Add compile_grammar command to setup.py (ref: #2765)

setup.py

@@ -4,9 +4,9 @@ from setuptools import setup, find_packages
 import os
 import sys
 from distutils import log
+from distutils.cmd import Command
 
 import sphinx
-from sphinx.pycode.pgen2.driver import compile_grammar
 
 long_desc = '''
 Sphinx is a tool that makes it easy to create intelligent and beautiful
@@ -73,10 +73,6 @@ extras_require = {
 if sys.platform == 'win32':
     requires.append('colorama>=0.3.5')
 
-# Compile grammars before packaging
-compile_grammar('sphinx/pycode/Grammar-py2.txt')
-compile_grammar('sphinx/pycode/Grammar-py3.txt')
-
 # Provide a "compile_catalog" command that also creates the translated
 # JavaScript files if Babel is available.
 
@@ -173,6 +169,31 @@ else:
     cmdclass['compile_catalog'] = compile_catalog_plusjs
 
 
+class CompileGrammarCommand(Command):
+    description = 'Compile python grammar file for pycode'
+    user_options = []
+
+    def initialize_options(self):
+        pass
+
+    def finalize_options(self):
+        pass
+
+    def run(self):
+        from sphinx.pycode.pgen2.driver import compile_grammar
+
+        compile_grammar('sphinx/pycode/Grammar-py2.txt')
+        print('sphinx/pycode/Grammar-py2.txt ... done')
+
+        compile_grammar('sphinx/pycode/Grammar-py3.txt')
+        print('sphinx/pycode/Grammar-py3.txt ... done')
+
+    def sub_commands(self):
+        pass
+
+cmdclass['compile_grammar'] = CompileGrammarCommand
+
+
 setup(
     name='Sphinx',
     version=sphinx.__version__,