within extra arguments to <%block>, <%def>, i.e.
  <%block name="foo" cache_key="${somekey}">.
  Filters can also be used in this way, i.e.
  <%def name="foo()" filter="myfilter">
  then template.render(myfilter=some_callable)
  [ticket:180]

  system, whereby the usage of Beaker is just the
  default plugin.   Template and TemplateLookup
  now accept a string "cache_impl" parameter which
  refers to the name of a cache plugin, defaulting
  to the name 'beaker'.  New plugins can be
  registered as pkg_resources entrypoints under
  the group "mako.cache", or registered directly
  using mako.cache.register_plugin().  The
  core plugin is the mako.cache.CacheImpl
  class.

- The <%def>, <%block> and <%page> tags now accept
  any argument named "cache_*", and the key
  minus the "cache_" prefix will be passed as keyword
  arguments to the CacheImpl methods.

- Template and TemplateLookup now accept an argument
  cache_args, which refers to a dictionary containing
  cache parameters.  The cache_dir, cache_url, cache_type,
  cache_timeout arguments are deprecated (will probably
  never be removed, however) and can be passed
  now as cache_args={'url':<some url>, 'type':'memcached',
  'timeout':50, 'dir':'/path/to/some/directory'}

HTML file writing, consistently cleanup the modules/cache directories, use
nose skiptests for unsupported features.

- added "cache_enabled=True" flag to Template,
  TemplateLookup.  Setting this to False causes cache
  operations to "pass through" and execute every time;
  this flag should be integrated in Pylons with its own
  cache_enabled configuration setting.

cache sends in a "defname" parameter so that the cache can map settings to that name, instead of the key.
eliminates the need to store all Value objects which will use up RAM in a dynamic-key scenario.

  e.g.  ${local.cache.get('somekey')} or
  template.cache.invalidate_body()

- the Cache object now supports invalidate_def(name),
  invalidate_body(), invalidate_closure(name),
  invalidate(key), which will remove the given key
  from the cache, if it exists.  The cache arguments
  (i.e. storage type) are derived from whatever has
  been already persisted for that template.
  [ticket:92]

an expired section, instead of the original context
passed in [ticket:87]

a cached block would raise an error when called within a
cache-refresh operation that was initiated after the
initiating template had completed rendering.

  directly to the %page or %def, i.e.
  <%def name="foo(x)" cached="True" cache_key="${x}"/>
  [ticket:78]

  caching, combined with an expression-based cache_key,
  combined with the usage of <%namespace import="*"/>

cache function optional