The problem I do see is that it's inherently recursive, meaning we are
limited by the Python stack (unless we do it with a manual stack).
Actually, it seems that hash() itself works regardless of this fact,
which is interesting. If I create a highly nested expression, one
where I know that recursively calling hashable_content() will overflow
the stack, I can still hash it.
Does the hash code depend on the subexpressions?
(x+(y+z)) should have a different hash code than (x+(y+a)), for example.
Yes, but that's not exactly sub-expressions. x + y + z is denested
into Add(x, y, z).
Lol okay :-)
> A better example would be x + y*z, which is Add(x,
Mul(y, z)).
Okay... then make sure that the hash isn't recomputed for each level of
nesting, else you'll get quadratic slowdown with number of nesting levels.
Oh. And hash codes must not be changed once they have been computed,
that's what Python wants.
BTW what's the typical pattern in Python to make sure that no
hash-relevant attributes are modified?
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