[Tutor] email validation

[Danny Yoo]

On Sat, Aug 1, 2015 at 2:03 PM, Válas Péter <turtle at 64.hu> wrote:
> Hi Stephanie,
>
> the function should be defined first, and used after. So put it before
> main().



It's perfectly legal and ok to say:

###########################
def main():
     callHelper()

def callHelper():
     print("I am the helper")

main()
###########################



Rather, the problem is due to putting the helper function accidentally
nested *within* main:

############################
def main():
     callHelper()

    def callHelper():
         print("I am the helper but can't be called until after the definition")

main()
#############################



One technical way to "fix" this is to move it up a bit:

#############################
def main():
    def callHelper():
         print("I am the helper but can't be called until after the definition")

    callHelper()

main()
#############################



But this is usually unsatisfactory because we can't then access
callHelper from outside.  There can be valid reasons to hide function
definitions at times, but this isn't one of those situations.


Válas's suggestion, to move the helper's definition above, does make sense:

#############################
def callHelper():
     print("I am the helper but can't be called until after the definition")

def main():
    callHelper()

main()
#############################

but a key point needs to be made: don't just move it *up*, but move it *out*.