It is annoying that the template doesn't resolve the symbol at template caller.

[sls1005]

> before the macro substitution.

I think it happens _after_ the macro substitution, in which `i` has been 
_gensym_ 'd. This later caused `i` to be unaccessible with its original name 
(when `fmt` resolves).

This macro/template thing seems to be some kind of FIFO. And the secret is to 
use the _symbol_ directly.
    
    
    import strformat
    import macros
    
    macro t1(): untyped =
      return quote do:
        var i = 10
        echo "i is " & $i
    
    proc p1() =
      t1()
    
    when isMainModule:
      p1()
    
    
    Run