Can't deserialize a string that looks like a float properly

Under Syck if you register a domain type, the block will get the tag name and the value yielded to it as they are in the actual raw YAML.

In Psych however the value string has already been tokenized by the call at the bottom of Psych::Visitors::ToRuby#deserialize, before #accept is called.

This is a problem because if your serialized value string happens to look like a floating point number, then it will get parsed as a Float and your deserializer won't be able to get the original string so that it can parse it properly (without float's precision problems).

Is there another way to add domain class parsing in a way that won't get tokenized? It seems that at the moment we have to extend the big case statement in #deserialize (or use alias_method_chain to add a special case).

If not could we maybe rearrange slightly so that #tokenize is not called before #accept?

Start with Psych::Visitors::ToRuby#deserialize and trace how #tokenize runs before #accept for registered domain types. Determine how deserialization can preserve the raw string for domain parsing without float conversion; done means the domain deserializer receives the original value and no precision is lost.