Conditionally evaluates expressions
(if testexpr thenexpr [elseexpr])
Arguments
Expression to be tested.
Expression evaluated if testexpr is not nil.
Expression evaluated if testexpr is nil.
Return Values
The if function returns the value of the selected expression. If elseexpr is missing and testexpr is nil, then it returns nil.
Examples
Command: (if (= 1 3) "YES!!" "no.")
"no."
Command: (if (= 2 (+ 1 1)) "YES!!")
"YES!!"
Command: (if (= 2 (+ 3 4)) "YES!!")
nil
The progn function.
