In response to Paul Hudak's letter regarding modifications to Haskell,
we are interested in the question of the addition of 'records'.
Working from an unpublished paper by Sean Bechhofer we have developed
a system of extensible records for Gofer/Haskell. This is based not on
subtyping but instead uses the type class mechanism to handle
constraints on the existence of fields.
We have an implementation of a parser and type-checker, including all
Gofer's features (even constructor classes). The work has been written
up as a Diploma project. We have not tried to build either an
interpreter or a compiler, but we don't forsee any particular
difficulties with this.
We would be grateful to hear about any other systems (including John
Peterson's proposal) and from anyone interested in our work. Finally,
when and where will FPCA be?
Giuliano Procida
Barnaby Hilken
