@inproceedings
{
  DidrichBSTT2000,

  author        = "Klaus Didrich and Wolfgang Grieskamp and 
                   Florian Schintke and Till Tantau and
                   Baltasar Tranc{\'o}n-y-Widemann",
  title         = "Reflections in Opal -- Meta Information in a
                   Functional Programming Language",
  abstract      = "We  report on an extension of  the Opal system that
                   allows  the    use  of  \emph{reflections}.   Using
                   reflections,  a  programmer  can  query information
                   like the type  of an object  at runtime.  The  type
                   can  in turn  be  queried  for properties  like the
                   constructor  and  deconstructor functions, and  the
                   resulting reflected   functions  can be  evaluated.
                   These   facilities    can  be  used    for  generic
                   meta-programming.     We   describe  the reflection
                   interface of Opal and  its applications, and sketch
                   the  implementation.    For an  existing   language
                   implementation  like Opal's    the extension by   a
                   reflection facility is challenging: in a statically
                   typed language the management of \emph{runtime type
                   information}   seems  to  be  an  alien  objective.
                   However, it turns out that runtime type information
                   can be   incorporated   in an   elegant   way by  a
                   source-level transformation and an appropriate  set
                   of    library   modules.     We    show  how   this
                   transformation can be   done without changing   the
                   Opal core system  and causing runtime overhead only
                   where reflections are actually used.",
  booktitle     = "Proceedings of the 11th International Workshop on 
                   Implementation of Functional Languages, Lochem, 
                   The Netherlands, September 1999, (IFL'99), 
                   Selected Papers", 
  editor        = "P. Koopman and C. Clack",
  pages         = "149--164",
  series        = "Lecture Notes on Computer Science",
  volume        = "1868",
  publisher     = "Springer",
  year          = "2000"
}