move StringIO to compat

Author: jck

myhdl/_compat.py

@@ -7,9 +7,13 @@
     string_types = (str,)
     integer_types = (int,)
     long = int
+
+    from io import StringIO
     import builtins
 else:
     string_types = (str, unicode)
     integer_types = (int, long)
     long = long
+
+    from cStringIO import StringIO
     import __builtin__ as builtins

myhdl/_unparse.py

@@ -24,7 +24,7 @@
 
 
 import compiler
-from cStringIO import StringIO
+from myhdl._compat import StringIO
 
 def _unparse(ast):
     v = _UnparseVisitor()

myhdl/_util.py

@@ -29,9 +29,8 @@
 import inspect
 
 from tokenize import generate_tokens, untokenize, INDENT
-from cStringIO import StringIO
 
-from myhdl._compat import integer_types
+from myhdl._compat import integer_types, StringIO
 
 def _printExcInfo():
     kind, value = sys.exc_info()[:2]

myhdl/conversion/_toVHDL.py

@@ -34,14 +34,13 @@
 #from compiler import ast as astNode
 import ast
 from types import GeneratorType, ClassType
-from cStringIO import StringIO
 import warnings
 from copy import copy
 import string
 
 import myhdl
 from myhdl import *
-from myhdl._compat import integer_types
+from myhdl._compat import integer_types, StringIO
 from myhdl import ToVHDLError, ToVHDLWarning
 from myhdl._extractHierarchy import (_HierExtr, _isMem, _getMemInfo,
                                      _UserVhdlCode, _userCodeMap)

myhdl/conversion/_toVerilog.py

@@ -34,7 +34,7 @@
 import string
 
 from types import GeneratorType, ClassType, TypeType
-from cStringIO import StringIO
+from myhdl._compat import StringIO
 import warnings
 
 import myhdl