Visual Haskell

Toby Watson Toby Watson" <
Mon, 2 Apr 2001 18:44:45 +0100

Hi, Good find!

NB: I just skimmed the paper so far, but it is a long-term area of interest
for me...

I find most of these visual systems awkward to use in practice. Quite often
this is because they have very poor interface designs (they are like old
modal CAD systems). This is troublesome, leading many - I believe - to
suggest that the idea is not plausible.

I think that a usable visual programming language is possible but it would
have to be a good graphical tool rather than just a translation of a textual

I am encouraged by the FP notion of the creation of new glue, as if you
could create new control structures and domain specific languages. Once this
concept has been incorporated, i.e. the user-development of new visual
syntax as first class then I think we will see some progress in VPLs.
Unfortunately this is a big task, to my mind it involves revising our
current method of building interactive software (the event loop) to make it
more modular and reasonable to expect users to contribute new modules or
systems thereof. The FP community have delivered a number of promising
architectures (Haggis, Fudgets, Exene) in this area as has Rob Pike
(newsqueak, 8 and a half, mux?).

My interest in the area was peaked by a presentation on VPL. VPL was
exceptionally usable dataflow image-processing oriented system. It had
functions as first class objects and apply.

On related note the types of a function adding two integers together, two
lists of integers together and dataflow or pipe adding two streams of
integers together would seem to be similar. Does anyone know of some formal
work on this, what are the terms I would use to investigate?

I think you can see where I'm going with this - the user has a notion of
'things connected together', but without being too concerned about the
underlying system. I imagine a 'live' type system flagging up mismatches. I
think there is analagous situation when beginners try to plumb monads
together with pure code. The idea would be to get visual syntax to help out.
Consider the conversation, "Oh, you can connect red stripey objects together
but when you want to join up a blue object you need a red/blue adaptor".


----- Original Message -----
From: "Jason J. Libsch" <>
To: <>
Sent: Monday, April 02, 2001 5:57 PM
Subject: Visual Haskell

> I recently ran across a paper, Visual Haskell- a First Attempt, and was
> tremendously impressed.  Has anybody here played with this language or
> read the paper?  I would be interested to hear other's opinion on such a
> language.
>  /jason
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