Bump version, document disable_subscript_by_getitem

doc/Makefile

@@ -3,7 +3,7 @@
 
 # You can set these variables from the command line.
 SPHINXOPTS    =
-SPHINXBUILD   = sphinx-build
+SPHINXBUILD   = python `which sphinx-build`
 PAPER         =
 BUILDDIR      = _build
 

doc/_static/akdoc.css

 pre {
-  line-height: 100%;
+  line-height: 110%;
 }
 
 .footer {
@@ -23,17 +23,17 @@ code {
 }
 
 h1 {
-  padding-bottom:5px;
+  padding-bottom:7px;
   border-bottom: 1px solid #ccc;
 }
 
 h2 {
-  padding-bottom:1px;
+  padding-bottom:5px;
   border-bottom: 1px solid #ccc;
 }
 
 h3 {
-  padding-bottom:1px;
+  padding-bottom:5px;
   border-bottom: 1px solid #ccc;
 }
 

doc/_templates/layout.html

 {% extends "!layout.html" %}
-{% set css_files = css_files + ['_static/akdoc.css']%}
+{% set bootswatch_css_custom = ['_static/akdoc.css']%}

doc/conf.py

@@ -31,7 +31,7 @@ extensions = [
     'sphinx.ext.intersphinx',
     'sphinx.ext.coverage',
     'sphinx.ext.mathjax',
-    'sphinx.ext.viewcode'
+    #'sphinx.ext.viewcode'
     ]
 
 # Add any paths that contain templates here, relative to this directory.

pymbolic/__init__.py

@@ -134,7 +134,7 @@ import pymbolic.mapper.distributor
 import pymbolic.mapper.flattener
 import pymbolic.primitives
 
-from pymbolic.polynomial import Polynomial
+from pymbolic.polynomial import Polynomial  # noqa
 
 var = pymbolic.primitives.Variable
 variables = pymbolic.primitives.variables

pymbolic/mapper/__init__.py

@@ -334,7 +334,7 @@ class IdentityMapper(Mapper):
                     )
 
     def map_subscript(self, expr, *args):
-        return expr.__class__(
+        return type(expr)(
                 self.rec(expr.aggregate, *args),
                 self.rec(expr.index, *args))
 

pymbolic/primitives.py

@@ -25,6 +25,8 @@ THE SOFTWARE.
 import pymbolic.traits as traits
 
 __doc__ = """
+.. autofunction:: disable_subscript_by_getitem
+
 Expression base class
 ---------------------
 
@@ -37,6 +39,13 @@ Expression base class
         The :class:`pymbolic.mapper.Mapper` method called for objects of
         this type.
 
+    .. method:: __getitem__
+
+        Deprecated, see :func:`disable_subscript_by_getitem`. Use :meth:`index`
+        instead.
+
+    .. automethod:: index
+
     .. automethod:: stringifier
 
     .. automethod:: __eq__
@@ -178,10 +187,32 @@ _SUBSCRIPT_BY_GETITEM = True
 
 
 def disable_subscript_by_getitem():
+    """In prior versions of :mod:`pymbolic`, directly subscripting an :class:`Expression`
+    subclass generated a :class:`Subscript`. For various reasons, this was a
+    very bad idea.  For example, the following code snippet would result in an
+    infinite loop::
+
+        for el in expr:
+            print(el)
+
+    :mod:`numpy` does similar things under the hodd, leading to hard-to-debug
+    infinite loops. As a result, this behavior is being deprecated. In Pymbolic
+    2016.x, it will disappear entirely.  It can also be disabled by this
+    function. Once disabled, it cannot be reenabled.
+
+    See also :meth:`Expression.index`.
+
+    .. versionadded:: 2014.3
+    """
+
     global _SUBSCRIPT_BY_GETITEM
     _SUBSCRIPT_BY_GETITEM = False
 
-    del Expression.__getitem__
+    try:
+        del Expression.__getitem__
+    except AttributeError:
+        # Yay, somebody did the sane thing before us.
+        pass
 
 
 class Expression(object):
@@ -395,6 +426,11 @@ class Expression(object):
             return NotImplemented
 
     def index(self, subscript):
+        """Return an expression representing ``self[subscript]``.
+
+        .. versionadded:: 2014.3
+        """
+
         if subscript == ():
             return self
         else:

pymbolic/version.py

-VERSION = (2014, 2)
+VERSION = (2014, 3)
 VERSION_STATUS = ""
 VERSION_TEXT = ".".join(str(x) for x in VERSION) + VERSION_STATUS

test/test_pymbolic.py

@@ -22,9 +22,11 @@ OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
 """
 
+import pymbolic
 import pymbolic.primitives as prim
 import pytest
 
+
 from pymbolic.mapper import IdentityMapper
 
 try:
@@ -33,6 +35,8 @@ except NameError:
     from functools import reduce
 
 
+pymbolic.disable_subscript_by_getitem()
+
 def test_integer_power():
     from pymbolic.algorithm import integer_power
 
@@ -250,6 +254,7 @@ def test_mappers():
         WalkMapper()(expr)
         DependencyMapper()(expr)
 
+
 # {{{ geometric algebra
 
 @pytest.mark.parametrize("dims", [2, 3, 4, 5])