recursion
it is legal for one
function to call another; it is also legal for a function to call itself. it may
not be obvious why what is a good thing, but it turns out to be one of the most
magical things a program can do. for example:
if a recursion never
reaches a base case, it goes on making recursive calls forever, and the program
never terminates. this is known as infinite recursion, and it is generally not a
good idea. in most programming environments, a program with infinite recursion
does not really run forever. python reports an error message when the maximum
recursion depth is reached:
when the error occurs,
there are 1000 recurse frames on the stack.
form thinking in
python