interpolation with quasi-quotation: stick haskell variables into haskell
strings Note there is no dependency on haskell-src-extras. If you don't
mind that dependency, you may want to look at using these packages:
Interpolation, interpolatedstring-perl6, interpolatedstring-qq. This
package has 1 other general feature that those others may not (but would
be easy to duplicate): instead of using quasi-quoting you can also use an
external file. It also has url/embeding interpolation, with @ and ^,
which are used in Yesod. This package also uses blaze-builder for efficiently
constructing strings.

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