arrays: if(null == [ ])

[Gor Gyolchanyan]

So, null arrays and empty arrays are always the same, except for an empty
string, which is a valid non-nill array of characters with length 0, right?

On Mon, May 14, 2012 at 2:24 PM, simendsjo <simendsjo at gmail.com> wrote:

> On Mon, 14 May 2012 12:08:17 +0200, Gor Gyolchanyan <
> gor.f.gyolchanyan at gmail.com> wrote:
>
>  Hi! I have a small question:
>> Is the test for a null array equivalent to a test for zero-length array?
>> This is particularly interesting for strings.
>> For instance, I could return an empty string from a toString-like function
>> and the empty string would be printed, but If I returned a null string,
>> that would indicate, that there is no string representation and it would
>> cause some default string to be printed.
>> So, the question is, if a null array is any different from an empty array?
>>
>>
> This passes. null and [] is a null string, but "" gives a non-null string.
> Tested on dmd-head and 2.059.
>
> void main() {
>    string s1 = null;
>    assert(s1 is null);
>    assert(s1.length == 0);
>    assert(s1.ptr is null);
>    assert(s1 == []);
>    assert(s1 == "");
>
>    string s2 = [];
>    assert(s2 is null);
>    assert(s2.length == 0);
>    assert(s2.ptr is null);
>    assert(s2 == []);
>    assert(s2 == "");
>
>    string s3 = "";
>    assert(s3 !is null);
>    assert(s3.length == 0);
>    assert(s3.ptr !is null);
>    assert(s3 == []);
>    assert(s3 == "");
> }
>



-- 
Bye,
Gor Gyolchanyan.
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