Nick Sabalausky:
I can do that just as easily without a REPL.
With a much reduced interactivity and more slowly.
In Python you have full run-time introspection available from the
REPL. You have commands like dir() and help(). Plus the error
messages. If you are using iPython or a graphical shell things
gets even better. Combined with the time you save not compiling &
running your whole proggy again, it allows you a different flow
of work. And when you do exploratory programming such saved time
is important, because it helps you to not lose your current train
of thoughts.
Most exploratory mathematics systems have a REPL, because for
some people and for some kinds of problems, it's much better to
have it. It's not for everyone nor for every kind problem.
Bye,
bearophile