Re: optional params before `untyped` body

[timothee]

with this PR 
[https://github.com/nim-lang/Nim/pull/11754](https://github.com/nim-lang/Nim/pull/11754)
 we can do it as follows:


dispatch foo:
for a in 0..<3:
  echo a
echo 10


Run

Re: optional params before `untyped` body

[Araq]

Yeah, well... there is no good solution at the moment. Eventually overloading 
will work better and the "untyped params have all at the same position" 
restriction will be removed.

Re: optional params before `untyped` body

[mratsim]

Especially given that overloading requires untyped parameters at the same 
position for all overloads.

Re: optional params before `untyped` body

[moigagoo]

I am so interested in knowing the answer to this one. Couldn't find a way to do 
that, had to use overloading. Works fine but feel like a hack rather than an 
idiomatic solution.

optional params before `untyped` body

[timothee]

Is there a way to have optional params before an untyped body in 
templates/macros?

The last case gives an error, that's the one I want: 


template foo(a1 = 10, a2 = "", body: untyped) = discard

# works
foo(3, "asdf"):
  for a in 0..<3:
echo a
  echo 10

foo(body = (echo 10))

# doesn't work: Error: type mismatch: got 
foo():
  for a in 0..<3:
echo a
  echo 10


Run

The rule could be: allow optional typed parameters before an untyped statement 
list; it would be un-ambiguous.

Workarounds are not great:

  * create a dummy type to group all optional params
  * create multiple overloads of the template