[Haskell-cafe] Channel9 Interview: Software Composability and the Future of Languages

Robert Dockins robdockins at fastmail.fm
Sat Jan 27 19:40:29 EST 2007

On Friday 26 January 2007 22:14, Tim Newsham wrote:
> > impractical language, only useful for research. Erik Meijer at one point
> > states that programming in Haskell is too hard and compares it to
> > assembly programming!
> He brings up a very good point.  Using a monad lets you deal with
> side effects but also forces the programmer to specify an exact
> ordering.  This *is* a bit like making me write assembly language
> programming.  I have to write:
>    > do {
>    >    x <- getSomeNum
>    >    y <- anotherWayToGetANum
>    >    return (x + y)
>    > }
> even if the computation of x and y are completely independant of
> each other.  Yes, I can use liftM2 to hide the extra work (or
> fmap) but I had to artificially impose an order on the computation.
> I, the programmer, had to pick an order.

Humm.  While I can accept that this is a valid criticism of Haskell's monadic 
structure for dealing with I/O, I fail to see how it could drive a decision 
to prefer an imperative language like C#, where every statement has this 
property (overspecification of evaluation order).  The only mainstream-ish 
general-purpose language I know of that I know of that attempts to addresses 
this problem head-on is Fortress.  (Although, to be honest, I don't know 
enough about Fortress to know how it handles I/O to even know if it is an 
actual improvement over the situation in Haskell.)

> Ok, maybe "assembly language" is a bit extreme (I get naming, allocation
> and garbage collection!) but it is primitive and overspecifies the
> problem.
> Tim Newsham
> http://www.thenewsh.com/~newsham/

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