On Fri, May 11, 2007 at 03:10:42PM +0100, Neil Mitchell wrote:
Hi,
de Bruijn indicies look quite nice, and seem to eliminate a lot of complexity when dealing with free variables: http://en.wikipedia.org/wiki/De_Bruijn_index
So I was wondering, are they suitable for use in a compiler? If so, what are their disadvantages/advantages? Is there any particular reason that GHC (as an example) doesn't use them in its Core?
I'm trying to decide if I should use them in my compilers data type - and would like some recommendations before I start.
From what I've heard, the main disadvantage is that they make Core nigh-impossible to read - which is important because you will spend much much more time debugging your compiler than writing it.
There is a brief discussion of the tradeoffs in section 2.5 of the paper "Secrets of the Glasgow Haskell Compiler inliner": http://research.microsoft.com/~simonpj/Papers/inlining/index.htm Stefan