Replacing tango.text.Ascii.isearch

[Steven Schveighoffer]

On 10/5/22 12:59 PM, torhu wrote:
> I need a case-insensitive check to see if a string contains another 
> string for a "quick filter" feature. It should preferrably be perceived 
> as instant by the user, and needs to check a few thousand strings in 
> typical cases. Is a regex the best option, or what would you suggest?

https://dlang.org/phobos/std_uni.html#asLowerCase

```d
bool isearch(S1, S2)(S1 haystack, S2 needle)
{
     import std.uni;
     import std.algorithm;
     return haystack.asLowerCase.canFind(needle.asLowerCase);
}
```

untested.

-Steve