biotagging as a simple stateful filter

[Kapendev]

On Tuesday, 28 July 2026 at 08:12:41 UTC, monkyyy wrote:
> Im not entire sure this is correct; and I had to fight phoboes 
> overly constrained type theory; but for future reference

Needs an `import std`, but works. I got this:

```
h:outside
e:outside
l:outside
l:outside
o:outside
,:outside
  :outside
y:outside
o:outside
u:outside
.:outside
  :outside
1:begin
2:inside
3:inside
,:inside
4:inside
5:inside
6:inside
.:inside
7:inside
8:inside
9:inside
!:outside
[1, 2, 5, 6]
[1, 2, 5]
3
4
100,000.01
```