automatic conversion to invariant (string?)

[Janice Caron]

On 20/03/2008, Yossarian <xtauer01 at stud.fit.vutbr.cz> wrote:
>  >     char[] s = cast(char[]) "hello";
>
> i think that
>  char[] s = "hello" ; // this should compile without explicit cast. imho.

In fact, I just wrote that for illustration purposes. I was trying to
imply that s was a char[], pre-initialised with "hello". In real code,
you should /never/ do

    char[] s = cast(char[]) "hello";

so I was guilty of using a really bad example. The reason you should
never use it is because casting away invariance is undefined, and in
this case, the literal might be in a ROM segment. The correct way to
do it should be, as others have pointed out:

    char[]s = "hello".dup;


>    // int[] c = [3, 5]; compiles.

In the future, it probably won't. Don't rely on it.


>  string t = s;           // wouldn't it be logical to use not copy-on-write, but
>  initialize new string with old char[]?

Since that line won't compile anyway, the question is moot.


>  s[0] = 'j';             // change only s, not t.

No can do. A string is nothing but a struct consisting of { ptr,
length }. Element assignment should not cause a heap allocation.