Make it possible to get the right version parser for a certain environment

jedi/api/environment.py

@@ -11,6 +11,8 @@ from jedi.evaluate.project import Project
 from jedi.cache import memoize_method
 from jedi.evaluate.compiled.subprocess import get_subprocess
 
+import parso
+
 _VersionInfo = namedtuple('VersionInfo', 'major minor micro')
 
 _SUPPORTED_PYTHONS = ['2.7', '3.3', '3.4', '3.5', '3.6']
@@ -35,6 +37,11 @@ class Environment(object):
     def get_subprocess(self):
         return get_subprocess(self._executable)
 
+    @memoize_method
+    def get_parser(self):
+        version_string = '%s.%s' % (self.version_info.major, self.version_info.minor)
+        return parso.load_grammar(version=version_string)
+
     @memoize_method
     def get_sys_path(self):
         # It's pretty much impossible to generate the sys path without actually
@@ -115,4 +122,4 @@ def _get_version(executable):
     if match is None:
         raise InvalidPythonEnvironment()
 
-    return _VersionInfo(*match.groups())
+    return _VersionInfo(*[int(m) for m in match.groups()])

test/test_api/test_environment.py

@@ -15,6 +15,8 @@ def test_find_python_environments():
     for env in envs:
         assert env.version_info
         assert env.get_sys_path()
+        parser_version = env.get_parser().version_info
+        assert parser_version[:2] == env.version_info[:2]
 
 
 @pytest.mark.parametrize(