Appendix A. Essential Perl Best Practices

Ten Essential Development Practices

1. Design the module's interface first.

   [Chapter 17: Interfaces]

2. Write the test cases before the code.

   [Chapter 18: Test Cases]

3. Create standard POD templates for modules and applications.

   [Chapter 7: Boilerplates]

4. Use a revision control system.

   [Chapter 19: Revision Control]

5. Create consistent command-line and configuration interfaces.

   [Chapter 14: Command-Line Structure, Chapter 19: Configuration Files]

6. Agree upon a coherent layout style and automate it with perltidy.

   [Chapter 2: Automated Layout]

7. Code in commented paragraphs.

   [Chapter 2: Chunking]

8. Throw exceptions instead of returning special values or setting flags.

   [Chapter 13: Exceptions]

9. Add new test cases before you start debugging.

   [Chapter 18: Debugging and Testing]

10. Don't optimize codebenchmark it.

    [Chapter 19: Benchmarking]

Ten Essential Coding Practices

1. Always use strict and use warnings.

   [Chapter 18: Strictures, Warnings]

2. Use grammatical templates when forming identifiers.

   [Chapter 3: Identifiers, Booleans, Reference Variables, Arrays and Hashes]

3. Use lexical variables, not package variables.

   [Chapter 5: Lexical Variables]

4. Label every loop that is exited explicitly, and every next, last, or redo.

   [Chapter 6: Loop Labels]

5. Don't use bareword filehandles; use indirect filehandles.

   [Chapter 10: Filehandles, Indirect Filehandles]

6. In a subroutine, always unpack @_ first, using a hash of named arguments if there are more than three parameters.

   [Chapter 9: Argument Lists, Named Arguments]

7. Always return via an explicit return.

   [Chapter 9: Implicit Returns]

8. Always use the /x, /m, and /s flags, and the \A and \z anchors.

   [Chapter 12: Extended Formatting, Line Boundaries, Matching Anything, String Boundaries]

9. Use capturing parentheses in regexes only when deliberately capturing, then give the captured substrings proper names.

   [Chapter 12: Capturing Parentheses, Capture Variables]

10. Never make variables part of a module's interface.

    [Chapter 17: Interface Variables]

Ten Essential Module Practices

1. Write tests using the Test::Simple or Test::More modules.

   [Chapter 18: Modular Testing]

2. use English for the less familiar punctuation variables.

   [Chapter 5: Punctuation Variables]

3. Use named constants created with the Readonly module.

   [Chapter 4: Constants]

4. Use the "non-builtin builtins" from Scalar::Util, List::Util, and List::MoreUtils.

   [Chapter 8: Utilities]

5. Use IO::Prompt when prompting for interactive input.

   [Chapter 10: Simple Prompting, Power Prompting]

6. Use the Carp and Exception::Class modules to create OO exceptions that report from the caller's location.

   [Chapter 13: Reporting Failure, Exception Classes]

7. Use the Fatal module to make builtins throw exceptions on failure.

   [Chapter 13: Builtin Failures, Contextual Failure]

8. Create aliases using the Data::Alias or Lexical::Alias module.

   [Chapter 6: Necessary Subscripting]

9. Use Regexp::Common instead of writing your own regexes.

   [Chapter 12: Canned Regexes]

10. Use the Class::Std module to create properly encapsulated classes.

    [Chapter 16: Automating Class Hierarchies, Attribute Demolition, Attribute Building]