Hi,
I'm coming from a background in Python, without a lot of
experience in statically typed languages, and I'm struggling to
see how to make a certain function in D.
This is what I have in Python:
```
from typing import Union
Number = Union[int, float]
def clamp(value: Number, mini: Number, maxi: Number) -> Number:
if value >= maxi:
return maxi
if value <= mini:
return mini
return value
```
In Python, I could supply this function with any type really; it
doesn't type check, and essentially only runs
`value.__ge__(maxi)` and `value.__le__(mini)`. How can I simulate
this in D? There are already implementations of `clamp` out
there, but that isn't the point.
I hear that there is a "variant" type, that allows one to pass
any type; but I either want to restrict it to certain types, or
only to types that possess some kind of `__ge__` or `__le__`
method. The only way I found on how to do the former was
overloading, like:
```
bool test(int a) {...}
bool test(float a) {...}
```
Unfortunately this doesn't seem to work well with the return
type, and I feel like it's wrong to rewrite identical functions
over and over.
