adamc@623: (** Row folding *)
adamc@623: 
adamc@623: con folder = K ==> fn r :: {K} =>
adamc@623:                       tf :: ({K} -> Type)
adamc@653:                       -> (nm :: Name -> v :: K -> r :: {K} -> [[nm] ~ r] =>
adamc@653:                           tf r -> tf ([nm = v] ++ r))
adamc@623:                       -> tf [] -> tf r
adamc@623: 
adamc@822: fun fold [K] [tf :: {K} -> Type]
adamc@653:          (f : (nm :: Name -> v :: K -> r :: {K} -> [[nm] ~ r] =>
adamc@653:                tf r -> tf ([nm = v] ++ r)))
adamc@1093:          (i : tf []) [r ::: {K}] (fl : folder r) = fl [tf] f i
adamc@653: 
adamc@627: structure Folder = struct
adamc@822:     fun nil [K] [tf :: {K} -> Type]
adamc@653:             (f : nm :: Name -> v :: K -> r :: {K} -> [[nm] ~ r] =>
adamc@653:              tf r -> tf ([nm = v] ++ r))
adamc@627:             (i : tf []) = i
adamc@627: 
adamc@822:     fun cons [K] [r ::: {K}] [nm :: Name] [v :: K] [[nm] ~ r] (fold : folder r)
adamc@822:              [tf :: {K} -> Type]
adamc@653:              (f : nm :: Name -> v :: K -> r :: {K} -> [[nm] ~ r] =>
adamc@653:               tf r -> tf ([nm = v] ++ r))
adam@1472:              (i : tf []) = f [nm] [v] [r] (fold [tf] f i)
adamc@628: 
adamc@822:     fun concat [K] [r1 ::: {K}] [r2 ::: {K}] [r1 ~ r2]
adamc@628:         (f1 : folder r1) (f2 : folder r2)
adamc@822:         [tf :: {K} -> Type]
adamc@653:         (f : nm :: Name -> v :: K -> r :: {K} -> [[nm] ~ r] =>
adamc@653:          tf r -> tf ([nm = v] ++ r))
adamc@628:         (i : tf []) =
adamc@629:         f1 [fn r1' => [r1' ~ r2] => tf (r1' ++ r2)]
adamc@822:            (fn [nm :: Name] [v :: K] [r1' :: {K}] [[nm] ~ r1']
adamc@653:                             (acc : [r1' ~ r2] => tf (r1' ++ r2))
adamc@653:                             [[nm = v] ++ r1' ~ r2] =>
adam@1472:                f [nm] [v] [r1' ++ r2] acc)
adam@1472:            (fn [[] ~ r2] => f2 [tf] f i)
adamc@630: 
adamc@822:     fun mp [K1] [K2] [f ::: K1 -> K2] [r ::: {K1}]
adamc@630:         (fold : folder r)
adamc@822:         [tf :: {K2} -> Type]
adamc@653:         (f : nm :: Name -> v :: K2 -> r :: {K2} -> [[nm] ~ r] =>
adamc@653:          tf r -> tf ([nm = v] ++ r))
adamc@630:         (i : tf []) =
adamc@630:         fold [fn r => tf (map f r)]
adamc@822:         (fn [nm :: Name] [v :: K1] [rest :: {K1}] [[nm] ~ rest] (acc : tf (map f rest)) =>
adam@1472:             f [nm] [f v] [map f rest] acc)
adamc@630:         i
adamc@627: end
adamc@627: 
adamc@623: 
adamc@422: fun not b = if b then False else True
adamc@422: 
adam@1649: con ident = K ==> fn t :: K => t
adamc@356: con record (t :: {Type}) = $t
adamc@637: con fst = K1 ==> K2 ==> fn t :: (K1 * K2) => t.1
adamc@637: con snd = K1 ==> K2 ==> fn t :: (K1 * K2) => t.2
adamc@637: con fst3 = K1 ==> K2 ==> K3 ==> fn t :: (K1 * K2 * K3) => t.1
adamc@637: con snd3 = K1 ==> K2 ==> K3 ==> fn t :: (K1 * K2 * K3) => t.2
adamc@637: con thd3 = K1 ==> K2 ==> K3 ==> fn t :: (K1 * K2 * K3) => t.3
adamc@329: 
adamc@643: con mapU = K ==> fn f :: K => map (fn _ :: Unit => f)
adamc@445: 
adam@1434: con ex = K ==> fn tf :: (K -> Type) =>
adam@1434:             res ::: Type -> (choice :: K -> tf choice -> res) -> res
adamc@339: 
adam@1434: fun ex_intro [K] [tf :: K -> Type] [choice :: K] (body : tf choice) : ex tf =
adam@1434:  fn [res] (f : choice :: K -> tf choice -> res) =>
adamc@356:     f [choice] body
adamc@339: 
adam@1434: fun ex_elim [K] [tf ::: K -> Type] (v : ex tf) [res ::: Type] = @@v [res]
adam@1434: 
adamc@822: fun compose [t1 ::: Type] [t2 ::: Type] [t3 ::: Type]
adamc@356:             (f1 : t2 -> t3) (f2 : t1 -> t2) (x : t1) = f1 (f2 x)
adamc@325: 
adamc@822: fun show_option [t ::: Type] (_ : show t) =
adamc@777:     mkShow (fn opt : option t =>
adamc@777:                case opt of
adamc@777:                    None => ""
adamc@777:                  | Some x => show x)
adamc@777: 
adamc@822: fun read_option [t ::: Type] (_ : read t) =
adamc@777:     mkRead (fn s =>
adamc@777:                case s of
adamc@777:                    "" => None
adamc@777:                  | _ => Some (readError s : t))
adamc@777:            (fn s =>
adamc@777:                case s of
adamc@777:                    "" => Some None
adamc@777:                  | _ => case read s of
adamc@777:                             None => None
adamc@777:                           | v => Some v)
adamc@777: 
adam@1360: fun txt [t] [ctx ::: {Unit}] [use ::: {Type}] (_ : show t) (v : t) : xml ctx use [] =
adamc@564:     cdata (show v)
adamc@328: 
adamc@1093: fun map0 [K] [tf :: K -> Type] (f : t :: K -> tf t) [r ::: {K}] (fl : folder r) =
adamc@993:     fl [fn r :: {K} => $(map tf r)]
adamc@993:     (fn [nm :: Name] [t :: K] [rest :: {K}] [[nm] ~ rest] acc =>
adamc@993:         acc ++ {nm = f [t]})
adamc@993:     {}
adamc@993: 
adamc@1093: fun mp [K] [tf1 :: K -> Type] [tf2 :: K -> Type] (f : t ::: K -> tf1 t -> tf2 t) [r ::: {K}] (fl : folder r) =
adamc@898:     fl [fn r :: {K} => $(map tf1 r) -> $(map tf2 r)]
adamc@898:     (fn [nm :: Name] [t :: K] [rest :: {K}] [[nm] ~ rest] acc r =>
adamc@898:         acc (r -- nm) ++ {nm = f r.nm})
adamc@898:     (fn _ => {})
adamc@898: 
adamc@905: fun map2 [K] [tf1 :: K -> Type] [tf2 :: K -> Type] [tf3 :: K -> Type]
adamc@1093:          (f : t ::: K -> tf1 t -> tf2 t -> tf3 t) [r ::: {K}] (fl : folder r) =
adamc@905:     fl [fn r :: {K} => $(map tf1 r) -> $(map tf2 r) -> $(map tf3 r)]
adamc@905:     (fn [nm :: Name] [t :: K] [rest :: {K}] [[nm] ~ rest] acc r1 r2 =>
adamc@905:         acc (r1 -- nm) (r2 -- nm) ++ {nm = f r1.nm r2.nm})
adamc@905:     (fn _ _ => {})
adamc@898: 
adamc@937: fun map3 [K] [tf1 :: K -> Type] [tf2 :: K -> Type] [tf3 :: K -> Type] [tf :: K -> Type]
adamc@1093:          (f : t ::: K -> tf1 t -> tf2 t -> tf3 t -> tf t) [r ::: {K}] (fl : folder r) =
adamc@937:     fl [fn r :: {K} => $(map tf1 r) -> $(map tf2 r) -> $(map tf3 r) -> $(map tf r)]
adamc@937:     (fn [nm :: Name] [t :: K] [rest :: {K}] [[nm] ~ rest] acc r1 r2 r3 =>
adamc@937:         acc (r1 -- nm) (r2 -- nm) (r3 -- nm) ++ {nm = f r1.nm r2.nm r3.nm})
adamc@937:     (fn _ _ _ => {})
adamc@937: 
adamc@822: fun foldUR [tf :: Type] [tr :: {Unit} -> Type]
adamc@411:            (f : nm :: Name -> rest :: {Unit}
adamc@629:                 -> [[nm] ~ rest] =>
adamc@411:                       tf -> tr rest -> tr ([nm] ++ rest))
adamc@1093:            (i : tr []) [r ::: {Unit}] (fl : folder r) =
adamc@653:     fl [fn r :: {Unit} => $(mapU tf r) -> tr r]
adamc@822:        (fn [nm :: Name] [t :: Unit] [rest :: {Unit}] [[nm] ~ rest] acc r =>
adam@1472:            f [nm] [rest] r.nm (acc (r -- nm)))
adamc@653:        (fn _ => i)
adamc@411: 
adamc@822: fun foldUR2 [tf1 :: Type] [tf2 :: Type] [tr :: {Unit} -> Type]
adamc@418:            (f : nm :: Name -> rest :: {Unit}
adamc@629:                 -> [[nm] ~ rest] =>
adamc@418:                       tf1 -> tf2 -> tr rest -> tr ([nm] ++ rest))
adamc@1093:            (i : tr []) [r ::: {Unit}] (fl : folder r) =
adamc@653:     fl [fn r :: {Unit} => $(mapU tf1 r) -> $(mapU tf2 r) -> tr r]
adamc@822:        (fn [nm :: Name] [t :: Unit] [rest :: {Unit}] [[nm] ~ rest] acc r1 r2 =>
adam@1472:            f [nm] [rest] r1.nm r2.nm (acc (r1 -- nm) (r2 -- nm)))
adamc@653:        (fn _ _ => i)
adamc@418: 
adamc@822: fun foldR [K] [tf :: K -> Type] [tr :: {K} -> Type]
adamc@623:            (f : nm :: Name -> t :: K -> rest :: {K}
adamc@629:                 -> [[nm] ~ rest] =>
adamc@356:                       tf t -> tr rest -> tr ([nm = t] ++ rest))
adamc@1093:            (i : tr []) [r ::: {K}] (fl : folder r) =
adamc@653:     fl [fn r :: {K} => $(map tf r) -> tr r]
adamc@822:        (fn [nm :: Name] [t :: K] [rest :: {K}] [[nm] ~ rest] (acc : _ -> tr rest) r =>
adam@1472:            f [nm] [t] [rest] r.nm (acc (r -- nm)))
adamc@653:        (fn _ => i)
adamc@336: 
adamc@822: fun foldR2 [K] [tf1 :: K -> Type] [tf2 :: K -> Type] [tr :: {K} -> Type]
adamc@623:             (f : nm :: Name -> t :: K -> rest :: {K}
adamc@629:                  -> [[nm] ~ rest] =>
adamc@367:                        tf1 t -> tf2 t -> tr rest -> tr ([nm = t] ++ rest))
adamc@1093:             (i : tr []) [r ::: {K}] (fl : folder r) =
adamc@653:     fl [fn r :: {K} => $(map tf1 r) -> $(map tf2 r) -> tr r]
adamc@822:        (fn [nm :: Name] [t :: K] [rest :: {K}] [[nm] ~ rest] 
adamc@653:                         (acc : _ -> _ -> tr rest) r1 r2 =>
adam@1472:            f [nm] [t] [rest] r1.nm r2.nm (acc (r1 -- nm) (r2 -- nm)))
adamc@653:        (fn _ _ => i)
adamc@332: 
adamc@910: fun foldR3 [K] [tf1 :: K -> Type] [tf2 :: K -> Type] [tf3 :: K -> Type] [tr :: {K} -> Type]
adamc@910:             (f : nm :: Name -> t :: K -> rest :: {K}
adamc@910:                  -> [[nm] ~ rest] =>
adamc@910:                        tf1 t -> tf2 t -> tf3 t -> tr rest -> tr ([nm = t] ++ rest))
adamc@1093:             (i : tr []) [r ::: {K}] (fl : folder r) =
adamc@910:     fl [fn r :: {K} => $(map tf1 r) -> $(map tf2 r) -> $(map tf3 r) -> tr r]
adamc@910:        (fn [nm :: Name] [t :: K] [rest :: {K}] [[nm] ~ rest] 
adamc@910:                         (acc : _ -> _ -> _ -> tr rest) r1 r2 r3 =>
adam@1472:            f [nm] [t] [rest] r1.nm r2.nm r3.nm (acc (r1 -- nm) (r2 -- nm) (r3 -- nm)))
adamc@910:        (fn _ _ _ => i)
adamc@910: 
adamc@1172: fun mapUX [tf :: Type] [ctx :: {Unit}]
adamc@1172:           (f : nm :: Name -> rest :: {Unit} -> [[nm] ~ rest] => tf -> xml ctx [] []) =
adamc@1172:     @@foldR [fn _ => tf] [fn _ => xml ctx [] []]
adamc@1172:       (fn [nm :: Name] [u :: Unit] [rest :: {Unit}] [[nm] ~ rest] r acc =>
adam@1472:           <xml>{f [nm] [rest] r}{acc}</xml>)
adamc@1172:       <xml/>
adamc@1172: 
adamc@1172: fun mapX [K] [tf :: K -> Type] [ctx :: {Unit}]
adamc@623:             (f : nm :: Name -> t :: K -> rest :: {K}
adamc@629:                  -> [[nm] ~ rest] =>
adamc@720:                        tf t -> xml ctx [] []) =
adamc@1093:     @@foldR [tf] [fn _ => xml ctx [] []]
adamc@1093:       (fn [nm :: Name] [t :: K] [rest :: {K}] [[nm] ~ rest] r acc =>
adam@1472:           <xml>{f [nm] [t] [rest] r}{acc}</xml>)
adamc@1093:       <xml/>
adamc@336: 
adamc@1173: fun mapUX2 [tf1 :: Type] [tf2 :: Type] [ctx :: {Unit}]
adamc@1173:            (f : nm :: Name -> rest :: {Unit}
adamc@1173:                 -> [[nm] ~ rest] =>
adamc@1173:             tf1 -> tf2 -> xml ctx [] []) =
adamc@1173:     @@foldUR2 [tf1] [tf2] [fn _ => xml ctx [] []]
adamc@1173:       (fn [nm :: Name] [rest :: {Unit}] [[nm] ~ rest] v1 v2 acc =>
adam@1472:           <xml>{f [nm] [rest] v1 v2}{acc}</xml>)
adamc@1173:       <xml/>
adamc@1173: 
adamc@1172: fun mapX2 [K] [tf1 :: K -> Type] [tf2 :: K -> Type] [ctx :: {Unit}]
adamc@623:              (f : nm :: Name -> t :: K -> rest :: {K}
adamc@629:                   -> [[nm] ~ rest] =>
adamc@720:                         tf1 t -> tf2 t -> xml ctx [] []) =
adamc@1093:     @@foldR2 [tf1] [tf2] [fn _ => xml ctx [] []]
adamc@1093:       (fn [nm :: Name] [t :: K] [rest :: {K}] [[nm] ~ rest]
adamc@1093:                        r1 r2 acc =>
adam@1472:           <xml>{f [nm] [t] [rest] r1 r2}{acc}</xml>)
adamc@1093:       <xml/>
adamc@445: 
adamc@1172: fun mapX3 [K] [tf1 :: K -> Type] [tf2 :: K -> Type] [tf3 :: K -> Type] [ctx :: {Unit}]
adamc@910:              (f : nm :: Name -> t :: K -> rest :: {K}
adamc@910:                   -> [[nm] ~ rest] =>
adamc@910:                         tf1 t -> tf2 t -> tf3 t -> xml ctx [] []) =
adamc@1093:     @@foldR3 [tf1] [tf2] [tf3] [fn _ => xml ctx [] []]
adamc@1093:       (fn [nm :: Name] [t :: K] [rest :: {K}] [[nm] ~ rest]
adamc@1093:                        r1 r2 r3 acc =>
adam@1472:           <xml>{f [nm] [t] [rest] r1 r2 r3}{acc}</xml>)
adamc@1093:       <xml/>
adamc@910: 
adam@1394: fun query1 [t ::: Name] [fs ::: {Type}] [state ::: Type] (q : sql_query [] [] [t = fs] [])
adamc@1177:            (f : $fs -> state -> transaction state) (i : state) =
adamc@1177:     query q (fn r => f r.t) i
adamc@1177: 
adam@1394: fun query1' [t ::: Name] [fs ::: {Type}] [state ::: Type] (q : sql_query [] [] [t = fs] [])
adamc@1177:             (f : $fs -> state -> state) (i : state) =
adamc@1177:     query q (fn r s => return (f r.t s)) i
adamc@1177: 
adam@1394: fun queryL [tables] [exps] [tables ~ exps] (q : sql_query [] [] tables exps) =
adamc@1081:     query q
adamc@1081:     (fn r ls => return (r :: ls))
adamc@1081:     []
adamc@1081: 
adam@1394: fun queryL1 [t ::: Name] [fs ::: {Type}] (q : sql_query [] [] [t = fs] []) =
adam@1321:     query q
adam@1321:     (fn r ls => return (r.t :: ls))
adam@1321:     []
adam@1321: 
adamc@822: fun queryI [tables ::: {{Type}}] [exps ::: {Type}]
adam@1394:            [tables ~ exps] (q : sql_query [] [] tables exps)
adamc@682:            (f : $(exps ++ map (fn fields :: {Type} => $fields) tables)
adamc@682:                 -> transaction unit) =
adamc@682:     query q
adamc@682:           (fn fs _ => f fs)
adamc@682:           ()
adamc@682: 
adam@1394: fun queryI1 [nm ::: Name] [fs ::: {Type}] (q : sql_query [] [] [nm = fs] [])
adam@1363:             (f : $fs -> transaction unit) =
adam@1363:     query q
adam@1363:           (fn fs _ => f fs.nm)
adam@1363:           ()
adam@1363: 
adamc@1004: fun queryX [tables ::: {{Type}}] [exps ::: {Type}] [ctx ::: {Unit}] [inp ::: {Type}]
adam@1394:            [tables ~ exps] (q : sql_query [] [] tables exps)
adamc@621:            (f : $(exps ++ map (fn fields :: {Type} => $fields) tables)
adamc@1004:                 -> xml ctx inp []) =
adamc@356:     query q
adamc@356:           (fn fs acc => return <xml>{acc}{f fs}</xml>)
adamc@360:           <xml/>
adamc@341: 
adam@1405: fun rev [a] (ls : list a) : list a =
adam@1405:     let
adam@1405:         fun rev' ls acc =
adam@1405:             case ls of
adam@1405:                 [] => acc
adam@1405:               | x :: ls => rev' ls (x :: acc)
adam@1405:     in
adam@1405:         rev' ls []
adam@1405:     end
adam@1405: 
adam@1405: fun queryXI [tables ::: {{Type}}] [exps ::: {Type}] [ctx ::: {Unit}] [inp ::: {Type}]
adam@1405:             [tables ~ exps] (q : sql_query [] [] tables exps)
adam@1405:             (f : int -> $(exps ++ map (fn fields :: {Type} => $fields) tables)
adam@1405:                  -> xml ctx inp []) =
adam@1405:     let
adam@1405:         fun qxi ls i =
adam@1405:             case ls of
adam@1405:                 [] => <xml/>
adam@1405:               | x :: ls => <xml>{f i x}{qxi ls (i+1)}</xml>
adam@1405:     in
adam@1405:         ls <- queryL q;
adam@1406:         return (qxi (rev ls) 0)
adam@1405:     end
adam@1405: 
adamc@1076: fun queryX1 [nm ::: Name] [fs ::: {Type}] [ctx ::: {Unit}] [inp ::: {Type}]
adam@1394:             (q : sql_query [] [] [nm = fs] [])
adamc@1076:             (f : $fs -> xml ctx inp []) =
adamc@1076:     query q
adamc@1076:           (fn fs acc => return <xml>{acc}{f fs.nm}</xml>)
adamc@1076:           <xml/>
adamc@1076: 
adam@1405: fun queryX1I [nm ::: Name] [fs ::: {Type}] [ctx ::: {Unit}] [inp ::: {Type}]
adam@1405:              (q : sql_query [] [] [nm = fs] [])
adam@1405:              (f : int -> $fs -> xml ctx inp []) =
adam@1405:     let
adam@1405:         fun qx1i ls i =
adam@1405:             case ls of
adam@1405:                 [] => <xml/>
adam@1405:               | x :: ls => <xml>{f i x.nm}{qx1i ls (i+1)}</xml>
adam@1405:     in
adam@1405:         ls <- queryL q;
adam@1406:         return (qx1i (rev ls) 0)
adam@1405:     end
adam@1405: 
adamc@1032: fun queryX' [tables ::: {{Type}}] [exps ::: {Type}] [ctx ::: {Unit}] [inp ::: {Type}]
adam@1394:             [tables ~ exps] (q : sql_query [] [] tables exps)
adamc@621:             (f : $(exps ++ map (fn fields :: {Type} => $fields) tables)
adamc@1032:                  -> transaction (xml ctx inp [])) =
adamc@469:     query q
adamc@469:           (fn fs acc =>
adamc@469:               r <- f fs;
adamc@469:               return <xml>{acc}{r}</xml>)
adamc@469:           <xml/>
adamc@469: 
adamc@1110: fun queryX1' [nm ::: Name] [fs ::: {Type}] [ctx ::: {Unit}] [inp ::: {Type}]
adam@1394:              (q : sql_query [] [] [nm = fs] [])
adamc@1110:              (f : $fs -> transaction (xml ctx inp [])) =
adamc@1110:     query q
adamc@1110:           (fn fs acc =>
adamc@1110:               r <- f fs.nm;
adamc@1110:               return <xml>{acc}{r}</xml>)
adamc@1110:           <xml/>
adamc@1110: 
adamc@1110: fun queryXE' [exps ::: {Type}] [ctx ::: {Unit}] [inp ::: {Type}]
adam@1394:              (q : sql_query [] [] [] exps)
adamc@1110:              (f : $exps -> transaction (xml ctx inp [])) =
adamc@1110:     query q
adamc@1110:           (fn fs acc =>
adamc@1110:               r <- f fs;
adamc@1110:               return <xml>{acc}{r}</xml>)
adamc@1110:           <xml/>
adamc@1110: 
adamc@1072: fun hasRows [tables ::: {{Type}}] [exps ::: {Type}]
adamc@1072:             [tables ~ exps]
adam@1394:             (q : sql_query [] [] tables exps) =
adamc@1072:     query q
adamc@1072:           (fn _ _ => return True)
adamc@1072:           False
adamc@1072: 
adamc@822: fun oneOrNoRows [tables ::: {{Type}}] [exps ::: {Type}]
adamc@629:                 [tables ~ exps]
adam@1394:                 (q : sql_query [] [] tables exps) =
adamc@356:     query q
adamc@356:           (fn fs _ => return (Some fs))
adamc@356:           None
adamc@440: 
adam@1394: fun oneOrNoRows1 [nm ::: Name] [fs ::: {Type}] (q : sql_query [] [] [nm = fs] []) =
adamc@1003:     query q
adamc@1003:           (fn fs _ => return (Some fs.nm))
adamc@1003:           None
adamc@1003: 
adam@1394: fun oneOrNoRowsE1 [tabs ::: {Unit}] [nm ::: Name] [t ::: Type] [tabs ~ [nm]] (q : sql_query [] [] (mapU [] tabs) [nm = t]) =
adamc@1006:     query q
adamc@1006:           (fn fs _ => return (Some fs.nm))
adamc@1006:           None
adamc@1006: 
adamc@822: fun oneRow [tables ::: {{Type}}] [exps ::: {Type}]
adam@1394:            [tables ~ exps] (q : sql_query [] [] tables exps) =
adamc@440:     o <- oneOrNoRows q;
adamc@440:     return (case o of
adamc@440:                 None => error <xml>Query returned no rows</xml>
adamc@440:               | Some r => r)
adamc@440: 
adam@1394: fun oneRow1 [nm ::: Name] [fs ::: {Type}] (q : sql_query [] [] [nm = fs] []) =
adamc@1076:     o <- oneOrNoRows q;
adamc@1076:     return (case o of
adamc@1076:                 None => error <xml>Query returned no rows</xml>
adamc@1076:               | Some r => r.nm)
adamc@1076: 
adam@1394: fun oneRowE1 [tabs ::: {Unit}] [nm ::: Name] [t ::: Type] [tabs ~ [nm]] (q : sql_query [] [] (mapU [] tabs) [nm = t]) =
adamc@1003:     o <- oneOrNoRows q;
adamc@1003:     return (case o of
adamc@1003:                 None => error <xml>Query returned no rows</xml>
adamc@1003:               | Some r => r.nm)
adamc@1003: 
adamc@1074: fun nonempty [fs] [us] (t : sql_table fs us) =
adamc@1074:     oneRowE1 (SELECT COUNT( * ) > 0 AS B FROM t)
adamc@1074: 
adamc@822: fun eqNullable [tables ::: {{Type}}] [agg ::: {{Type}}] [exps ::: {Type}]
adam@1778:     [t ::: Type] (_ : sql_injectable (option t))
adam@1778:     (e1 : sql_exp tables agg exps (option t))
adam@1778:     (e2 : sql_exp tables agg exps (option t)) =
adamc@471:     (SQL ({e1} IS NULL AND {e2} IS NULL) OR {e1} = {e2})
adamc@470: 
adamc@822: fun eqNullable' [tables ::: {{Type}}] [agg ::: {{Type}}] [exps ::: {Type}]
adam@1778:     [t ::: Type] (_ : sql_injectable (option t))
adam@1778:     (e1 : sql_exp tables agg exps (option t))
adamc@470:     (e2 : option t) =
adamc@470:     case e2 of
adamc@471:         None => (SQL {e1} IS NULL)
adamc@564:       | Some _ => sql_binary sql_eq e1 (sql_inject e2)
adam@1360: 
adam@1360: fun mkRead' [t ::: Type] (f : string -> option t) (name : string) : read t =
adam@1360:     mkRead (fn s => case f s of
adam@1360:                         None => error <xml>Invalid {txt name}: {txt s}</xml>
adam@1360:                       | Some v => v) f