lib for developers : libList

[StephenG1CMZ]

L_INS({1,2,3},0,99) = {1,2,3,99} ?? (From your example)

I am unsure how an index of 0 should be parsed in this case.
When a value is read, 0 refers to the last value, and when it is written, the new value about to be added.

Does this mean it should be inserted before the value yet to be written (i.e. appended at the end)?
Or does it mean that it should be inserted before {1,2,3}(0) i.e. 3, giving {1,2,99,3}?

Given that {1,2,3,99} is trivial
{1,2,3}(0):=99
Perhaps {1,2,99,3} is more useful?
Of course, it should also be offset by 1 from your -1 position.

For comparison:
In Java and Python, lists are indexed from 0, so "insert before position 0" would be {99,1,2,3}
Although (0) is a useful syntax in PPL, here it is less obvious to me what it should refer to.