constant_folding.py 文件源码

def visit_BinOp(self, node):
        node  = self.generic_visit(node)
        left  = node.left
        right = node.right
        if all(isinstance(value, ast.Num) for value in (left, right)):
            if isinstance(node.op, tuple(self._operators.keys())):
                val  = self._operators[type(node.op)](left.n, right.n)
                node = ast.copy_location(ast.Num(n = val), node)
                return node
        elif all(isinstance(value, ast.Str) for value in (left, right)):
           if isinstance(node.op, ast.Add):
                val  = left.s + right.s
                node = ast.copy_location(ast.Str(s = val), node)
                return node
        return self.fold(node)

    #def visit_GeneratorExp(self, node):
    #    return self.comprehension(node)