When its first operand is a constant expression expr,
the operator in evaluates to true iff the constant value
of the expression expr is contained in the interval range1.
When both its operands are ranges (intervals),
the operator in evaluates to true iff all values
in range1 are contained in the interval range2.
in is also used as a keyword for loops over the different
elements of a list.
Example 1:
> 5 in [-4;7];
true
> 4 in [-1;1];
false
> 0 in sin([-17;17]);
true
Example 2:
> [5;7] in [2;8];
true
> [2;3] in [4;5];
false
> [2;3] in [2.5;5];
false