Check in a simple pure-python based Markdown previewer.

third_party/Python-Markdown/markdown/__main__.py

Index: third_party/Python-Markdown/markdown/__main__.py
diff --git a/third_party/Python-Markdown/markdown/__main__.py b/third_party/Python-Markdown/markdown/__main__.py
new file mode 100644
index 0000000000000000000000000000000000000000..17bfa9f3c494a3f297452a2443e57034dea3ffed
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+++ b/third_party/Python-Markdown/markdown/__main__.py
@@ -0,0 +1,136 @@
+"""
+COMMAND-LINE SPECIFIC STUFF
+=============================================================================
+
+"""
+
+import sys
+import optparse
+import codecs
+import warnings
+import markdown
+try:
+    import yaml
+except ImportError:  # pragma: no cover
+    import json as yaml
+
+import logging
+from logging import DEBUG, WARNING, CRITICAL
+
+logger = logging.getLogger('MARKDOWN')
+
+
+def parse_options(args=None, values=None):
+    """
+    Define and parse `optparse` options for command-line usage.
+    """
+    usage = """%prog [options] [INPUTFILE]
+       (STDIN is assumed if no INPUTFILE is given)"""
+    desc = "A Python implementation of John Gruber's Markdown. " \
+           "https://pythonhosted.org/Markdown/"
+    ver = "%%prog %s" % markdown.version
+
+    parser = optparse.OptionParser(usage=usage, description=desc, version=ver)
+    parser.add_option("-f", "--file", dest="filename", default=None,
+                      help="Write output to OUTPUT_FILE. Defaults to STDOUT.",
+                      metavar="OUTPUT_FILE")
+    parser.add_option("-e", "--encoding", dest="encoding",
+                      help="Encoding for input and output files.",)
+    parser.add_option("-s", "--safe", dest="safe", default=False,
+                      metavar="SAFE_MODE",
+                      help="Deprecated! 'replace', 'remove' or 'escape' HTML "
+                      "tags in input")
+    parser.add_option("-o", "--output_format", dest="output_format",
+                      default='xhtml1', metavar="OUTPUT_FORMAT",
+                      help="'xhtml1' (default), 'html4' or 'html5'.")
+    parser.add_option("-n", "--no_lazy_ol", dest="lazy_ol",
+                      action='store_false', default=True,
+                      help="Observe number of first item of ordered lists.")
+    parser.add_option("-x", "--extension", action="append", dest="extensions",
+                      help="Load extension EXTENSION.", metavar="EXTENSION")
+    parser.add_option("-c", "--extension_configs",
+                      dest="configfile", default=None,
+                      help="Read extension configurations from CONFIG_FILE. "
+                      "CONFIG_FILE must be of JSON or YAML format. YAML"
+                      "format requires that a python YAML library be "
+                      "installed. The parsed JSON or YAML must result in a "
+                      "python dictionary which would be accepted by the "
+                      "'extension_configs' keyword on the markdown.Markdown "
+                      "class. The extensions must also be loaded with the "
+                      "`--extension` option.",
+                      metavar="CONFIG_FILE")
+    parser.add_option("-q", "--quiet", default=CRITICAL,
+                      action="store_const", const=CRITICAL+10, dest="verbose",
+                      help="Suppress all warnings.")
+    parser.add_option("-v", "--verbose",
+                      action="store_const", const=WARNING, dest="verbose",
+                      help="Print all warnings.")
+    parser.add_option("--noisy",
+                      action="store_const", const=DEBUG, dest="verbose",
+                      help="Print debug messages.")
+
+    (options, args) = parser.parse_args(args, values)
+
+    if len(args) == 0:
+        input_file = None
+    else:
+        input_file = args[0]
+
+    if not options.extensions:
+        options.extensions = []
+
+    extension_configs = {}
+    if options.configfile:
+        with codecs.open(
+            options.configfile, mode="r", encoding=options.encoding
+        ) as fp:
+            try:
+                extension_configs = yaml.load(fp)
+            except Exception as e:
+                message = "Failed parsing extension config file: %s" % \
+                          options.configfile
+                e.args = (message,) + e.args[1:]
+                raise
+
+    opts = {
+        'input': input_file,
+        'output': options.filename,
+        'extensions': options.extensions,
+        'extension_configs': extension_configs,
+        'encoding': options.encoding,
+        'output_format': options.output_format,
+        'lazy_ol': options.lazy_ol
+    }
+
+    if options.safe:
+        # Avoid deprecation warning if user didn't set option
+        opts['safe_mode'] = options.safe
+
+    return opts, options.verbose
+
+
+def run():  # pragma: no cover
+    """Run Markdown from the command line."""
+
+    # Parse options and adjust logging level if necessary
+    options, logging_level = parse_options()
+    if not options:
+        sys.exit(2)
+    logger.setLevel(logging_level)
+    console_handler = logging.StreamHandler()
+    logger.addHandler(console_handler)
+    if logging_level <= WARNING:
+        # Ensure deprecation warnings get displayed
+        warnings.filterwarnings('default')
+        logging.captureWarnings(True)
+        warn_logger = logging.getLogger('py.warnings')
+        warn_logger.addHandler(console_handler)
+
+    # Run
+    markdown.markdownFromFile(**options)
+
+
+if __name__ == '__main__':  # pragma: no cover
+    # Support running module as a commandline command.
+    # Python 2.7 & 3.x do: `python -m markdown [options] [args]`.
+    run()