님 (프로그래밍 언어)

# Let's declare a function that takes any type of number and displays its double
# In Nim functions with side effect are called "proc"
proc timesTwo(i: SomeNumber) =
  echo i * 2


# Let's write another function that takes any ordinal type, and returns
# the double of the input in its original type, if it is a number;
# or returns the input itself otherwise.
# We use a generic Type(T), and precise that it can only be an Ordinal
func twice_if_is_number[T: SomeOrdinal](i: T): T =
  when T is SomeNumber: # A `when` is an `if` evaluated during compile time
    result = i * 2 # You can also write `return i * 2`
  else:
    # If the Ordinal is not a number it is converted to int,
    # multiplied by two, and reconverted to its based type
    result = (i.int * 2).T

echo twice_if_is_number(67) # Passes an int to the function
echo twice_if_is_number(67u8) # Passes an uint8
echo twice_if_is_number(true) # Passes a bool (Which is also an Ordinal)