Steven Schveighoffer wrote:
On Mon, 04 May 2009 10:22:49 -0400, Qian Xu
<quian...@stud.tu-ilmenau.de> wrote:
Steven Schveighoffer wrote:
I think you might have a bug?
"".dup is the same as s.dup, not sure why you would expect it to be
not-null.
-Steve
If I have not explained clearly.
Here is the full code:
char[] s;
assert(s is null);
assert(s.dup is null);
assert("" !is null); // OK
assert("".dup !is null); // FAILED
At least the last two lines behave not consistent.
Either both are failed, or both are passed.
OK, your original post was this:
assert( s.dup is null); // OK
assert("".dup !is null); // FAILED
The compiler always returns a null array if you dup an empty array. The
reason being: why allocate memory for something that is zero length?
If anything, the oddity is this line:
assert("" !is null);
If I remember correctly, string literals are stored with a null
appended, so as to make them easier to use with OS calls, etc. Could it
be that "" stores a 1-byte string, consisting with just this null? Then
this behavior would be understandable.
But of course, no memory is allocated for literals, so at least needless
memory allocation does not occur.
To be consistent, I think assert("" is null); should pass, but it's a
minor inconsistency at best.
I usually never compare arrays to null for this reason...
-Steve
