[Matplotlib-users] Patch to fix stale tex cache issues [Was: using different font families with?LaTeX-generated text]

[Alexander S. <a.s...@gm...>]

p.s.

If I may make another suggestion (I don't have time to volunteer for
implementing them in the forseeable future, but I might eventually if there's
interest): Maybe the way configuration is handled could be improved:

1. It seems to me that letting users manipulate some raw dictionary
   (`rcParams`) in order to customize behavior is bad.
   
   Just now, on my first dig into matplotlib I've found a number of bugs that
   result from bad state in rcParams. As a user this has also caused me some
   wasted time, because typos and other illegal param choices are not caught
   early (but are relativley likely, because matplotlib has many and complex
   options).

   Using some dedicated class-instance instead of a dict would allow for:
   - automatic conistency checks on setting
   - possibly even change propagation (likely faster and certainly less error
     prone if done right: I'm not sure how many places rcParams dependent
     results apart from the tex-stuff are cached and should be recomputed when
     certain params change, but obviously an push/'event'-based solutin could
     be faster than pull/polling)
   - possibly better performance, because e.g. using immutable values would
     allow identity based checks to see if a rcParam changed and obviate the
     need to copy; 
   - convenient doc lookup and searching an display of available alternatives
     (e.g. font-families etc)
   - better factoring of the matplotlibrc parsing and validation see below:


2. It also seems to me that having some custom config file format rather than
   just (a literal-only subset of) python is suboptimal. Why make people learn
   another and more limited syntax when python literals are already familiar
   and both more powerful and easier to use (e.g. the latex-preamble setting
   can't express multiple package options, because param values can't contain
   ',')? It would also get rid of the IMO undesirable coupling of
   string-parsing and type-checking that the validate_* functions do at the
   moment; really setting an rcParam should also do the latter but not the
   former (and guaranteed validation on setting would also avoid the need to
   sprinkle random checks on reading through the code).

   IMO it would be much nicer if there was some more declarative way to
   specify options, check their validity on setting and assoicate docs with
   them (sort of like e.g. emcs-custom vars).
  
   Valid files in the old-syntax could be translated automatically quite
   easily, so I don't think it's a compatiblity issue.

cheers,

'as