On 10/10/2014 11:11 AM, Brad Anderson wrote:
left-hand const is primarily a problem for new users of the language
(particularly the large amount coming from C++). These users aren't running
linters, they are still just trying to get basic projects off the ground. This
issue is one of the top things I see new users have problems with in the D IRC
channel. You can find new users having problems with it on Stack Overflow too.
Const works differently in D than in C++, and this doesn't change that. First
off,
const int foo();
returning const(int) is pointless. More likely, someone coming from C++ might
write:
const T *foo(); // in C++ returns pointer to const T
expecting it to be:
const(T)* foo(); // D way to return pointer to const T
and:
const T *p; // C++: pointer to const char
// D: const pointer to const char
which means different things in C++ and D. Fortunately, nearly all these issues
quickly run afoul of the compiler's type checker, and can be as quickly
corrected. C++ doesn't have a notion of transitive const, so the C++ syntax
cannot be generally applied and have it mean the same thing.
At some point, the new D user needs to spend a bit of time learning the const
system and unlearning the C++ one.
