Hello, I have `infix fun A.function(b): X` , then...

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[Davide Giuseppe Farella]

Hello, I have
infix fun A.function(b): X ,
then I have operator fun X.invoke(f: () -> Unit)
so I’m trying to call a function b { ... }
But I get B cannot get invoked as a function, I’ve tried to use plus
a function b +{ ... }
But I got something similar.

If it use infix infix operator fun X.invoke(f: () -> Unit) is fine ( a function b invoke { ... } ), but cannot get rid of that explicit invoke

If I do like (a function b) { ... } is also fine, but still ugly 🙂

Any solution?
Thanks 🙂

[Ruckus]

You already found the solution (using parens). Unfortunately this is a matter of precedence, and you change precedence with parens.

[Davide Giuseppe Farella]

Ye, but that’s very ugly and make very little sense that:
a func b run { ... } OK
a func b + { ... } NO
😕

[Ruckus]

It makes perfect sense. Operator precedence is fundamental. By that logic, you can claim it makes no sense these have the same result:
3 * 6 + 4
4 + 3 * 6
Clearly the first should be 22 and the second 42, since the + came first.

[Ruckus]

But that's absurd because we understand the precedence of the operators.

[Ruckus]

Do you think it's ugly to have to do (4 + 3) * 6?

[Shawn]

i wonder what a PEMDAS-style mnemonic for Kotlin order of operations would look like 😛

[Davide Giuseppe Farella]

Ok, talking about math operators it sounds different, the + was just a try that could be nice, it’s not supposed to be a math stuff.
But why a func b plus { ... } is fine?

[Davide Giuseppe Farella]

Ok, perhaps I got it 🙂

[Ruckus]

In Kotlin, invoke is an operator just like plus. Is your later example, you have no invoke. That last bit is a lambda passed in to plus.

[Davide Giuseppe Farella]

Yup, got it. Thank you 🙂
I’ll try to declare the plus operator on B and handle like:
A.func(BPlus)
I might get out if it 🙂

[Ruckus]

It is unfortunate that the operator symbols have a different precedence that their names infix counterparts.

[Davide Giuseppe Farella]

Kinda like it 🙂 Thank you again