On Sun, Jan 30, 2011 at 12:37 AM, Rafael Cunha de Almeida wrote:

Hello,

I'm new to yesod and haskell web development in general. I read a bit about yesod and it looked nice. I thought it was really cool that I'd be able to view my changes to a template without recompiling, something I've always found very appealing in interpreted language's frameworks.

However, after running yesod it created a Setting.hs file which uses H.cassiusFileDebug and H.juliusFileDebug for the purpose of dynamically generating such files, but hamlet files doesn't seem to work that way. Why was that changed? Am I to expect such feature will come back in the future? Or is already possible it just need to be set somewhere else?

[]'s Rafael

Hi Rafael, I should probably document this properly somewhere. There are two reasons I do not use hamletFileDebug in the scaffolded site: * It does not handle Hamlet's polymorphism. A Hamlet template can be converted to a type of Html, Hamlet or Widget, while hamletFileDebug only works with Hamlet. In theory, this could be fixed. * hamletFileDebug does not work at all when you add new variables to the template. This is a problem that cannot be fixed. The first issue does not affect Cassius and Julius since they do not have any polymorphism. The second one is not as big a deal for Cassius and Julius: it's simply not as common to interpolate variables in your CSS and Javascript. I personally found that hamletFileDebug only worked for me half the time. Instead, a more robust solution is to use wai-handler-devel (also included in the scaffolded site). This will automatically reinterpret your app after a change to your Haskell or Hamlet template files. This is usually very fast for small sites, but gets slow for large sites. Hopefully in the near future, wai-handler-devel will switch from using the hint package to the plugins package, which will help alleviate that burden. Michael