`for i in N` is accepted, but incorrect

[dalance]

for i in N is valid syntax, but semantically incorrect.
It should be reported as error.

[taichi-ishitani]

How about treating this as syntax sugar of for i in 0..N?

[dalance]

That idea sounds good, and I also thought about it.
However, I feel inconsistency, since N means just N in other range constructs (like inside),
so N means 0..N in for statement only.

[taichi-ishitani]

How about considering N as a number describing how many times the loop is iterated in this context?

[dalance]

I think it may be confusable that the same string of characters has different meanings depending on the context.

• inside: N means just N and 0..N means from 0 to N.
• for: both N and 0..N mean from 0 to N.

If there is a special keyword like for i in cnt N, it may be clear.
However, I feel 0..N is sufficient instead of cnt N.

[taichi-ishitani]

How about instroducing repeat keyword instead of cnt?

repeat N {

}

repeat i in N {

}

[dalance]

Adding syntax increases cognitive load and maintenance costs.
Does the benefit justify these?