Convenient shortcut for creating binary operations

[hiker]

While doing some AI tests, I got the following python script for to create counter = counter + 1:

            increment = Assignment.create(
                counter_ref.copy(),
                # counter = counter + 1
                counter_ref.copy()
                + Literal("1", INTEGER_TYPE)       # Ooops :)
            )

Now obviously that doesn't work, but it's rather trivial to support this in PSyclone by adding:

   def __add__(self, other):
       return BinaryOperation.create(BinaryOperation.Operator.ADD,
                                     self, other)

to DataNode. It would obviously need proper testing of other (and might even be able to support counter_ref.copy() + 1???), but could easily be added for some binary (+-*/ mod and power at least?) operations.

[LonelyCat124]

I think the shortcuts are nice for development, but I have some slight concerns with readability to new developers, so to me I thinkwe'd need to consistently always comment what the math operations are doing to keep this readable - happy to be overruled on that if its a common thing to do to a tree. Alternatively I'd be happier from a readabilty standpoint if we instead defined things like add instead of overriding __add__ and just use the shortcut functions instead since its clearer these are functions defined on DataNode rather than just overriden arithmetic statements.

My other slight concern is that it lets people do operations like sum(...) on sets of Nodes and get a big binary operation, but that could just be user error rather than our problem.

[sergisiso]

I agree with @LonelyCat124, even if this specific case looks more readable, having just a subset of dunder methods could make it a bit inconsistent and may be harder to understand as a whole. Also, to use more readable constructions instead of the more explicit ones we already can use:

increment = Assignment.create(
  counter_ref.copy(),
  fortran_reader.psyir_from_expression("counter + 1", table)
)

or even fortran_reader.psyir_from_statement("counter = counter + 1", table) , which both support any Fortran expression.