The only primitive conditional in NESL is the if construct. The syntax is:
If the first expression is true, then the second expression is evaluated and its result is returned, otherwise the third expression is evaluated and its result is returned. The first expression must be of type bool, and the other two expressions must be of identical types. For example:
if (t and f) then 3 + 4 else (6 - 2)*7
if (t and f) then 3 else 2.6