Poker Hands in Egison

poker-hands.egi

(define $poker-hands
  (lambda [$Cs]
    (match Cs (Multiset Card)
      {[<cons <card $S $n>
         <cons <card ,S ,(- n 1)>
          <cons <card ,S ,(- n 2)>
           <cons <card ,S ,(- n 3)>
            <cons <card ,S ,(- n 4)>
             !<nil>>>>>>
        <straight-flush>]
       [<cons <card _ $n>
         <cons <card _ ,n>
          !<cons <card _ ,n>
            !<cons <card _ ,n>
              !<cons _
                !<nil>>>>>>
        <four-of-kind>]
       [<cons <card _ $m>
         <cons <card _ ,m>
          <cons <card _ ,m>
           <cons <card _ $n>
            !<cons <card _ ,n>
              !<nil>>>>>>
        <full-house>]
       [<cons <card $S _>
         !<cons <card ,S _>
           !<cons <card ,S _>
             !<cons <card ,S _>
               !<cons <card ,S _>
                 !<nil>>>>>>
        <flush>]
       [<cons <card _ $n>
         <cons <card _ ,(- n 1)>
          <cons <card _ ,(- n 2)>
           <cons <card _ ,(- n 3)>
            <cons <card _ ,(- n 4)>
             !<nil>>>>>>
        <straight>]
       [<cons <card _ $n>
         <cons <card _ ,n>
          <cons <card _ ,n>
           <cons _
            <cons _
             !<nil>>>>>>
        <three-of-kind>]
       [<cons <card _ $m>
         <cons <card _ ,m>
          !<cons <card _ $n>
            <cons <card _ ,n>
             !<cons _
               !<nil>>>>>>
        <two-pair>]
       [<cons <card _ $n>
         <cons <card _ ,n>
          <cons _
           <cons _
            <cons _
             !<nil>>>>>>
        <one-pair>]
       [<cons _
         <cons _
          <cons _
           <cons _
            <cons _
             !<nil>>>>>>
        <nothing>]})))