Pushing policies through

35 files changed, 145 insertions, 15 deletions

diff --git a/lib/ur/basis.urs b/lib/ur/basis.urs
index 8388e107..aad04b5f 100644
--- a/lib/ur/basis.urs
+++ b/lib/ur/basis.urs
@@ -795,4 +795,13 @@ type task_kind
 val initialize : task_kind
 
 
+(** Information flow security *)
+
+type sql_policy
+
+val query_policy : tables ::: {{Type}} -> exps ::: {Type}
+                   -> [tables ~ exps] => sql_query [] tables exps
+                   -> sql_policy
+
+
 val debug : string -> transaction unit
diff --git a/src/cjrize.sml b/src/cjrize.sml
index 6e41a69b..b98b3c25 100644
--- a/src/cjrize.sml
+++ b/src/cjrize.sml
@@ -674,6 +674,7 @@ fun cifyDecl ((d, loc), sm) =
              end
            | _ => (ErrorMsg.errorAt loc "Initializer has not been fully determined";
                    (NONE, NONE, sm)))
+      | L.DPolicy _ => (NONE, NONE, sm)
 
 fun cjrize ds =
     let
diff --git a/src/core.sml b/src/core.sml
index 90005f16..e5358f48 100644
--- a/src/core.sml
+++ b/src/core.sml
@@ -135,6 +135,7 @@ datatype decl' =
        | DCookie of string * int * con * string
        | DStyle of string * int * string
        | DTask of exp * exp
+       | DPolicy of exp
 
 withtype decl = decl' located
 
diff --git a/src/core_env.sml b/src/core_env.sml
index 9001e29c..478ef495 100644
--- a/src/core_env.sml
+++ b/src/core_env.sml
@@ -349,6 +349,7 @@ fun declBinds env (d, loc) =
             pushENamed env x n t NONE s
         end
       | DTask _ => env
+      | DPolicy _ => env
 
 fun patBinds env (p, loc) =
     case p of
diff --git a/src/core_print.sml b/src/core_print.sml
index d6be76a3..fd0556e6 100644
--- a/src/core_print.sml
+++ b/src/core_print.sml
@@ -618,6 +618,9 @@ fun p_decl env (dAll as (d, _) : decl) =
                                string "=",
                                space,
                                p_exp env e2]
+      | DPolicy e1 => box [string "policy",
+                           space,
+                           p_exp env e1]
 
 fun p_file env file =
     let
diff --git a/src/core_util.sml b/src/core_util.sml
index 247dd32e..eedcd2bb 100644
--- a/src/core_util.sml
+++ b/src/core_util.sml
@@ -992,6 +992,10 @@ fun mapfoldB {kind = fk, con = fc, exp = fe, decl = fd, bind} =
                         S.map2 (mfe ctx e2,
                              fn e2' =>
                                 (DTask (e1', e2'), loc)))
+              | DPolicy e =>
+                S.map2 (mfe ctx e,
+                     fn e' =>
+                        (DPolicy e', loc))
 
         and mfvi ctx (x, n, t, e, s) =
             S.bind2 (mfc ctx t,
@@ -1147,6 +1151,7 @@ fun mapfoldB (all as {bind, ...}) =
                                             bind (ctx, NamedE (x, n, t, NONE, s))
                                         end
                                       | DTask _ => ctx
+                                      | DPolicy _ => ctx
                             in
                                 S.map2 (mff ctx' ds',
                                      fn ds' =>
@@ -1210,7 +1215,8 @@ val maxName = foldl (fn ((d, _) : decl, count) =>
                           | DDatabase _ => count
                           | DCookie (_, n, _, _) => Int.max (n, count)
                           | DStyle (_, n, _) => Int.max (n, count)
-                          | DTask _ => count) 0
+                          | DTask _ => count
+                          | DPolicy _ => count) 0
               
 end
 
diff --git a/src/corify.sml b/src/corify.sml
index 6931600e..88473455 100644
--- a/src/corify.sml
+++ b/src/corify.sml
@@ -1080,6 +1080,9 @@ fun corifyDecl mods (all as (d, loc : EM.span), st) =
       | L.DTask (e1, e2) =>
         ([(L'.DTask (corifyExp st e1, corifyExp st e2), loc)], st)
 
+      | L.DPolicy e1 =>
+        ([(L'.DPolicy (corifyExp st e1), loc)], st)
+
 and corifyStr mods ((str, _), st) =
     case str of
         L.StrConst ds =>
@@ -1137,7 +1140,8 @@ fun maxName ds = foldl (fn ((d, _), n) =>
                              | L.DDatabase _ => n
                              | L.DCookie (_, _, n', _) => Int.max (n, n')
                              | L.DStyle (_, _, n') => Int.max (n, n')
-                             | L.DTask _ => n)
+                             | L.DTask _ => n
+                             | L.DPolicy _ => n)
                        0 ds
 
 and maxNameStr (str, _) =
diff --git a/src/css.sml b/src/css.sml
index 7189904f..3df35ed1 100644
--- a/src/css.sml
+++ b/src/css.sml
@@ -287,6 +287,7 @@ fun summarize file =
                   | DCookie _ => st
                   | DStyle (_, n, s) => (IM.insert (globals, n, (SOME s, [])), classes)
                   | DTask _ => st
+                  | DPolicy _ => st
             end
 
         val (globals, classes) = foldl decl (IM.empty, IM.empty) file
diff --git a/src/elab.sml b/src/elab.sml
index a0f9a4e8..e040a059 100644
--- a/src/elab.sml
+++ b/src/elab.sml
@@ -171,6 +171,7 @@ datatype decl' =
        | DCookie of int * string * int * con
        | DStyle of int * string * int
        | DTask of exp * exp
+       | DPolicy of exp
 
      and str' =
          StrConst of decl list
diff --git a/src/elab_env.sml b/src/elab_env.sml
index 5092c6fb..dd050c9e 100644
--- a/src/elab_env.sml
+++ b/src/elab_env.sml
@@ -1623,5 +1623,6 @@ fun declBinds env (d, loc) =
             pushENamedAs env x n t
         end
       | DTask _ => env
+      | DPolicy _ => env
 
 end
diff --git a/src/elab_print.sml b/src/elab_print.sml
index 62b5262f..86448659 100644
--- a/src/elab_print.sml
+++ b/src/elab_print.sml
@@ -806,6 +806,9 @@ fun p_decl env (dAll as (d, _) : decl) =
                                string "=",
                                space,
                                p_exp env e2]
+      | DPolicy e1 => box [string "policy",
+                           space,
+                           p_exp env e1]
 
 and p_str env (str, _) =
     case str of
diff --git a/src/elab_util.sml b/src/elab_util.sml
index d0e140c5..8345e3f3 100644
--- a/src/elab_util.sml
+++ b/src/elab_util.sml
@@ -854,7 +854,8 @@ fun mapfoldB {kind = fk, con = fc, exp = fe, sgn_item = fsgi, sgn = fsg, str = f
                                                                                 c), loc)))
                                                  | DStyle (tn, x, n) =>
                                                    bind (ctx, NamedE (x, (CModProj (n, [], "css_class"), loc)))
-                                                 | DTask _ => ctx,
+                                                 | DTask _ => ctx
+                                                 | DPolicy _ => ctx,
                                                mfd ctx d)) ctx ds,
                      fn ds' => (StrConst ds', loc))
               | StrVar _ => S.return2 strAll
@@ -985,6 +986,10 @@ fun mapfoldB {kind = fk, con = fc, exp = fe, sgn_item = fsgi, sgn = fsg, str = f
                            S.map2 (mfe ctx e2,
                                 fn e2' =>
                                    (DTask (e1', e2'), loc)))
+              | DPolicy e1 =>
+                S.map2 (mfe ctx e1,
+                     fn e1' =>
+                        (DPolicy e1', loc))
 
         and mfvi ctx (x, n, c, e) =
             S.bind2 (mfc ctx c,
@@ -1128,6 +1133,7 @@ and maxNameDecl (d, _) =
       | DCookie (n1, _, n2, _) => Int.max (n1, n2)
       | DStyle (n1, _, n2) => Int.max (n1, n2)
       | DTask _ => 0
+      | DPolicy _ => 0
 and maxNameStr (str, _) =
     case str of
         StrConst ds => maxName ds
diff --git a/src/elaborate.sml b/src/elaborate.sml
index 1651f344..07818a57 100644
--- a/src/elaborate.sml
+++ b/src/elaborate.sml
@@ -2595,6 +2595,7 @@ and sgiOfDecl (d, loc) =
       | L'.DCookie (tn, x, n, c) => [(L'.SgiVal (x, n, (L'.CApp (cookieOf (), c), loc)), loc)]
       | L'.DStyle (tn, x, n) => [(L'.SgiVal (x, n, styleOf ()), loc)]
       | L'.DTask _ => []
+      | L'.DPolicy _ => []
 
 and subSgn' counterparts env strLoc sgn1 (sgn2 as (_, loc2)) =
     ((*prefaces "subSgn" [("sgn1", p_sgn env sgn1),
@@ -3729,6 +3730,15 @@ and elabDecl (dAll as (d, loc), (env, denv, gs)) =
                     checkCon env e2' t2 t2';
                     ([(L'.DTask (e1', e2'), loc)], (env, denv, gs2 @ gs1 @ gs))
                 end
+              | L.DPolicy e1 =>
+                let
+                    val (e1', t1, gs1) = elabExp (env, denv) e1
+
+                    val t1' = (L'.CModProj (!basis_r, [], "sql_policy"), loc)
+                in
+                    checkCon env e1' t1 t1';
+                    ([(L'.DPolicy e1', loc)], (env, denv, gs1 @ gs))
+                end
 
         (*val tcs = List.filter (fn TypeClass _ => true | _ => false) (#3 (#2 r))*)
     in
diff --git a/src/elisp/urweb-defs.el b/src/elisp/urweb-defs.el
index c697a274..8054d829 100644
--- a/src/elisp/urweb-defs.el
+++ b/src/elisp/urweb-defs.el
@@ -108,7 +108,7 @@ notion of \"the end of an outline\".")
                  "datatype" "type" "open" "include"
                  urweb-module-head-syms
                  "con" "map" "where" "extern" "constraint" "constraints"
-                 "table" "sequence" "class" "cookie" "task")
+                 "table" "sequence" "class" "cookie" "task" "policy")
   "Symbols starting an sexp.")
 
 ;; (defconst urweb-not-arg-start-re
@@ -135,7 +135,7 @@ notion of \"the end of an outline\".")
      (("case" "datatype" "if" "then" "else"
        "let" "open" "sig" "struct" "type" "val"
        "con" "constraint" "table" "sequence" "class" "cookie"
-       "task")))))
+       "task" "policy")))))
 
 (defconst urweb-starters-indent-after
   (urweb-syms-re "let" "in" "struct" "sig")
@@ -190,7 +190,7 @@ for all symbols and in all lines starting with the given symbol."
 	  '("datatype" "fun"
 	    "open" "type" "val" "and"
 	    "con" "constraint" "table" "sequence" "class" "cookie"
-            "task"))
+            "task" "policy"))
   "The starters of new expressions.")
 
 (defconst urweb-exptrail-syms
diff --git a/src/elisp/urweb-mode.el b/src/elisp/urweb-mode.el
index 107ea3bc..c9fe5f19 100644
--- a/src/elisp/urweb-mode.el
+++ b/src/elisp/urweb-mode.el
@@ -136,7 +136,7 @@ See doc for the variable `urweb-mode-info'."
 	       "datatype" "else" "end" "extern" "fn" "map"
 	       "fun" "functor" "if" "include"
 	       "of" "open" "let" "in"
-	       "rec" "sequence" "sig" "signature" "cookie" "style" "task"
+	       "rec" "sequence" "sig" "signature" "cookie" "style" "task" "policy"
 	       "struct" "structure" "table" "view" "then" "type" "val" "where"
 	       "with"
 
@@ -226,7 +226,7 @@ See doc for the variable `urweb-mode-info'."
     ("\\<\\(\\(data\\)?type\\|con\\|class\\)\\s-+\\(\\sw+\\)"
      (1 font-lock-keyword-face)
      (3 (amAttribute font-lock-type-def-face)))
-    ("\\<\\(val\\|table\\|sequence\\|cookie\\|style\\|task\\)\\s-+\\(\\sw+\\>\\s-*\\)?\\(\\sw+\\)\\s-*[=:]"
+    ("\\<\\(val\\|table\\|sequence\\|cookie\\|style\\|task\\|policy\\)\\s-+\\(\\sw+\\>\\s-*\\)?\\(\\sw+\\)\\s-*[=:]"
      (1 font-lock-keyword-face)
      (3 (amAttribute font-lock-variable-name-face)))
     ("\\<\\(structure\\|functor\\)\\s-+\\(\\sw+\\)"
diff --git a/src/expl.sml b/src/expl.sml
index 17797626..1212383f 100644
--- a/src/expl.sml
+++ b/src/expl.sml
@@ -148,6 +148,7 @@ datatype decl' =
        | DCookie of int * string * int * con
        | DStyle of int * string * int
        | DTask of exp * exp
+       | DPolicy of exp
 
      and str' =
          StrConst of decl list
diff --git a/src/expl_env.sml b/src/expl_env.sml
index 0bf7323f..583e4881 100644
--- a/src/expl_env.sml
+++ b/src/expl_env.sml
@@ -344,6 +344,7 @@ fun declBinds env (d, loc) =
             pushENamed env x n t
         end
       | DTask _ => env
+      | DPolicy _ => env
 
 fun sgiBinds env (sgi, loc) =
     case sgi of
diff --git a/src/expl_print.sml b/src/expl_print.sml
index 5284eecb..15838729 100644
--- a/src/expl_print.sml
+++ b/src/expl_print.sml
@@ -720,6 +720,9 @@ fun p_decl env (dAll as (d, _) : decl) =
                                string "=",
                                space,
                                p_exp env e2]
+      | DPolicy e1 => box [string "policy",
+                           space,
+                           p_exp env e1]
 
 and p_str env (str, _) =
     case str of
diff --git a/src/explify.sml b/src/explify.sml
index aff91a34..0013906f 100644
--- a/src/explify.sml
+++ b/src/explify.sml
@@ -196,6 +196,7 @@ fun explifyDecl (d, loc : EM.span) =
       | L.DCookie (nt, x, n, c) => SOME (L'.DCookie (nt, x, n, explifyCon c), loc)
       | L.DStyle (nt, x, n) => SOME (L'.DStyle (nt, x, n), loc)
       | L.DTask (e1, e2) => SOME (L'.DTask (explifyExp e1, explifyExp e2), loc)
+      | L.DPolicy e1 => SOME (L'.DPolicy (explifyExp e1), loc)
 
 and explifyStr (str, loc) =
     case str of
diff --git a/src/mono.sml b/src/mono.sml
index 898feb9b..33ab5bd4 100644
--- a/src/mono.sml
+++ b/src/mono.sml
@@ -1,4 +1,4 @@
-(* Copyright (c) 2008, Adam Chlipala
+(* Copyright (c) 2008-2010, Adam Chlipala
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -123,6 +123,8 @@ datatype exp' =
 
 withtype exp = exp' located
 
+datatype policy = PolQuery of exp
+
 datatype decl' =
          DDatatype of (string * int * (string * int * typ option) list) list
        | DVal of string * int * typ * exp * string
@@ -141,6 +143,8 @@ datatype decl' =
 
        | DTask of exp * exp
 
+       | DPolicy of policy
+
 withtype decl = decl' located
 
 type file = decl list
diff --git a/src/mono_env.sml b/src/mono_env.sml
index c2e6cf02..87f96488 100644
--- a/src/mono_env.sml
+++ b/src/mono_env.sml
@@ -130,6 +130,7 @@ fun declBinds env (d, loc) =
       | DCookie _ => env
       | DStyle _ => env
       | DTask _ => env
+      | DPolicy _ => env
 
 fun patBinds env (p, loc) =
     case p of
diff --git a/src/mono_print.sml b/src/mono_print.sml
index d1f5fc27..50c4717a 100644
--- a/src/mono_print.sml
+++ b/src/mono_print.sml
@@ -412,6 +412,12 @@ fun p_datatype env (x, n, cons) =
                         cons]
     end
 
+fun p_policy env pol =
+    case pol of
+        PolQuery e => box [string "query",
+                           space,
+                           p_exp env e]
+
 fun p_decl env (dAll as (d, _) : decl) =
     case d of
         DDatatype x => box [string "datatype",
@@ -506,6 +512,9 @@ fun p_decl env (dAll as (d, _) : decl) =
                                string "=",
                                space,
                                p_exp env e2]
+      | DPolicy p => box [string "policy",
+                          space,
+                          p_policy env p]
 
                           
 fun p_file env file =
diff --git a/src/mono_shake.sml b/src/mono_shake.sml
index e53b6930..358b31d2 100644
--- a/src/mono_shake.sml
+++ b/src/mono_shake.sml
@@ -58,6 +58,13 @@ fun shake file =
                   | ((DDatabase {expunge = n1, initialize = n2, ...}, _), (page_cs, page_es)) =>
                     (page_cs, IS.addList (page_es, [n1, n2]))
                   | ((DTask (e1, e2), _), st) => usedVars (usedVars st e2) e1
+                  | ((DPolicy pol, _), st) =>
+                    let
+                        val e1 = case pol of
+                                     PolQuery e1 => e1
+                    in
+                        usedVars st e1
+                    end
                   | (_, st) => st) (IS.empty, IS.empty) file
 
         val (cdef, edef) = foldl (fn ((DDatatype dts, _), (cdef, edef)) =>
@@ -74,7 +81,8 @@ fun shake file =
                                    | ((DJavaScript _, _), acc) => acc
                                    | ((DCookie _, _), acc) => acc
                                    | ((DStyle _, _), acc) => acc
-                                   | ((DTask _, _), acc) => acc)
+                                   | ((DTask _, _), acc) => acc
+                                   | ((DPolicy _, _), acc) => acc)
                                  (IM.empty, IM.empty) file
 
         fun typ (c, s) =
@@ -141,7 +149,8 @@ fun shake file =
                       | (DJavaScript _, _) => true
                       | (DCookie _, _) => true
                       | (DStyle _, _) => true
-                      | (DTask _, _) => true) file
+                      | (DTask _, _) => true
+                      | (DPolicy _, _) => true) file
     end
 
 end
diff --git a/src/mono_util.sml b/src/mono_util.sml
index a75843c4..094f216b 100644
--- a/src/mono_util.sml
+++ b/src/mono_util.sml
@@ -534,6 +534,16 @@ fun mapfoldB {typ = fc, exp = fe, decl = fd, bind} =
                         S.map2 (mfe ctx e2,
                              fn e2' =>
                                 (DTask (e1', e2'), loc)))
+              | DPolicy pol =>
+                S.map2 (mfpol ctx pol,
+                     fn p' =>
+                        (DPolicy p', loc))
+
+        and mfpol ctx pol =
+            case pol of
+                PolQuery e =>
+                S.map2 (mfe ctx e,
+                        PolQuery)
 
         and mfvi ctx (x, n, t, e, s) =
             S.bind2 (mft t,
@@ -621,6 +631,7 @@ fun mapfoldB (all as {bind, ...}) =
                                       | DCookie _ => ctx
                                       | DStyle _ => ctx
                                       | DTask _ => ctx
+                                      | DPolicy _ => ctx
                             in
                                 S.map2 (mff ctx' ds',
                                      fn ds' =>
@@ -674,7 +685,8 @@ val maxName = foldl (fn ((d, _) : decl, count) =>
                           | DJavaScript _ => count
                           | DCookie _ => count
                           | DStyle _ => count
-                          | DTask _ => count) 0
+                          | DTask _ => count
+                          | DPolicy _ => count) 0
 
 end
 
diff --git a/src/monoize.sml b/src/monoize.sml
index 25ea87f5..6f229766 100644
--- a/src/monoize.sml
+++ b/src/monoize.sml
@@ -3738,6 +3738,20 @@ fun monoDecl (env, fm) (all as (d, loc)) =
                       fm,
                       [(L'.DTask (e1, e2), loc)])
             end
+          | L.DPolicy e =>
+            let
+                val (e, make) =
+                    case #1 e of
+                        L.EApp ((L.ECApp ((L.ECApp ((L.EFfi ("Basis", "query_policy"), _), _), _), _), _), e) =>
+                        (e, L'.PolQuery)
+                      | _ => (poly (); (e, L'.PolQuery))
+
+                val (e, fm) = monoExp (env, St.empty, fm) e
+            in
+                SOME (env,
+                      fm,
+                      [(L'.DPolicy (make e), loc)])
+            end
     end
 
 datatype expungable = Client | Channel
diff --git a/src/reduce.sml b/src/reduce.sml
index b7ad567a..cefe1955 100644
--- a/src/reduce.sml
+++ b/src/reduce.sml
@@ -746,6 +746,15 @@ fun reduce file =
                       namedC,
                       namedE))
                 end
+              | DPolicy e1 =>
+                let
+                    val e1 = exp (namedC, namedE) [] e1
+                in
+                    ((DPolicy e1, loc),
+                     (polyC,
+                      namedC,
+                      namedE))
+                end
 
         val (file, _) = ListUtil.foldlMap doDecl (IS.empty, IM.empty, IM.empty) file
     in
diff --git a/src/reduce_local.sml b/src/reduce_local.sml
index b040a1ec..4c5ab52e 100644
--- a/src/reduce_local.sml
+++ b/src/reduce_local.sml
@@ -252,6 +252,7 @@ fun reduce file =
               | DCookie _ => d
               | DStyle _ => d
               | DTask (e1, e2) => (DTask (exp [] e1, exp [] e2), loc)
+              | DPolicy e1 => (DPolicy (exp [] e1), loc)
     in
         map doDecl file
     end
diff --git a/src/shake.sml b/src/shake.sml
index 686a043c..f679c6e8 100644
--- a/src/shake.sml
+++ b/src/shake.sml
@@ -90,6 +90,11 @@ fun shake file =
                         st
                     else
                         usedVars (usedVars st e1) e2
+                  | ((DPolicy e1, _), st) =>
+                    if !sliceDb then
+                        st
+                    else
+                        usedVars st e1
                   | (_, acc) => acc) (IS.empty, IS.empty) file
 
         val (cdef, edef) = foldl (fn ((DCon (_, n, _, c), _), (cdef, edef)) => (IM.insert (cdef, n, [c]), edef)
@@ -116,7 +121,8 @@ fun shake file =
                                      (cdef, IM.insert (edef, n, ([], c, dummye)))
                                    | ((DStyle (_, n, _), _), (cdef, edef)) =>
                                      (cdef, IM.insert (edef, n, ([], dummyt, dummye)))
-                                   | ((DTask _, _), acc) => acc)
+                                   | ((DTask _, _), acc) => acc
+                                   | ((DPolicy _, _), acc) => acc)
                                  (IM.empty, IM.empty) file
 
         fun kind (_, s) = s
@@ -203,7 +209,8 @@ fun shake file =
                       | (DDatabase _, _) => not (!sliceDb)
                       | (DCookie _, _) => not (!sliceDb)
                       | (DStyle _, _) => not (!sliceDb)
-                      | (DTask _, _) => not (!sliceDb)) file
+                      | (DTask _, _) => not (!sliceDb)
+                      | (DPolicy _, _) => not (!sliceDb)) file
     end
 
 end
diff --git a/src/source.sml b/src/source.sml
index dc867026..9768cfc0 100644
--- a/src/source.sml
+++ b/src/source.sml
@@ -168,6 +168,7 @@ datatype decl' =
        | DCookie of string * con
        | DStyle of string
        | DTask of exp * exp
+       | DPolicy of exp
 
      and str' =
          StrConst of decl list
diff --git a/src/source_print.sml b/src/source_print.sml
index e3b4fe94..590d15d5 100644
--- a/src/source_print.sml
+++ b/src/source_print.sml
@@ -669,6 +669,9 @@ fun p_decl ((d, _) : decl) =
                                string "=",
                                space,
                                p_exp e2]
+      | DPolicy e1 => box [string "policy",
+                           space,
+                           p_exp e1]
 
 and p_str (str, _) =
     case str of
diff --git a/src/unnest.sml b/src/unnest.sml
index e030bbc6..77589bfb 100644
--- a/src/unnest.sml
+++ b/src/unnest.sml
@@ -423,6 +423,7 @@ fun unnest file =
                   | DCookie _ => default ()
                   | DStyle _ => default ()
                   | DTask _ => explore ()
+                  | DPolicy _ => explore ()
             end
 
         and doStr (all as (str, loc), st) =
diff --git a/src/urweb.grm b/src/urweb.grm
index ad3de6b2..3df9554f 100644
--- a/src/urweb.grm
+++ b/src/urweb.grm
@@ -202,7 +202,7 @@ fun patType loc (p : pat) =
  | LET | IN
  | STRUCTURE | SIGNATURE | STRUCT | SIG | END | FUNCTOR | WHERE | EXTERN | SQL | SELECT1
  | INCLUDE | OPEN | CONSTRAINT | CONSTRAINTS | EXPORT | TABLE | SEQUENCE | VIEW
- | COOKIE | STYLE | TASK
+ | COOKIE | STYLE | TASK | POLICY
  | CASE | IF | THEN | ELSE | ANDALSO | ORELSE
 
  | XML_BEGIN of string | XML_END | XML_BEGIN_END of string
@@ -481,6 +481,7 @@ decl   : CON SYMBOL cargl2 kopt EQ cexp (let
        | COOKIE SYMBOL COLON cexp       ([(DCookie (SYMBOL, cexp), s (COOKIEleft, cexpright))])
        | STYLE SYMBOL                   ([(DStyle SYMBOL, s (STYLEleft, SYMBOLright))])
        | TASK eapps EQ eexp             ([(DTask (eapps, eexp), s (TASKleft, eexpright))])
+       | POLICY eexp                    ([(DPolicy eexp, s (POLICYleft, eexpright))])
 
 dtype  : SYMBOL dargs EQ barOpt dcons   (SYMBOL, dargs, dcons)
 
diff --git a/src/urweb.lex b/src/urweb.lex
index 45f555dd..8930c463 100644
--- a/src/urweb.lex
+++ b/src/urweb.lex
@@ -416,6 +416,7 @@ xint = x[0-9a-fA-F][0-9a-fA-F];
 <INITIAL> "cookie"    => (Tokens.COOKIE (pos yypos, pos yypos + size yytext));
 <INITIAL> "style"     => (Tokens.STYLE (pos yypos, pos yypos + size yytext));
 <INITIAL> "task"      => (Tokens.TASK (pos yypos, pos yypos + size yytext));
+<INITIAL> "policy"    => (Tokens.POLICY (pos yypos, pos yypos + size yytext));
 
 <INITIAL> "Type"      => (Tokens.TYPE (pos yypos, pos yypos + size yytext));
 <INITIAL> "Name"      => (Tokens.NAME (pos yypos, pos yypos + size yytext));
diff --git a/tests/policy.ur b/tests/policy.ur
new file mode 100644
index 00000000..db87b582
--- /dev/null
+++ b/tests/policy.ur
@@ -0,0 +1,3 @@
+table fruit : { Id : int, Nam : string, Weight : float }
+
+policy query_policy (SELECT * FROM fruit)
diff --git a/tests/policy.urp b/tests/policy.urp
new file mode 100644
index 00000000..b26ebd4a
--- /dev/null
+++ b/tests/policy.urp
@@ -0,0 +1 @@
+policy