means that when I need to add more to the standard object, I can
> do things relative to those named points, without having to calculate
> where they are. Does that make sense? Is it possible?
Of course. Macro-programming is at the heart of TeX.
Xy-pic extends that for constructing graphics as well.
You just have to remember to start the expansion tokens with an active
control-sequence that turns on Xy-pic parsing, so that the non-active
characters can be interpreted within the correct context.
Hope this helps,
> Scott Morrison
> xy-pic mailing list
More information about the xy-pic