Fractional precedences? Re: Operator precedence help

John Cotton Ericson John.Ericson at Obsidian.Systems
Wed Sep 2 22:29:36 UTC 2020

I definitely prefer this approach. I do not like absolutely levels, 
whether natural numbers or fractional. At the end of the day, that's all 
order-maintance for a *global* total preorder, and such a design will 
always result in unforeseeable interactions between 
independently-developed operators, not to mention increasingly 
ludicrously-precise fractions.

This may sound like low-priority design pedantry, but I suspect 
(probably because I myself was taught with scheme) that 
spooky-action-at-a-distance precedence greatly harms beginning 
programmers, causing confusion or at least delaying the understanding 
that expressions are arbitrarily deep trees.


On 8/17/20 12:12 PM, Carter Schonwald wrote:
> Oh yeah!
> I feel like everyone’s wondered about that approach. But it definitely 
> would need some experiments to validate. But in some ways it’d be 
> super fascinating.
> On Mon, Aug 17, 2020 at 9:40 AM Henning Thielemann 
> <lemming at <mailto:lemming at>> 
> wrote:
>     On Sun, 16 Aug 2020, Carter Schonwald wrote:
>     > I do think that the work needed to actually support fractional
>     > precedence in ghc is pretty minimal.  Or at least I remember
>     having a
>     > conversation about it a few years ago, and the conclusion was that
>     >  adding precedence would be super easy to do, but just lacked
>     any good
>     > motivating example from real libraries.
>     I remember this discussion, too, and I guess that it was started
>     by Simon
>     Marlow and it ended with recalling that decades ago something more
>     advanced was discussed: Groups of equal precedence and relations
>     between
>     the groups. But that one was too complicated to be implemented.
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