explaining cross module templates

main.nim

import templates

let myThing = someProcThatReturnsOption()

printFileBool(myThing, "string") # calls the template
# this essentially expands to:
# it's a fancy copy / paste, but creates a new scope. This is what is known in the lisp world as "hygenic".
# A template will not import other things into your module automatigically.
block:
  if not myThing.isNone: # it's just a copy / paste. Nim will not automagically "import Option" for you.
    echo "I'm not None!"

templates.nim

import Option # Note: This will not get imported into any other modules.

template printFileBool*(token: untyped, tname: string) =
    if not token.isNone:
      echo "I'm not None!"
      
# You could do this:
template ImportAndPrintFileBool*(token: untyped, tname: string) =
    import Option # this line will get copy / pasted into the module, and you will have the proc available there.
                  # It's hacky though. You will import every time you call the template, which is silly.
    if not token.isNone:
      echo "I'm not None!"