emitter: don't output numbers in SINGLE_QUOTED style.

* specs/lib_lyaml_spec.yaml (loading): Indent another level...
(lyaml): ...move under new top level.
(dumping): Specify behaviour for emitting table elements.
* lib/lyaml.lua (dumper_mt.dump_scalar): Use PLAIN style unless
a string would convert to a number, and then SINGLE_QUOTED style.
* NEWS: Update.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
emitter: emit lyaml.null nodes correctly.

* specs/lib_lyaml_spec.yaml (scalars): Remove pending call.
* lib/lyaml.lua (null): Put null singleton identifier in its own
metatable.
(isnull): Predicate function for detecting null nodes.
(dump_node): Use it to dump nulls correctly.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
lyaml: implement anchor matching in lyaml.dump ().

Closes #2.
* specs/lib_lyaml_spec.yaml (anchors and aliases): Specify correct
behaviours when replacing anchor matches with YAML anchor and
alias syntax.
* lib/lyaml.lua (dumper_mt.get_anchor): Move matched anchor to new
aliased property.
(dumper_mt.get_alias): Look up already matched anchor in aliased
property.
(dumper_mt.dump_alias): Emit an ALIAS event.
(dumper_mt.dump_mapping, dumper_mt.dump_sequence)
(dumper_mt.dump_scalar): Look up anchor with `get_anchor`, and
replace event with ALIAS if match found with `get_alias`.
* NEWS: Update.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>
Release version 5

* NEWS: Record release date.
maint: post-release administrivia.

* configure.ac (AC_INIT): Bump release version to 6.
* NEWS: Add header line for next release.
* .prev-version: Record previous version.
* ./local.mk (old_NEWS_hash): Auto-update.

Signed-off-by: Gary V. Vaughan <gary@gnu.org>