    # File lib/compass/commands/registry.rb, line 12
        def abbreviation_of(name)
          re = /^#{Regexp.escape(name)}/
          matching = @commands.keys.select{|k| k.to_s =~ re}
          if matching.size == 1
            matching.first
          elsif name =~ /^-/
            nil
          elsif matching.size > 1
            raise Compass::Error, "Ambiguous abbreviation '#{name}'. Did you mean one of: #{matching.join(", ")}"
          else
            raise Compass::Error, "Command not found: #{name}"
          end
        end