Mirror of forum.nim-lang.org

6452 :: First take: parameters

• neo (orginal) [2020-06-20T11:57:00+02:00] view original

  Is there a way to improve on:

  proc lfecho*[T](data: T) = echo '\L', data
  Run

  How can I fix:

  proc lfecho(x: varargs[typed]) = echo '\L', x
  
  proc lf2echo(x: varargs[typed, `$`]) = echo '\L', x
  Run

  Can I rename a standard library procedure?

---

• juancarlospaco (orginal) [2020-06-20T13:10:34+02:00] view original

  I dont understand what the problem is, if any.

---

• juancarlospaco (orginal) [2020-06-20T13:38:20+02:00] view original

  Something like this? https://github.com/Yardanico/nimpylib/blob/master/src/pylib/print.nim#L13

---

• neo (orginal) [2020-06-20T14:11:46+02:00] view original

  Compiler outputs errors for the lines to be fixed.

  The question would be how to declare and pass a varargs set as parameter to a procedure.

  I found a solution by using a generic parameter. I wonder if that introduces some level of overhead. In any case I'd like to fix those errors.

---

• neo (orginal) [2020-06-20T15:06:43+02:00] view original

  Besides using a generic, your link is the way to go.

  proc lf2echo(x: varargs[typed, `$`]) =
    echo x
  
  proc lf2echo(x: varargs[typed]) =
    echo x
  Run

  Same error for both forms.

  : invalid type: 'typed' in this context: 'proc (x: varargs[typed])' for proc
  (26, 10) Error: type mismatch: got <varargs[typed]>
  but expected one of:
  proc echo(x: varargs[typed, `$`])
    first type mismatch at position: 1
    required type for x: varargs[typed]
    but expression 'x' is of type: varargs[typed]
  Run

  The way to present echo with the expected

  [typed, `$`]
  Run

  seems to be a macro, quite close to the C va_arg() macro.

  Thanks for the exact reference.

---

• neo (orginal) [2020-06-20T20:51:17+02:00] view original

  proc lfecho*[T](data: T) = echo '\L', data
  Run

  only works for a single parameter.

  The following is the solution:

  import strutils
  
  proc lf2echo(data: varargs[string ,`$`]) =
    echo '\L', join data
  
  lf2echo "N", ' ', "I'm"
  Run

---

• neo (orginal) [2020-06-22T15:17:21+02:00] view original

  Thanks, also another solution from the tutorial advanced-types-varargs

  proc lfecho(data: varargs[string ,`$`]) =
    write(stdout, "\L")
    for s in items(data):
      write(stdout, s)
  Run

---