--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/sql.sml	Mon Mar 12 12:00:23 2012 -0700
@@ -0,0 +1,428 @@
+structure Sql = struct
+
+open Mono
+
+val debug = ref false
+
+type lvar = int
+
+datatype func =
+         DtCon0 of string
+       | DtCon1 of string
+       | UnCon of string
+       | Other of string
+
+datatype exp =
+         Const of Prim.t
+       | Var of int
+       | Lvar of lvar
+       | Func of func * exp list
+       | Recd of (string * exp) list
+       | Proj of exp * string
+
+datatype reln =
+         Known
+       | Sql of string
+       | PCon0 of string
+       | PCon1 of string
+       | Eq
+       | Ne
+       | Lt
+       | Le
+       | Gt
+       | Ge
+
+datatype prop =
+         True
+       | False
+       | Unknown
+       | And of prop * prop
+       | Or of prop * prop
+       | Reln of reln * exp list
+       | Cond of exp * prop
+
+datatype chunk =
+         String of string
+       | Exp of Mono.exp
+
+fun chunkify e =
+    case #1 e of
+        EPrim (Prim.String s) => [String s]
+      | EStrcat (e1, e2) =>
+        let
+            val chs1 = chunkify e1
+            val chs2 = chunkify e2
+        in
+            case chs2 of
+                String s2 :: chs2' =>
+                (case List.last chs1 of
+                     String s1 => List.take (chs1, length chs1 - 1) @ String (s1 ^ s2) :: chs2'
+                   | _ => chs1 @ chs2)
+              | _ => chs1 @ chs2
+        end
+      | _ => [Exp e]
+
+type 'a parser = chunk list -> ('a * chunk list) option
+
+fun always v chs = SOME (v, chs)
+
+fun parse p s =
+    case p (chunkify s) of
+        SOME (v, []) => SOME v
+      | _ => NONE
+
+fun const s chs =
+    case chs of
+        String s' :: chs => if String.isPrefix s s' then
+                                SOME ((), if size s = size s' then
+                                              chs
+                                          else
+                                              String (String.extract (s', size s, NONE)) :: chs)
+                            else
+                                NONE
+      | _ => NONE
+
+fun follow p1 p2 chs =
+    case p1 chs of
+        NONE => NONE
+      | SOME (v1, chs) =>
+        case p2 chs of
+            NONE => NONE
+          | SOME (v2, chs) => SOME ((v1, v2), chs)
+
+fun wrap p f chs =
+    case p chs of
+        NONE => NONE
+      | SOME (v, chs) => SOME (f v, chs)
+
+fun wrapP p f chs =
+    case p chs of
+        NONE => NONE
+      | SOME (v, chs) =>
+        case f v of
+            NONE => NONE
+          | SOME r => SOME (r, chs)
+
+fun alt p1 p2 chs =
+    case p1 chs of
+        NONE => p2 chs
+      | v => v
+
+fun altL ps =
+    case rev ps of
+        [] => (fn _ => NONE)
+      | p :: ps =>
+        foldl (fn (p1, p2) => alt p1 p2) p ps
+
+fun opt p chs =
+    case p chs of
+        NONE => SOME (NONE, chs)
+      | SOME (v, chs) => SOME (SOME v, chs)
+
+fun skip cp chs =
+    case chs of
+        String "" :: chs => skip cp chs
+      | String s :: chs' => if cp (String.sub (s, 0)) then
+                                skip cp (String (String.extract (s, 1, NONE)) :: chs')
+                            else
+                                SOME ((), chs)
+      | _ => SOME ((), chs)
+
+fun keep cp chs =
+    case chs of
+        String "" :: chs => keep cp chs
+      | String s :: chs' =>
+        let
+            val (befor, after) = Substring.splitl cp (Substring.full s)
+        in
+            if Substring.isEmpty befor then
+                NONE
+            else
+                SOME (Substring.string befor,
+                      if Substring.isEmpty after then
+                          chs'
+                      else
+                          String (Substring.string after) :: chs')
+        end
+      | _ => NONE
+
+fun ws p = wrap (follow (skip (fn ch => ch = #" "))
+                        (follow p (skip (fn ch => ch = #" ")))) (#1 o #2)
+
+fun log name p chs =
+    (if !debug then
+         (print (name ^ ": ");
+          app (fn String s => print s
+                | _ => print "???") chs;
+          print "\n")
+     else
+         ();
+     p chs)
+
+fun list p chs =
+    altL [wrap (follow p (follow (ws (const ",")) (list p)))
+               (fn (v, ((), ls)) => v :: ls),
+          wrap (ws p) (fn v => [v]),
+          always []] chs
+
+val ident = keep (fn ch => Char.isAlphaNum ch orelse ch = #"_")
+
+val t_ident = wrapP ident (fn s => if String.isPrefix "T_" s then
+                                       SOME (String.extract (s, 2, NONE))
+                                   else
+                                       NONE)
+val uw_ident = wrapP ident (fn s => if String.isPrefix "uw_" s andalso size s >= 4 then
+                                        SOME (str (Char.toUpper (String.sub (s, 3)))
+                                              ^ String.extract (s, 4, NONE))
+                                    else
+                                        NONE)
+
+val field = wrap (follow t_ident
+                         (follow (const ".")
+                                 uw_ident))
+                 (fn (t, ((), f)) => (t, f))
+
+datatype Rel =
+         Exps of exp * exp -> prop
+       | Props of prop * prop -> prop
+
+datatype sqexp =
+         SqConst of Prim.t
+       | SqTrue
+       | SqFalse
+       | SqNot of sqexp
+       | Field of string * string
+       | Computed of string
+       | Binop of Rel * sqexp * sqexp
+       | SqKnown of sqexp
+       | Inj of Mono.exp
+       | SqFunc of string * sqexp
+       | Unmodeled
+       | Null
+
+fun cmp s r = wrap (const s) (fn () => Exps (fn (e1, e2) => Reln (r, [e1, e2])))
+
+val sqbrel = altL [cmp "=" Eq,
+                   cmp "<>" Ne,
+                   cmp "<=" Le,
+                   cmp "<" Lt,
+                   cmp ">=" Ge,
+                   cmp ">" Gt,
+                   wrap (const "AND") (fn () => Props And),
+                   wrap (const "OR") (fn () => Props Or)]
+
+datatype ('a, 'b) sum = inl of 'a | inr of 'b
+
+fun string chs =
+    case chs of
+        String s :: chs =>
+        if size s >= 2 andalso String.sub (s, 0) = #"'" then
+            let
+                fun loop (cs, acc) =
+                    case cs of
+                        [] => NONE
+                      | c :: cs =>
+                        if c = #"'" then
+                            SOME (String.implode (rev acc), cs)
+                        else if c = #"\\" then
+                            case cs of
+                                c :: cs => loop (cs, c :: acc)
+                              | _ => raise Fail "Iflow.string: Unmatched backslash escape"
+                        else
+                            loop (cs, c :: acc)
+            in
+                case loop (String.explode (String.extract (s, 1, NONE)), []) of
+                    NONE => NONE
+                  | SOME (s, []) => SOME (s, chs)
+                  | SOME (s, cs) => SOME (s, String (String.implode cs) :: chs)
+            end
+        else
+            NONE
+      | _ => NONE                            
+
+val prim =
+    altL [wrap (follow (wrapP (follow (keep Char.isDigit) (follow (const ".") (keep Char.isDigit)))
+                              (fn (x, ((), y)) => Option.map Prim.Float (Real64.fromString (x ^ "." ^ y))))
+                       (opt (const "::float8"))) #1,
+          wrap (follow (wrapP (keep Char.isDigit)
+                              (Option.map Prim.Int o Int64.fromString))
+                       (opt (const "::int8"))) #1,
+          wrap (follow (opt (const "E")) (follow string (opt (const "::text"))))
+               (Prim.String o #1 o #2)]
+
+fun known' chs =
+    case chs of
+        Exp (EFfi ("Basis", "sql_known"), _) :: chs => SOME ((), chs)
+      | _ => NONE
+
+fun sqlify chs =
+    case chs of
+        Exp (EFfiApp ("Basis", f, [(e, _)]), _) :: chs =>
+        if String.isPrefix "sqlify" f then
+            SOME (e, chs)
+        else
+            NONE
+      | Exp (ECase (e, [((PCon (_, PConFfi {mod = "Basis", con = "True", ...}, NONE), _),
+                         (EPrim (Prim.String "TRUE"), _)),
+                        ((PCon (_, PConFfi {mod = "Basis", con = "False", ...}, NONE), _),
+                         (EPrim (Prim.String "FALSE"), _))], _), _) :: chs =>
+        SOME (e, chs)
+                          
+      | _ => NONE
+
+fun constK s = wrap (const s) (fn () => s)
+
+val funcName = altL [constK "COUNT",
+                     constK "MIN",
+                     constK "MAX",
+                     constK "SUM",
+                     constK "AVG"]
+
+val unmodeled = altL [const "COUNT(*)",
+                      const "CURRENT_TIMESTAMP"]
+
+fun sqexp chs =
+    log "sqexp"
+    (altL [wrap prim SqConst,
+           wrap (const "TRUE") (fn () => SqTrue),
+           wrap (const "FALSE") (fn () => SqFalse),
+           wrap (const "NULL") (fn () => Null),
+           wrap field Field,
+           wrap uw_ident Computed,
+           wrap known SqKnown,
+           wrap func SqFunc,
+           wrap unmodeled (fn () => Unmodeled),
+           wrap sqlify Inj,
+           wrap (follow (const "COALESCE(") (follow sqexp (follow (const ",")
+                                                                  (follow (keep (fn ch => ch <> #")")) (const ")")))))
+                (fn ((), (e, _)) => e),
+           wrap (follow (const "(NOT ") (follow sqexp (const ")")))
+                (fn ((), (e, _)) => SqNot e),
+           wrap (follow (ws (const "("))
+                        (follow (wrap
+                                     (follow sqexp
+                                             (alt
+                                                  (wrap
+                                                       (follow (ws sqbrel)
+                                                               (ws sqexp))
+                                                       inl)
+                                                  (always (inr ()))))
+                                     (fn (e1, sm) =>
+                                         case sm of
+                                             inl (bo, e2) => Binop (bo, e1, e2)
+                                           | inr () => e1))
+                                (const ")")))
+                (fn ((), (e, ())) => e)])
+    chs
+
+and known chs = wrap (follow known' (follow (const "(") (follow sqexp (const ")"))))
+                     (fn ((), ((), (e, ()))) => e) chs
+                
+and func chs = wrap (follow funcName (follow (const "(") (follow sqexp (const ")"))))
+                    (fn (f, ((), (e, ()))) => (f, e)) chs
+
+datatype sitem =
+         SqField of string * string
+       | SqExp of sqexp * string
+
+val sitem = alt (wrap (follow sqexp (follow (const " AS ") uw_ident))
+                      (fn (e, ((), s)) => SqExp (e, s)))
+                (wrap field SqField)
+
+val select = log "select"
+             (wrap (follow (const "SELECT ") (list sitem))
+                   (fn ((), ls) => ls))
+
+val fitem = wrap (follow uw_ident
+                         (follow (const " AS ")
+                                 t_ident))
+                 (fn (t, ((), f)) => (t, f))
+
+val from = log "from"
+           (wrap (follow (const "FROM ") (list fitem))
+                 (fn ((), ls) => ls))
+
+val wher = wrap (follow (ws (const "WHERE ")) sqexp)
+           (fn ((), ls) => ls)
+
+type query1 = {Select : sitem list,
+              From : (string * string) list,
+              Where : sqexp option}
+
+val query1 = log "query1"
+                (wrap (follow (follow select from) (opt wher))
+                      (fn ((fs, ts), wher) => {Select = fs, From = ts, Where = wher}))
+
+datatype query =
+         Query1 of query1
+       | Union of query * query
+
+val orderby = log "orderby"
+              (wrap (follow (ws (const "ORDER BY "))
+                            (follow (list sqexp)
+                                    (opt (ws (const "DESC")))))
+                    ignore)
+
+fun query chs = log "query"
+                (wrap
+                     (follow
+                          (alt (wrap (follow (const "((")
+                                             (follow query
+                                                     (follow (const ") UNION (")
+                                                             (follow query (const "))")))))
+                                     (fn ((), (q1, ((), (q2, ())))) => Union (q1, q2)))
+                               (wrap query1 Query1))
+                          (opt orderby))
+                     #1)
+                chs
+
+datatype dml =
+         Insert of string * (string * sqexp) list
+       | Delete of string * sqexp
+       | Update of string * (string * sqexp) list * sqexp
+
+val insert = log "insert"
+             (wrapP (follow (const "INSERT INTO ")
+                            (follow uw_ident
+                                    (follow (const " (")
+                                            (follow (list uw_ident)
+                                                    (follow (const ") VALUES (")
+                                                            (follow (list sqexp)
+                                                                    (const ")")))))))
+              (fn ((), (tab, ((), (fs, ((), (es, ())))))) =>
+                  (SOME (tab, ListPair.zipEq (fs, es)))
+                  handle ListPair.UnequalLengths => NONE))
+
+val delete = log "delete"
+                 (wrap (follow (const "DELETE FROM ")
+                               (follow uw_ident
+                                       (follow (const " AS T_T WHERE ")
+                                               sqexp)))
+                       (fn ((), (tab, ((), es))) => (tab, es)))
+
+val setting = log "setting"
+              (wrap (follow uw_ident (follow (const " = ") sqexp))
+               (fn (f, ((), e)) => (f, e)))
+
+val update = log "update"
+                 (wrap (follow (const "UPDATE ")
+                               (follow uw_ident
+                                       (follow (const " AS T_T SET ")
+                                               (follow (list setting)
+                                                       (follow (ws (const "WHERE "))
+                                                               sqexp)))))
+                       (fn ((), (tab, ((), (fs, ((), e))))) =>
+                           (tab, fs, e)))
+
+val dml = log "dml"
+              (altL [wrap insert Insert,
+                     wrap delete Delete,
+                     wrap update Update])
+
+datatype querydml =
+         Query of query
+       | Dml of dml
+
+val querydml = log "querydml" (altL [wrap dml Dml, wrap query Query])
+
+end