rectifiedIndexOf()

[Basile B.]

On Friday, 5 May 2023 at 16:51:25 UTC, apz28 wrote:
> On Friday, 5 May 2023 at 14:50:45 UTC, Salih Dincer wrote:
>> On Friday, 5 May 2023 at 02:43:15 UTC, Basile B. wrote:
>>> As often in D you can use a struct to help...
>>> `opCast` is used for the `if` condition and the original 
>>> value for reading back in the array, via `alias this`.
>>
> Or as below
>
>     struct IndexOfResult
>     {
>         ptrdiff_t value;
>         alias value this;
>
>         bool opCast(T : bool)() const @nogc pure @safe
>         {
>             return value >= 0;
>         }
>     }
>
>     void main()
>     {
>         import std.string : indexOf;
>         import std.stdio : writeln, writefln;
>
>         enum chr = 'a';
>         enum arr = "dlang";
>         if (auto res = IndexOfResult(arr.indexOf(chr)))
>         {
>             assert(arr[res] == chr);
>             res.writefln!"[ --> %s ]";
>         }
>         else
>             writeln("Not found!");
>     }

Yeah IndexOfResult is a much better name... but you should not 
change the comparison operator... in theory using `!=-1` allows 
`-2`, ie `size_t.max-1` to be a valid result.