Mirror of forum.nim-lang.org

1780 :: Procedure works differently depending on parenthesis .

• niceume (orginal) [2015-11-08T17:39:31+01:00] view original

  I'm new to Nim. I'm wondering whether this behavior is intended or not.

  In the following code, I tried something like closure. The 1st time and the 3rt time cl_test is called, the count value increased. But the 2nd time cl_test is called without parenthesis, the count value does not increase.

  
  var count: int = 10
  proc cl_test(): int=
    count = count + 1
  
  echo (count, "\n")
  # returns 10
  
  # 1st time cl_test() is called
  discard cl_test()
  echo(count, "\n")
  # returns 11
  
  # 2nd time cl_test is called
  discard cl_test
  echo(count, "\n")
  # returns 11
  
  # 3rd time cl_test() is called
  discard cl_test()
  echo(count, "\n")
  # returns 12
  
  Run

  Nim Compiler Version 0.11.2 (2015-05-04) [Windows: amd64]

---

• mora (orginal) [2015-11-08T19:19:56+01:00] view original

  Hi niceume!

  Actually this is not a bug. You must write () to those function calls which function has no parameters. Let me show in an example:

  var f = cl_test
  var g = cl_test()
  Run

  Here f is the actual function, while g is the returned value.

  Peter

---

• niceume (orginal) [2015-11-08T22:01:51+01:00] view original

  Thanks, Peter !

  I got it! Without parenthesis, it's a function. This is a cool feature, and I like it.

---