19     Writing PHP

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While it is almost certain that you read this book to learn the PHP programming language, I believe that there is a lot more to learning a language than just memorising its syntax and functions. For example, learning to program to a fixed style means your code will be easier to maintain by yourself and by others, and learning to debug properly means your code will have fewer bugs and you will have fewer headaches.

This chapter is designed to fill you in on the practical aspects of being a PHP programmer, and should hopefully make your programming life easier, as well as help you find and solve problems with the minimum of fuss.

The topics covered in this chapter are:

• How to analyse your system requirements

• Using a development tool to help you code

• File layout schemes and group development

• Documentation and testing

• Distribution your code and licensing your work

• How to debug your scripts

• Troubleshooting hints and tips

• Where to get help if you still have a problem

Chapter contents

19.1. The design process

19.1.1. Analysing the requirements
19.1.2. Designing the solution
19.1.3. Developing the code
19.1.4. Implementing the application
19.1.5. Maintenance and support

19.2. Which IDEs are good

19.2.1. Line numbering
19.2.2. Syntax highlighting
19.2.3. Online help
19.2.4. Code insight
19.2.5. Interactive debugging
19.2.6. Profiling
19.2.7. Popular IDEs

19.3. Laying out your files

19.3.1. Directory structuring

19.4. Group development

19.4.1. How to develop code
19.4.2. Version control

19.5. Documenting your project
19.6. Testing: php_check_syntax()
19.7. Distributing your code

19.7.1. Charging for your work
19.7.2. PHP Encoders
19.7.3. Cross-platform code 1: Loading extensions
19.7.4. Cross-platform code 2: Using extensions
19.7.5. Cross-platform code 3: Path and line separators
19.7.6. Cross-platform code 4: Coping with php.ini differences
19.7.7. Cross-platform code 5: Checking the PHP version with phpversion() and version_compare()

19.8. Debugging

19.8.1. What is a bug?
19.8.2. The most basic debugging technique: debug_zval_dump()
19.8.3. Making assertions: assert() and assert_options()
19.8.4. Triggering your own errors: trigger_error()
19.8.5. Source highlighting: highlight_file() and highlight_string()
19.8.6. Handling MySQL errors: mysql_error()
19.8.7. Exception handling
19.8.8. Backtracing your code: debug_backtrace()
19.8.9. Debuggers
19.8.10. Custom error handlers: set_error_handler(), restore_error_handler(), and error_log()
19.8.11. Custom exception handlers: set_exception_handler() and restore_exception_handler()
19.8.12. Using @ to disable errors
19.8.13. phpinfo()

19.9. Debugging practice
19.10. Coding style

19.10.1. Comments and whitespace
19.10.2. Variable naming
19.10.3. Functions
19.10.4. Distinguishing code blocks

19.11. Output style

19.11.1. Options for Tidy

19.12. Troubleshooting

19.12.1. Error types
19.12.2. Choosing what types of errors you see: error_reporting()
19.12.3. Common errors

19.13. Getting Help

19.13.1. The documentation
19.13.2. Mailing lists
19.13.3. Websites
19.13.4. IRC
19.13.5. Conferences
19.13.6. User groups
19.13.7. Submitting a bug
19.13.8. Contacting the author

19.14. Getting qualified
19.15. Summary
19.16. Exercises
19.17. Further reading
19.18. Next chapter