[metapost] augment drawoptions

[Stephan Hennig]

Taco Hoekwater schrieb:

> You cannot save _op_ because it is a macro, not a variable.
> 
> You could do explicit macro definitions and restores with expandafter:
> 
> def savedrawoptions =
>    expandafter def expandafter _savedop_ expandafter = _op_ enddef;
> enddef
> 
> def restoredrawoptions =
>    expandafter def expandafter _op_ expandafter = _savedop_ enddef;
> enddef
> 
> But it is not very elegant.

Thank you!  Although, I guess you cannot save and modify drawoptions
over multiple levels this way, it is sufficient for my purposes.

> In fact, I cannot come up an elegant solution to the problem that
> does not require rewriting quite a bit of plain.mp.

I would find native support for local draw options (and altering draw
options) a useful addition to MetaPost.  What do people think?

Best regards,
Stephan Hennig