Szathmáry László honlapja @ DEIK | Nim2 / Create a custom operator (operator overloading)

See https://nim-lang.github.io/Nim/tut1.html#procedures-operators for more info about operators.

An operator can be infix (a + b) or prefix (-a).
There are NO postfix operators in Nim.

"Apart from a few built-in keyword operators such as and, or, not, operators always consist of these characters: + - * \ / < > = @ $ ~ & % ! ? ^ . |. User-defined operators are allowed. Nothing stops you from defining your own !?+~ operator, but doing so may reduce readability."

To define a new operator, enclose the operator in backticks "`".

func `%`(a, b: int): int =
a mod b

echo 10 % 3 # 1

𝥶Modulo is called mod in Nim, % won't work. But, if you insist, you can define your own % operator for modulo.

proc `++`(x: var int) =
inc x

var a = 5

++a

echo a # 6

𝥶Similarly, there's no ++ operator in Nim to increment the value of an integer. Do you need it? You can create an operator called ++ that does exactly this.

Honestly, I don't think it's a good idea to create your own % (modulo) or ++ (increment) operator to mimic other languages. Learn how to do it in Nim and follow the Nim way.