[Haskell-cafe] Re: Automatic fixity allocation for symbolic operators

Arie Peterson ariep at xs4all.nl
Mon Oct 16 12:40:04 EDT 2006

Good evening,

Bulat Ziganshin wrote:

> but when you want to have user-defined operators, that will mean that
> you need either to define precedences to all other operators
> (including those from other libs), or sometimes user programs will not
> compile because they used combination of operators with undefined
> precedence
> good for making good headache :)

Why is that?

A library would indeed only declare the relative precedence of its
operators with respect to operators that 1) it knows of; and 2) are
related (or general) enough so that there is a reasonable choice of
precedence. I think it is even good to force the user to declare any
other, more uncommon, precedences; better than the current situation,
where the relative precedence of operators from unrelated libraries is
fixed pretty much arbitrarily, as an artefact of the imposed total order.




Mr. Pelican Shit may be Willy.


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