Szathmáry László honlapja @ DEIK | Nim2 / Write and use your own module

Say you want to put some procedures in a separate file (module). How to do it and how to use that module? Let's see a simple example. It's very similar to Python.

$ ls -al
total 16
drwxr-xr-x  2 jabba jabba 4096 ápr    4 17.35 .
drwxr-xr-x 27 jabba jabba 4096 ápr    4 16.31 ..
-rwxr--r--  1 jabba jabba  408 ápr    4 17.30 main.nim
-rw-r--r--  1 jabba jabba  141 ápr    4 17.26 mymath.nim

mymath.nim :

# this is private in the module
proc hello() =
echo "hello world"

# the '*' indicates that it's public
func twice*(n: int): int =
2 * n

main.nim :

import mymath

proc main() =
echo twice(5) # 10; everything is imported from the module that is public

echo mymath.twice(5) # 10; you can use the module name (qualified access) if you want

# hello() # ERROR: not visible

# ############################################################################

when isMainModule:
main()

How to compile:

$ nim c main.nim

That is, you need to compile just the main file. The compiler will find and compile the dependencies for you.