dictionary of operators

[rbossy at jouy.inra.fr]

Hi,

In the standard library module "operator", it would be nice to have a dictionary
mapping operators strings with their respective functions. Something like:

  {
    '+': add,
    '-': sub,
    'in': contains,
    'and': and_,
    'or': or_,
    ...
  }



Rationale:

Recently I had to implement a small language interpreter and I ended up building
such a dictionary. Indeed the parser (I used PLY then pybison) returned an AST,
where all arithmetic were represented by a single node type, like this:

  class Arithmetic(Expression):
      def __init__(self, op, lft, rgt):
          self.op = op
          self.lft = lft
          self.rgt = rgt

      def eval(self, scope):
          return self.op(self.lft.eval(scope), self.rgt.eval(scope))

The dictionary allowed the parser to have a single rule action like this:

  Arithmetic(opstr[term[1]], term[0], term[2])



Does such a dictionary already exist? Is it really a good and useful idea?

Thanks,
RB