The YAML specification is huge. Really, really huge. It contains all the functionality of XML, except with flexibility and choice, which makes it easier to read, but with a formal specification that is more complex than XML.

The original pure-Perl implementation YAML costs just over 4 megabytes of memory to load. Just like with Windows .ini files (3 meg to load) and CSS (3.5 meg to load) the situation is just asking for a YAML::Tiny module, an incomplete but correct and usable subset of the functionality, in as little code as possible.

Like the other ::Tiny modules, YAML::Tiny has no non-core dependencies, does not require a compiler to install, is back-compatible to Perl v5.8.1, and can be inlined into other modules if needed.

In exchange for this adding this extreme flexibility, it provides support for only a limited subset of YAML. But the subset supported contains most of the features for the more common uses of YAML.