#217: Idea: local variable caching of filters/filter stacks

Analyzing the generated .py files from my current project, there's lots of this pattern, as my default_filters are ['h', 'unicode']:

        __M_writer(unicode(filters.html_escape(x)))
        __M_writer(u'some_constant_stuff')
        __M_writer(unicode(filters.html_escape(y)))
        __M_writer(u'more_constant_stuff')
        __M_writer(unicode(filters.html_escape(z)))
        __M_writer(u'even_more_constants')

so it would seem to make sense, to reduce name lookups (in favor of LOAD_FAST) to either

• cache the filter callables as locals in the function (as is being done with __M_writer) to something like

  __M_f_unicode = unicode
  __M_f_filters__html_escape = filters.html_escape
  

• and/or maybe better yet create a single cached callable for all of these filter "stacks":

  __M_f_unicode___filters__html_escape =
    lambda *args,**kwargs:
      __M_f_unicode(__M_f_filters__html_escape(*args,**kwargs))
  

  and have the codegen use those instead.

I haven't studied the codegen more deeply to find out what sort of magic this would require though :)