memoize doesn't account for method overrides

[jwoertink]

I ran in to this random issue where I have 2 methods that I wanted to memoize both, but one takes an additional arg that the other doesn't.

memoize def account : Account
  Account.new(self)
end

memoize def account(date_range : Tuple(Time, Time)) : Account
  Account.new(self, date_range)
end

Error: instance variable '@__memoized_account' of must be (Tuple(Account, Tuple(Time, Time)) | Nil), not Tuple(Account)

If we can figure out how to handle the method overrides, that would be cool, though not at the cost of performance, or massive memory allocation like I'd expect it might lead to. I'm also cool with just raising a compile-time error (if possible) that says you can't memoize the second method because it's already being memoized as account

[matthewmcgarvey]

It would probably be easiest to use the number of arguments of the method in the method name.

If no arguments are given, everything would use _0 at the end

[jwoertink]

That could work. Though, if we do that, then we should also see about raising an error if you try to define one that clashes.

memoize def account(number : String)
end

memoize def account(number : Int32)
end

[NotWearingPants]

The best way is to just

{{ name = UUID.random.hexstring }}
@__memoized_{{name}}

or something like @__memoized_{{Sha1(method_def.body)}}
but I could not for the life of me figure out how Crystal's annoying macro system works. It just won't let me call UUID.

Another way is to keep a counter which just increments with every call to memoize and do @__memoized_{{counter}}, but again Crystal doesn't seem to let me. Tried prefixing with nothing, or $, or @@.

Another way is to define the variable inside a closure and not have to worry about a unique name, but I couldn't figure it out either.

[jwoertink]

@NotWearingPants Thanks for the suggestion. I like that idea of just creating a hash and using that as the differentiator.

And yeah, the macro system can be quite tricky if you're not used to working with it. Thanks again!