The if, then, ifelse and else keywords add a condition to an expression.
Note: see wikipedia for more explanation about if else constructs.
Syntax
if boolean_condition then value
else value
if boolean_condition then value
elseif boolean_condition then value
elseif boolean_condition then value
elseif boolean_condition then value
else value
Returns
The value after the then of the first condition that returns true. If all conditions return false, then the value after else is returned.
