62 lines
2.3 KiB
Plaintext
62 lines
2.3 KiB
Plaintext
.. highlight:: yaml
|
|
|
|
=====================================================
|
|
Differences between D:YAML and the YAML specification
|
|
=====================================================
|
|
|
|
There are some differences between D:YAML and the YAML 1.1 specification. Some
|
|
are caused by difficulty of implementation of some features, such as multiple
|
|
Unicode encodings within single stream, and some by unnecessary restrictions or
|
|
ambiguities in the specification.
|
|
|
|
Still, D:YAML tries to be as close to the specification as possible. It should
|
|
never load documents with different meaning than according to the specification,
|
|
and documents that fail to load should be very rare (for instance, very few
|
|
files use multiple Unicode encodings).
|
|
|
|
|
|
--------------------------
|
|
List of known differences:
|
|
--------------------------
|
|
|
|
Differences that can cause valid YAML documents not to load:
|
|
|
|
* No support for byte order marks and multiple Unicode encodings in a stream.
|
|
* Plain scalars in flow context cannot contain ``,``, ``:`` and ``?``.
|
|
This might change with ``:`` in the future.
|
|
See http://pyyaml.org/wiki/YAMLColonInFlowContext for details.
|
|
* The specification does not restrict characters for anchors and
|
|
aliases. This may lead to problems, for instance, the document::
|
|
|
|
[ *alias, value ]
|
|
|
|
can be interpteted in two ways, as::
|
|
|
|
[ "value" ]
|
|
|
|
and::
|
|
|
|
[ *alias , "value" ]
|
|
|
|
Therefore we restrict aliases and anchors to ASCII alphanumeric characters.
|
|
* The specification is confusing about tabs in plain scalars. We don't use tabs
|
|
in plain scalars at all.
|
|
* There is no support for recursive data structures in DYAML.
|
|
|
|
Other differences:
|
|
|
|
* Indentation is ignored in the flow context, which is less restrictive than the
|
|
specification. This allows code such as::
|
|
|
|
key: {
|
|
}
|
|
|
|
* Indentation rules for quoted scalars are loosed: They don't need to adhere
|
|
indentation as ``"`` and ``'`` clearly mark the beginning and the end of them.
|
|
* We allow ``_`` in tag handles.
|
|
* Right now, two mappings with the same contents but different orderings are
|
|
considered unequal, even if they are unordered mappings. This is because all
|
|
mappings are ordered in the D:YAML implementation. This should change in
|
|
future, once D associative arrays work with variant types or a map class or
|
|
struct appears in Phobos.
|