cs.tagset 20240316

Tags and sets of tags with __format__ support and optional ontology information.

Tags and sets of tags with format support and optional ontology information.

Latest release 20240316: Fixed release upload artifacts.

See cs.fstags for support for applying these to filesystem objects such as directories and files.

See cs.sqltags for support for databases of entities with tags, not directly associated with filesystem objects. This is suited to both log entries (entities with no "name") and large collections of named entities; both accept Tags and can be searched on that basis.

All of the available complexity is optional: you can use Tags without bothering with TagSets or TagsOntologys.

This module contains the following main classes:

• Tag: an object with a .name and optional .value (default None) and also an optional reference .ontology for associating semantics with tag values. The .value, if not None, will often be a string, but may be any Python object. If you're using these via cs.fstags, the object will need to be JSON transcribeable.
• TagSet: a dict subclass representing a set of Tags to associate with something; it also has setlike .add and .discard methods. As such it only supports a single Tag for a given tag name, but that tag value can of course be a sequence or mapping for more elaborate tag values.
• TagsOntology: a mapping of type names to TagSets defining the type and also to entries for the metadata for specific per-type values.

Here's a simple example with some Tags and a TagSet.

>>> tags = TagSet()
>>> # add a "bare" Tag named 'blue' with no value
>>> tags.add('blue')
>>> # add a "topic=tagging" Tag
>>> tags.set('topic', 'tagging')
>>> # make a "subtopic" Tag and add it
>>> subtopic = Tag('subtopic', 'ontologies')
>>> tags.add(subtopic)
>>> # Tags have nice repr() and str()
>>> subtopic
Tag(name='subtopic',value='ontologies')
>>> print(subtopic)
subtopic=ontologies
>>> # a TagSet also has a nice repr() and str()
>>> tags
TagSet:{'blue': None, 'topic': 'tagging', 'subtopic': 'ontologies'}
>>> print(tags)
blue subtopic=ontologies topic=tagging
>>> tags2 = TagSet({'a': 1}, b=3, c=[1,2,3], d='dee')
>>> tags2
TagSet:{'a': 1, 'b': 3, 'c': [1, 2, 3], 'd': 'dee'}
>>> print(tags2)
a=1 b=3 c=[1,2,3] d=dee
>>> # since you can print a TagSet to a file as a line of text
>>> # you can get it back from a line of text
>>> TagSet.from_line('a=1 b=3 c=[1,2,3] d=dee')
TagSet:{'a': 1, 'b': 3, 'c': [1, 2, 3], 'd': 'dee'}
>>> # because TagSets are dicts you can format strings with them
>>> print('topic:{topic} subtopic:{subtopic}'.format_map(tags))
topic:tagging subtopic:ontologies
>>> # TagSets have convenient membership tests
>>> # test for blueness
>>> 'blue' in tags
True
>>> # test for redness
>>> 'red' in tags
False
>>> # test for any "subtopic" tag
>>> 'subtopic' in tags
True
>>> # test for subtopic=ontologies
>>> print(subtopic)
subtopic=ontologies
>>> subtopic in tags
True
>>> # test for subtopic=libraries
>>> subtopic2 = Tag('subtopic', 'libraries')
>>> subtopic2 in tags
False

Ontologies

Tags and TagSets suffice to apply simple annotations to things. However, an ontology brings meaning to those annotations.

See the TagsOntology class for implementation details, access methods and more examples.

Consider a record about a movie, with these tags (a TagSet):

title="Avengers Assemble"
series="Avengers (Marvel)"
cast={"Scarlett Johansson":"Black Widow (Marvel)"}

where we have the movie title, a name for the series in which it resides, and a cast as an association of actors with roles.

An ontology lets us associate implied types and metadata with these values.

Here's an example ontology supporting the above TagSet:

type.cast type=dict key_type=person member_type=character description="members of a production"
type.character description="an identified member of a story"
type.series type=str
character.marvel.black_widow type=character names=["Natasha Romanov"]
person.scarlett_johansson fullname="Scarlett Johansson" bio="Known for Black Widow in the Marvel stories."

The type information for a cast is defined by the ontology entry named type.cast, which tells us that a cast Tag is a dict, whose keys are of type person and whose values are of type character. (The default type is str.)

To find out the underlying type for a character we look that up in the ontology in turn; because it does not have a specified type Tag, it it taken to be a str.

Having the types for a cast, it is now possible to look up the metadata for the described cast members.

The key "Scarlett Johansson" is a person (from the type definition of cast). The ontology entry for her is named person.scarlett_johansson which is computed as:

• person: the type name
• scarlett_johansson: obtained by downcasing "Scarlett Johansson" and replacing whitespace with an underscore. The full conversion process is defined by the TagsOntology.value_to_tag_name function.

The key "Black Widow (Marvel)" is a character (again, from the type definition of cast). The ontology entry for her is named character.marvel.black_widow which is computed as:

• character: the type name
• marvel.black_widow: obtained by downcasing "Black Widow (Marvel)", replacing whitespace with an underscore, and moving a bracketed suffix to the front as an unbracketed prefix. The full conversion process is defined by the TagsOntology.value_to_tag_name function.

Format Strings

You can just use str.format_map as shown above for the direct values in a TagSet, since it subclasses dict.

However, TagSets also subclass cs.lex.FormatableMixin and therefore have a richer format_as method which has an extended syntax for the format component. Command line tools like fstags use this for output format specifications.

An example:

>>> # an ontology specifying the type for a colour
>>> # and some information about the colour "blue"
>>> ont = TagsOntology(
...   {
...       'type.colour':
...       TagSet(description="a colour, a hue", type="str"),
...       'colour.blue':
...       TagSet(
...           url='https://en.wikipedia.org/wiki/Blue',
...           wavelengths='450nm-495nm'
...       ),
...   }
... )
>>> # tag set with a "blue" tag, using the ontology above
>>> tags = TagSet(colour='blue', labels=['a', 'b', 'c'], size=9, _ontology=ont)
>>> tags.format_as('The colour is {colour}.')
'The colour is blue.'
>>> # format a string about the tags showing some metadata about the colour
>>> tags.format_as('Information about the colour may be found here: {colour:metadata.url}')
'Information about the colour may be found here: https://en.wikipedia.org/wiki/Blue'

Function as_unixtime(tag_value)

Convert a tag value to a UNIX timestamp.

This accepts int, float (already a timestamp) and date or datetime (use datetime.timestamp() for a nonnaive datetime, otherwise time.mktime(tag_value.time_tuple())`, which assumes the local time zone).

Class BaseTagSets(cs.resources.MultiOpenMixin, cs.context.ContextManagerMixin, collections.abc.MutableMapping, collections.abc.Mapping, collections.abc.Collection, collections.abc.Sized, collections.abc.Iterable, collections.abc.Container)

Base class for collections of TagSet instances such as cs.fstags.FSTags and cs.sqltags.SQLTags.

Examples of this include:

• cs.cdrip.MBSQLTags: a mapping of MusicbrainsNG entities to their associated TagSet
• cs.fstags.FSTags: a mapping of filesystem paths to their associated TagSet
• cs.sqltags.SQLTags: a mapping of names to TagSets stored in an SQL database

Subclasses must implement:

• get(name,default=None): return the TagSet associated with name, or default.
• __setitem__(name,tagset): associate a TagSetwith the key name; this is called by the __missing__ method with a newly created TagSet.
• keys(self): return an iterable of names

Subclasses may reasonably want to override the following:

• startup_shutdown(self): context manager to allocate and release any needed resources such as database connections

Subclasses may implement:

• __len__(self): return the number of names

The TagSet factory used to fetch or create a TagSet is named TagSetClass. The default implementation honours two class attributes:

• TAGSETCLASS_DEFAULT: initially TagSet
• TAGSETCLASS_PREFIX_MAPPING: a mapping of type names to TagSet subclasses

The type name of a TagSet name is the first dotted component. For example, artist.nick_cave has the type name artist. A subclass of BaseTagSets could utiliise an ArtistTagSet subclass of TagSet and provide:

TAGSETCLASS_PREFIX_MAPPING = {
  'artist': ArtistTagSet,
}

in its class definition. Accesses to artist.* entities would result in ArtistTagSet instances and access to other enitities would result in ordinary TagSet instances.

Method BaseTagSets.__init__(self, *, ontology=None): Initialise the collection.

Class MappingTagSets(BaseTagSets, cs.resources.MultiOpenMixin, cs.context.ContextManagerMixin, collections.abc.MutableMapping, collections.abc.Mapping, collections.abc.Collection, collections.abc.Sized, collections.abc.Iterable, collections.abc.Container)

A BaseTagSets subclass using an arbitrary mapping.

If no mapping is supplied, a dict is created for the purpose.

Example:

>>> tagsets = MappingTagSets()
>>> list(tagsets.keys())
[]
>>> tagsets.get('foo')
>>> tagsets['foo'] = TagSet(bah=1, zot=2)
>>> list(tagsets.keys())
['foo']
>>> tagsets.get('foo')
TagSet:{'bah': 1, 'zot': 2}
>>> list(tagsets.keys(prefix='foo'))
['foo']
>>> list(tagsets.keys(prefix='bah'))
[]

Class RegexpTagRule

A regular expression based Tag rule.

This applies a regular expression to a string and returns inferred Tags.

Function selftest(argv)

Run some ad hoc self tests.

Class Tag(Tag, builtins.tuple, cs.lex.FormatableMixin, cs.lex.FormatableFormatter, string.Formatter)

A Tag has a .name (str) and a .value and an optional .ontology.

The name must be a dotted identifier.

Terminology:

• A "bare" Tag has a value of None.
• A "naive" Tag has an ontology of None.

The constructor for a Tag is unusual:

• both the value and ontology are optional, defaulting to None
• if name is a str then we always construct a new Tag with the suppplied values
• if name is not a str it should be a Taglike object to promote; it is an error if the value parameter is not None in this case
• an optional prefix may be supplied which is prepended to name with a dot ('.') if not empty

The promotion process is as follows:

• if name is a Tag subinstance then if the supplied ontology is not None and is not the ontology associated with name then a new Tag is made, otherwise the original Tag is returned unchanged
• otherwise a new Tag is made from name using its .value and overriding its .ontology if the ontology parameter is not None

Examples:

>>> ont = TagsOntology({'colour.blue': TagSet(wavelengths='450nm-495nm')})
>>> tag0 = Tag('colour', 'blue')
>>> tag0
Tag(name='colour',value='blue')
>>> tag = Tag(tag0)
>>> tag
Tag(name='colour',value='blue')
>>> tag = Tag(tag0, ontology=ont)
>>> tag # doctest: +ELLIPSIS
Tag(name='colour',value='blue',ontology=...)
>>> tag = Tag(tag0, prefix='surface')
>>> tag
Tag(name='surface.colour',value='blue')

Method Tag.__init__(self, *a, **kw): Dummy __init__ to avoid FormatableMixin.__init__ because we subclass namedtuple which has no __init__.

Function tag_or_tag_value(*da, **dkw)

A decorator for functions or methods which may be called as:

func(name[,value])

or as:

func(Tag)

The optional decorator argument no_self (default False) should be supplied for plain functions as they have no leading self parameter to accomodate.

Example:

@tag_or_tag_value
def add(self, tag_name, value, *, verbose=None):

This defines a .add() method which can be called with name and value or with single Taglike object (something with .name and .value attributes), for example:

tags = TagSet()
....
tags.add('colour', 'blue')
....
tag = Tag('size', 9)
tags.add(tag)

Class TagBasedTest(TagBasedTest, builtins.tuple, TagSetCriterion, cs.deco.Promotable)

A test based on a Tag.

Attributes:

• spec: the source text from which this choice was parsed, possibly None
• choice: the apply/reject flag
• tag: the Tag representing the criterion
• comparison: an indication of the test comparison

The following comparison values are recognised:

• None: test for the presence of the Tag
• '=': test that the tag value equals tag.value
• '<': test that the tag value is less than tag.value
• '<=': test that the tag value is less than or equal to tag.value
• '>': test that the tag value is greater than tag.value
• '>=': test that the tag value is greater than or equal to tag.value
• '~/': test if the tag value as a regexp is present in tag.value
• '~': test if a matching tag value is present in tag.value

Class TagFile(cs.fs.FSPathBasedSingleton, cs.obj.SingletonMixin, cs.fs.HasFSPath, BaseTagSets, cs.resources.MultiOpenMixin, cs.context.ContextManagerMixin, collections.abc.MutableMapping, collections.abc.Mapping, collections.abc.Collection, collections.abc.Sized, collections.abc.Iterable, collections.abc.Container)

A reference to a specific file containing tags.

This manages a mapping of name => TagSet, itself a mapping of tag name => tag value.

Class TagsCommandMixin

Utility methods for cs.cmdutils.BaseCommand classes working with tags.

Optional subclass attributes:

• TAGSET_CRITERION_CLASS: a TagSetCriterion duck class, default TagSetCriterion. For example, cs.sqltags has a subclass with an .extend_query method for computing an SQL JOIN used in searching for tagged entities.

Class TagSet(builtins.dict, cs.dateutils.UNIXTimeMixin, cs.lex.FormatableMixin, cs.lex.FormatableFormatter, string.Formatter, cs.mappings.AttrableMappingMixin)

A setlike class associating a set of tag names with values.

This actually subclasses dict, so a TagSet is a direct mapping of tag names to values. It accepts attribute access to simple tag values when they do not conflict with the class methods; the reliable method is normal item access.

NOTE: iteration yields Tags, not dict keys.

Also note that all the Tags from a TagSet share its ontology.

Subclasses should override the set and discard methods; the dict and mapping methods are defined in terms of these two basic operations.

TagSets have a few special properties:

• id: a domain specific identifier; this may reasonably be None for entities not associated with database rows; the cs.sqltags.SQLTags class associates this with the database row id.
• name: the entity's name; a read only alias for the 'name' Tag. The cs.sqltags.SQLTags class defines "log entries" as TagSets with no name.
• unixtime: a UNIX timestamp, a float holding seconds since the UNIX epoch (midnight, 1 January 1970 UTC). This is typically the row creation time for entities associated with database rows, but usually the event time for TagSets describing an event.

Because TagSet subclasses cs.mappings.AttrableMappingMixin you can also access tag values as attributes provided that they do not conflict with instance attributes or class methods or properties.

Method TagSet.__init__(self, *a, _id=None, _ontology=None, **kw): Initialise the TagSet.

Parameters:

• positional parameters initialise the dict and are passed to dict.__init__
• _id: optional identity value for databaselike implementations
• _ontology: optional TagsOntology to use for this TagSet`
• other alphabetic keyword parameters are also used to initialise the dict and are passed to dict.__init__

Class TagSetCriterion(cs.deco.Promotable)

A testable criterion for a TagSet.

Class TagSetPrefixView(cs.lex.FormatableMixin, cs.lex.FormatableFormatter, string.Formatter)

A view of a TagSet via a prefix.

Access to a key k accesses the TagSet with the key prefix+'.'+k.

This is a kind of funny hybrid of a Tag and a TagSet in that some things such as __format__ will format the Tag named prefix if it exists in preference to the subtags.

Example:

>>> tags = TagSet(a=1, b=2)
>>> tags
TagSet:{'a': 1, 'b': 2}
>>> tags['sub.x'] = 3
>>> tags['sub.y'] = 4
>>> tags
TagSet:{'a': 1, 'b': 2, 'sub.x': 3, 'sub.y': 4}
>>> sub = tags.sub
>>> sub
TagSetPrefixView:sub.{'x': 3, 'y': 4}
>>> sub.z = 5
>>> sub
TagSetPrefixView:sub.{'x': 3, 'y': 4, 'z': 5}
>>> tags
TagSet:{'a': 1, 'b': 2, 'sub.x': 3, 'sub.y': 4, 'sub.z': 5}

Class TagSetsSubdomain(cs.obj.SingletonMixin, cs.mappings.PrefixedMappingProxy, cs.mappings.RemappedMappingProxy)

A view into a BaseTagSets for keys commencing with a prefix being the subdomain plus a dot ('.').

Class TagsOntology(cs.obj.SingletonMixin, BaseTagSets, cs.resources.MultiOpenMixin, cs.context.ContextManagerMixin, collections.abc.MutableMapping, collections.abc.Mapping, collections.abc.Collection, collections.abc.Sized, collections.abc.Iterable, collections.abc.Container)

An ontology for tag names. This is based around a mapping of names to ontological information expressed as a TagSet.

Normally an object's tags are not a self contained repository of all the information; instead a tag just names some information.

As a example, consider the tag colour=blue. Meta information about blue is obtained via the ontology, which has an entry for the colour blue. We adopt the convention that the type is just the tag name, so we obtain the metadata by calling ontology.metadata(tag) or alternatively ontology.metadata(tag.name,tag.value) being the type name and value respectively.

The ontology itself is based around TagSets and effectively the call ontology.metadata('colour','blue') would look up the TagSet named colour.blue in the underlying Tagsets.

For a self contained dataset this means that it can be its own ontology. For tags associated with arbitrary objects such as the filesystem tags maintained by cs.fstags the ontology would be a separate tags collection stored in a central place.

There are two main categories of entries in an ontology:

• metadata: other entries named typename.value_key contains a TagSet holding metadata for a value of type typename whose value is mapped to value_key
• types: an optional entry named type.typename contains a TagSet describing the type named typename; really this is just more metadata where the "type name" is type

Metadata are TagSets instances describing particular values of a type. For example, some metadata for the Tag colour="blue":

colour.blue url="https://en.wikipedia.org/wiki/Blue" wavelengths="450nm-495nm"

Some metadata associated with the Tag actor="Scarlett Johansson":

actor.scarlett_johansson role=["Black Widow (Marvel)"]
character.marvel.black_widow fullname=["Natasha Romanov"]

The tag values are lists above because an actor might play many roles, etc.

There's a convention for converting human descriptions such as the role string "Black Widow (Marvel)" to its metadata.

• the value "Black Widow (Marvel)" if converted to a key by the ontology method value_to_tag_name; it moves a bracket suffix such as (Marvel) to the front as a prefix marvel. and downcases the rest of the string and turns spaces into underscores. This yields the value key marvel.black_widow.
• the type is role, so the ontology entry for the metadata is role.marvel.black_widow

This requires type information about a role. Here are some type definitions supporting the above metadata:

type.person type=str description="A person."
type.actor type=person description="An actor's stage name."
type.character type=str description="A person in a story."
type.role type_name=character description="A character role in a performance."
type.cast type=dict key_type=actor member_type=role description="Cast members and their roles."

The basic types have their Python names: int, float, str, list, dict, date, datetime. You can define subtypes of these for your own purposes as illustrated above.

For example:

type.colour type=str description="A hue."

which subclasses str.

Subtypes of list include a member_type specifying the type for members of a Tag value:

type.scene type=list member_type=str description="A movie scene."

Subtypes of dict include a key_type and a member_type specifying the type for keys and members of a Tag value:

Accessing type data and metadata:

A TagSet may have a reference to a TagsOntology as .ontology and so also do any of its Tags.

Class TagsOntologyCommand(cs.cmdutils.BaseCommand)

A command line for working with ontology types.

Command line usage:

Usage: tagsontology subcommand [...]
  Subcommands:
    edit [{/name-regexp | entity-name}]
      Edit entities.
      With no arguments, edit all the entities.
      With an argument starting with a slash, edit the entities
      whose names match the regexp.
      Otherwise the argument is expected to be an entity name;
      edit the tags of that entity.
    help [-l] [subcommand-names...]
      Print help for subcommands.
      This outputs the full help for the named subcommands,
      or the short help for all subcommands if no names are specified.
      -l  Long help even if no subcommand-names provided.
    meta tag=value
    shell
      Run a command prompt via cmd.Cmd using this command's subcommands.
    type
        With no arguments, list the defined types.
      type type_name
        With a type name, print its `Tag`s.
      type type_name edit
        Edit the tags defining a type.
      type type_name edit meta_names_pattern...
        Edit the tags for the metadata names matching the
        meta_names_patterns.
      type type_name list
      type type_name ls
        List the metadata names for this type and their tags.
      type type_name + entity_name [tags...]
        Create type_name.entity_name and apply the tags.

Release Log

Release 20240316: Fixed release upload artifacts.

Release 20240305:

• Tag.from_str2: make the ontology optional.
• TagSetPrefixView: provide len() and update().

Release 20240211:

• TagFile.parse_tag_line: recognise dotted_identifiers directly, avoids misparsing bare "nan" as float NaN.
• Tag.parse_value: BUGFIX parse - always to the primary types first (int, float) before trying any funny extra types.

Release 20240201: TagsOntology.metadata: actually call the .items() method!

Release 20231129:

• TagSet.getattr: rework the attribute lookup with greater precision.
• TagSetPrefixView.getattr: if the attribute is not there, raise Attribute error, do not try to fall back to something else.
• TagSet: drop ATTRABLE_MAPPING_DEFAULT=None, caused far more confusion that it was worth.

Release 20230612:

• TagFile.save_tagsets: catch and warn about exceptions from update_mapping[key].update, something is wrong with my SQLTags usage.
• TagFile.save_tagsets: update_mapping: do not swallow AttributeError.

Release 20230407: Move the (optional) ORM open/close from FSTags.startup_shutdown to TagFile.save, greatly shortens the ORM lock.

Release 20230212: Mark TagSetCriterion as Promotable.

Release 20230210:

• TagFile: new optional update_mapping secondary mapping to which to mirror file tags, for example to an SQLTags.
• New .uuid:UUID property returning the UUID for the tag named 'uuid' or None.

Release 20230126: New TagSet.is_stale() method based on .expiry attribute, intended for TagSets which are caches of other primary data.

Release 20221228:

• TagFile: drop _singleton_key, FSPathBasedSingleton provides a good default.
• TagFile.save_tagsets,tags_line: new optional prune=False parameter to drop empty top level dict/lists.
• TagFile.save: plumb prune=False parameter.

Release 20220806: New TagSetCriterion.promote(obj)->TagSetCriterion class method.

Release 20220606:

• Tag.parse_value: bugfix parse of float.
• TagSet.edit: accept optional comments parameter with addition header comment lines, be more tolerant of errors, avoid losing data on error.

Release 20220430:

• TagSetPrefixView: new as_dict() method.
• TagSetPrefixView.str: behave like TagSet.str.
• TagFile.save_tagsets: do not try to save if the file is missing and the tagsets are empty.
• New TagSet.from_tags(tags) factory to make a new TagSet from an iterable of tags.
• TagSetPrefixView: add .get and .setdefault mapping methods.
• RegexpTagRule: accept optional tag_prefix parameter.
• Tagset: new from_ini() and save_as_ini() methods to support cs.timeseries config files, probably handy elsewhere.

Release 20220311: Assorted internal changes.

Release 20211212:

• Tag: new fallback_parse parameter for value parsing, default get_nonwhite.
• Tag: new from_arg factory with fallback_parse grabbing the whole string for command line arguments, thus supporting unquoted strings for ease of use.
• TagSetCriterion: new optional fallback_parse parameter and from_arg method as for the Tag factories.
• Tag.transcribe_value: accept optional json_options to control the JSON encoder, used for human friendly multiline edits in cs.app.tagger.
• Rename edit_many to edit_tagsets for clarity.
• TagsOntology: new type_values method to return values for a type (derived from their metadata entries).
• Tag: new alt_values method returning its TagsOntology.type_values.
• (Internal) New _FormatStringTagProxy which proxies a Tag but uses str(self.__proxied.value) for str to support format strings.
• (Internal) TagSet.get_value: if arg_name matches a Tag, return a _FormatStringTagProxy.
• Tag.new: accept (tag_name,value) or (Tag) as initialisation parameters.

Release 20210913:

• TagSet.get_value: raise KeyError in strict mode, leave placeholder otherwise.
• Other small changes.

Release 20210906: Many many updates; some semantics have changed.

Release 20210428: Bugfix TagSet.set: internal in place changes to a complex tag value were not noticed, causing TagFile to not update on shutdown.

Release 20210420:

• TagSet: also subclass cs.dateutils.UNIXTimeMixin.
• Various TagSetNamespace updates and bugfixes.

Release 20210404: Bugfix TagBasedTest.COMPARISON_FUNCS["="]: if cmp_value is None, return true (the tag is present).

Release 20210306:

• ExtendedNamespace,TagSetNamespace: move the .[:alpha:]* attribute support from ExtendedNamespace to TagSetNamespace because it requires Tags.
• TagSetNamespace.getattr: new _i, _s, _f suffixes to return int, str or float tag values (or None); fold _lc in with these.
• Pull most of TaggedEntity out into TaggedEntityMixin for reuse by domain specific tagged entities.
• TaggedEntity: new .set and .discard methods.
• TaggedEntity: new as_editable_line, from_editable_line, edit and edit_entities methods to support editing entities using a text editor.
• ontologies: type entries are now prefixed with "type." and metadata entries are prefixed with "meta."; provide a worked ontology example in the introduction and improve related docstrings.
• TagsOntology: new .types(), .types_names(), .meta(type_name,value), .meta_names() methods.
• TagsOntology.getitem: create missing TagSets on demand.
• New TagsOntologyCommand, initially with a "type [type_name [{edit|list}]]" subcommand, ready for use as the cmd_ont subcommand of other tag related commands.
• TagSet: support initialisation like a dict including keywords, and move the ontology parameter to _onotology.
• TagSet: include AttrableMappingMixin to enable attribute access to values when there is no conflict with normal methods.
• UUID encode/decode support.
• Honour $TAGSET_EDITOR or $EDITOR as preferred interactive editor for tags.
• New TagSet.subtags(prefix) to extract a subset of the tags.
• TagsOntology.value_metadata: new optional convert parameter to override the default "convert human friendly name" algorithm, particularly to pass convert=str to things which are already the basic id.
• Rename TaggedEntity to TagSet.
• Rename TaggedEntities to TagSets.
• TagSet: new csvrow and from_csvrow methods imported from obsolete TaggedEntityMixin class.
• Move BaseTagFile from cs.fstags to TagFile in cs.tagset.
• TagSet: support access to the tag "c.x" via attributes provided there is no "c" tag in the way.
• TagSet.unixtime: implement the autoset-to-now semantics.
• New as_timestamp(): convert date, datetime, int or float to a UNIX timestamp.
• Assorted docstring updates and bugfixes.

Release 20200716:

• Update for changed cs.obj.SingletonMixin API.
• Pull in TaggedEntity from cs.sqltags and add the .csvrow property and the .from_csvrow factory.

Release 20200521.1: Fix DISTINFO.install_requires, drop debug import.

Release 20200521:

• New ValueDetail and KeyValueDetail classes for returning ontology information; TagInfo.detail now returns a ValueDetail for scalar types, a list of ValueDetails for sequence types and a list of KeyValueDetails for mapping types; drop various TagInfo mapping/iterable style methods, too confusing to use.
• Plumb ontology parameter throughout, always optional.
• Drop TypedTag, Tags now use ontologies for this.
• New TagsCommandMixin to support BaseCommands which manipulate Tags.
• Many improvements and bugfixes.

Release 20200318:

• Note that the TagsOntology stuff is in flux and totally alpha.
• Tag.prefix_name factory returning a new tag if prefix is not empty, ptherwise self.
• TagSet.update: accept an optional prefix for inserting "foreign" tags with a distinguishing name prefix.
• Tag.as_json: turn sets and tuples into lists for encoding.
• Backport for Python < 3.7 (no fromisoformat functions).
• TagSet: drop unused and illplaced .titleify, .episode_title and .title methods.
• TagSet: remove "defaults", unused.
• Make TagSet a direct subclass of dict, adjust uses of .update etc.
• New ExtendedNamespace class which is a SimpleNamespace with some inferred attributes and a partial mapping API (keys and getitem).
• New TagSet.ns() returning the Tags as an ExtendedNamespace, which doubles as a mapping for str.format_map; TagSet.format_kwargs is now an alias for this.
• New Tag.from_string factory to parse a str into a Tag.
• New TagsOntology and TypedTag classes to provide type and value-detail information; very very alpha and subject to change.

Release 20200229.1: Initial release: pull TagSet, Tag, TagChoice from cs.fstags for independent use.