null == "" is true?

[Steven Schveighoffer]

On 7/12/22 12:27 PM, Antonio wrote:
> It works
> 
> ```d
> void main()
> {
>     assert(null=="");
> }
> ```
> 
> why?

A string is not exactly a reference type. It's a length and a pointer. 
This can be confusing to newcomers, especially ones that come from 
languages that treat arrays and strings as object references.

`null` as an array with `0` length and `null` pointer.

`""` is an array with `0` length and a pointer to a zero character (not 
`null`).

The algorithm to compare *any* arrays is first verify the lengths are 
the same. Then for each element in the array, compare them. Since there 
are 0 elements in both the empty string and the null string, they are equal.

-Steve