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Re: Meaning of "Clean" Perl code

by eyepopslikeamosquito (Archbishop)
on Jul 25, 2005 at 15:21 UTC ( [id://477868] : note . print w/replies, xml ) Need Help??

in reply to Meaning of "Clean" Perl code

It is perhaps easier to describe "unclean" code. For example:

  • Code with lots of code smells (see also wikipedia Code_smell)
  • Lots of magic numbers
  • A 5000-line main program
  • A sub that reads and writes global variables
  • A sub that does not have a single purpose; for example, instead of a sin function and a tan function, someone defines a sin_and_tan function
  • Some of a sub's parameters are not used
  • A sub that is 1000 lines long, aka "Big-Arsed Function"
  • Duplicated code
  • Code with gaping security holes
  • Code that leaks resources
  • Code that is not thread-safe or signal-safe

Conversely, some clean Perl code attributes are:

  • strict-safe
  • warnings-safe
  • taint-safe
  • Good variable naming
  • Minimize variable scope
  • Prefer lexicals to globals
  • Good commenting
  • Consistent indentation and visually pleasing layout
  • Easy to understand
  • Simple, Clear, General
  • Easy to use module interfaces
  • Comprehensive test suite

Finally, TheDamian's new book Perl Best Practices provides much sound advice on writing clean Perl code.

Update: See also Is it correct? by GrandFather:

  • Does it work correctly?
  • Do you understand it?
  • Would anyone else understand it?
  • Will you understand it in a month's time?
  • Does it strike a good balance between terseness and verbosity?
  • Could you make changes to it without it being likely to break in unforeseen ways?
  • Is it fast enough?

Update: See also: On Coding Standards and Code Reviews and Re: I need perl coding standards (Coding Standards References)