In this new article on his blog Fabien Potencier looks at the current state of the YAML markup language and how well it's supported in the world of PHP.
YAML can be used to describe both simple and complex data structures. It's an easy to learn language that describes data. As PHP, it has a syntax for simple types like strings, booleans, floats, integers, arrays, and even more complex ones like objects. Nowadays, YAML is a heavily used format for configuration files, mainly because even non programmers are able to understand and modify YAML files easily.
He spends a little time describing the YAML markup format and shows how to parse it using the Symfony component, how to get it and install it (via svn checkout).