[Haskell-cafe] Defining Haskell using "arrows"
andy.elvey at paradise.net.nz
Sat Nov 6 13:28:50 EST 2004
Hi all -
I'm a first-timer here, and am *very* much attracted by Haskell's elegance
and power ... :-)
I have only poked around briefly with Haskell so far (at the "hello world"
level). One thing that I have come across, and which really got me thinking,
was the page on the Haskell website about "arrows". They really seem to take
elegance and the "generic-ness" of algorithms to a new level.
I was thinking - arrows are a relatively recent concept. Haskell's grammar
(as defined in the Haskell report) has now been around for quite some time.
So - I thought "what if?" What if Haskell were to be defined (er,
*re*-defined) in terms of arrows? In other words, what if it were possible
to start totally "from scratch", re-defining Haskell's grammar using arrows?
(and preferably, *only* arrows ... ).
This would presumably involve somehow coding up the arrows first, and then
(haivng got them), using them to create/define the rest of the language.
My reason for suggesting this - simply to see if it were possible to do a
very small (but still quite comprehensive) Haskell implementation. Small
meaning maybe 2-3 MB or so ... As an interesting "benchmark" of this, the
Rebol language (though proprietary - sigh!) - comes in at 0.5 Mb or so,
including a GUI. So, "very small but very powerful" is possible (although
undoubtedly pretty difficult ... )
As a Haskell newbie, I have to defer to everyone else on this list (in terms
of my Haskell ability), but just thought I'd post this idea anyway. I was
thinking " I wonder if anyone has thought of this? ....... " .
Arrows seem to be a recent "add-on", as it were, so I thought -given their
power and flexibility, why not turn things totally around, and put them at
the *very core* of the language, using them to define the language itself.
Anyway, I'm keen to hear people's thoughts on this! Very many thanks in
advance ... :-)
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