I just discovered the beautiful Haml and Sass, and want to develop in these languages but with live previews. Coda and Espresso both allow for beautiful live previews of HTML files, but previews of an Haml file simply show it as plain text.
While there exist sugars for Espresso that add syntax highlighting, which is nice, I would like something that automatically compiles Haml files to HTML, and then lets me preview that instead of Haml.
Does anything like this exist for either Coda, or Espresso, or for any other web development tool out there?
(If it makes a difference, I'm not developing for Ruby on Rails, I'm making a static website, so the Ruby on Rails plugin shouldn't help AFAIK. Software I tried out were StaticMatic and Middleman. StaticMatic's development seems discontinued, and for some reason MiddleMan refuses to work after creating my initial directory structure. Maybe I'm using it wrong.)
I don't use Espresso, so no comment there. However, Coda does not provide any support for Haml or Sass that I can find. I've been closely following the Coda forums, as I am a paid user, and it looks as though a 2.0 version is forthcoming. Who knows, perhaps that'll be included.
For now, since you're not using Ruby on Rails, I might suggest TextMate. It doesn't do Haml or Sass "right out of the box", but it can be configured to do so using "Bundles."
Installing HAML bundle for TextMate is a primer on how to setup TextMate for Haml/Sass, and I suspect there are others.
That said, for roughly the cost of TextMate you can purchase RubyMine ($69), which does both Haml (via RubyGem) and Sass (via Plugin), and can also handle running Sass --watch internally. I know you're not using Ruby, so maybe the idea of using a tool made primarily for Ruby doesn't appeal, but it does work in both the Haml and Sass environments very nicely.
The third option would be BBEdit, which can also handle both Haml and Sass. Some information on the plugin for BBEdit is in BBEdit-Codeless-Language-Module-for-HAML-SASS.
I hope this helps.
P.S.: I'm a paid user on all the platforms I mentioned. While I use RubyMine as my primary tool, I find that TextMate still gets a lot of use when I'm programming and need a quick, friendly window to examine code in. I used to use BBEdit when I needed to do complex regular expression-style search and replacements, but then I discovered how to do the same thing in TextMate, so BBEdit is sort of collecting dust. Coda? It looks pretty, but doesn't get the job done so much any more (though Panic's Transmit is still very much a core application).