Mah-jong in next Egison

mah-jong

;
; Mah-jong example
;

(define $shuntsu : (PatternConstructor [Hai (Collection Hai)] (Collection Hai))
  (pattern-constructor [$pat1 $pat2]
    <cons (& <num $s $n> pat1)
     <cons <num ,s ,(+ n 1)>
      <cons <num ,s ,(+ n 2)>
       pat2>>>))

(define $kohtsu : (PatternConstructor [Hai (Collection Hai)] (Collection Hai))
  (pattern-constructor [$pat1 $pat2]
    <cons (& $pat pat1)
     <cons ,pat
      <cons ,pat
       pat2>>>))

(define $twin : (PatternConstructor [Hai (Collection Hai)] (Collection Hai))
  (pattern-constructor [$pat1 $pat2]
    <cons (& $pat pat1)
     <cons ,pat
      pat2>>))

(define $agari? : (\ (Collection Hai) Bool)
  (function (multiset hai)
    {[(twin $th_1 (| (shuntsu $sh_1 (shuntsu $sh_2 (shuntsu $sh_3 (shuntsu $sh_4 <nil>))))
                     (shuntsu $sh_1 (shuntsu $sh_2 (shuntsu $sh_3 (kohtsu $kh_1 <nil>))))
                     (shuntsu $sh_1 (shuntsu $sh_2 (kohtsu $kh_1 (kohtsu $kh_2 <nil>))))
                     (shuntsu $sh_1 (kohtsu $kh_1 (kohtsu $kh_2 (kohtsu $kh_3 <nil>))))
                     (kohtsu $kh_1 (kohtsu $kh_2 (kohtsu $kh_3 (kohtsu $kh_4 <nil>))))
                     (twin $th_2 (twin $th_3 (twin $th_4 (twin $th_5 (twin $th_6 (twin $th_7 <nil>))))))
                     ))
      #t]
     [_
      #f]}))