let (|A|B|C|) c =
   if (c = 'a') then A
   else if (c = 'b') then B
   else C

let (|A|B|D|) c =
   if (c = '1') then A
   else if (c = '2') then B
   else D

let check myvar =
  match myvar with
    | A -> printf "match An"
    | n -> printf "match other %An" n

check 'x' // match other 'x'
check 'a' // match other 'a'     !!
check '1' // match A

module Pat1 =
 let (|A|B|C|) c =
   if (c = 'a') then A
   else if (c = 'b') then B
   else C

module Pat2 =
 let (|A|B|D|) c =
   if (c = '1') then A
   else if (c = '2') then B
   else D

let check myvar =
  match myvar with
  | Pat1.A -> printf "match An"
  | n -> printf "match other %An" n