string:sub

[David Burgess <dabsoft@...>]

It seems to me that negative values of string.sub() are inconsistent 
with not only the first parameter but also with string.find().

Examples:

>s="123456789"
>=s:sub(-1)
9
>=s:sub(1,0)

>=s:sub(1,-1)
123456789
>=s:sub(1,-2)
12345678
>=s:find("56")
5	6
>=s:sub(1,6-2)
1234
>=s:sub(-1)
9

I am boldly suggesting that the second parameter with negative indices 
behave the same as the first. I guess this implies that the value 0 for
the second parameter would return the length of the string.
Maybe I have used too many similar functions in other languages but -1 
meaning the last character seems intuitive to me.

Anyone else of a like view?

DB