Functions (defn) have (1) a static type signature and (2) an implementation
You can define them seperately
  type signature -> defmulti
  implementation -> defmethod

Thus, you can have multiple defmethods per defmulti.
However, you cannot have:
  defmulti a(x:?) -> ?
  defn a(x:Int) -> Int
because it is unclear which to call (2 matching static type signatures)

; [a b c] <- a tuple
;
; val rest = List(1,2,3)
; val b = List(0,rest) --> (0,1,2,3)
; val c = list(0,rest) --> (0,(1,2,3))

; label<Int> myret :
;    for i in 0 to 10 do :
;       if i == 5:
;          myret(i)
;    0

; val v = Vector<Int>()
; add(v,10)
; add(v,20)
; add(v,32)
; for x in v do :
;    println(x)


1. explain curly braces in 
     print{o, _} $
     match(k) :
        (k:RegKind) : "reg:"
   My guess is you are passing in a different function depending on the type of k, so you need to lazily evaluate the print, which signifies the {}'s.
2. explain where in
     Circuit(modules*, main(c)) where :
        val modules* =
           for m in modules(c) map :
              Module(name(m), ports(m), to-command(body(m)))
   My guess is you are again evaluating modules* before Circuit, so you are passing in modules lazily?
3. difference between defn and defmethod?

a typeof T
a and b
a or b
a as T


append(list1,list2) -> list1,list2
List(x,list) -> x,list
list() -> empty
list(a) -> a
list(a,b) -> a,b 

println-all([a b c])

to extract values (with correct type-age) from a tuple:
val x = [1 "hi"]
val [a,b] = x
a typeof Int
b typeof String

to combine symbols: symbol-join