(define $edge-table
  (relational-matcher "edge"
    {["from_id" itos stoi]
     ["to_id" itos stoi]}))

(define $edge-table
  (matcher
    {[<cons <edge ,$px ,$py> $> [edge-table]
      ; select * from edge where from_id = px and to_id = py                                                                                                                                                
      {[$tgt (match (pure-mysql (database-name tgt) (simple-select {"from_id to_id"} (table-name tgt) {["from_id" (itos px)] ["to_id" (itos py)]})) (list [integer integer])
               {[<nil> {}]
                [_ {tgt}]})]}]
     [<cons <edge ,$px $> $> [integer edge-table]
      ; select to_id from edge where from_id = px                                                                                                                                                           
      {[$tgt (map (lambda [$x] [(stoi x) tgt]) (pure-mysql (database-name tgt) (simple-select {"to_id"} (table-name tgt) {["from_id" (itos px)]})))]}]
     [<cons <edge $ ,$px> $> [integer edge-table]
      ; select from_id from edge where to_id = px                                                                                                                                                           
      {[$tgt (map (lambda [$x] [(stoi x) tgt]) (pure-mysql (database-name tgt) (simple-select {"from_id"} (table-name tgt) {["to_id" (itos px)]})))]}]
     [$ [something]
      {[$tgt {tgt}]}]
     }))