Hello Steve,
> I just want to say that Haskell is a fat old slow
> dinosaur compared with Clean. [...]
By Haskell you probably mean the Glasgow Haskell Compiler (GHC). And
compilation by GHC is certainly slower than by the Clean compiler. On the
other hand, the generated code is comparable, sometimes faster, sometimes
slower. See:
Benchmarking implementations of lazy functional languages II -- Two years
later
( http://hypatia.dcs.qmw.ac.uk/SEL-HPC/Articles/GeneratedHtml/functional.imp
lemen.html#HartelPH1994a )
In this article you can read that GHC has improved considerably since the
first article and Clean "not significantly". If this is a trend then by now
(four years later) GHC's code could be always faster than Clean's. Maybe
it's time for a new benchmark.
The reason that GHC's compilation times are longer is that it is written in
Haskell (as opposed to C for the Clean compiler). However, during
development many people use the Haskell interpreter Hugs. This interpreter
is fast, interactive and light-weight. So by using both GHC and Hugs you can
get speed in both areas.
An advantage of a compiler written in Haskell is that it is easier to
maintain and that more people can experiment with it. The source code of the
Clean compiler is a secret.
Another thing you mention is that Haskell is old. This remark shows that you
have not been paying attention to the Haskell community. Things move rather
fast. So fast that it has been decided to freeze Haskell at a certain point
(Haskell 98). But research continues on what you might call Haskell 2 or
Haskell 2000. Some features that have been implemented lately include
implicit arguments, extensible records and class constraints.
I've used both languages a lot and I like them both. Where Clean stands out
in comparison to Haskell is that it has a library for making
platform-independent GUIs. In the Haskell world there is not yet a standard
GUI framework. I would love to see a library with the simplicity of TkGofer
for Hugs and/or GHC.
In Haskell I like the IO monad very much. It gives you input and output,
exceptions and mutable variables. In combination with implicit arguments it
allows you to elegantly write down inherently imperative code.
As a teacher I think the type systems of both languages are very complex,
possibly too complex. Therefore, error messages are often hard to
understand. If we want to make (more) students enthusiastic about functional
programming this is a problem that should be tackled in the near future.
Arjan
teacher, former member of the Clean team, Haskell enthusiast and Mondrian
hacker
