Status of this Document
This document reflects the third version of YAML data serialization
language. The content of the specification was arrived at by concensus
of its authors and through user feedback on the yaml-core mailing list.
We encourage implementers to please update their software with support
for this version. In the interest of interoperability, we also ask them
to deprecate older implementations as their user community may permit.
The primary objective of the 1.2 revision of this specification is to
bring YAML into compliance with JSON as an official subset. An expected
source of incompatibility with prior versions of YAML, especially the
syck implementation, is the change in implicit typing rules. We have
removed odd and infrequent implicit rules and have updated these rules
align them with JSON's productions. In this version of YAML, boolean
values may be serialized as ``true`` or ``false``; the empty scalar as
``null``. Unquoted numeric values are a superset of JSON's numeric
production. Other changes in the specification were production bug
fixes and defining 3 built-in implicit typing rule sets: untyped,
strict JSON, and the default YAML typing.
The primary objective of the 1.1 revision of this specification was to
fix problems with tagging rules. In particular the single exclamation
was reserved for locally defined types and a simple prefixing mechanism
was included to help usability. This revision also fixed numerous
production edge cases and introduced a type repository.
The list of known errors in this specification is available at
http://yaml.org/spec/1.1/errata.html -- please report errors in this
document to yaml-core@...