Idea: generalized version of `Pair` and `Triple` c...

# library-development

[Sam Stone]

Idea: generalized version of Pair and Triple called Tuple that uses code gen to create variables first, second, etc. (or ItemN like in C#), based on the number of arguments passed in.

Is this possible? Where would I begin? I have never made a compiler plugin.

[ephemient]

doesn't seem compiler related to me

[ephemient]

you need real classes (e.g. Tuple4, Tuple5, etc.) for them to be passed around

[ephemient]

and since you can only have a finite number of classes, you can simply write overloads

fun <T1, T2, T3, T4> Tuple(first: t1, second: t2, third: t3, fourth: t4): Tuple4
fun <T1, T2, T3, T4, T5> Tuple(first: t1, second: t2, third: t3, fourth: t4, fifth: t5): Tuple5
...

if you want them all to have a "constructor" named Tuple

[ephemient]

hmm, on further thought, in principle you could have the compiler synthesize types Tuple<T1, T2, T3, T4> etc. that are all backed by some internal class TupleN(data: Array<Any>). dunno about it being worthwhile though, since unnamed tuples aren't an encouraged pattern in Kotlin

[Sam Stone]

1. The last solution wouldn't provide type-safe property access.
2. What do you mean by "unnamed tuples"?
3. Why would it need to be backed by an internal class?

[aru]

Isn't that a built-in data class feature with componentN() functions? https://kotlinlang.org/docs/data-classes.html

[Sam Stone]

@aru
1. N only goes up to the 40's as of recent
2. The only way to do it that way is to have many nullable properties, so no type safety.