[Numpy-discussion] More on Numexpr-unsupported objects

[Ivan V. i B. <iv...@ca...>]

This is somehow related with this previous thread about raising
``TypeError`` on unsupported objects in Numexpr:
http://www.mail-archive.com/num...@li.../msg03146.html

There is still a case where unsupported objects can get into expressions
without Numexpr noticing.  For instance:

>>> import numexpr
>>> numexpr.evaluate('[]')
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "numexpr/compiler.py", line 594, in evaluate
    _names_cache[expr_key] = getExprNames(ex, context)
  File "numexpr/compiler.py", line 570, in getExprNames
    ast = expressionToAST(ex)
  File "numexpr/compiler.py", line 84, in expressionToAST
    this_ast = ASTNode(ex.astType, ex.astKind, ex.value,
AttributeError: 'list' object has no attribute 'astType'

The attached patch makes the error clearer and more consistent with the
error added in the aforementioned thread:

>>> import numpy
>>> import numexpr
>>> numexpr.evaluate('[]')
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "numexpr/compiler.py", line 596, in evaluate
    _names_cache[expr_key] = getExprNames(ex, context)
  File "numexpr/compiler.py", line 571, in getExprNames
    ex = stringToExpression(text, {}, context)
  File "numexpr/compiler.py", line 229, in stringToExpression
    raise TypeError("unsupported expression type: %s" % type(ex))
TypeError: unsupported expression type: <type 'list'>

Though I admit it may be strange for this error to be triggered.

(I had a little mess with using ``expressions.ExpressionNode`` instead
of ``expr.ExpressionNode``...  I still don't see why the private copy of
the module is necessary.)

::

	Ivan Vilata i Balaguer   >qo<   http://www.carabos.com/
	       Cárabos Coop. V.  V  V   Enjoy Data
	                          ""