Mirror of forum.nim-lang.org

4974 :: Giving my library access to types in the file that import it

• hugogranstrom (orginal) [2019-06-27T19:28:29+02:00] view original

  I have a library cool_lib.nim where I have a few types with a proc, let's say:

  proc abs*(x: MyType): float = ....
  proc abs*(x: MyType2): float = ....
  Run

  And they are used in a generic proc:

  proc coolProc*[T](x: T): T =
    ....
    let a = abs(x)
    ....
  Run

  Now I want to let my user pass their own types (with a abs proc) to coolProc like this:

  import cool_lib
  
  type CoolType = object ....
  proc abs(x: CoolType): float = ....
  var coolVar = CoolType(...)
  coolProc(coolVar)
  Run

  How can I access the abs proc of CoolType from my library? I guess I could just include cool_lib instead but that seems like a workaround. Is there a reasonably easy way to do it with imports?

---

• cdunn2001 (orginal) [2019-06-27T23:13:22+02:00] view original

  What if coolProc were a template?

---

• enthus1ast (orginal) [2019-06-27T23:20:21+02:00] view original

  Maybe i do not understand correctly but for me it "just works"

  coolLib.nim

  proc abs*(x: int): float =
    return 0.1
  proc abs*(x: float): float =
    return 0.2
  
  proc coolProc*[T](x: T): T =
    let a = abs(x)
    echo a
  Run

  coolMain.nim

  import coolLib
  
  type CoolType = object
  
  proc abs(x: CoolType): float =
    return 0.3
  
  var coolVar = CoolType()
  echo coolProc(coolVar)
  Run

  outputs:

  
  Hint: /home/david/nimPlayground/coolMain  [Exec]
  0.3
  ()
  Run

---

• hugogranstrom (orginal) [2019-06-28T11:16:41+02:00] view original

  That's embarrassing.... XD I must have mistyped something. Thank you :-D

---