LINT
PHP & JavaScript Code Checkers
Lint :: Dave Ross :: Suburban Chicago PHP & Web Design Meetup :: suburbanchicagophp.org :: Sept 3, 2009

History of Lint
• Bell Labs, Late 1970s
• First public appearance Unix V7 (1979)
• Written for C language
• Named for bits of crud in sheeps’ wool
Lint :: Dave Ross :: Suburban Chicago PHP & Web Design Meetup :: suburbanchicagophp.org :: Sept 3, 2009

Static Code Analysis
• Analyzes code without executing it
• Detects syntax errors (missing semicolons,
missing curly braces)
• Detects some bugs & unsafe code
Lint :: Dave Ross :: Suburban Chicago PHP & Web Design Meetup :: suburbanchicagophp.org :: Sept 3, 2009

PHP -l
• PHP’s built-in Lint tool
• Command-line tool
• php -l somefile.php
• Same code PHP uses to parse code at
runtime
Lint :: Dave Ross :: Suburban Chicago PHP & Web Design Meetup :: suburbanchicagophp.org :: Sept 3, 2009

PHPLint
• http://www.icosaedro.it/phplint/
• Windows & Unix
Lint :: Dave Ross :: Suburban Chicago PHP & Web Design Meetup :: suburbanchicagophp.org :: Sept 3, 2009

PHPLint On-Line
• http://www.icosaedro.it/phplint/phplint-on-line.html
• Only checks one file at a time
• Can’t check dependencies
Lint :: Dave Ross :: Suburban Chicago PHP & Web Design Meetup :: suburbanchicagophp.org :: Sept 3, 2009

PHPLint On-Line
Lint :: Dave Ross :: Suburban Chicago PHP & Web Design Meetup :: suburbanchicagophp.org :: Sept 3, 2009

JSLint by Doug Crockford
• JavaScript Lint tool
• jslint.com
• “Warning: JSLint will hurt your feelings”
• Detects really obscure JavaScript errors
• See “JavaScript: The Good Parts”
http://www.youtube.com/watch?
v=hQVTIJBZook
Lint :: Dave Ross :: Suburban Chicago PHP & Web Design Meetup :: suburbanchicagophp.org :: Sept 3, 2009

Lint :: Dave Ross :: Suburban Chicago PHP & Web Design Meetup :: suburbanchicagophp.org :: Sept 3, 2009

Not Psychic
• Lint tools wont find every error
• They’ll find technical errors
• You’re on your own for logical errors
Lint :: Dave Ross :: Suburban Chicago PHP & Web Design Meetup :: suburbanchicagophp.org :: Sept 3, 2009

Any Questions?
Dave Ross
PHP & Javascript developer
WordPress plugin developer
http://daveross.tel
http://davidmichaelross.com
Lint :: Dave Ross :: Suburban Chicago PHP & Web Design Meetup :: suburbanchicagophp.org :: Sept 3, 2009