Implement command to print minimal requirements

setup.py

@@ -11,28 +11,12 @@ Vdirsyncer is a synchronization tool for vdir. See the README for more details.
 
 
 import platform
+import re
 
-from setuptools import find_packages, setup
+from setuptools import find_packages, setup, Command
 
 
-setup(
+requirements = [
-    name='vdirsyncer',
-    use_scm_version={
-        'write_to': 'vdirsyncer/version.py',
-    },
-    setup_requires=['setuptools_scm'],
-    author='Markus Unterwaditzer',
-    author_email='markus@unterwaditzer.net',
-    url='https://github.com/untitaker/vdirsyncer',
-    description='Synchronize calendars and contacts',
-    license='MIT',
-    long_description=open('README.rst').read(),
-    packages=find_packages(exclude=['tests.*', 'tests']),
-    include_package_data=True,
-    entry_points={
-        'console_scripts': ['vdirsyncer = vdirsyncer.cli:main']
-    },
-    install_requires=[
     # https://github.com/mitsuhiko/click/issues/200
     'click>=5.0',
     'click-log>=0.1.3',
@@ -52,8 +36,49 @@ setup(
     'requests_toolbelt >=0.3.0',
     # https://github.com/untitaker/python-atomicwrites/commit/4d12f23227b6a944ab1d99c507a69fdbc7c9ed6d  # noqa
     'atomicwrites>=0.1.7'
-    ],
+]
+
+
+class PrintRequirements(Command):
+
+    description = 'Prints minimal requirements'
+
+    user_options = []
+
+    def initialize_options(self):
+        pass
+
+    def finalize_options(self):
+        pass
+
+    def run(self):
+        [
+            print(requirement.replace(">", "=").replace(" ", ""))
+            for requirement in requirements
+        ]
+
+setup(
+    name='vdirsyncer',
+    use_scm_version={
+        'write_to': 'vdirsyncer/version.py',
+    },
+    setup_requires=['setuptools_scm'],
+    author='Markus Unterwaditzer',
+    author_email='markus@unterwaditzer.net',
+    url='https://github.com/untitaker/vdirsyncer',
+    description='Synchronize calendars and contacts',
+    license='MIT',
+    long_description=open('README.rst').read(),
+    packages=find_packages(exclude=['tests.*', 'tests']),
+    include_package_data=True,
+    entry_points={
+        'console_scripts': ['vdirsyncer = vdirsyncer.cli:main']
+    },
+    install_requires=requirements,
     extras_require={
         'remotestorage': ['requests-oauthlib']
+    },
+    cmdclass={
+        'requirements': PrintRequirements
     }
 )