Custom tag support

[cubuspl42]

Currently, in the public API tags aren't exposed at all. Is there any reason for that? This makes custom tags (like !Foo) completely disappear.

[klausries]

A full support of YAML would be a major plus for Dart in many applications.
Consider a static web site generator as an application.

[jonasfj]

Feel free to up-vote, but I think the current set of features supports the uses cases the Dart team have for parsing configuration files.

If you want advanced custom syntax, then why not a fully fledged parser for a domain specific language using something like package:petitparser. If you search for "yaml bad" or look at compatibility results from yaml-test-suite, then there are plenty of good reasons not to use YAML for DSLs with complex syntax. I would suggest writing a parser instead.

If you really want custom tag support I think it might be best implemented in a community package. Adding such features here are liable to cause more bugs, and it's not clear that this is something we need in Dart tooling or that most users of package:yaml needs.