\DOC upto

\TYPE {upto : int -> int -> int list}

\SYNOPSIS
Builds a list of integers.

\DESCRIBE
An invocation {upto b t} returns the list {[b, b+1, ..., t]}, if {b <= t}.
Otherwise, the empty list is returned.

\FAILURE
Never fails.

\EXAMPLE
{
- upto 2 10;
> val it = [2,3,4,5,6,7,8,9,10]
}

\ENDDOC