Szathmáry László honlapja @ DEIK | Nim2 / Ignore the return value

proc twice(n: int): int =
echo "# twice() is called"
return 2 * n

twice(8) # ERROR: you do nothing with the return value

discard twice(8) # OK

If you have a function that returns a value, then you must do something with the returned value. If you do not need the return value, you must express it explicitly with the discard keyword. It means: I know that the function returns something, but I drop the returned value.

Missing body

If you want to leave the body of a precudure empty, in order to avoid a syntax error, you can use discard:

missing body
def main(): pass if __name__ == "__main__": main()	proc main() = discard when isMainModule: main()