refactor: Move some compat code to compat.py

Author: justinmk

pynvim/compat.py

@@ -1,7 +1,12 @@
-"""Code for supporting compatibility across python versions."""
+"""Code for compatibility across Python versions."""
 
 import sys
 import warnings
+if sys.version_info >= (3, 7):
+    import types
+    import importlib
+else:
+    import imp  # Deprecated in Python 3.7+
 if sys.version_info >= (3, 4):
     from importlib.machinery import PathFinder
     original_find_module = PathFinder.find_spec
@@ -10,13 +15,17 @@
 
 
 IS_PYTHON3 = sys.version_info >= (3, 0)
-IS_PYTHON3_7 = sys.version_info >= (3, 7)
 
+if sys.version_info >= (3, 7):
+    load_module = importlib.import_module
+    new_module = types.ModuleType
+else:
+    load_module = imp.load_module
+    new_module = imp.new_module
 
 if IS_PYTHON3:
     def find_module(fullname, path):
-        """Compatibility wrapper for imp.find_module
-        (or find_spec in Python 3.7+).
+        """Compat wrapper for imp.find_module, or find_spec in Python 3.7+.
 
         Automatically decodes arguments (must be Unicode in Python3).
         """

pynvim/plugin/script_host.py

@@ -1,17 +1,12 @@
 """Legacy python/python3-vim emulation."""
-try:
-    import types
-    import importlib
-except ImportError:
-    import imp
 import io
 import logging
 import os
 import sys
 
 from .decorators import plugin, rpc_export
 from ..api import Nvim, walk
-from ..compat import IS_PYTHON3, IS_PYTHON3_7, find_module
+from ..compat import IS_PYTHON3, find_module, load_module, new_module
 from ..msgpack_rpc import ErrorResponse
 from ..util import format_exc_skip
 
@@ -41,10 +36,7 @@ def __init__(self, nvim):
         """Initialize the legacy python-vim environment."""
         self.setup(nvim)
         # context where all code will run
-        if IS_PYTHON3_7:
-            self.module = types.ModuleType('__main__')
-        else:
-            self.module = imp.new_module('__main__')
+        self.module = new_module('__main__')
         nvim.script_context = self.module
         # it seems some plugins assume 'sys' is already imported, so do it now
         exec('import sys', self.module.__dict__)
@@ -239,10 +231,7 @@ def load_module(self, fullname, path=None):
                 return sys.modules[fullname]
             except KeyError:
                 pass
-            if IS_PYTHON3_7:
-                return importlib.import_module(fullname, *self.module)
-            else:
-                return imp.load_module(fullname, *self.module)
+            return load_module(fullname, *self.module)
 
     class VimPathFinder(object):
         @staticmethod