Closures and subs

[Klaas-Jan Stol]

Hello,
I've been playing with closures and subs but I have a little bit of 
trouble with those.
I'm a bit confused by all different flavours of syntax, I've been trying 
to read and understand all documents concerning this subject, the most 
useful was reading the test scripts. However, that is PASM, and I like 
PIR better :-).

A general question is: what syntax should one use in what context?
(I understand that PCC should be used whenever one wants to interact 
with other languages. Also, calling functions can be done in many ways)

A more specific question is this:
I'm trying to create a closure, and I think I've implemented this code 
(it's lua code, but I'm not sure if it's 100% correct,
anyway, I'm trying to get a feeling for how one should translate this). 
So, actually I have 2 questions;

(1): did I translate the function below correctly (I think the Lua 
syntax won't be a problem, it's quite straightforward).
(2): what is causing my strange result (see below).

function main()
  
   local p = 123;   
   local q = 345;

   foo(q);
   foo(q);
   function foo(a) # nested function, it does have access to p in "main"
      print(p);
      p = p + p;
      print(typeof(a));
      print(a);
   end
end
I would translate this to this PIR code:
.sub _main
       new_pad 0
       # local p = 123
       .local pmc p
       p = new .PerlInt
       p = 123
       store_lex 0, "p", p
       # local q = 345
       .local pmc q
       q = new .PerlInt
       q = 345
       store_lex 0, "q", q
       newsub $P0, .Closure, _foo
       # foo(q)
       .arg q  
       $P0()

       # foo(q)
       .arg q
       $P0()
       end
.end
.sub _foo
       .param pmc a
      
       # print(p);
       find_lex $P0, "p"
       print $P0

       # p = p + p;
       $P0 = $P0 + $P0
       store_lex "p", $P0
       # print(typeof(a));
       $S0 = typeof a   
       print $S0      # ????
      
       # print(a);
       print a         # ERROR!
.end

My problem with the last 2 statements is:
- the statement print(typeof(a)); print "SArray", which I don't understand.
- "print a" causes an error: "get_string() not implemented in SArray" ( 
I know that is because of a being an SArray)

I know there are more important issues at the moment, but if someone 
could spare a moment, that'd be great. I'm trying to get a grip on 
function syntax.

Regards,
Klaas-Jan Stol