module Sprockets::Engines

# => CoffeeScriptTemplate
environment.engines('.coffee')

# => [CoffeeScriptTemplate, SassTemplate, ...]
environment.engines

register under that extension will be returned.
`Environment`. If an `ext` argument is supplied, the `Engine`
Returns an `Array` of `Engine`s registered on the

def engines(ext = nil)
  if ext
    ext = Sprockets::Utils.normalize_extension(ext)
    @engines[ext]
  else
    @engines.dup
  end
end