[metapost] Re: pdf output and extensions

[Taco Hoekwater]

Hi Larry,

> I suspect flaky thinking here, not just flaky terminology. For
> example, what is this
> 
>   envelope <big Omega shaped path> withpen <medium sized circular pen>;
> 
> the path being embedded but the inked region having two boundary
> components? This sort of thing will really occur.

It will return the path that is currently only written to the
PostScript output file. We are not talking about any new
functionality here, other than allowing access to the internal
envelope structure that is already there in current MetaPost.

> At any rate "envelope" is a subject on which at least four mp and mf
> activists, myself included, have done a good deal of work. You can
> see traces of this on the "tex-fonts" list of a couple of years back.
> To get a respectable mp solution (or solutions!) will require a lot
> of patience consultation testing and possibly multiple publications
> and programs.

This is certainly true. But patiently waiting for progress to 
automagically appear won't do either. One has to start somewhere,
and allowing access to a calculation MP does anyway seems like a
nice place to start.

> The envelope problem might offer a good occasion to accomplish
> something still more fundamantal to the health and prosperity of mp:
> 
> 4*.  Implement protocols in mp for use of #external functions
> and code modules#.
> 
> I am sure that would lead gracefully to solution of other hard
> problems.

Can you sketch what you believe would be a nice way to
implement this in the MetaPost language? How you would like
to use this namespacing, I mean?

Greetings, Taco