Count the parentheses and only execute the code if the number of open and closed parentheses is the same. ^C cancel all lines and return to main prompt.
>>> (let factorial
--> (lambda (n)
--> (if (== n 0)
--> 1
--> (* n (factorial (- n 1))))))
0x1111020
>>> (factorial 10)
3628800
Count the parentheses and only execute the code if the number of open and closed parentheses is the same. ^C cancel all lines and return to main prompt.