Application letters at the Haskell workshop: suggestion

Koen Claessen
Fri, 14 Sep 2001 09:25:11 +0200 (MET DST)

Alastair David Reid wrote:

 | > existential types, functional dependencies, other
 | > experimental-but-apparently-crucial features [...]
 | I do use the IO monad, IORefs (sparingly), constructor
 | classes, lots of libraries, the foreign function
 | interface (lets you call C and C++), parser generators
 | (happy) and parser combinators, exception handling and
 | concurrency (even just the lame non-preemptive version
 | that Hugs provides).

One small point here: many libraries use experimental
features in their implementation. Many efficient parsing
combinator libraries for example rely on some kind of
continuation monad, which often needs existential types to
be implemented.