css - Passing Rulesets into Mixins not working -

i copied following text website: http://lesscss.org/features/#detached-rulesets-feature , simpleless giving me error on line copied to. did remove ruleset capabilities?

here copied:

// declare detached ruleset @detached-ruleset: { background: red; };  // use detached ruleset .top {     @detached-ruleset();  } 

i wanted test see if can name variable "detached-ruleset" whatever want can use more one, code less website doesn't work. 1 know whats going on?

this due simpleless not being updated 3 years, stated seven-phases-max in comment.

in honesty, best bet use less's own compiler of course date option.

all information can found in less documentation here