add __eq__ (==) to COMPARISON_OVERRIDES ? about quibbler

[maor10]

It's a bit problematic to override __eq__, because of the in keyword.
If I do:

a = iquib(3)
b = [a]
5 in b

I'll receive True- list_contains is a method implemented in C that must return a boolean, and it simply calls __eq__ over and over for its elements with the given argument (in our case 5).
We could do some nasty stuff and forcefully override list's contain method, but as we spoke previously this is essentially different from the overriding we do today- Python purposefully does not allow this. I suggest we use a helper method here.

For reference, the C method:

static int list_contains(PyListObject *a, PyObject *el)
{
	Py_ssize_t i;
	int cmp;

	for (i = 0, cmp = 0 ; cmp == 0 && i < Py_SIZE(a); ++i)
		cmp = PyObject_RichCompareBool(el, PyList_GET_ITEM(a, i), Py_EQ);
	return cmp;
}

[rkishony]

ok. so no overriding of eq

so, if the user wants to do Q==3 they will do something like:
q(lambda x: x==3, Q)

right? or is there a simpler syntax?

[maor10]

We could add a simpler syntax if you'd like- maybe qe(Q, 3) or something of the like (maybe Q.equals(3))? Wdyt?

[rkishony]

i'm not sure which one is best. and i trust that you know better the python-way of thinking

in general, there are already several functions that we decided not to override, including eq, len, str, ...

so we need some generic way

what I did in Matlab is taking all the problematic-to-overload functions and provide their quib-implementation with a new name starting quib...
for example, I couldn't overload size(), numel(), isempty() because Matlab expects them to return real values, so I offered new functions quibsize(), quibnumel(), quibisempty()

maybe we can do something like that?

note also that right now q(...) is interpreted as a graphic quib (evaluates immediately), so we need some alternative when we would like to apply a user function as a non-graphical functional quib