static IntrinsicSizeInBytes(parameters) to compute expected size of struct

[studgeek]

I have seen a common need where code has to compute a struct size outside of emboss to properly allocate that space. It then applies an emboss view on that allocated space.

For non-dynamically-sized structs the code can use static IntrinsicSizeInBytes to get the needed size. But for dynamically-sized structs (that determine size based on parameters or fields) the code usually has to do its own computation of struct size outside of emboss.

I have been thinking that for dynamically-sized structs where parameters are enough to determine the size, it would be handy if emboss generated a parameterized version of the static IntrinsicSizeInBytes function that can take the struct's parameters and use them to compute the size.

So

struct Bar(x: UInt:8, y: Int:32)

would generate something like

template <typename T>
auto MakeBarView(std::uint8_t x, std::int32_t y, T *data, size_t size);

and also generate the new

static constexpr auto IntrinsicSizeInBytes(std::uint8_t x, std::int32_t y) const;

Above assumes the parameters are enough to compute the size. If not, then no IntrinsicSizeInBytes would be created. I think recognizing these cases is probably one of the trickt parts of any implementation.