Custom pack_type handlers for distinct types about msgpack4nim HOT 5 CLOSED

fixed, now you can use something like this:

import msgpack4nim, strutils

type
  Guid {.skipUndistinct.} = distinct string

proc pack_type*[ByteStream](s: ByteStream, v: Guid) =
  s.pack_bin(len(v.string))
  s.write(v.string)

var b = Guid("AA")
var s = b.pack
echo s.tohex
echo s.stringify

automatic check for matching procs is not possible right now, Nim compiler still has issue in that particular area.

from msgpack4nim.

from msgpack4nim.

What about this?

proc pack*[ByteStream, T](s: ByteStream, val: T) =
  when compiles(s.pack_type(val)):
    s.pack_type (val)
  else:
    s.pack_type undistinct(val)

This works for me, without any need for special pragmas.

from msgpack4nim.

I already tried that, it only works for simple types.
For some unknown reason, when encountered object variant with self reference, the compiler protest with scary error. that's why I choose to use pragma.
you can try it with tests/test_codec.nim

from msgpack4nim.

Fair enough, thanks!

from msgpack4nim.