Shakespeare is a family of type-safe, efficient template languages.
Shakespeare templates are expanded at compile-time, ensuring that all
interpolated variables are in scope. Variables are interpolated
according to their type through a typeclass. Shakespeare templates can
be used inline with a quasi-quoter or in an external file. Note there is
no dependency on haskell-src-extras. Instead Shakespeare believes logic
should stay out of templates and has its own minimal Haskell parser.
Packages that use this: shakespeare-js, shakespeare-css,
shakespeare-text, hamlet, and xml-hamlet.

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