Desugaring rakefile (.sass => .css, .coffee => .js, .slim => .html)

rakefile.rb

require 'tilt'
require 'slim'
require 'sass'
require 'rake/clean'

@tilts = {}

def tilt_rule(to, from, options={})
  @tilts[from] = to

  rule to => from do |task|
    template = Tilt.new(task.source)
    template.options.merge(options)
    
    result = template.render
    open(task.name, 'wb') {|f| f << result }
  end
end

def desugared_files
  @desugared_files ||= FileList.new do |list|
    @tilts.each {|from, to| list.include FileList["**/*#{from}"].ext(to) }
  end
end

tilt_rule '.html', '.slim', {:format => :html5, :pretty => true}
tilt_rule '.css', '.sass'
tilt_rule '.js', '.coffee'

CLEAN.include desugared_files

desc "desugar all files (#{@tilts.map {|k,v| "#{k}=>#{v}" }.join(',')})"
task 'desugar' => desugared_files