David Sankel wrote:

I'm writing an interpreter for a call by need language... Is anyone aware of any papers out there that go into detail on the construction of an actual interpreter?

You might find the following call-by-need interpreter useful: http://okmij.org/ftp/tagless-final/tagless-typed.html#call-by-any http://okmij.org/ftp/tagless-final/course/CBAny.hs (the files also implement interpreters for the other two popular strategies). The key to call-by-need is the `share' function, whose more complex instance is described in the paper mentioned here yesterday: http://okmij.org/ftp/Computation/monads.html#lazy-sharing-nondet