The Ruby slim templates get compiled to an intermediate language (Temple). That is then compiled into an end form and everything is cached - the performance is

The Ruby slim templates get compiled to an intermediate language (Temple). That is then compiled into an end form and everything is cached - the performance is all the same. RoR didn't pick Haml because Haml abandons HTML. Take a look at the Hamlet language which give the best of both worlds. https://github.com/gregwebs/hamlet.js https://github.com/gregwebs/hamlet.js https://github.com/gregwebs/hamlet.rb https://github.com/gregwebs/hamlet.rb