Is it possible to create my own operator on `SqlExpressionBuilder` somehow ?

# exposed

[spand]

Is it possible to create my own operator on SqlExpressionBuilder somehow ?

[tapac]

With Expression<*> as a receiver?
I guess it's impossible as you need to have 2 receivers on a single function.

Why do you need that? To reduce function scope?

[spand]

I wanted to make my own helper functions.. ie. inInterval that checks a column c is: interval.start <= c && c < interval.end

[tapac]

The only thing is extension on Expression<DateTime?>.inInterval(..) but it will be available out of SqlExpressionBuilder scope.

[spand]

Yeah that what I ended up doing and importing greaterEq, and less. Would just be nice to have it encapsulated like the rest.

[spand]

Maybe it ought to be a language proposal to have multiple extension receivers.

[tapac]

https://github.com/Kotlin/KEEP/pull/176

[tapac]

Not sure what this is exactly about you need,

[spand]

Thanks. Will take a look

[tapac]

I found interesting approach here (https://discuss.kotlinlang.org/t/declare-member-extensions-outside-the-class/6759/6?u=tapac)

val SqlExpressionBuilder.inInterval: ExpressionWithColumnType<DateTime?>.(Interval) -> Expression<Boolean> get() = { interval ->
    val expr = this
    (expr greater interval.start) and (expr less interval.end) 

}

fun main() {
    Op.build {
        val expr = dateLiteral(DateTime.now())
        expr.inInterval(3)
    }
}

[spand]

That is an interesting approach 😉

[spand]

We only use infix however so I think I prefer the fun