def make_sources(task_name, extensions)
      extensions.collect { |ext|
        case ext
        when /%/
          task_name.pathmap(ext)
        when %r{/}
          ext
        when /^\./
          task_name.ext(ext)
        when String
          ext
        when Proc
          if ext.arity == 1
            ext.call(task_name)
          else
            ext.call
          end
        else
          fail "Don't know how to handle rule dependent: #{ext.inspect}"
        end
      }.flatten
    end
def make_sources(task_name, extensions)
      extensions.collect { |ext|
        case ext
        when /%/
          task_name.pathmap(ext)
        when %r{/}
          ext
        when /^\./
          task_name.ext(ext)
        when String
          ext
        when Proc
          if ext.arity == 1
            ext.call(task_name)
          else
            ext.call
          end
        else
          fail "Don't know how to handle rule dependent: #{ext.inspect}"
        end
      }.flatten
    end
Make a list of sources from the list of file name extensions /
 translation procs.