ENH: Check against collections.Mapping instead of dict

blaze/compute/core.py

@@ -1,6 +1,6 @@
 from __future__ import absolute_import, division, print_function
 
-from collections import defaultdict, Iterator
+from collections import defaultdict, Iterator, Mapping
 from datetime import date, datetime, timedelta
 import itertools
 import numbers
@@ -378,7 +378,7 @@ def swap_resources_into_scope(expr, scope):
     return expr, new_scope
 
 
-@dispatch(Expr, dict)
+@dispatch(Expr, Mapping)
 def compute(expr, d, return_type=no_default, **kwargs):
     """Compute expression against data sources.
 
@@ -451,11 +451,6 @@ def compute(expr, d, return_type=no_default, **kwargs):
     return result
 
 
-@dispatch(Field, dict)
-def compute_up(expr, data, **kwargs):
-    return data[expr._name]
-
-
 @compute_up.register(Join, object, object)
 def join_dataframe_to_selectable(expr, lhs, rhs, scope=None, **kwargs):
     lexpr, rexpr = expr._leaves()

blaze/compute/python.py

@@ -113,7 +113,7 @@ def pre_compute(expr, seq, scope=None, **kwargs):
             first = next(iter(seq))
     except StopIteration:
         return []
-    if isinstance(first, dict):
+    if isinstance(first, Mapping):
         leaf = expr._leaves()[0]
         return pluck(leaf.fields, seq)
     else:

blaze/expr/core.py

@@ -1,16 +1,15 @@
 from __future__ import absolute_import, division, print_function
 
+from collections import Mapping
 import datetime
 import numbers
 import inspect
 
 from pprint import pformat
 from functools import reduce, partial
 
-import numpy as np
 import toolz
 from toolz import unique, concat, first
-import pandas as pd
 
 from ..compatibility import _strtypes
 from ..dispatch import dispatch
@@ -365,12 +364,12 @@ def subs(o, d):
     return _subs(o, d)
 
 
-@dispatch((tuple, list), dict)
+@dispatch((tuple, list), Mapping)
 def _subs(o, d):
     return type(o)([subs(arg, d) for arg in o])
 
 
-@dispatch(Node, dict)
+@dispatch(Node, Mapping)
 def _subs(o, d):
     """
 
@@ -383,7 +382,7 @@ def _subs(o, d):
     return type(o)(*newargs)
 
 
-@dispatch(object, dict)
+@dispatch(object, Mapping)
 def _subs(o, d):
     """ Private dispatched version of ``subs``
 

blaze/expr/expressions.py

@@ -1,5 +1,6 @@
 from __future__ import absolute_import, division, print_function
 
+from collections import Mapping
 from keyword import iskeyword
 import re
 
@@ -323,7 +324,7 @@ def __init__(self, name, dshape, token=0):
         self._hash = None
 
     def __repr__(self):
-        fmt =  "<`{}` symbol; dshape='{}'>"
+        fmt = "<`{}` symbol; dshape='{}'>"
         return fmt.format(self._name, sanitized_dshape(self.dshape))
 
     def __str__(self):
@@ -339,7 +340,7 @@ def symbol(name, dshape, token=None):
     return Symbol(name, dshape, token=token or 0)
 
 
-@dispatch(Symbol, dict)
+@dispatch(Symbol, Mapping)
 def _subs(o, d):
     """ Subs symbols using symbol function
 
@@ -485,7 +486,6 @@ def sliceit(child, index):
     return s
 
 
-
 class Slice(Expr):
     """Elements `start` until `stop`. On many backends, a `step` parameter
     is also allowed.
@@ -671,9 +671,8 @@ def __str__(self):
 
 @copydoc(ReLabel)
 def relabel(child, labels=None, **kwargs):
-    labels = labels or dict()
-    labels = toolz.merge(labels, kwargs)
-    labels = dict((k, v) for k, v in labels.items() if k != v)
+    labels = {k: v
+              for k, v in toolz.merge(labels or {}, kwargs).items() if k != v}
     label_keys = set(labels)
     fields = child.fields
     if not label_keys.issubset(fields):
@@ -682,7 +681,7 @@ def relabel(child, labels=None, **kwargs):
                          ', '.join(map(repr, non_existent_fields)))
     if not labels:
         return child
-    if isinstance(labels, dict):  # Turn dict into tuples
+    if isinstance(labels, Mapping):  # Turn dict into tuples
         labels = tuple(sorted(labels.items()))
     if isscalar(child.dshape.measure):
         if child._name == labels[0][0]:

blaze/interactive.py

@@ -1,7 +1,6 @@
 from __future__ import absolute_import, division, print_function
 
-import sys
-from collections import Iterator
+from collections import Iterator, Mapping
 import decimal
 import datetime
 from functools import reduce, partial
@@ -182,7 +181,7 @@ def data(data_source, dshape=None, name=None, fields=None, schema=None, **kwargs
     return _Data(data_source, ds, name)
 
 
-@dispatch(_Data, dict)
+@dispatch(_Data, Mapping)
 def _subs(o, d):
     return o