Make function definition in a python file order independent

Question

I use Python CGI. I cannot call a function before it is defined.

In Oracle PL/SQL there was this trick of "forward declaration": naming all the functions on top so the order of defining doesn't matter.

Is there such a trick in Python as well?

example:

def do_something(ds_parameter):     helper_function(ds_parameter)     ....  def helper_function(hf_parameter):     ....  def main():     do_something(my_value)  main() 

David is right, my example is wrong. What about:

<start of cgi-script>  def do_something(ds_parameter):     helper_function(ds_parameter)      ....   def print_something():      do_something(my_value)   print_something()   def helper_function(hf_parameter):      ....   def main()     ....  main() 

Can I "forward declare" the functions at the top of the script?

Answer 1

All functions must be defined before any are used.

However, the functions can be defined in any order, as long as all are defined before any executable code uses a function.

You don't need "forward declaration" because all declarations are completely independent of each other. As long as all declarations come before all executable code.

Are you having a problem? If so, please post the code that doesn't work.

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In your example, print_something() is out of place.

The rule: All functions must be defined before any code that does real work

Therefore, put all the statements that do work last.

Answer 2

An even better illustration of your point would be:

def main():     print_something()      ....  def do_something(ds_parameter):     helper_function(ds_parameter)      ....   def print_something():      do_something(my_value)    def helper_function(hf_parameter):      ....    main() 

In other words, you can keep your definition of main() at the top, for editing convenience -- avoiding frequent scrolling, if most of the time is spent editing main.