Mercurial > urweb
changeset 1697:cb0f05bdc183
Refactor SQL parsing code from Iflow to Sql, add querydml parser.
| author | Edward Z. Yang <ezyang@mit.edu> |
|---|---|
| date | Mon, 12 Mar 2012 12:00:23 -0700 |
| parents | 177547450bb9 |
| children | aaae710417df |
| files | src/iflow.sml src/sources src/sql.sml |
| diffstat | 3 files changed, 431 insertions(+), 417 deletions(-) [+] |
line wrap: on
line diff
--- a/src/iflow.sml Mon Mar 12 12:00:13 2012 -0700 +++ b/src/iflow.sml Mon Mar 12 12:00:23 2012 -0700 @@ -28,6 +28,7 @@ structure Iflow :> IFLOW = struct open Mono +open Sql structure IS = IntBinarySet structure IM = IntBinaryMap @@ -57,43 +58,6 @@ val writers = SS.addList (SS.empty, writers) -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 - local open Print val string = PD.string @@ -226,8 +190,6 @@ AReln x => Reln x | ACond x => Cond x) -val debug = ref false - (* Congruence closure *) structure Cc :> sig type database @@ -828,384 +790,6 @@ PConVar n => "C" ^ Int.toString n | PConFfi {mod = m, datatyp = d, con = c, ...} => m ^ "." ^ d ^ "." ^ c -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]) - type check = exp * ErrorMsg.span structure St :> sig
--- a/src/sources Mon Mar 12 12:00:13 2012 -0700 +++ b/src/sources Mon Mar 12 12:00:23 2012 -0700 @@ -180,6 +180,8 @@ fuse.sig fuse.sml +sql.sml + iflow.sig iflow.sml
--- /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