Is there a theoretical reason why they can’t?

As a layman I would assume nothing is preventing it, other than the large amount of effort it would take to implement.

DarkNova6 3 days ago | parent | next [-]

From what I gathered the core problem is flattenability. It is backed by a dynamic array and you would need real templating to remove the indirection.

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joe_mwangi 3 days ago | parent [-]

They are researching to have immutable arrays. Also multifields (stack allocated arrays as fields in value classes). So, there is a possibility.

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J-Kuhn 2 days ago | parent [-]

The problem is not that the array is mutable, but that the size of the array may differ for different strings. (In fact, it usually* does differ if the string length is different).

This makes it impossible to flatten - as the VM needs to know the total size when creating the memory layout for a class...

* (with a small exception: if the strings use different coders, one can be twice as long and the backing arrays would still have the same size)

	▲	DarkNova6 2 days ago \| parent [-]
		Indeed. At this point you’d need to bring the size of the string into the type system (C++ Templates we meet again!) but then you look at a solution worse than the problem…

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theanonymousone 3 days ago | parent | prev [-]

No theoretical reason; It's backward compatibility/internal technicalities, as they mention in the JEP.