module Sprockets::Processing

def preprocessors(mime_type = nil)

recommended to subclass `Tilt::Template`.
All `Processor`s must follow the `Tilt::Template` interface. It is

processors.
Preprocessors are ran before Postprocessors and Engine

extension will be returned.
argument is supplied, the processors registered under that
Returns an `Array` of `Processor` classes. If a `mime_type` 
def preprocessors(mime_type = nil)
  if mime_type
    @preprocessors[mime_type].dup
  else
    deep_copy_hash(@preprocessors)
  end
end