Moved code to compat subpackage and ajusted imports

1 files changed, 66 insertions, 0 deletions

diff --git a/pint/compat/__init__.py b/pint/compat/__init__.py
index 7580e64..174c360 100644
--- a/pint/compat/__init__.py
+++ b/pint/compat/__init__.py
@@ -11,6 +11,33 @@
 
 from __future__ import division, unicode_literals, print_function, absolute_import
 
+import sys
+import tokenize
+
+from numbers import Number
+from decimal import Decimal
+
+
+PYTHON3 = sys.version >= '3'
+
+if PYTHON3:
+    from io import BytesIO
+    string_types = str
+    tokenizer = lambda input_string: tokenize.tokenize(BytesIO(input_string.encode('utf-8')).readline)
+
+    def u(x):
+        return x
+else:
+    from StringIO import StringIO
+    string_types = basestring
+    tokenizer = lambda input_string: tokenize.generate_tokens(StringIO(input_string).readline)
+
+    import codecs
+    string_types = basestring
+
+    def u(x):
+        return codecs.unicode_escape_decode(x)[0]
+
 try:
     from collections import Chainmap
 except:
@@ -20,3 +47,42 @@ try:
     from functools import lru_cache
 except:
     from .lrucache import lru_cache
+
+try:
+    import numpy as np
+    from numpy import ndarray
+
+    HAS_NUMPY = True
+    NUMPY_VER = np.__version__
+    NUMERIC_TYPES = (Number, Decimal, ndarray, np.number)
+
+    def _to_magnitude(value, force_ndarray=False):
+        if isinstance(value, NUMERIC_TYPES):
+            if force_ndarray:
+                return np.asarray(value)
+            else:
+                return value
+        elif isinstance(value, (list, tuple)):
+            return np.asarray(value)
+        else:
+            raise TypeError('Invalid type of magnitude for Quantity: {}'.format(type(value)))
+
+except ImportError:
+
+    np = None
+
+    class ndarray(object):
+        pass
+
+    HAS_NUMPY = False
+    NUMPY_VER = 0
+    NUMERIC_TYPES = (Number, Decimal)
+
+    def _to_magnitude(value, force_ndarray=False):
+        if isinstance(value, NUMERIC_TYPES):
+            return value
+        elif isinstance(value, (list, tuple)):
+            raise TypeError('lists and tuples are valid magnitudes for '
+                            'Quantity only when NumPy is present.')
+        else:
+            raise TypeError('Invalid type of magnitude for Quantity: {}'.format(type(value)))