Does using Haml and Sass slow things down?

When you use开发者_开发知识库 Haml and Sass, does it slow things down all the time or just for the first time the view is rendered?

I'm sure it isn't a big performance penalty, but just curious as to how things are rendered.

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As Michael and jxpx777 said, Sass gives you only a one-time slowdown. Haml, according to this benchmark, is as fast as Erb (assuming Haml 3 hasn't gotten slower than Haml 2.2). So the answer is, no it doesn't slow things down all the time.

Haml (like Erb, I will assume) has a precompiler, so it does some work up-front and then spits out the rendered views pretty fast.

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Not sure about haml. Sass will spit out a .css file when rails starts up so once it's created it has zero effect on speed as the web pages reference the outputted .css file.

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HAML shouldn't have too much performance difference to ERB. It's the same kind of process. SASS will experience a performance hit the first time it has to generate the CSS files, but I do that as part of my Capistrano deployment script so that no users have to see that performance hit.

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If you use this while writing your SASS, you'll not have any slowdown whatsoever, as it generates (and syntax checks) your SASS as you write it:

sass --watch screen.sass:screen.css

HAML is not slower than ERB.