(* Copyright (c) 2008, Adam Chlipala
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * - Redistributions of source code must retain the above copyright notice,
 *   this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright notice,
 *   this list of conditions and the following disclaimer in the documentation
 *   and/or other materials provided with the distribution.
 * - The names of contributors may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *)

structure MonoOpt :> MONO_OPT = struct

open Mono
structure U = MonoUtil

fun typ t = t
fun decl d = d

fun attrifyInt n =
    if n < 0 then
        "-" ^ Int64.toString (Int64.~ n)
    else
        Int64.toString n

fun attrifyFloat n =
    if n < 0.0 then
        "-" ^ Real.toString (Real.~ n)
    else
        Real.toString n

fun attrifyChar ch =
    case ch of
        #"\"" => "&quot;"
      | #"&" => "&amp;"
      | ch => str ch

val attrifyString = String.translate attrifyChar


val urlifyInt = attrifyInt
val urlifyFloat = attrifyFloat

val htmlifyInt = attrifyInt
val htmlifyFloat = attrifyFloat

val htmlifyString = String.translate (fn #"<" => "&lt;"
                                       | #"&" => "&amp;"
                                       | ch => str ch)

fun hexIt ch =
    let
        val s = Int.fmt StringCvt.HEX (ord ch)
    in
        case size s of
            0 => "00"
          | 1 => "0" ^ s
          | _ => s
    end

fun urlifyString s =
    case s of
        "" => "_"
      | _ =>
        (if String.sub (s, 0) = #"_" then
             "_"
         else
             "")
        ^ String.translate (fn #" " => "+"
                             | ch => if Char.isAlphaNum ch then
                                         str ch
                                     else
                                         "%" ^ hexIt ch) s


fun sqlifyInt n = #p_cast (Settings.currentDbms ()) (attrifyInt n, Settings.Int)
fun sqlifyFloat n = #p_cast (Settings.currentDbms ()) (attrifyFloat n, Settings.Float)

fun sqlifyString s = #sqlifyString (Settings.currentDbms ()) s
fun sqlifyChar ch = #sqlifyString (Settings.currentDbms ()) (str ch)

fun unAs s =
    let
        fun doChars (cs, acc) =
            case cs of
                #"T" :: #"_" :: #"T" :: #"." :: cs => doChars (cs, acc)
              | #"'" :: cs => doString (cs, acc)
              | ch :: cs => doChars (cs, ch :: acc)
              | [] => String.implode (rev acc)

        and doString (cs, acc) =
            case cs of
                #"\\" :: #"\\" :: cs => doString (cs, #"\\" :: #"\\" :: acc)
              | #"\\" :: #"'" :: cs => doString (cs, #"'" :: #"\\" :: acc)
              | #"'" :: cs => doChars (cs, #"'" :: acc)
              | ch :: cs => doString (cs, ch :: acc)
              | [] => String.implode (rev acc)
    in
        doChars (String.explode s, [])
    end

fun checkUrl s = CharVector.all Char.isGraph s andalso Settings.checkUrl s

fun exp e =
    case e of
        EPrim (Prim.String s) =>
        let
            val (_, chs) =
                CharVector.foldl (fn (ch, (lastSpace, chs)) =>
                                     let
                                         val isSpace = Char.isSpace ch
                                     in
                                         if isSpace andalso lastSpace then
                                             (true, chs)
                                         else
                                             (isSpace, ch :: chs)
                                     end)
                                 (false, []) s
        in
            EPrim (Prim.String (String.implode (rev chs)))
        end
                                       
      | EStrcat ((EPrim (Prim.String s1), loc), (EPrim (Prim.String s2), _)) =>
        let
            val s =
                if size s1 > 0 andalso size s2 > 0
                   andalso Char.isSpace (String.sub (s1, size s1 - 1))
                   andalso Char.isSpace (String.sub (s2, 0)) then
                    s1 ^ String.extract (s2, 1, NONE)
                else
                    s1 ^ s2
        in
            EPrim (Prim.String s)
        end

      | EStrcat ((EPrim (Prim.String s1), loc), (EStrcat ((EPrim (Prim.String s2), _), rest), _)) =>
        let
            val s =
                if size s1 > 0 andalso size s2 > 0
                   andalso Char.isSpace (String.sub (s1, size s1 - 1))
                   andalso Char.isSpace (String.sub (s2, 0)) then
                    s1 ^ String.extract (s2, 1, NONE)
                else
                    s1 ^ s2
        in
            EStrcat ((EPrim (Prim.String s), loc), rest)
        end

      | EStrcat ((EStrcat (e1, e2), loc), e3) =>
        optExp (EStrcat (e1, (EStrcat (e2, e3), loc)), loc)

      | EWrite (EStrcat (e1, e2), loc) =>
        ESeq ((optExp (EWrite e1, loc), loc),
              (optExp (EWrite e2, loc), loc))

      | ESeq ((EWrite (EPrim (Prim.String s1), _), loc),
              (EWrite (EPrim (Prim.String s2), _), _)) =>
        EWrite (EPrim (Prim.String (s1 ^ s2)), loc)
      | ESeq ((EWrite (EPrim (Prim.String s1), _), loc),
              (ESeq ((EWrite (EPrim (Prim.String s2), _), _),
                     e), _)) =>
        ESeq ((EWrite (EPrim (Prim.String (s1 ^ s2)), loc), loc),
              e)

      | EFfiApp ("Basis", "htmlifyString", [(EFfiApp ("Basis", "intToString", [(EPrim (Prim.Int n), _)]), _)]) =>
        EPrim (Prim.String (htmlifyInt n))
      | EFfiApp ("Basis", "htmlifyString", [(EFfiApp ("Basis", "intToString", es), _)]) =>
        EFfiApp ("Basis", "htmlifyInt", es)
      | EFfiApp ("Basis", "htmlifyString", [(EApp ((EFfi ("Basis", "intToString"), _),
                                                   (EPrim (Prim.Int n), _)), _)]) =>
        EPrim (Prim.String (htmlifyInt n))
      | EFfiApp ("Basis", "htmlifyString", [(EApp ((EFfi ("Basis", "intToString"), _),
                                                   e), _)]) =>
        EFfiApp ("Basis", "htmlifyInt", [e])
      | EWrite (EFfiApp ("Basis", "htmlifyInt", [e]), _) =>
        EFfiApp ("Basis", "htmlifyInt_w", [e])

      | EFfiApp ("Basis", "htmlifyString", [(EFfiApp ("Basis", "floatToString", [(EPrim (Prim.Float n), _)]), _)]) =>
        EPrim (Prim.String (htmlifyFloat n))
      | EFfiApp ("Basis", "htmlifyString", [(EFfiApp ("Basis", "floatToString", es), _)]) =>
        EFfiApp ("Basis", "htmlifyFloat", es)
      | EFfiApp ("Basis", "htmlifyString", [(EApp ((EFfi ("Basis", "floatToString"), _),
                                                   (EPrim (Prim.Float n), _)), _)]) =>
        EPrim (Prim.String (htmlifyFloat n))
      | EFfiApp ("Basis", "htmlifyString", [(EApp ((EFfi ("Basis", "floatToString"), _),
                                                   e), _)]) =>
        EFfiApp ("Basis", "htmlifyFloat", [e])
      | EWrite (EFfiApp ("Basis", "htmlifyFloat", [e]), _) =>
        EFfiApp ("Basis", "htmlifyFloat_w", [e])

      | EFfiApp ("Basis", "htmlifyString", [(EFfiApp ("Basis", "boolToString",
                                                      [(ECon (Enum, PConFfi {con = "True", ...}, NONE), _)]), _)]) =>
        EPrim (Prim.String "True")
      | EFfiApp ("Basis", "htmlifyString", [(EFfiApp ("Basis", "boolToString",
                                                      [(ECon (Enum, PConFfi {con = "False", ...}, NONE), _)]), _)]) =>
        EPrim (Prim.String "False")
      | EFfiApp ("Basis", "htmlifyString", [(EFfiApp ("Basis", "boolToString", es), _)]) =>
        EFfiApp ("Basis", "htmlifyBool", es)
      | EFfiApp ("Basis", "htmlifyString", [(EApp ((EFfi ("Basis", "boolToString"), _),
                                                   (ECon (Enum, PConFfi {con = "True", ...}, NONE), _)), _)]) =>
        EPrim (Prim.String "True")
      | EFfiApp ("Basis", "htmlifyString", [(EApp ((EFfi ("Basis", "boolToString"), _),
                                                   (ECon (Enum, PConFfi {con = "False", ...}, NONE), _)), _)]) =>
        EPrim (Prim.String "False")
      | EFfiApp ("Basis", "htmlifyString", [(EApp ((EFfi ("Basis", "boolToString"), _),
                                                   e), _)]) =>
        EFfiApp ("Basis", "htmlifyBool", [e])
      | EWrite (EFfiApp ("Basis", "htmlifyBool", [e]), _) =>
        EFfiApp ("Basis", "htmlifyBool_w", [e])

      | EFfiApp ("Basis", "htmlifyString", [(EApp ((EFfi ("Basis", "timeToString"), _), e), _)]) =>
        EFfiApp ("Basis", "htmlifyTime", [e])
      | EFfiApp ("Basis", "htmlifyString_w", [(EApp ((EFfi ("Basis", "timeToString"), _), e), _)]) =>
        EFfiApp ("Basis", "htmlifyTime_w", [e])
      | EWrite (EFfiApp ("Basis", "htmlifyTime", [e]), _) =>
        EFfiApp ("Basis", "htmlifyTime_w", [e])

      | EFfiApp ("Basis", "htmlifyString", [(EPrim (Prim.String s), _)]) =>
        EPrim (Prim.String (htmlifyString s))
      | EWrite (EFfiApp ("Basis", "htmlifyString", [(EPrim (Prim.String s), _)]), loc) =>
        EWrite (EPrim (Prim.String (htmlifyString s)), loc)
      | EWrite (EFfiApp ("Basis", "htmlifyString", [e]), _) =>
        EFfiApp ("Basis", "htmlifyString_w", [e])
      | EFfiApp ("Basis", "htmlifyString_w", [(EPrim (Prim.String s), loc)]) =>
        EWrite (EPrim (Prim.String (htmlifyString s)), loc)

      | EFfiApp ("Basis", "attrifyInt", [(EPrim (Prim.Int n), _)]) =>
        EPrim (Prim.String (attrifyInt n))
      | EWrite (EFfiApp ("Basis", "attrifyInt", [(EPrim (Prim.Int n), _)]), loc) =>
        EWrite (EPrim (Prim.String (attrifyInt n)), loc)
      | EWrite (EFfiApp ("Basis", "attrifyInt", [e]), _) =>
        EFfiApp ("Basis", "attrifyInt_w", [e])

      | EFfiApp ("Basis", "attrifyFloat", [(EPrim (Prim.Float n), _)]) =>
        EPrim (Prim.String (attrifyFloat n))
      | EWrite (EFfiApp ("Basis", "attrifyFloat", [(EPrim (Prim.Float n), _)]), loc) =>
        EWrite (EPrim (Prim.String (attrifyFloat n)), loc)
      | EWrite (EFfiApp ("Basis", "attrifyFloat", [e]), _) =>
        EFfiApp ("Basis", "attrifyFloat_w", [e])

      | EFfiApp ("Basis", "attrifyString", [(EPrim (Prim.String s), _)]) =>
        EPrim (Prim.String (attrifyString s))
      | EWrite (EFfiApp ("Basis", "attrifyString", [(EPrim (Prim.String s), _)]), loc) =>
        EWrite (EPrim (Prim.String (attrifyString s)), loc)
      | EWrite (EFfiApp ("Basis", "attrifyString", [e]), _) =>
        EFfiApp ("Basis", "attrifyString_w", [e])

      | EFfiApp ("Basis", "attrifyChar", [(EPrim (Prim.Char s), _)]) =>
        EPrim (Prim.String (attrifyChar s))
      | EWrite (EFfiApp ("Basis", "attrifyChar", [(EPrim (Prim.Char s), _)]), loc) =>
        EWrite (EPrim (Prim.String (attrifyChar s)), loc)
      | EWrite (EFfiApp ("Basis", "attrifyChar", [e]), _) =>
        EFfiApp ("Basis", "attrifyChar_w", [e])

      | EFfiApp ("Basis", "attrifyCss_class", [(EPrim (Prim.String s), _)]) =>
        EPrim (Prim.String s)
      | EWrite (EFfiApp ("Basis", "attrifyCss_class", [(EPrim (Prim.String s), _)]), loc) =>
        EWrite (EPrim (Prim.String s), loc)
      | EWrite (EFfiApp ("Basis", "attrifyCss_class", [e]), _) =>
        EFfiApp ("Basis", "attrifyString_w", [e])

      | EFfiApp ("Basis", "urlifyInt", [(EPrim (Prim.Int n), _)]) =>
        EPrim (Prim.String (urlifyInt n))
      | EWrite (EFfiApp ("Basis", "urlifyInt", [(EPrim (Prim.Int n), _)]), loc) =>
        EWrite (EPrim (Prim.String (urlifyInt n)), loc)
      | EWrite (EFfiApp ("Basis", "urlifyInt", [e]), _) =>
        EFfiApp ("Basis", "urlifyInt_w", [e])

      | EFfiApp ("Basis", "urlifyFloat", [(EPrim (Prim.Float n), _)]) =>
        EPrim (Prim.String (urlifyFloat n))
      | EWrite (EFfiApp ("Basis", "urlifyFloat", [(EPrim (Prim.Float n), _)]), loc) =>
        EWrite (EPrim (Prim.String (urlifyFloat n)), loc)
      | EWrite (EFfiApp ("Basis", "urlifyFloat", [e]), _) =>
        EFfiApp ("Basis", "urlifyFloat_w", [e])

      | EFfiApp ("Basis", "urlifyString", [(EPrim (Prim.String s), _)]) =>
        EPrim (Prim.String (urlifyString s))
      | EWrite (EFfiApp ("Basis", "urlifyString", [(EPrim (Prim.String s), _)]), loc) =>
        EWrite (EPrim (Prim.String (urlifyString s)), loc)
      | EWrite (EFfiApp ("Basis", "urlifyString", [e]), _) =>
        EFfiApp ("Basis", "urlifyString_w", [e])

      | EFfiApp ("Basis", "urlifyBool", [(ECon (Enum, PConFfi {con = "True", ...}, NONE), _)]) =>
        EPrim (Prim.String "1")
      | EFfiApp ("Basis", "urlifyBool", [(ECon (Enum, PConFfi {con = "False", ...}, NONE), _)]) =>
        EPrim (Prim.String "0")
      | EWrite (EFfiApp ("Basis", "urlifyBool", [(ECon (Enum, PConFfi {con = "True", ...}, NONE), _)]), loc) =>
        EWrite (EPrim (Prim.String "1"), loc)
      | EWrite (EFfiApp ("Basis", "urlifyBool", [(ECon (Enum, PConFfi {con = "False", ...}, NONE), _)]), loc) =>
        EWrite (EPrim (Prim.String "0"), loc)
      | EWrite (EFfiApp ("Basis", "urlifyBool", [e]), _) =>
        EFfiApp ("Basis", "urlifyBool_w", [e])

      | EFfiApp ("Basis", "sqlifyInt", [(EPrim (Prim.Int n), _)]) =>
        EPrim (Prim.String (sqlifyInt n))
      | EFfiApp ("Basis", "sqlifyIntN", [(ENone _, _)]) =>
        EPrim (Prim.String "NULL")
      | EFfiApp ("Basis", "sqlifyIntN", [(ESome (_, (EPrim (Prim.Int n), _)), _)]) =>
        EPrim (Prim.String (sqlifyInt n))

      | EFfiApp ("Basis", "sqlifyFloat", [(EPrim (Prim.Float n), _)]) =>
        EPrim (Prim.String (sqlifyFloat n))
      | EFfiApp ("Basis", "sqlifyBool", [b as (_, loc)]) =>
        optExp (ECase (b,
                       [((PCon (Enum, PConFfi {mod = "Basis", datatyp = "bool", con = "True", arg = NONE}, NONE), loc),
                         (EPrim (Prim.String (#trueString (Settings.currentDbms ()))), loc)),
                        ((PCon (Enum, PConFfi {mod = "Basis", datatyp = "bool", con = "False", arg = NONE}, NONE), loc),
                         (EPrim (Prim.String (#falseString (Settings.currentDbms ()))), loc))],
                       {disc = (TFfi ("Basis", "bool"), loc),
                        result = (TFfi ("Basis", "string"), loc)}), loc)
      | EFfiApp ("Basis", "sqlifyString", [(EPrim (Prim.String n), _)]) =>
        EPrim (Prim.String (sqlifyString n))
      | EFfiApp ("Basis", "sqlifyChar", [(EPrim (Prim.Char n), _)]) =>
        EPrim (Prim.String (sqlifyChar n))

      | EWrite (ECase (discE, pes, {disc, ...}), loc) =>
        optExp (ECase (discE,
                       map (fn (p, e) => (p, (EWrite e, loc))) pes,
                       {disc = disc,
                        result = (TRecord [], loc)}), loc)

      | EApp ((ECase (discE, pes, {disc, result = (TFun (_, ran), _)}), loc), arg as (ERecord [], _)) =>
        let
            fun doBody e =
                case #1 e of
                    EAbs (_, _, _, body) => MonoReduce.subExpInExp (0, arg) body
                  | _ => (EApp (e, arg), loc)
        in
            optExp (ECase (discE,
                           map (fn (p, e) => (p, doBody e)) pes,
                           {disc = disc,
                            result = ran}), loc)
        end

      | ECase (discE, pes, {disc, result = (TFun (dom, ran), loc)}) =>
        let
            fun doBody (p, e) =
                let
                    val pb = MonoEnv.patBindsN p
                in
                    (EApp (MonoEnv.liftExpInExp pb e, (ERel pb, loc)), loc)
                end
        in
            EAbs ("x", dom, ran,
                  (optExp (ECase (MonoEnv.liftExpInExp 0 discE,
                                  map (fn (p, e) => (p, doBody (p, e))) pes,
                                  {disc = disc,
                                   result = ran}), loc), loc))
        end

      | EWrite (EQuery {exps, tables, state, query,
                        initial = (EPrim (Prim.String ""), _),
                        body = (EStrcat ((EPrim (Prim.String s), _),
                                         (EStrcat ((ERel 0, _),
                                                   e'), _)), _)}, loc) =>
        if CharVector.all Char.isSpace s then
            EQuery {exps = exps, tables = tables, query = query,
                    state = (TRecord [], loc),
                    initial = (ERecord [], loc),
                    body = (optExp (EWrite e', loc), loc)}
        else
            e

      | EWrite (EQuery {exps, tables, state, query,
                        initial = (EPrim (Prim.String ""), _),
                        body}, loc) =>
        let
            fun passLets (depth, (e', _), lets) =
                case e' of
                    EStrcat ((ERel x, _), e'') =>
                    if x = depth then
                        let
                            val body = (optExp (EWrite e'', loc), loc)
                            val body = foldl (fn ((x, t, e'), e) =>
                                                 (ELet (x, t, e', e), loc))
                                             body lets
                        in
                            EQuery {exps = exps, tables = tables, query = query,
                                    state = (TRecord [], loc),
                                    initial = (ERecord [], loc),
                                    body = body}
                        end
                    else
                        e
                  | ELet (x, t, e', e'') =>
                    passLets (depth + 1, e'', (x, t, e') :: lets)
                  | _ => e
        in
            passLets (0, body, [])
        end

      (*| EWrite (EQuery {exps, tables, state, query,
                        initial = (EPrim (Prim.String ""), _),
                        body = (EStrcat ((ERel 0, _), e'), _)}, loc) =>
        EQuery {exps = exps, tables = tables, query = query,
                state = (TRecord [], loc),
                initial = (ERecord [], loc),
                body = (optExp (EWrite e', loc), loc)}*)

      | EWrite (ELet (x, t, e1, e2), loc) =>
        optExp (ELet (x, t, e1, (EWrite e2, loc)), loc)

      | EWrite (EPrim (Prim.String ""), loc) =>
        ERecord []

      | ESignalBind ((ESignalReturn e1, loc), e2) =>
        optExp (EApp (e2, e1), loc)

      | EFfiApp ("Basis", "bless", [(se as EPrim (Prim.String s), loc)]) =>
        (if checkUrl s then
             ()
         else
             ErrorMsg.errorAt loc ("Invalid URL " ^ s ^ " passed to 'bless'");
         se)
      | EFfiApp ("Basis", "checkUrl", [(se as EPrim (Prim.String s), loc)]) =>
        (if checkUrl s then
             ESome ((TFfi ("Basis", "string"), loc), (se, loc))
         else
             ENone (TFfi ("Basis", "string"), loc))
      | EFfiApp ("Basis", "blessMime", [(se as EPrim (Prim.String s), loc)]) =>
        (if Settings.checkMime s then
             ()
         else
             ErrorMsg.errorAt loc ("Invalid string " ^ s ^ " passed to 'blessMime'");
         se)

      | EFfiApp ("Basis", "checkString", [(EPrim (Prim.String s), loc)]) => 
        let
            fun uwify (cs, acc) =
                case cs of
                    [] => String.concat (rev acc)
                  | #"(" :: #"_" :: cs => uwify (cs, "(uw_" :: acc)
                  | #" " :: #"_" :: cs => uwify (cs, " uw_" :: acc)
                  | #"'" :: cs =>
                    let
                        fun waitItOut (cs, acc) =
                            case cs of
                                [] => raise Fail "MonoOpt: Unterminated SQL string literal"
                              | #"'" :: cs => uwify (cs, "'" :: acc)
                              | #"\\" :: #"'" :: cs => waitItOut (cs, "\\'" :: acc)
                              | #"\\" :: #"\\" :: cs => waitItOut (cs, "\\\\" :: acc)
                              | c :: cs => waitItOut (cs, str c :: acc)
                    in
                        waitItOut (cs, "'" :: acc)
                    end
                  | c :: cs => uwify (cs, str c :: acc)

            val s = case String.explode s of
                        #"_" :: cs => uwify (cs, ["uw_"])
                      | cs => uwify (cs, [])
        in
            EPrim (Prim.String s)
        end

      | EFfiApp ("Basis", "viewify", [(EPrim (Prim.String s), loc)]) => 
        let
            fun uwify (cs, acc) =
                case cs of
                    [] => String.concat (rev acc)
                  | #"A" :: #"S" :: #" " :: #"_" :: cs => uwify (cs, "AS uw_" :: acc)
                  | #"'" :: cs =>
                    let
                        fun waitItOut (cs, acc) =
                            case cs of
                                [] => raise Fail "MonoOpt: Unterminated SQL string literal"
                              | #"'" :: cs => uwify (cs, "'" :: acc)
                              | #"\\" :: #"'" :: cs => waitItOut (cs, "\\'" :: acc)
                              | #"\\" :: #"\\" :: cs => waitItOut (cs, "\\\\" :: acc)
                              | c :: cs => waitItOut (cs, str c :: acc)
                    in
                        waitItOut (cs, "'" :: acc)
                    end
                  | c :: cs => uwify (cs, str c :: acc)

            val s = uwify (String.explode s, [])
        in
            EPrim (Prim.String s)
        end

      | EFfiApp ("Basis", "unAs", [(EPrim (Prim.String s), _)]) => 
        EPrim (Prim.String (unAs s))
      | EFfiApp ("Basis", "unAs", [e']) =>
        let
            fun parts (e as (_, loc)) =
                case #1 e of
                    EStrcat (s1, s2) =>
                    (case (parts s1, parts s2) of
                         (SOME p1, SOME p2) => SOME (p1 @ p2)
                       | _ => NONE)
                  | EPrim (Prim.String s) => SOME [(EPrim (Prim.String (unAs s)), loc)]
                  | EFfiApp ("Basis", f, [_]) =>
                    if String.isPrefix "sqlify" f then
                        SOME [e]
                    else
                        NONE
                  | _ => NONE
        in
            case parts e' of
                SOME [e] => #1 e
              | SOME es =>
                (case rev es of
                     (e as (_, loc)) :: es => #1 (foldl (fn (e, es) => (EStrcat (e, es), loc)) e es)
                   | [] => raise Fail "MonoOpt impossible nil")
              | NONE => e
        end

      | EFfiApp ("Basis", "str1", [(EPrim (Prim.Char ch), _)]) =>
        EPrim (Prim.String (str ch))
      | EFfiApp ("Basis", "attrifyString", [(EFfiApp ("Basis", "str1", [e]), _)]) =>
        EFfiApp ("Basis", "attrifyChar", [e])
      | EFfiApp ("Basis", "attrifyString_w", [(EFfiApp ("Basis", "str1", [e]), _)]) =>
        EFfiApp ("Basis", "attrifyChar_w", [e])
        
      | _ => e

and optExp e = #1 (U.Exp.map {typ = typ, exp = exp} e)

val optimize = U.File.map {typ = typ, exp = exp, decl = decl}

val optExp = U.Exp.map {typ = typ, exp = exp}

end