User defined operators

[MarkNicholls]

User defined operators

[michaelhkay]

I don't see that a syntax like that offers any significant benefits over our current

a => concatPrint(b)

What does Haskell do about operator precedence?

[MarkNicholls]

actually the => observations is pretty relevant, I don't especially use it (as its a tad contrary to my intuition/indoctrination elsewhere).

but lets carry on a tiny bit more (though i suspect you've undermined the motivation enough already)

so you can do this (and use it as a use case)

ghci> pure (+) <*> Just 3 <*> Just 5
Just 8

so here we're taking the normal operator + and then adding 2 maybe int s

(this sort of thing is only really useful (to me) if its targeted as a specific domain, not as a general style - though others will vehemently disagree)

so in XPath world thats (something like - don't take this too literally)

pure((+)) => maybe:apply(maybe:some(3)) => maybe:apply(maybe:some(5))

ew....though what I'm suggesting isn't much better.

pure((+)) 'maybe:apply' maybe:some(3) 'maybe:apply' maybe:some(5)

backtick operators have fixed precedence and are left associative.

tbh, I don't think my suggestion is really powerful enough to make my expressions 'elegant',

I was wondering if there was an easy preprocessing of the expression that could be done that would introduce user defined expressions into the language without too much cost.

But I'm doubting if there is much benefit.

I'll try using => and see how far it gets me.

[MarkNicholls]

closing, I think this is premature without me trynig out '=>' more

[michaelhkay]

I'm not reopening the issue because it's not a serious proposal, but a bit of fun would be to allow all Unicode non-ASCII math symbols such as ≈ to be used as function names and possibly as binary operators, e.g.

declare %precedence(6) function ≈ ($x as xs:numeric, $y as xs:numeric) as xs:boolean {
    return abs($x - $y)  lt 1e-9
}

[MarkNicholls]

My hope was there was a simple thing that would turn a function into an operator, and then Id ask for a loosening of the function naming, and then youd have something pretty usable, but I need to wrestle with what is there first. On 13 Aug 2024, at 10:37, Michael Kay ***@***.***> wrote:  I'm not reopening the issue because it's not a serious proposal, but a bit of fun would be to allow all Unicode non-ASCII math symbols such as ≈ to be used as function names and possibly as binary operators, e.g. declare %precedence(6) function ≈ ($x as xs:numeric, $y as xs:numeric) as xs:boolean { return abs($x - $y) lt 1e9 } — Reply to this email directly, view it on GitHub<#1376 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/AAY5JGJ6BP6VY64FXGQF5EDZRHHWXAVCNFSM6AAAAABMLTG4KSVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDEOBVHAYTGNBYGI>. You are receiving this because you modified the open/close state.Message ID: ***@***.***>