[Haskell-cafe] Fractional/negative fixity?

Henning Thielemann haskell at henning-thielemann.de
Wed Nov 8 08:37:10 EST 2006


On Tue, 7 Nov 2006, David House wrote:

> On 07/11/06, Jon Fairbairn <jon.fairbairn at cl.cam.ac.uk> wrote:
> > I must say though, that I don't like the reasoning that we
> > can put in fractional fixities because it's a small
> > change. The way to hell is through a series of small
> > steps. If using integers to express fixities is a bit of a
> > hack, switching to rational numbers is a hack on top of a
> > hack.
> 
> Well, It's a _conceptually_ simple idea, one that doesn't make
> understanding the language much harder.
> 
> Also, it provides an infinite space for fixities. I think the problem
> 'binds tighter than X but not as tight as Y', where X and Y are only
> fixity integer apart is somewhat common, and this would fix it.

In school we learnt "dot operations (multiplication, division) bind more
tightly than dash operations (addition, subtraction)". I imagine we would
have learnt "dot operations have precedence 7, dash operations have
precedence 6". :-)


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