Merge lp:~matthias-troffaes/pybtex/even-simpler-plugin-loader into lp:pybtex

[Matthias C. M. Troffaes]

An implementation just using entry points for all plugins.

[Matthias C. M. Troffaes (matthias-troffaes)]

This is now ready for initial review. IMHO this implementation looks a lot cleaner than the old implementation

https://code.launchpad.net/~matthias-troffaes/pybtex/simple-plugin-loader/+merge/195366

Thoughts?

[Andrey Golovizin (ero-sennin)]

This makes sense.

There are some things though.

- I'd want to keep Plugin.name, Plugin.aliases and Plugin.suffixes. The idea is that all information about a plugin should be contained in a plugin itself and not be scattered all over. Also, this way it would be possible to call register_plugin(SomePlugin) without extra arguments, and register_plugin() would care about registering all the necessary entry points for you.

- Please add a license header to plugin_test.py and use two blank lines between top-level definitions. (Just a nitpick.)

[Matthias C. M. Troffaes (matthias-troffaes)]

Ok, great! License & pep8 fixes are of course no problem.

Concerning the first point, I sort of convinced myself that, eventually, names/aliases/suffixes do not belong to the plugin class, at least not as static class attributes, because we cannot know in advance what kind of aliases or suffixes a user is going to register for a plugin. This is already the case for the entry point plugins in the original code: in fact their name/suffixes/aliases attributes were entirely ignored IIRC. For reasons purely due to causality: with entry point plugins, we need to know the name before we even have the class.

Could you bring yourself to think of name, aliases, and suffixes as belonging to the registry system, rather than belonging to the Plugin classes?

[Andrey Golovizin (ero-sennin)]

Yes, I think you are right here. So, let's have it merged after you finish with PEP8 fixes.

[Matthias C. M. Troffaes (matthias-troffaes)]

(Sorry for the not so quick response.)

Ok, very good! I'll fix the pep8 issue as soon as I find some spare time.

[Matthias C. M. Troffaes (matthias-troffaes)]

Ready for review.

[Andrey Golovizin (ero-sennin)]

> Copyright (c) 2007, 2008, 2009, 2010, 2011, 2012 Andrey Golovizin

Should be "Copyright (c) 2014 Matthias C. M. Troffaes" instead. :) And you should add a line with your name to pybtex/plugin/__init__.py too. Otherwise it's ready for merging.

[lp:~matthias-troffaes/pybtex/even-simpler-plugin-loader]

928. By Matthias C. M. Troffaes on 2014-02-04

Update copyright notices.

[Matthias C. M. Troffaes (matthias-troffaes)]

Ok, done.

[Andrey Golovizin (ero-sennin)]

Great, merged. Thanks for the good work!

review: Approve

=== modified file 'pybtex/__init__.py'
--- pybtex/__init__.py	2013-08-08 18:12:52 +0000
+++ pybtex/__init__.py	2014-02-04 13:09:32 +0000
@@ -48,7 +48,7 @@
         encoding=bib_encoding,
         wanted_entries=aux_data.citations,
         min_crossrefs=min_crossrefs,
-    ).parse_files(aux_data.data, bib_parser.get_default_suffix())
+    ).parse_files(aux_data.data, bib_parser.default_suffix)
 
     if style is None:
         style = aux_data.style
@@ -63,5 +63,5 @@
     formatted_bibliography = style.format_bibliography(bib_data, aux_data.citations)
 
     output_backend = find_plugin('pybtex.backends', output_backend)
-    output_filename = filename + output_backend.get_default_suffix()
+    output_filename = filename + output_backend.default_suffix
     output_backend(output_encoding).write_to_file(formatted_bibliography, output_filename)

=== modified file 'pybtex/backends/__init__.py'
--- pybtex/backends/__init__.py	2013-08-08 11:51:24 +0000
+++ pybtex/backends/__init__.py	2014-02-04 13:09:32 +0000
@@ -24,12 +24,9 @@
 from pybtex.utils import deprecated
 
 
-available_plugins = ('latex', 'html', 'plaintext')
-
-
 class BaseBackend(Plugin):
-    default_plugin = 'latex'
-    RenderType = basestring #: the result of render and render_sequence
+    RenderType = basestring  #: the result of render and render_sequence
+    default_suffix = None  #: the default suffix for an output file
 
     def __init__(self, encoding=None):
         self.encoding = encoding

=== modified file 'pybtex/backends/html.py'
--- pybtex/backends/html.py	2013-08-09 19:30:08 +0000
+++ pybtex/backends/html.py	2014-02-04 13:09:32 +0000
@@ -35,9 +35,7 @@
 """
 
 class Backend(BaseBackend):
-    name = 'html'
-    suffixes = '.html',
-
+    default_suffix = '.html'
     symbols = {
         'ndash': u'–',
         'newblock': u'\n',

=== modified file 'pybtex/backends/latex.py'
--- pybtex/backends/latex.py	2013-08-09 19:38:46 +0000
+++ pybtex/backends/latex.py	2014-02-04 13:09:32 +0000
@@ -23,9 +23,7 @@
 
 
 class Backend(BaseBackend):
-    name = 'latex'
-    suffixes = '.bbl', '.tex', '.latex'
-
+    default_suffix = '.bbl'
     symbols = {
         'ndash': u'--',
         'newblock': u'\n\\newblock ',

=== modified file 'pybtex/backends/plaintext.py'
--- pybtex/backends/plaintext.py	2013-08-09 19:30:08 +0000
+++ pybtex/backends/plaintext.py	2014-02-04 13:09:32 +0000
@@ -23,10 +23,7 @@
 
 
 class Backend(BaseBackend):
-    name = 'plaintext'
-    aliases = 'text',
-    suffixes = '.txt',
-
+    default_suffix = '.txt'
     symbols = {
         'ndash': u'-',
         'newblock': u' ',

=== modified file 'pybtex/bibtex/__init__.py'
--- pybtex/bibtex/__init__.py	2013-08-08 18:12:52 +0000
+++ pybtex/bibtex/__init__.py	2014-02-04 13:09:32 +0000
@@ -50,7 +50,7 @@
     bst_script = bst.parse_file(bst_filename, bst_encoding)
     base_filename = path.splitext(aux_filename)[0]
     bbl_filename = base_filename + path.extsep + 'bbl'
-    bib_filenames = [filename + bib_format.get_default_suffix() for filename in aux_data.data]
+    bib_filenames = [filename + bib_format.default_suffix for filename in aux_data.data]
     bbl_file = pybtex.io.open_unicode(bbl_filename, 'w', encoding=output_encoding)
     interpreter = Interpreter(bib_format, bib_encoding)
     interpreter.run(bst_script, aux_data.citations, bib_filenames, bbl_file, min_crossrefs=min_crossrefs)

=== modified file 'pybtex/database/input/__init__.py'
--- pybtex/database/input/__init__.py	2012-02-12 20:44:25 +0000
+++ pybtex/database/input/__init__.py	2014-02-04 13:09:32 +0000
@@ -30,9 +30,8 @@
 
 
 class BaseParser(Plugin):
-    default_plugin = 'bibtex'
+    default_suffix = None
     filename = '<INPUT>'
-
     unicode_io = False
 
     def __init__(self, encoding=None, wanted_entries=None, min_crossrefs=2, **kwargs):

=== modified file 'pybtex/database/input/bibtex.py'
--- pybtex/database/input/bibtex.py	2013-07-31 13:35:20 +0000
+++ pybtex/database/input/bibtex.py	2014-02-04 13:09:32 +0000
@@ -296,8 +296,7 @@
 
 
 class Parser(BaseParser):
-    name = 'bibtex'
-    suffixes = '.bib',
+    default_suffix = '.bib'
     unicode_io = True
 
     macros = None

=== modified file 'pybtex/database/input/bibtexml.py'
--- pybtex/database/input/bibtexml.py	2012-02-12 20:44:25 +0000
+++ pybtex/database/input/bibtexml.py	2014-02-04 13:09:32 +0000
@@ -32,8 +32,7 @@
         return s[len(bibtexns):]
 
 class Parser(BaseParser):
-    name = 'bibtexml'
-    suffixes = '.xml', '.bibtexml'
+    default_suffix = '.xml'
 
     def parse_stream(self, stream):
         t = ET.parse(stream)

=== modified file 'pybtex/database/input/bibyaml.py'
--- pybtex/database/input/bibyaml.py	2012-02-12 20:44:25 +0000
+++ pybtex/database/input/bibyaml.py	2014-02-04 13:09:32 +0000
@@ -25,9 +25,7 @@
 
 
 class Parser(BaseParser):
-    name = 'bibyaml'
-    aliases = 'yaml',
-    suffixes = '.yaml', '.bibyaml'
+    default_suffix = '.yaml'
 
     def parse_stream(self, stream):
         t = yaml.safe_load(stream)

=== modified file 'pybtex/database/output/__init__.py'
--- pybtex/database/output/__init__.py	2012-02-12 20:44:25 +0000
+++ pybtex/database/output/__init__.py	2014-02-04 13:09:32 +0000
@@ -27,7 +27,6 @@
 
 class BaseWriter(Plugin):
     unicode_io = False
-    default_plugin = 'bibtex'
 
     def __init__(self, encoding=None):
         self.encoding = encoding or pybtex.io.get_default_encoding()

=== modified file 'pybtex/database/output/bibtex.py'
--- pybtex/database/output/bibtex.py	2013-08-02 10:39:18 +0000
+++ pybtex/database/output/bibtex.py	2014-02-04 13:09:32 +0000
@@ -28,8 +28,6 @@
 class Writer(BaseWriter):
     """Outputs BibTeX markup"""
 
-    name = 'bibtex'
-    suffixes = '.bib',
     unicode_io = True
 
     def quote(self, s):

=== modified file 'pybtex/database/output/bibtexml.py'
--- pybtex/database/output/bibtexml.py	2012-02-12 20:44:25 +0000
+++ pybtex/database/output/bibtexml.py	2014-02-04 13:09:32 +0000
@@ -67,9 +67,6 @@
 class Writer(BaseWriter):
     """Outputs BibTeXML markup"""
 
-    name = 'bibtexml'
-    suffixes = '.xml', '.bibtexml'
-
     def write_stream(self, bib_data, stream):
         def write_persons(persons, role):
             if persons:

=== modified file 'pybtex/database/output/bibyaml.py'
--- pybtex/database/output/bibyaml.py	2013-08-02 10:39:18 +0000
+++ pybtex/database/output/bibyaml.py	2014-02-04 13:09:32 +0000
@@ -27,10 +27,6 @@
 class Writer(BaseWriter):
     """Outputs YAML markup"""
 
-    name = 'bibyaml'
-    aliases = 'yaml',
-    suffixes = '.yaml', '.bibyaml'
-
     def write_stream(self, bib_data, stream):
         def process_person_roles(entry):
             for role, persons in entry.persons.iteritems():

=== modified file 'pybtex/plugin/__init__.py'
--- pybtex/plugin/__init__.py	2012-02-12 20:44:25 +0000
+++ pybtex/plugin/__init__.py	2014-02-04 13:09:32 +0000
@@ -1,4 +1,5 @@
 # Copyright (c) 2007, 2008, 2009, 2010, 2011, 2012  Andrey Golovizin
+# Copyright (c) 2014  Matthias C. M. Troffaes
 #
 # Permission is hereby granted, free of charge, to any person obtaining
 # a copy of this software and associated documentation files (the
@@ -19,14 +20,31 @@
 # TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 # SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
-import os
-import sys
-from itertools import chain
+
+import os.path  # splitext
+import pkg_resources
 
 from pybtex.exceptions import PybtexError
 
 
+class Plugin(object):
+    pass
+
+
+#: default pybtex plugins
+_DEFAULT_PLUGINS = {
+    "pybtex.database.input": "bibtex",
+    "pybtex.database.output": "bibtex",
+    "pybtex.backends": "latex",
+    "pybtex.style.labels": "number",
+    "pybtex.style.names": "plain",
+    "pybtex.style.sorting": "none",
+    "pybtex.style.formatting": "unsrt",
+}
+
+
 class PluginGroupNotFound(PybtexError):
+
     def __init__(self, group_name):
         message = u'plugin group {group_name} not found'.format(
             group_name=group_name,
@@ -35,135 +53,120 @@
 
 
 class PluginNotFound(PybtexError):
-    def __init__(self, plugin_group, name=None, filename=None):
-        assert plugin_group
-        if name:
+
+    def __init__(self, plugin_group, name):
+        if not name.startswith('.'):
             message = u'plugin {plugin_group}.{name} not found'.format(
                 plugin_group=plugin_group,
                 name=name,
             )
-        elif filename:
-            message = u'cannot determine file type for {filename}'.format(
-                plugin_group=plugin_group,
-                filename=filename,
-            )
         else:
-            message = u'' # FIXME
+            assert plugin_group.endswith('.suffixes')
+            message = (
+                u'plugin {plugin_group} for suffix {suffix} not found'.format(
+                    plugin_group=plugin_group,
+                    suffix=name,
+                )
+            )
 
         super(PluginNotFound, self).__init__(message)
 
 
-class Plugin(object):
-    name = None
-    aliases = ()
-    suffixes = ()
-    default_plugin = None
-
-    @classmethod
-    def get_default_suffix(cls):
-        return cls.suffixes[0]
-
-
-class PluginLoader(object):
-    def find_plugin(plugin_group, name):
-        raise NotImplementedError
-
-    def enumerate_plugin_names(self, plugin_group):
-        raise NotImplementedError
-
-
-class BuiltInPluginLoader(PluginLoader):
-    def get_group_info(self, plugin_group):
-        from pybtex.plugin.registry import plugin_registry
-        try:
-            return plugin_registry[plugin_group]
-        except KeyError:
-            raise PluginGroupNotFound(plugin_group)
-
-    def find_plugin(self, plugin_group, name=None, filename=None):
-        plugin_group_info = self.get_group_info(plugin_group)
-        module_name = None
-        if name:
-            if name in plugin_group_info['plugins']:
-                module_name = name
-            elif name in plugin_group_info['aliases']:
-                module_name = plugin_group_info['aliases'][name]
-            else:
-                raise PluginNotFound(plugin_group, name=name)
-        elif filename:
-            suffix = os.path.splitext(filename)[1]
-            if suffix in plugin_group_info['suffixes']:
-                module_name = plugin_group_info['suffixes'][suffix]
-            else:
-                raise PluginNotFound(plugin_group, filename=filename)
-        else:
-            module_name = plugin_group_info['default_plugin']
-
-        class_name = plugin_group_info['class_name']
-        return self.import_plugin(plugin_group, module_name, class_name)
-
-    def import_plugin(self, plugin_group, module_name, class_name):
-        module = __import__(str(plugin_group), globals(), locals(), [str(module_name)])
-        return getattr(getattr(module, module_name), class_name)
-
-    def enumerate_plugin_names(self, plugin_group):
-        plugin_group_info = self.get_group_info(plugin_group)
-        return plugin_group_info['plugins']
-
-
-class EntryPointPluginLoader(PluginLoader):
-    def find_plugin(self, plugin_group, name=None, filename=None):
-        try:
-            import pkg_resources
-        except ImportError:
-            raise PluginNotFound(plugin_group)
-
-        def load_entry_point(group, name):
-            entry_points = pkg_resources.iter_entry_points(group, name)
-            try:
-                entry_point = entry_points.next()
-            except StopIteration:
-                raise PluginNotFound(plugin_group, name, filename)
-            else:
-                return entry_point.load()
-
-        if name:
-            return load_entry_point(plugin_group, name)
-        elif filename:
-            suffix = os.path.splitext(filename)[1]
-            return load_entry_point(plugin_group + '.suffixes', suffix)
-        else:
-            raise PluginNotFound(plugin_group)
-
-    def enumerate_plugin_names(self, plugin_group):
-        try:
-            import pkg_resources
-        except ImportError:
-            return
-        entry_points = pkg_resources.iter_entry_points(plugin_group)
-        return [entry_point.name for entry_point in entry_points]
-
-
-plugin_loaders = [EntryPointPluginLoader(), BuiltInPluginLoader()]
+def _load_entry_point(group, name):
+    entry_points = pkg_resources.iter_entry_points(group, name)
+    try:
+        entry_point = entry_points.next()
+    except StopIteration:
+        raise PluginNotFound(group, name)
+    else:
+        return entry_point.load()
 
 
 def find_plugin(plugin_group, name=None, filename=None):
-    if isinstance(name, type) and issubclass(name, Plugin):
-        plugin = name
-        #assert plugin.group_name == plugin_group
-        return plugin
+    """Find a :class:`Plugin` class within *plugin_group* which
+    matches *name*, or *filename* if *name* is not specified, or
+    the default plugin if neither *name* nor *filename* is
+    specified.
+
+    If *name* is specified, return the :class:`Plugin` class
+    registered under *name*. If *filename* is specified, look at
+    its suffix (i.e. extension) and return the :class:`Plugin`
+    class registered for this suffix.
+    """
+    if plugin_group not in _DEFAULT_PLUGINS:
+        raise PluginGroupNotFound(plugin_group)
+    if name:
+        return _load_entry_point(plugin_group, name)
+    elif filename:
+        suffix = os.path.splitext(filename)[1]
+        return _load_entry_point(plugin_group + '.suffixes', suffix)
     else:
-        for loader in plugin_loaders:
-            try:
-                return loader.find_plugin(plugin_group, name, filename)
-            except PluginNotFound:
-                continue
-        raise PluginNotFound(plugin_group, name, filename)
+        return _load_entry_point(plugin_group, _DEFAULT_PLUGINS[plugin_group])
 
 
 def enumerate_plugin_names(plugin_group):
-    results = (
-        loader.enumerate_plugin_names(plugin_group)
-        for loader in plugin_loaders
-    )
-    return chain(*results)
+    """Enumerate all plugin names for the given *plugin_group*."""
+    return (entry_point.name
+            for entry_point in pkg_resources.iter_entry_points(plugin_group))
+
+
+class _FakeEntryPoint(pkg_resources.EntryPoint):
+
+    def __init__(self, name, klass):
+        self.name = name
+        self.klass = klass
+
+    def __str__(self):
+        return "%s = :%s" % (self.name, self.klass.__name__)
+
+    def __repr__(self):
+        return (
+            "_FakeEntryPoint(name=%r, klass=%s)"
+            % (self.name, self.klass.__name__))
+
+    def load(self, require=True, env=None, installer=None):
+        return self.klass
+
+    def require(self, env=None, installer=None):
+        pass
+
+
+def register_plugin(plugin_group, name, klass, force=False):
+    """Register a plugin on the fly.
+
+    This works by adding *klass* as a pybtex entry point, under entry
+    point group *plugin_group* and entry point name *name*.
+
+    To register a suffix, append ".suffixes" to the plugin group, and
+    *name* is then simply the suffix, which should start with a
+    period.
+
+    If *force* is ``False``, then existing entry points are not
+    overwritten. If an entry point with the given group and name
+    already exists, then returns ``False``, otherwise returns
+    ``True``.
+
+    If *force* is ``True``, then existing entry points are
+    overwritten, and the function always returns ``True``.
+    """
+    if not plugin_group.endswith(".suffixes"):
+        # registering a name
+        if plugin_group not in _DEFAULT_PLUGINS:
+            raise PluginGroupNotFound(plugin_group)
+    else:
+        # registering a suffix
+        group, _1, _2 = plugin_group.rpartition(".suffixes")
+        assert _1 == ".suffixes" and _2 == ""
+        if not name.startswith('.'):
+            raise ValueError("a suffix must start with a period")
+        if group not in _DEFAULT_PLUGINS:
+            raise PluginGroupNotFound(group)
+    dist = pkg_resources.get_distribution('pybtex')
+    ep_map = pkg_resources.get_entry_map(dist)
+    if plugin_group not in ep_map:
+        ep_map[plugin_group] = {}
+    if name in ep_map[plugin_group] and not force:
+        return False
+    else:
+        ep_map[plugin_group][name] = _FakeEntryPoint(name, klass)
+        return True

=== removed file 'pybtex/plugin/make_registry.py'
--- pybtex/plugin/make_registry.py	2011-02-27 17:25:55 +0000
+++ pybtex/plugin/make_registry.py	1970-01-01 00:00:00 +0000
@@ -1,63 +0,0 @@
-#!/usr/bin/env python
-
-import os
-import imp
-import pkgutil
-import json
-
-
-plugin_types = (
-    ('pybtex.database.input', 'Parser'),
-    ('pybtex.database.output', 'Writer'),
-    ('pybtex.backends', 'Backend'),
-    ('pybtex.style.labels', 'LabelStyle'),
-    ('pybtex.style.names', 'NameStyle'),
-    ('pybtex.style.sorting', 'SortingStyle'),
-    ('pybtex.style.formatting', 'Style'),
-)
-
-
-def import_from(module_name, obj_name):
-    module = __import__(module_name, globals(), locals(), [obj_name])
-    return module, getattr(module, obj_name)
-
-
-def iter_plugins(base_module, class_name):
-    plugin_dir = os.path.dirname(base_module.__file__)
-    for loader, name, is_pkg in pkgutil.iter_modules([plugin_dir]):
-        plugin_module = imp.load_module(name, *imp.find_module(name, [plugin_dir]))
-        yield getattr(plugin_module, class_name)
-
-
-def get_plugin_group_info(plugin_group, class_name):
-    base_module, base_plugin = import_from(plugin_group, 'Base' + class_name)
-    info = {
-        'class_name': class_name,
-        'default_plugin': base_plugin.default_plugin,
-        'plugins': [],
-        'aliases': {},
-        'suffixes': {},
-    }
-    for plugin in iter_plugins(base_module, class_name):
-        info['plugins'].append(plugin.name)
-        info['aliases'].update(dict.fromkeys(plugin.aliases, plugin.name))
-        info['suffixes'].update(dict.fromkeys(plugin.suffixes, plugin.name))
-    return info
-
-
-def get_plugin_registry():
-    return dict(
-        (plugin_group, get_plugin_group_info(plugin_group, class_name))
-        for plugin_group, class_name in plugin_types
-    )
-
-
-def write_plugin_registry(filename):
-    with open(filename, 'wb') as registry_file:
-        registry_file.write('plugin_registry = ')
-        json.dump(get_plugin_registry(), registry_file, indent=4)
-        registry_file.write('\n')
-
-
-if __name__ == '__main__':
-    write_plugin_registry('registry.py')

=== removed file 'pybtex/plugin/registry.py'
--- pybtex/plugin/registry.py	2013-08-09 19:38:46 +0000
+++ pybtex/plugin/registry.py	1970-01-01 00:00:00 +0000
@@ -1,103 +0,0 @@
-plugin_registry = {
-    "pybtex.database.output": {
-        "class_name": "Writer", 
-        "suffixes": {
-            ".xml": "bibtexml", 
-            ".bibtexml": "bibtexml", 
-            ".bibyaml": "bibyaml", 
-            ".bib": "bibtex", 
-            ".yaml": "bibyaml"
-        }, 
-        "aliases": {
-            "yaml": "bibyaml"
-        }, 
-        "default_plugin": "bibtex", 
-        "plugins": [
-            "bibtex", 
-            "bibtexml", 
-            "bibyaml"
-        ]
-    }, 
-    "pybtex.style.formatting": {
-        "class_name": "Style", 
-        "suffixes": {}, 
-        "aliases": {}, 
-        "default_plugin": "unsrt", 
-        "plugins": [
-            "plain", 
-            "unsrt",
-            "alpha",
-            "unsrtalpha",
-        ]
-    }, 
-    "pybtex.style.labels": {
-        "class_name": "LabelStyle", 
-        "suffixes": {}, 
-        "aliases": {}, 
-        "default_plugin": "number", 
-        "plugins": [
-            "number",
-            "alpha",
-        ]
-    }, 
-    "pybtex.backends": {
-        "class_name": "Backend", 
-        "suffixes": {
-            ".html": "html", 
-            ".latex": "latex", 
-            ".txt": "plaintext", 
-            ".bbl": "latex", 
-            ".tex": "latex"
-        }, 
-        "aliases": {
-            "text": "plaintext"
-        }, 
-        "default_plugin": "latex", 
-        "plugins": [
-            "html", 
-            "latex", 
-            "plaintext"
-        ]
-    }, 
-    "pybtex.database.input": {
-        "class_name": "Parser", 
-        "suffixes": {
-            ".xml": "bibtexml", 
-            ".bibtexml": "bibtexml", 
-            ".bibyaml": "bibyaml", 
-            ".bib": "bibtex", 
-            ".yaml": "bibyaml"
-        }, 
-        "aliases": {
-            "yaml": "bibyaml"
-        }, 
-        "default_plugin": "bibtex", 
-        "plugins": [
-            "bibtex", 
-            "bibtexml", 
-            "bibyaml"
-        ]
-    }, 
-    "pybtex.style.names": {
-        "class_name": "NameStyle", 
-        "suffixes": {}, 
-        "aliases": {
-            "last_first": "lastfirst"
-        }, 
-        "default_plugin": "plain", 
-        "plugins": [
-            "lastfirst", 
-            "plain"
-        ]
-    }, 
-    "pybtex.style.sorting": {
-        "class_name": "SortingStyle", 
-        "suffixes": {}, 
-        "aliases": {}, 
-        "default_plugin": "none", 
-        "plugins": [
-            "author_year_title", 
-            "none"
-        ]
-    }
-}

=== modified file 'pybtex/style/formatting/__init__.py'
--- pybtex/style/formatting/__init__.py	2013-08-07 07:30:30 +0000
+++ pybtex/style/formatting/__init__.py	2014-02-04 13:09:32 +0000
@@ -31,7 +31,6 @@
 
 
 class BaseStyle(Plugin):
-    default_plugin = 'unsrt'
     default_name_style = None
     default_label_style = None
     default_sorting_style = None

=== modified file 'pybtex/style/formatting/alpha.py'
--- pybtex/style/formatting/alpha.py	2012-08-09 10:25:06 +0000
+++ pybtex/style/formatting/alpha.py	2014-02-04 13:09:32 +0000
@@ -23,6 +23,5 @@
 
 
 class Style(UnsrtStyle):
-    name = 'alpha'
     default_sorting_style = 'author_year_title'
     default_label_style = 'alpha'

=== modified file 'pybtex/style/formatting/plain.py'
--- pybtex/style/formatting/plain.py	2012-02-12 20:44:25 +0000
+++ pybtex/style/formatting/plain.py	2014-02-04 13:09:32 +0000
@@ -23,5 +23,4 @@
 
 
 class Style(UnsrtStyle):
-    name = 'plain'
     default_sorting_style = 'author_year_title'

=== modified file 'pybtex/style/formatting/unsrt.py'
--- pybtex/style/formatting/unsrt.py	2012-08-07 13:19:51 +0000
+++ pybtex/style/formatting/unsrt.py	2014-02-04 13:09:32 +0000
@@ -37,7 +37,6 @@
 date = words [optional_field('month'), field('year')]
 
 class Style(BaseStyle):
-    name = 'unsrt'
 
     def format_names(self, role, as_sentence=True):
         formatted_names = names(role, sep=', ', sep2 = ' and ', last_sep=', and ')

=== modified file 'pybtex/style/formatting/unsrtalpha.py'
--- pybtex/style/formatting/unsrtalpha.py	2012-08-09 10:25:06 +0000
+++ pybtex/style/formatting/unsrtalpha.py	2014-02-04 13:09:32 +0000
@@ -23,5 +23,4 @@
 
 
 class Style(UnsrtStyle):
-    name = 'unsrtalpha'
     default_label_style = 'alpha'

=== modified file 'pybtex/style/labels/__init__.py'
--- pybtex/style/labels/__init__.py	2013-08-02 08:12:50 +0000
+++ pybtex/style/labels/__init__.py	2014-02-04 13:09:32 +0000
@@ -22,12 +22,8 @@
 from pybtex.plugin import Plugin
 from pybtex.textutils import width
 
-available_plugins = ('number', 'alpha')
-
 
 class BaseLabelStyle(Plugin):
-    default_plugin = 'number'
-
     def get_longest_label(self, formatted_entries):
         labels = (entry.label for entry in formatted_entries)
         return max(labels, key=width)

=== modified file 'pybtex/style/labels/alpha.py'
--- pybtex/style/labels/alpha.py	2013-08-05 12:55:10 +0000
+++ pybtex/style/labels/alpha.py	2014-02-04 13:09:32 +0000
@@ -51,7 +51,6 @@
     return _nonalnum_pattern.sub(u'', _strip_accents(s))
 
 class LabelStyle(BaseLabelStyle):
-    name = 'alpha'
 
     def format_labels(self, sorted_entries):
         labels = [self.format_label(entry) for entry in sorted_entries]

=== modified file 'pybtex/style/labels/number.py'
--- pybtex/style/labels/number.py	2013-08-01 16:52:31 +0000
+++ pybtex/style/labels/number.py	2014-02-04 13:09:32 +0000
@@ -24,7 +24,6 @@
 
 
 class LabelStyle(BaseLabelStyle):
-    name = 'number'
 
     def format_labels(self, sorted_entries):
         for number, entry in enumerate(sorted_entries):

=== modified file 'pybtex/style/names/__init__.py'
--- pybtex/style/names/__init__.py	2012-02-12 20:44:25 +0000
+++ pybtex/style/names/__init__.py	2014-02-04 13:09:32 +0000
@@ -27,12 +27,7 @@
 from pybtex.style.template import join, together, node, _format_list
 
 
-available_plugins = ('plain', 'lastfirst')
-
-
 class BaseNameStyle(Plugin):
-    default_plugin = 'plain'
-
     def format(self, person, abbr=False):
         raise NotImplementedError
 

=== modified file 'pybtex/style/names/lastfirst.py'
--- pybtex/style/names/lastfirst.py	2012-02-12 20:44:25 +0000
+++ pybtex/style/names/lastfirst.py	2014-02-04 13:09:32 +0000
@@ -25,8 +25,6 @@
 
 
 class NameStyle(BaseNameStyle):
-    name = 'lastfirst'
-    aliases = 'last_first',
 
     def format(self, person, abbr=False):
         r"""

=== modified file 'pybtex/style/names/plain.py'
--- pybtex/style/names/plain.py	2012-02-12 20:44:25 +0000
+++ pybtex/style/names/plain.py	2014-02-04 13:09:32 +0000
@@ -25,7 +25,6 @@
 
 
 class NameStyle(BaseNameStyle):
-    name = 'plain'
 
     def format(self, person, abbr=False):
         r"""

=== modified file 'pybtex/style/sorting/__init__.py'
--- pybtex/style/sorting/__init__.py	2012-02-12 20:44:25 +0000
+++ pybtex/style/sorting/__init__.py	2014-02-04 13:09:32 +0000
@@ -23,8 +23,6 @@
 
 
 class BaseSortingStyle(Plugin):
-    default_plugin = 'none'
-
     def sorting_key(self, entry):
         raise NotImplementedError
 

=== modified file 'pybtex/style/sorting/author_year_title.py'
--- pybtex/style/sorting/author_year_title.py	2012-08-09 13:05:30 +0000
+++ pybtex/style/sorting/author_year_title.py	2014-02-04 13:09:32 +0000
@@ -23,7 +23,6 @@
 
 
 class SortingStyle(BaseSortingStyle):
-    name = 'author_year_title'
 
     def sorting_key(self, entry):
         if entry.type in ('book', 'inbook'):

=== modified file 'pybtex/style/sorting/none.py'
--- pybtex/style/sorting/none.py	2012-02-12 20:44:25 +0000
+++ pybtex/style/sorting/none.py	2014-02-04 13:09:32 +0000
@@ -23,7 +23,6 @@
 
 
 class SortingStyle(BaseSortingStyle):
-    name = 'none'
 
     def sort(self, entries):
         return entries

=== added file 'pybtex/tests/plugin_test.py'
--- pybtex/tests/plugin_test.py	1970-01-01 00:00:00 +0000
+++ pybtex/tests/plugin_test.py	2014-02-04 13:09:32 +0000
@@ -0,0 +1,119 @@
+# Copyright (c) 2014  Matthias C. M. Troffaes
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+# IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+# CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+# TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+# SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+import nose.tools
+
+import pybtex.database.input.bibtex
+import pybtex.plugin
+import pybtex.style.formatting.plain
+
+
+def test_plugin_loader():
+    """Check that all enumerated plugins can be imported."""
+    for group in pybtex.plugin._DEFAULT_PLUGINS:
+        for name in pybtex.plugin.enumerate_plugin_names(group):
+            pybtex.plugin.find_plugin(group, name)
+
+
+class TestPlugin1(pybtex.plugin.Plugin):
+    pass
+
+
+class TestPlugin2(pybtex.plugin.Plugin):
+    pass
+
+
+class TestPlugin3(pybtex.plugin.Plugin):
+    pass
+
+
+def test_register_plugin_1():
+    nose.tools.assert_true(
+        pybtex.plugin.register_plugin(
+            'pybtex.style.formatting', 'yippikayee', TestPlugin1))
+    nose.tools.assert_is(
+        TestPlugin1, pybtex.plugin.find_plugin(
+            'pybtex.style.formatting', 'yippikayee'))
+    nose.tools.assert_false(
+        pybtex.plugin.register_plugin(
+            'pybtex.style.formatting', 'yippikayee', TestPlugin2))
+    nose.tools.assert_is(
+        TestPlugin1, pybtex.plugin.find_plugin(
+            'pybtex.style.formatting', 'yippikayee'))
+    nose.tools.assert_true(
+        pybtex.plugin.register_plugin(
+            'pybtex.style.formatting', 'yippikayee', TestPlugin2, force=True))
+    nose.tools.assert_is(
+        TestPlugin2, pybtex.plugin.find_plugin(
+            'pybtex.style.formatting', 'yippikayee'))
+
+
+def test_register_plugin_2():
+    nose.tools.assert_false(
+        pybtex.plugin.register_plugin(
+            'pybtex.style.formatting', 'plain', TestPlugin2))
+    plugin = pybtex.plugin.find_plugin('pybtex.style.formatting', 'plain')
+    nose.tools.assert_is_not(plugin, TestPlugin2)
+    nose.tools.assert_is(plugin, pybtex.style.formatting.plain.Style)
+
+
+def test_register_plugin_3():
+    nose.tools.assert_true(
+        pybtex.plugin.register_plugin(
+            'pybtex.style.formatting.suffixes', '.woo', TestPlugin3))
+    plugin = pybtex.plugin.find_plugin(
+        'pybtex.style.formatting', filename='test.woo')
+    nose.tools.assert_is(plugin, TestPlugin3)
+
+
+def test_bad_find_plugin():
+    nose.tools.assert_raises(
+        pybtex.plugin.PluginGroupNotFound,
+        lambda: pybtex.plugin.find_plugin("pybtex.invalid.group", "__oops"))
+    nose.tools.assert_raises(
+        pybtex.plugin.PluginNotFound,
+        lambda: pybtex.plugin.find_plugin("pybtex.style.formatting", "__oops"))
+    nose.tools.assert_raises(
+        pybtex.plugin.PluginNotFound,
+        lambda: pybtex.plugin.find_plugin("pybtex.style.formatting",
+                                          filename="oh.__oops"))
+
+
+def test_bad_register_plugin():
+    nose.tools.assert_raises(
+        pybtex.plugin.PluginGroupNotFound,
+        lambda: pybtex.plugin.register_plugin(
+            "pybtex.invalid.group", "__oops", TestPlugin1))
+    nose.tools.assert_raises(
+        pybtex.plugin.PluginGroupNotFound,
+        lambda: pybtex.plugin.register_plugin(
+            "pybtex.invalid.group.suffixes", ".__oops", TestPlugin1))
+    # suffixes must start with a dot
+    nose.tools.assert_raises(
+        ValueError,
+        lambda: pybtex.plugin.register_plugin(
+            "pybtex.style.formatting.suffixes", "notasuffix", TestPlugin1))
+
+
+def test_plugin_suffix():
+    plugin = pybtex.plugin.find_plugin(
+        "pybtex.database.input", filename="test.bib")
+    nose.tools.assert_is(plugin, pybtex.database.input.bibtex.Parser)

=== modified file 'setup.py'
--- setup.py	2013-08-07 07:36:40 +0000
+++ setup.py	2014-02-04 13:09:32 +0000
@@ -92,6 +92,66 @@
     ],
     include_package_data=True,
     cmdclass={'sdist' : Sdist},
+    entry_points={
+        'pybtex.database.input': [
+            'bibtex = pybtex.database.input.bibtex:Parser',
+            'bibtexml = pybtex.database.input.bibtexml:Parser',
+            'bibyaml = pybtex.database.input.bibyaml:Parser',
+            'yaml = pybtex.database.input.bibyaml:Parser',
+            ],
+        'pybtex.database.input.suffixes': [
+            '.bib = pybtex.database.input.bibtex:Parser',
+            '.xml = pybtex.database.input.bibtexml:Parser',
+            '.bibtexml = pybtex.database.input.bibtexml:Parser',
+            '.bibyaml = pybtex.database.input.bibyaml:Parser',
+            '.yaml = pybtex.database.input.bibyaml:Parser',
+            ],
+        'pybtex.database.output': [
+            'bibtex = pybtex.database.output.bibtex:Writer',
+            'bibtexml = pybtex.database.output.bibtexml:Writer',
+            'bibyaml = pybtex.database.output.bibyaml:Writer',
+            'yaml = pybtex.database.output.bibyaml:Writer',
+            ],
+        'pybtex.database.output.suffixes': [
+            '.bib = pybtex.database.output.bibtex:Writer',
+            '.xml = pybtex.database.output.bibtexml:Writer',
+            '.bibtexml = pybtex.database.output.bibtexml:Writer',
+            '.bibyaml = pybtex.database.output.bibyaml:Writer',
+            '.yaml = pybtex.database.output.bibyaml:Writer',
+            ],
+        'pybtex.backends': [
+            'latex = pybtex.backends.latex:Backend',
+            'html = pybtex.backends.html:Backend',
+            'plaintext = pybtex.backends.plaintext:Backend',
+            'text = pybtex.backends.plaintext:Backend',
+            ],
+        'pybtex.backends.suffixes': [
+            '.bbl = pybtex.backends.latex:Backend',
+            '.tex = pybtex.backends.latex:Backend',
+            '.latex = pybtex.backends.latex:Backend',
+            '.html = pybtex.backends.html:Backend',
+            '.txt = pybtex.backends.plaintext:Backend',
+            ],
+        'pybtex.style.labels': [
+            'number = pybtex.style.labels.number:LabelStyle',
+            'alpha = pybtex.style.labels.alpha:LabelStyle',
+            ],
+        'pybtex.style.names': [
+            'plain = pybtex.style.names.plain:NameStyle',
+            'lastfirst = pybtex.style.names.lastfirst:NameStyle',
+            'last_first = pybtex.style.names.lastfirst:NameStyle',
+            ],
+        'pybtex.style.sorting': [
+            'none = pybtex.style.sorting.none:SortingStyle',
+            'author_year_title = pybtex.style.sorting.author_year_title:SortingStyle',
+            ],
+        'pybtex.style.formatting': [
+            'plain = pybtex.style.formatting.plain:Style',
+            'unsrt = pybtex.style.formatting.unsrt:Style',
+            'alpha = pybtex.style.formatting.alpha:Style',
+            'unsrtalpha = pybtex.style.formatting.unsrtalpha:Style',
+            ],
+        },
     zip_safe=True,
     **extra
     )