what exactly is string length?

[mw]

On Friday, 2 April 2021 at 05:01:27 UTC, rikki cattermole wrote:
>
> On 02/04/2021 5:51 PM, mw wrote:
>> Then how can I construct `t`? to make this assertion true:
>> 
>>     assert(t == "head-abc-tail");  // failed!
>
> Slice it.
>
> string t = text("head-", s[0 .. 3], "-tail");
>
> http://ddili.org/ders/d.en/slices.html

This is just an example, what if the exact length is not known 
statically, is there a functions to trim the `\0`s?