James is right on about where HAML falls short; but thats not HAML's problem, its more of a preference. I will be the first to say that HAML is no appropriate for everything. Here is how I apply various templating engines in my Rails projects:<p>HAML - Great for application markup (as opposed to document markup... see ERB below) for a number of reasons. (1) application markup tends to be heavy in javascript where you need a clean DOM. HAML reduces the chance of screwing up the DOM and makes it easier to look at during development. (2) Lots of conditionals in the view and I'm too lazy to factor them out into partials or helpers. Sometimes its just easier to express if/then and loops in HAML than it is in ERB... slightly less markup.<p>ERB - Document/content markup. If I have big docs with lots of links and paragraphs, but nothing to heavy going on thats dynamic/conditional, ERB is the easiest way to go.<p>Mix 'n' match! Then you can have the best of both worlds!
Eh, different strokes for different folks. My only major criticism of Haml is that it makes me actively adverse to how incredibly verbose HTML is, which probably isn't a good trait for a web developer.
I'd say his main points boil down to poor tooling and creating a solution for a problem that doesn't really exist... except that many of us do see issues with existing templating options and Haml+Sass works really well.<p>I will concede that it can cause friction with designers though.
This was me until about the 3rd time I played around with Haml. Then it occurred to me how much noise I got rid of by using it, after which I was hooked.<p>Jquery + Haml is a very close impedance match and a real pleasure to use for development.
I use real code to show how HAML kicks ERB-ass: <a href="http://railsnotes.com/395-response-to-thoughts-on-haml" rel="nofollow">http://railsnotes.com/395-response-to-thoughts-on-haml</a>
Web designers often send me half heartedly formated html that is full of repetitive nested structures that I do not understand. When trying to turn it into a collection of partials I have inevitably destroyed some important tag. Everything breaks and I have to start over.<p>Turning it into haml has two benefits. I can visualize the structure of repeating elements so I have a better idea what to break into partials and I will never forget a closing tag which causes everything to break in some horrific way.
I agree with the author on editor support for closing tags. I often find myself noticing something is wrong when I tell the editor (emacs) to auto-indent everything and it doesn't look the way I expect it to. I also find ERB to be quite simple and straightforward.<p>That said, I'm quite interested in using Sass.
This post is a negative critique of Haml which points out that it is not an improvement over HTML - it makes working with designers more cumbersome for one thing. A somewhat different viewpoint from a StackOverflow user:<p><a href="http://stackoverflow.com/questions/93540/your-attitude-to-haml/430325#430325" rel="nofollow">http://stackoverflow.com/questions/93540/your-attitude-to-ha...</a>