Shakespeare is a template family for type-safe, efficient templates with
simple variable interpolation . Shakespeare templates can be used inline
with a quasi-quoter or in an external file. Shakespeare interpolates
variables according to the type being inserted. In this case, the
variable type needs a ToJavascript instance. There is also
shakespeare-coffeescript for coffeescript templates. Coffescript is a
language that compiles down to javascript. It expects a coffeescript
compiler in your path, and variable should be a ToCoffee instance. And
we even have a Roy template for the adventorous FP addicts.

WWW: http://www.yesodweb.com/book/shakespearean-templates