I believe that this does actually qualify as duck typing. The saying "if it
walks like a duck and quacks like a duck, then it's a duck" refers to a form of
generic or type agnostic code where a type is usable based on its
functionality. Aka, the types `int` and `float` have a `+=(_: int)` and as such
they are valid for use in the `proc` with `auto`.
Structural typing means that types are interchangeable if their definitions are
equal. In Nim this happens with tuples. If tuples have the same elements (by
number and type), they are synonyms and interchangeable.
The above is an example of duck typing.
Here's some structural typing:
type
Vec = tuple [x, y, z: float]
Color = tuple [r, g, b: float]
proc interpolate(vecOrColor: Vec; weight: float): Vec =
# mix color or vector values
let a = Vec(1.0, 1.0, 1.0)
interpolate(a) # works
let b = Color(r: 1.0, g: 2.0, b: 3.0)
interpolate(b) # also works
(Hopefully I have the correct syntax there, I'm not somewhere with the
compiler)
