While typing D code I usually come across the problem that neither const
nor immutable describe the usage pattern of the memory I'm currently
working on 100%. Sometimes I have immutable data that has been shared
among threads that I want to pass to a function. Then I have some const
data that I want to pass to the same function. Currently you don't have
any other choice but to write that function two times. But the function
itself does not need the "extended" properties of const or immutable:
const: can be casted back to mutable
immutable: can be implicitly shared among threads
The only thing the function cares about is, that it will not change the
data passed to it. It would be kind of nice to have a thrid storage
class "readonly". It can not be casted back to mutable and it can not be
implicitly shared among threads, but both const and immutable implicitly
convert to readonly, because both of these storage classes lose one of
their properties during conversion. That way you only have to write the
function once and can pass both const and immutable data to it.
Just an idea, comments and critics welcome.
--
Kind Regards
Benjamin Thaut
