Add a way to profile the diff parser.

scripts/diff_parser_profile.py

@@ -0,0 +1,44 @@
+#!/usr/bin/env python
+"""
+Profile a piece of Python code with ``cProfile`` that uses the diff parser.
+
+Usage:
+  profile.py <file> [-d] [-s <sort>]
+  profile.py -h | --help
+
+Options:
+  -h --help     Show this screen.
+  -d --debug    Enable Jedi internal debugging.
+  -s <sort>     Sort the profile results, e.g. cum, name [default: time].
+"""
+
+import cProfile
+
+from docopt import docopt
+from jedi.parser import load_grammar
+from jedi.parser.diff import DiffParser
+from jedi.parser import ParserWithRecovery
+from jedi._compatibility import u
+from jedi.common import splitlines
+import jedi
+
+
+def run(parser, lines):
+    diff_parser = DiffParser(parser)
+    diff_parser.update(lines)
+
+
+def main(args):
+    jedi.set_debug_function(notices=args['--debug'])
+    with open(args['<file>']) as f:
+        code = f.read()
+    grammar = load_grammar()
+    parser = ParserWithRecovery(grammar, u(code))
+
+    code =  code + '\na\n'  # Add something so the diff parser needs to run.
+    lines = splitlines(code, keepends=True)
+    cProfile.runctx('run(parser, lines)', globals(), locals(), sort=args['-s'])
+
+if __name__ == '__main__':
+    args = docopt(__doc__)
+    main(args)