Peter Alexander wrote:
D does not support logical const due to the weak guarantees that it
provides.
So, without logical const, how are D users supposed to provide lazy
evaluation and memoization in their interfaces, given that the interface
should *seem* const, e.g.
class Matrix
{
double getDeterminant() const { /* expensive calculation */ }
}
If it turns out that getDeterminant is called often with the raw matrix
data remaining unchanged, how can we add caching to this class without
rewriting the const-ness of all code that touches it?
And how do we write generic code when it's practically impossible to
determine const-ness from a glance? e.g. getDeterminant looks like it
should be const, but wouldn't be if it had caching, so writing generic
code that uses getDeterminant would be very difficult.
What are the use cases for logical const? Are there any other important
ones, apart from caching?
