prevent import py2/3 module in py3/2. removed exec wrapper from hclass

share/lib/python/neuron/__init__.py

@@ -233,10 +233,16 @@ def test_rxd(exitOnError=True):
 # using the idiom self.basemethod = self.baseattr('methodname')
 # ------------------------------------------------------------------------------
 
+import sys, types
+
 if sys.version_info[0] == 2:
   from neuron.hclass2 import hclass
+  # Add hclass3, the py3 variant of hclass2 to the module cache so that hclass3.py
+  # is never read by the Python 2 interpreter and can contain Python 3 only syntax.
+  sys.modules["neuron.hclass3"] = types.ModuleType("neuron.hclass3")
 else:
-  from neuron.hclass3 import hclass
+  from neuron.hclass3 import hclass, nonlocal_hclass
+  sys.modules["neuron.hclass2"] = types.ModuleType("neuron.hclass2")
 
 # global list of paths already loaded by load_mechanisms
 nrn_dll_loaded = []

share/lib/python/neuron/hclass2.py

@@ -4,12 +4,12 @@
 # h.anyclass methods may be overridden. If so the base method can be called
 # using the idiom self.basemethod = self.baseattr('methodname')
 # ------------------------------------------------------------------------------
-      
+
 from neuron import h, hoc
 import nrn
 
 #avoid syntax error if compiled by python 3
-exec('''
+
 class MetaHocObject(type):
   """Provides Exception for Inheritance of multiple HocObject"""
   def __new__(cls, name, bases, attrs):
@@ -22,7 +22,7 @@ def __new__(cls, name, bases, attrs):
       raise TypeError('Multiple Inheritance of HocObject in %s' % name
         + ' through %s not allowed' % ','.join(m))
       #note that join(b.__name__ for b in m) is not valid for Python 2.3
-  
+
     return type.__new__(cls, name, bases, attrs)
 
 def hclass(c):
@@ -38,4 +38,3 @@ def __new__(cls, *args, **kwds):
             return hoc.HocObject.__new__(cls, *args, **kwds2)
     setattr(hc, 'htype', c)
     return hc
-''')

share/lib/python/neuron/hclass3.py

@@ -4,12 +4,12 @@
 # h.anyclass methods may be overridden. If so the base method can be called
 # using the idiom self.basemethod = self.baseattr('methodname')
 # ------------------------------------------------------------------------------
-      
+
 from neuron import h, hoc
 import nrn
 
 #avoid syntax error if compiled by python 2
-exec('''
+
 class MetaHocObject(type):
   """Provides Exception for Inheritance of multiple HocObject"""
   def __new__(cls, name, bases, attrs):
@@ -22,7 +22,7 @@ def __new__(cls, name, bases, attrs):
       raise TypeError('Multiple Inheritance of HocObject in %s' % name
         + ' through %s not allowed' % ','.join(m))
       #note that join(b.__name__ for b in m) is not valid for Python 2.3
-  
+
     return type.__new__(cls, name, bases, attrs)
 
 def hclass(c):
@@ -38,4 +38,3 @@ def __new__(cls, *args, **kwds):
             return hoc.HocObject.__new__(cls, *args, **kwds2)
     setattr(hc, 'htype', c)
     return hc
-''')