Merge 0966a7a into 1e551e1

README.rst

@@ -237,6 +237,14 @@ It is the same with block level lexer. It would take a while to understand
 the whole mechanism. But you won't do the trick a lot.
 
 
+Command Line Support
+--------------------
+
+Mistune can be called as a script to transform Markdown to HTML. Example usage::
+
+    python -m mistune < in.md > out.html
+
+
 Contribution & Extensions
 -------------------------
 

mistune.py

@@ -10,6 +10,7 @@
 
 import re
 import inspect
+import sys
 
 __version__ = '0.7.3'
 __author__ = 'Hsiaoming Yang <me@lepture.com>'
@@ -1156,3 +1157,31 @@ def markdown(text, escape=True, **kwargs):
     :param parse_inline_html: parse text only in inline level html.
     """
     return Markdown(escape=escape, **kwargs)(text)
+
+
+def usage():
+    message = (
+        'When run as a script, mistune reads markdown from stdin and writes'
+        ' html to stdout.'
+        '\n'
+        'Example usage:\n'
+        '\n'
+        '  python -m mistune < in.md > out.html\n'
+    )
+
+    sys.stderr.write(message)
+
+    raise SystemExit(1)
+
+
+def main(argv):
+    if '--help' in argv:
+        usage()
+
+    src_text = sys.stdin.read()
+    dest_text = markdown(src_text)
+    sys.stdout.write(dest_text)
+
+
+if __name__ == '__main__':
+    main(sys.argv)

tests/test_main.py

@@ -0,0 +1,55 @@
+import io
+import os
+import unittest
+import sys
+
+import mistune
+
+
+tests_dir = os.path.dirname(__file__)
+# Are we running in Python 2.x?
+py2 = sys.version_info < (3,)
+
+
+class MainTestCase(unittest.TestCase):
+    def setUp(self):
+        super(MainTestCase, self).setUp()
+        self._stdin = sys.stdin
+        self._stdout = sys.stdout
+        self._stderr = sys.stderr
+
+    def tearDown(self):
+        super(MainTestCase, self).tearDown()
+        sys.stdin = self._stdin
+        sys.stdout = self._stdout
+        sys.stderr = self._stderr
+
+    def test_display_help(self):
+        # If --help is in argv, a usage is emitted and SystemExit is raised.
+
+        argv = [mistune.__file__, '--help']
+        dest = io.BytesIO() if py2 else io.StringIO()
+        sys.stderr = dest
+
+        # Py26 doesn't have assertIn nor using assertRaises as a context manager.
+        self.assertRaises(SystemExit, mistune.main, argv)
+        self.assertTrue('When run as a script' in dest.getvalue())
+
+    def test_reads_stdin_writes_stdout(self):
+        src = os.path.join(tests_dir, 'fixtures', 'data', 'tree.md')
+        dest = io.BytesIO() if py2 else io.StringIO()
+
+        sys.stdin = open(src)
+        sys.stdout = dest
+
+        mistune.main([mistune.__file__])
+
+        expected = (
+            '<h2>Title here</h2>\n<p>Some text.</p>\n<p>In two paragraphs. And'
+            ' then a list.</p>\n<ul>\n<li>foo</li>\n<li>bar<ol>\n<li>meep</li>'
+            '\n<li>stuff</li>\n</ol>\n</li>\n</ul>\n'
+        )
+
+        self.assertEqual(dest.getvalue(), expected)
+
+