Support 'python -m trove_classifiers' (#23)

* README tweaks

* Support 'python -m trove_classifiers'

* Version 2020.04.09

Author: di

README.md

@@ -1,22 +1,27 @@
-Canonical source for [classifiers](https://pypi.org/classifiers/) on
-[PyPI](https://pypi.org). Classifiers [categorize
-projects](https://packaging.python.org/specifications/core-metadata/#classifier-multiple-use)
-per [PEP 301](https://www.python.org/dev/peps/pep-0301/). Use this
-package to validate classifiers in packages for PyPI upload or
-download.
+Canonical source for [classifiers][1] on [PyPI][2].
+
+Classifiers [categorize projects][3] per [PEP 301][4]. Use this package to
+validate classifiers in packages for PyPI upload or download.
 
 ## Usage
 
-To install [from PyPI](https://pypi.org/project/trove-classifiers/):
+To install [from PyPI][5]:
+
+```
+$ pip install trove-classifiers
+```
+
+This package can be invoked as a module to print a list of classifiers:
 
 ```
-> pip install trove-classifiers
+$ python -m trove_classifiers | grep -Ei pyramid
+Framework :: Pyramid
 ```
 
-This package's API is two importable objects:
+In addition, this package's API is two importable objects:
 
 ### Classifiers (`trove_classifiers.classifiers`)
-A `set` containing classifiers (as strings). Useful for determining membership
+A `set` containing classifiers (as strings). Useful for determining membership.
 
 Example - determine if a classifier is valid:
 
@@ -44,3 +49,9 @@ True
 >>> deprecated_classifiers["Natural Language :: Ukranian"]
 ['Natural Language :: Ukrainian']
 ```
+
+[1]: https://pypi.org/classifiers/
+[2]: https://pypi.org
+[3]: https://packaging.python.org/specifications/core-metadata/#classifier-multiple-use
+[4]: https://www.python.org/dev/peps/pep-0301/
+[5]: https://pypi.org/project/trove-classifiers/

setup.py

@@ -11,7 +11,7 @@
 
 setup(
     name='trove-classifiers',
-    version='2020.04.01',
+    version='2020.04.09',
     description="Canonical source for classifiers on PyPI (pypi.org).",
     long_description=long_description,
     long_description_content_type="text/markdown",

trove_classifiers/__main__.py

@@ -0,0 +1,4 @@
+from trove_classifiers import classifiers
+
+for classifier in sorted(classifiers):
+    print(classifier)