Perl To Python Migration

THE EXECUTION MODEL

Although not a vital part of your understanding of the differences between Perl and Python, understanding the similarities and differences between the two models of execution is a useful side note.

Perl

Perl's execution model, follows a very simple path. The model assumes you've just run a Perl script from a text file, which with some minor differences applies equally to the methods used for executing embedded scripts (from C/C++), in-line evaluations (through eval), and the one line scripts supplied on the command line.

Following the figure the basic execution process for Perl goes like this:

1.	Read the source code.
2.	Immediately execute any BEGIN blocks in the source.
3.	Import (and if necessary evaluate and execute) the ...