Re: Error: got proc, but expected proc {.closure.}

[doofenstein]

the error message could be better, but the problem is that a reguarly created 
proc (with name) is not a value.

There are two solutions: 
    
    
    proc calc(a: int, b: int): (int) -> int =
      let diff = a - b
      result = proc(c: int): int =
        result = c - diff
    
    
    Run

or
    
    
    proc calc(a: int, b: int): (int) -> int =
      let diff = a - b
      proc differentiate(c: int): int =
        result = c - diff
      differentiate
    
    
    Run