Status: New
Owner: ----
Labels: Type-Defect Priority-Medium
New issue 2030 by mattpap: Can't use 'boolean' operators with Relational
classes
http://code.google.com/p/sympy/issues/detail?id=2030
In [1]: eq = Eq(x, 0)
In [2]: x + eq
Out[2]: x + x = 0
In [3]: x + 2*eq
Out[3]: x + 2⋅x = 0
In [4]: eq | (x > 1)
(...)
TypeError: unsupported operand type(s) for |: 'Equality'
and 'StrictInequality'
In [5]: eq.__class__.mro()
Out[5]:
[<class 'sympy.core.relational.Equality'>,
<class 'sympy.core.relational.Relational'>, <class 'sympy.core.expr.
Expr'>, <class 'sympy.core.basic.Basic'>,
<class 'sympy.core.assumptions.AssumeMeths'>, <class 'sympy.core.eval
f.EvalfMixin'>, <type 'object'>]
Currently Relational is a subclass of Expr, which doesn't make much sense
(unless implemented properly, e.g. distribute arithmetics over lhs and rhs)
and is improperly printed. This way, when working with relational solvers,
we have to use explicit classes (And, Or).
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