diff --git a/Makefile b/Makefile
index 6a22b02..6cde888 100644
--- a/Makefile
+++ b/Makefile
@@ -2,21 +2,21 @@ INSTALL_ARGS := $(if $(PREFIX),--prefix $(PREFIX),)
 
 # Default rule
 default:
-	jbuilder build @install
+	dune build @install
 
 install:
-	jbuilder install $(INSTALL_ARGS)
+	dune install $(INSTALL_ARGS)
 
 uninstall:
-	jbuilder uninstall $(INSTALL_ARGS)
+	dune uninstall $(INSTALL_ARGS)
 
 reinstall: uninstall install
 
 test:
-	jbuilder build @runtest
+	dune build @runtest
 
 example:
-	jbuilder build examples/server.exe
+	dune build examples/server.exe
 
 clean:
 	rm -rf _build
diff --git a/dune-project b/dune-project
new file mode 100644
index 0000000..d29a4af
--- /dev/null
+++ b/dune-project
@@ -0,0 +1,2 @@
+(lang dune 2.0)
+(name sequoia)
diff --git a/mysql/dune b/mysql/dune
new file mode 100644
index 0000000..96c0c28
--- /dev/null
+++ b/mysql/dune
@@ -0,0 +1,4 @@
+(library
+ (name sequoia_mysql)
+ (public_name sequoia-mysql)
+ (libraries sequoia unix))
diff --git a/mysql/jbuild b/mysql/jbuild
deleted file mode 100644
index 3bfa920..0000000
--- a/mysql/jbuild
+++ /dev/null
@@ -1,8 +0,0 @@
-(jbuild_version 1)
-
-(library
- ((name sequoia_mysql)
-   (public_name sequoia-mysql)
-   (libraries
-    (sequoia
-     unix))))
diff --git a/mysql/mysql.ml b/mysql/mysql.ml
index 60873ae..9ac5cf4 100644
--- a/mysql/mysql.ml
+++ b/mysql/mysql.ml
@@ -105,7 +105,7 @@ module Field = struct
     | Null.Datetime (_, t) -> t
     | Null.Enum (_, t, _) -> t
     | fld -> table fld
-
+(*
   let to_string : type a b. (a, b) t -> string = function
     | Time (name, table) -> sprintf "%s.%s" (Table.name table) name
     | Timestamp (name, table) -> sprintf "%s.%s" (Table.name table) name
@@ -118,7 +118,7 @@ module Field = struct
     | Null.Datetime (name, table) -> sprintf "%s.%s" (Table.name table) name
     | Null.Enum (name, table, _) -> sprintf "%s.%s" (Table.name table) name
     | other -> to_string other
-
+ *)
   let to_string fld =
     let t = table fld in
     sprintf "%s.%s" (Table.name t) (name fld)
@@ -392,7 +392,7 @@ module Expr = struct
     Lit (Lit.Date { base_time with year; month; day })
   let datetime ?(year = 0) ?(month = 0) ?(day = 0)
                ?(hour = 0) ?(minute = 0) ?(second = 0) = fun _ ->
-    Lit (Lit.Datetime { base_time with year; month; day; minute; second })
+    Lit (Lit.Datetime { year; month; day; hour; minute; second })
 
   let enum inst = fun _ ->
     Lit (Lit.Enum inst)
@@ -419,17 +419,17 @@ module Expr = struct
   let compress f = fun src -> Compress (f src)
   let concat f = fun src -> Concat (f src)
   let concat_ws sep l = fun src -> Concat_ws (sep, List.map (fun f -> f src) l)
-  let connection_id () = fun src -> Connection_id
+  let connection_id () = fun _ -> Connection_id
   let conv f i j = fun src -> Conv (f src, i, j)
   let cos f = fun src -> Cos (f src)
   let cot f = fun src -> Cot (f src)
   let count ?(distinct = false) f = fun src -> Count (f src, distinct)
   let crc32 f = fun src -> Crc32 (f src)
-  let current_date () = fun src -> Current_date
-  let current_time () = fun src -> Current_time
-  let current_timestamp () = fun src -> Current_timestamp
-  let current_user () = fun src -> Current_user
-  let database () = fun src -> Database
+  let current_date () = fun _ -> Current_date
+  let current_time () = fun _ -> Current_time
+  let current_timestamp () = fun _ -> Current_timestamp
+  let current_user () = fun _ -> Current_user
+  let database () = fun _ -> Database
   let date_of : ('s M.Select.source -> [< `Date | `Datetime] time t) -> 's M.Select.source -> [`Date] time t = fun f src -> DateFn (f src)
   let date_add f i u = fun src -> Date_add (f src, i, u)
   let date_format f fmt = fun src -> Date_format (f src, fmt)
@@ -448,7 +448,7 @@ module Expr = struct
   let ifnull f g = fun src -> Ifnull (f src, g src)
   let last_day f = fun src -> Last_day (f src)
   let length f = fun src -> Length (f src)
-  let localtime () = fun src -> Localtime
+  let localtime () = fun _ -> Localtime
   let log f = fun src -> Log (f src)
   let log10 f = fun src -> Log10 (f src)
   let log2 f = fun src -> Log2 (f src)
@@ -460,7 +460,7 @@ module Expr = struct
   let minute f = fun src -> Minute (f src)
   let month f = fun src -> Month (f src)
   let monthname f = fun src -> Monthname (f src)
-  let now () = fun src -> Now
+  let now () = fun _ -> Now
   let nullif f g = fun src -> Nullif (f src, g src)
   let ord f = fun src -> Ord (f src)
   let pow f = fun src -> Pow (f src)
@@ -489,23 +489,23 @@ module Expr = struct
   let timestampdiff u f g = fun src -> Timestampdiff (u, f src, g src)
   let trim f = fun src -> Trim (f src)
   let uncompress f = fun src -> Uncompress (f src)
-  let utc_date () = fun src -> Utc_date
-  let utc_time () = fun src -> Utc_time
-  let utc_timestamp () = fun src -> Utc_timestamp
-  let uuid () = fun src -> Uuid
-  let uuid_short () = fun src -> Uuid_short
-  let week () = fun src -> Week
-  let weekday () = fun src -> Weekday
-  let weekofyear () = fun src -> Weekofyear
+  let utc_date () = fun _ -> Utc_date
+  let utc_time () = fun _ -> Utc_time
+  let utc_timestamp () = fun _ -> Utc_timestamp
+  let uuid () = fun _ -> Uuid
+  let uuid_short () = fun _ -> Uuid_short
+  let week () = fun _ -> Week
+  let weekday () = fun _ -> Weekday
+  let weekofyear () = fun _ -> Weekofyear
   let upper f = fun src -> Upper (f src)
-  let year () = fun src -> Year
+  let year () = fun _ -> Year
 
   let as_time f = fun src -> Cast (f src, Time)
   let as_timestamp f = fun src -> Cast (f src, Timestamp)
   let as_date f = fun src -> Cast (f src, Date)
   let as_datetime f = fun src -> Cast (f src, Datetime)
 
-  let rec build
+  let build
     : type a. handover:handover -> build_step -> a t -> build_step =
     fun ~handover st e ->
       let build_param = build_param D.placeholder in
@@ -543,7 +543,7 @@ module Expr = struct
       | Collation e -> fn "COLLATION(" [e] ")"
       | Compress e -> fn "COMPRESS(" [e] ")"
       | Concat l -> fn "CONCAT(" l ")"
-      | Concat_ws (s, l) -> fn "CONCAT_WS" l ")"
+      | Concat_ws (_s, l) -> fn "CONCAT_WS" l ")"
       | Connection_id -> fn "CONNECTION_ID" [] ")"
       | Conv (e1, i, j) -> fn "CONV(" [e1] (sprintf ", %d, %d)" i j)
       | Cos e -> fn "COS(" [e] ")"
@@ -576,13 +576,13 @@ module Expr = struct
       | If (b, t, f) ->
           let st1 = fn "IF(" [b] "" in
           let st2 = fn ~st:st1 (st1.repr ^ ", ") [t; f] ")" in
-          Sequoia.{ st2 with params = st1.params @ st2.params }
+          { st2 with params = st1.params @ st2.params }
       | From_days e -> fn "FROM_DAYS(" [e] ")"
       | From_unixtime e -> fn "FROM_UNIXTIME(" [e] ")"
       | Ifnull (e1, e2) ->
           let st1 = fn "IFNULL(" [e1] "" in
           let st2 = fn ~st:st1 (st1.repr ^ ", ") [e2] ")" in
-          Sequoia.{ st2 with params = st1.params @ st2.params }
+          { st2 with params = st1.params @ st2.params }
       | Last_day e -> fn "LAST_DAY(" [e] ")"
       | Length e -> fn "LENGTH(" [e] ")"
       | Localtime -> fn "LOCALTIME(" [] ")"
diff --git a/postgresql/dune b/postgresql/dune
new file mode 100644
index 0000000..3c5c752
--- /dev/null
+++ b/postgresql/dune
@@ -0,0 +1,4 @@
+(library
+ (name sequoia_postgresql)
+ (public_name sequoia-postgresql)
+ (libraries sequoia unix))
diff --git a/postgresql/jbuild b/postgresql/jbuild
deleted file mode 100644
index 242b876..0000000
--- a/postgresql/jbuild
+++ /dev/null
@@ -1,8 +0,0 @@
-(jbuild_version 1)
-
-(library
- ((name sequoia_postgresql)
-   (public_name sequoia-postgresql)
-   (libraries
-    (sequoia
-     unix))))
diff --git a/postgresql/postgresql.ml b/postgresql/postgresql.ml
index 8cd9f44..fdad42c 100644
--- a/postgresql/postgresql.ml
+++ b/postgresql/postgresql.ml
@@ -105,7 +105,7 @@ module Field = struct
     | Null.Datetime (_, t) -> t
     | Null.Enum (_, t, _) -> t
     | fld -> table fld
-
+(*
   let to_string : type a b. (a, b) t -> string = function
     | Time (name, table) -> sprintf "%s.%s" (Table.name table) name
     | Timestamp (name, table) -> sprintf "%s.%s" (Table.name table) name
@@ -118,7 +118,7 @@ module Field = struct
     | Null.Datetime (name, table) -> sprintf "%s.%s" (Table.name table) name
     | Null.Enum (name, table, _) -> sprintf "%s.%s" (Table.name table) name
     | other -> to_string other
-
+ *)
   let to_string fld =
     let t = table fld in
     sprintf "%s.%s" (Table.name t) (name fld)
@@ -392,7 +392,7 @@ module Expr = struct
     Lit (Lit.Date { base_time with year; month; day })
   let datetime ?(year = 0) ?(month = 0) ?(day = 0)
                ?(hour = 0) ?(minute = 0) ?(second = 0) = fun _ ->
-    Lit (Lit.Datetime { base_time with year; month; day; minute; second })
+    Lit (Lit.Datetime { year; month; day; hour; minute; second })
 
   let enum inst = fun _ ->
     Lit (Lit.Enum inst)
@@ -419,17 +419,17 @@ module Expr = struct
   let compress f = fun src -> Compress (f src)
   let concat f = fun src -> Concat (f src)
   let concat_ws sep l = fun src -> Concat_ws (sep, List.map (fun f -> f src) l)
-  let connection_id () = fun src -> Connection_id
+  let connection_id () = fun _ -> Connection_id
   let conv f i j = fun src -> Conv (f src, i, j)
   let cos f = fun src -> Cos (f src)
   let cot f = fun src -> Cot (f src)
   let count ?(distinct = false) f = fun src -> Count (f src, distinct)
   let crc32 f = fun src -> Crc32 (f src)
-  let current_date () = fun src -> Current_date
-  let current_time () = fun src -> Current_time
-  let current_timestamp () = fun src -> Current_timestamp
-  let current_user () = fun src -> Current_user
-  let database () = fun src -> Database
+  let current_date () = fun _ -> Current_date
+  let current_time () = fun _ -> Current_time
+  let current_timestamp () = fun _ -> Current_timestamp
+  let current_user () = fun _ -> Current_user
+  let database () = fun _ -> Database
   let date_of : ('s M.Select.source -> [< `Date | `Datetime] time t) -> 's M.Select.source -> [`Date] time t = fun f src -> DateFn (f src)
   let date_add f i u = fun src -> Date_add (f src, i, u)
   let date_format f fmt = fun src -> Date_format (f src, fmt)
@@ -448,7 +448,7 @@ module Expr = struct
   let ifnull f g = fun src -> Ifnull (f src, g src)
   let last_day f = fun src -> Last_day (f src)
   let length f = fun src -> Length (f src)
-  let localtime () = fun src -> Localtime
+  let localtime () = fun _ -> Localtime
   let log f = fun src -> Log (f src)
   let log10 f = fun src -> Log10 (f src)
   let log2 f = fun src -> Log2 (f src)
@@ -460,7 +460,7 @@ module Expr = struct
   let minute f = fun src -> Minute (f src)
   let month f = fun src -> Month (f src)
   let monthname f = fun src -> Monthname (f src)
-  let now () = fun src -> Now
+  let now () = fun _ -> Now
   let nullif f g = fun src -> Nullif (f src, g src)
   let ord f = fun src -> Ord (f src)
   let pow f = fun src -> Pow (f src)
@@ -489,23 +489,23 @@ module Expr = struct
   let timestampdiff u f g = fun src -> Timestampdiff (u, f src, g src)
   let trim f = fun src -> Trim (f src)
   let uncompress f = fun src -> Uncompress (f src)
-  let utc_date () = fun src -> Utc_date
-  let utc_time () = fun src -> Utc_time
-  let utc_timestamp () = fun src -> Utc_timestamp
-  let uuid () = fun src -> Uuid
-  let uuid_short () = fun src -> Uuid_short
-  let week () = fun src -> Week
-  let weekday () = fun src -> Weekday
-  let weekofyear () = fun src -> Weekofyear
+  let utc_date () = fun _ -> Utc_date
+  let utc_time () = fun _ -> Utc_time
+  let utc_timestamp () = fun _ -> Utc_timestamp
+  let uuid () = fun _ -> Uuid
+  let uuid_short () = fun _ -> Uuid_short
+  let week () = fun _ -> Week
+  let weekday () = fun _ -> Weekday
+  let weekofyear () = fun _ -> Weekofyear
   let upper f = fun src -> Upper (f src)
-  let year () = fun src -> Year
+  let year () = fun _ -> Year
 
   let as_time f = fun src -> Cast (f src, Time)
   let as_timestamp f = fun src -> Cast (f src, Timestamp)
   let as_date f = fun src -> Cast (f src, Date)
   let as_datetime f = fun src -> Cast (f src, Datetime)
 
-  let rec build
+  let build
     : type a. handover:handover -> build_step -> a t -> build_step =
     fun ~handover st e ->
       let build_param = build_param D.placeholder in
@@ -543,7 +543,7 @@ module Expr = struct
       | Collation e -> fn "COLLATION(" [e] ")"
       | Compress e -> fn "COMPRESS(" [e] ")"
       | Concat l -> fn "CONCAT(" l ")"
-      | Concat_ws (s, l) -> fn "CONCAT_WS" l ")"
+      | Concat_ws (_s, l) -> fn "CONCAT_WS" l ")"
       | Connection_id -> fn "CONNECTION_ID" [] ")"
       | Conv (e1, i, j) -> fn "CONV(" [e1] (sprintf ", %d, %d)" i j)
       | Cos e -> fn "COS(" [e] ")"
@@ -577,13 +577,13 @@ module Expr = struct
       | If (b, t, f) ->
           let st1 = fn "CASE WHEN " [b] " THEN " in
           let st2 = fn ~st:st1 (st1.repr ^ " ELSE ") [t; f] " END " in
-          Sequoia.{ st2 with params = st1.params @ st2.params }
+          { st2 with params = st1.params @ st2.params }
       | From_days e -> fn "FROM_DAYS(" [e] ")"
       | From_unixtime e -> fn "FROM_UNIXTIME(" [e] ")"
       | Ifnull (e1, e2) ->
           let st1 = fn "IFNULL(" [e1] "" in
           let st2 = fn ~st:st1 (st1.repr ^ ", ") [e2] ")" in
-          Sequoia.{ st2 with params = st1.params @ st2.params }
+          { st2 with params = st1.params @ st2.params }
       | Last_day e -> fn "LAST_DAY(" [e] ")"
       | Length e -> fn "LENGTH(" [e] ")"
       | Localtime -> fn "LOCALTIME(" [] ")"
diff --git a/ppx/dune b/ppx/dune
new file mode 100644
index 0000000..28d143c
--- /dev/null
+++ b/ppx/dune
@@ -0,0 +1,5 @@
+(library
+ (name sequoia_ppx)
+ (public_name sequoia-ppx)
+ (kind ppx_rewriter)
+ (libraries ppxlib sequoia))
diff --git a/ppx/jbuild b/ppx/jbuild
deleted file mode 100644
index 5048228..0000000
--- a/ppx/jbuild
+++ /dev/null
@@ -1,11 +0,0 @@
-(jbuild_version 1)
-
-(library
- ((name sequoia_ppx)
-   (public_name sequoia-ppx)
-   (kind ppx_rewriter)
-   (libraries
-    (sequoia
-     ppx_tools_versioned
-     ocaml-compiler-libs
-     ocaml-migrate-parsetree))))
diff --git a/ppx/sequoia_ppx.ml b/ppx/sequoia_ppx.ml
index e330c7f..5c3cce8 100644
--- a/ppx/sequoia_ppx.ml
+++ b/ppx/sequoia_ppx.ml
@@ -1,12 +1,10 @@
-open Migrate_parsetree
-open Ast_404
-
-open Ast_mapper
-open Ast_helper
+open Ppxlib
 open Asttypes
-open Longident
 open Parsetree
-open Ast_convenience_404
+open Ast_builder.Default
+open Ast_helper
+open Longident
+let lident x = Longident.Lident x
 
 open Printf
 
@@ -23,9 +21,9 @@ let load_state () =
   | None -> None
 
 let error loc msg =
-  raise @@ Location.Error (Location.error ~loc msg)
+  Location.Error.(raise @@ make ~loc ~sub:[] msg)
 
-let construct s = Exp.construct (lid s)
+let construct s = Exp.construct (Located.lident ~loc:Location.none s)
 
 let there = construct "There" None
 let skip x = construct "Skip" (Some x)
@@ -50,27 +48,27 @@ let find_reference loc refs ref =
   with Not_found ->
     error loc (sprintf "reference for %s.%s not found" (fst ref) (snd ref))
 
-module StringSet = Set.Make(struct
+module StringSet = Stdlib.Set.Make(struct
   type t = string
-  let compare = compare
+  let compare = Stdlib.compare
 end)
 
 let rec map_expr_list loc f = function
   | { pexp_desc =
-      Pexp_construct ({ txt = Lident "::" } as cons,
-                      Some ({ pexp_desc = Pexp_tuple [expr; rest]; pexp_loc } as args)) } as e ->
+      Pexp_construct ({ txt = Lident "::"; _ } as cons,
+                      Some ({ pexp_desc = Pexp_tuple [expr; rest]; pexp_loc; _ } as args)); _ } as e ->
     let l = [f pexp_loc expr; map_expr_list pexp_loc f rest] in
     { e with pexp_desc = Pexp_construct (cons,
                                          Some { args with pexp_desc = Pexp_tuple l }) }
   | { pexp_desc =
-      Pexp_construct ({ txt = Lident "[]" }, None) } as e ->
+      Pexp_construct ({ txt = Lident "[]"; _ }, None); _ } as e ->
     e
 
-  | { pexp_desc = Pexp_open (ovr, loc, ({ pexp_loc } as e)) } as expr ->
+  | { pexp_desc = Pexp_open (ovr, ({ pexp_loc; _ } as e)); _ } as expr ->
       let e = map_expr_list pexp_loc f e in
-      { expr with pexp_desc = Pexp_open (ovr, loc, e) }
+      { expr with pexp_desc = Pexp_open (ovr, e) }
 
-  | e ->
+  | _ ->
       error loc "unexpected element in select expression"
 
 let add_table t u ts =
@@ -81,7 +79,7 @@ let add_table t u ts =
 
 let rec map_query st loc = function
   | { pexp_desc =
-      Pexp_let (rec_flag, [{ pvb_expr } as b], ({ pexp_loc } as expr)) } ->
+      Pexp_let (rec_flag, [{ pvb_expr; _ } as b], ({ pexp_loc; _ } as expr)); _ } ->
 
       let e = map_query st loc pvb_expr in
       let binding = { b with pvb_expr = e } in
@@ -89,9 +87,9 @@ let rec map_query st loc = function
       Exp.let_ rec_flag [binding] expr
 
   (* nested let%sql = ... *)
-  | { pexp_desc = Pexp_extension ({ txt = "sql"; loc }, pstr) } ->
+  | { pexp_desc = Pexp_extension ({ txt = "sql"; loc }, pstr); _ } ->
       begin match pstr with
-      | PStr [{ pstr_desc = Pstr_eval (expr, _) }] ->
+      | PStr [{ pstr_desc = Pstr_eval (expr, _); _ }] ->
           let expr =
             match load_state () with
             | Some st -> map_query st loc expr
@@ -104,26 +102,26 @@ let rec map_query st loc = function
   (* from MyTable.table *)
   | { pexp_desc =
       Pexp_apply ({ pexp_desc =
-                    Pexp_ident { txt = Lident "from"; loc } },
+                    Pexp_ident { txt = Lident "from"; _ }; _ },
                   [(_, { pexp_desc =
-                         Pexp_ident { txt = Ldot (Lident t, _) } })]) } as e ->
+                         Pexp_ident { txt = Ldot (Lident t, _); _ }; _ })]); _ } as e ->
       st.tables := [t];
       e
 
   (* {left,right,inner}_join (that Table.fk) *)
   | { pexp_desc =
       Pexp_apply
-        (({ pexp_desc = Pexp_ident { txt = Lident join_fun } } as join),
+        (({ pexp_desc = Pexp_ident { txt = Lident join_fun; _ }; _ } as join),
          [(Nolabel,
            ({ pexp_desc =
              Pexp_apply
                (({ pexp_desc =
-                   Pexp_ident { txt = Lident "that" } } as rel),
+                   Pexp_ident { txt = Lident "that"; _ }; _ } as rel),
                 (([(Nolabel,
                     { pexp_desc =
                       Pexp_ident
                         { txt = Ldot (Lident tbl, fld)
-                        ; loc } })]) as args)) } as join_args))]) } as e
+                        ; loc; _ }; _ })]) as args)); _ } as join_args))]); _ } as e
         when join_fun = "left_join"
           || join_fun = "right_join"
           || join_fun = "inner_join" ->
@@ -144,17 +142,17 @@ let rec map_query st loc = function
   (* {left,right,inner}_join (this Table.fk) *)
   | { pexp_desc =
       Pexp_apply
-        (({ pexp_desc = Pexp_ident { txt = Lident join_fun } } as join),
+        (({ pexp_desc = Pexp_ident { txt = Lident join_fun; _ }; _ } as join),
          [(Nolabel,
            ({ pexp_desc =
              Pexp_apply
                (({ pexp_desc =
-                   Pexp_ident { txt = Lident "this" } } as rel),
+                   Pexp_ident { txt = Lident "this"; _ }; _ } as rel),
                 (([(Nolabel,
                     { pexp_desc =
                       Pexp_ident
                         { txt = Ldot (Lident tbl, fld)
-                        ; loc } })]) as args)) } as join_args))]) } as e
+                        ; loc; _ }; _ })]) as args)); _ } as join_args))]); _ } as e
         when join_fun = "left_join"
           || join_fun = "right_join"
           || join_fun = "inner_join" ->
@@ -175,17 +173,17 @@ let rec map_query st loc = function
   (* {left,right,inner}_join (self Table.k) *)
   | { pexp_desc =
       Pexp_apply
-        (({ pexp_desc = Pexp_ident { txt = Lident join_fun } } as join),
+        (({ pexp_desc = Pexp_ident { txt = Lident join_fun; _ }; _ } as join),
          [(Nolabel,
            ({ pexp_desc =
              Pexp_apply
-               (({ pexp_desc = Pexp_ident { txt = Lident "self" } } as rel),
+               (({ pexp_desc = Pexp_ident { txt = Lident "self"; _ }; _ } as rel),
                 (([ (Nolabel,
                      { pexp_desc =
                        Pexp_ident
-                         { txt = Ldot (Lident tbl, fld) ; loc } })
+                         { txt = Ldot (Lident tbl, _fld) ; loc; _ }; _ })
                   ; _
-                  ]) as args)) } as join_args))]) } as e
+                  ]) as args)); _ } as join_args))]); _ } as e
         when join_fun = "left_join"
           || join_fun = "right_join"
           || join_fun = "inner_join" ->
@@ -205,30 +203,30 @@ let rec map_query st loc = function
   (* select *)
   | { pexp_desc =
       Pexp_apply (({ pexp_desc =
-                     Pexp_ident { txt = Lident "select"; loc } } as select), [lbl, args]) } as e ->
+                     Pexp_ident { txt = Lident "select"; loc; _ }; _ } as select), [lbl, args]); _ } as e ->
       { e with pexp_desc =
                Pexp_apply (select, [lbl, map_expr_list loc (map_select st) args]) }
 
   (* select ~distinct:... *)
   | { pexp_desc =
       Pexp_apply (({ pexp_desc =
-                     Pexp_ident { txt = Lident "select"; loc } } as select),
-                     [(Labelled "distinct", _) as dist; lbl, args]) } as e ->
+                     Pexp_ident { txt = Lident "select"; loc; _ }; _ } as select),
+                     [(Labelled "distinct", _) as dist; lbl, args]); _ } as e ->
       { e with pexp_desc =
                Pexp_apply (select, [dist; lbl, map_expr_list loc (map_select st) args]) }
 
   (* group_by Expr.[...] *)
   | { pexp_desc =
       Pexp_apply (({ pexp_desc =
-                     Pexp_ident { txt = Lident "group_by"; loc } } as gb), [lbl, args]) } as e ->
+                     Pexp_ident { txt = Lident "group_by"; loc; _ }; _ } as gb), [lbl, args]);_ } as e ->
       { e with pexp_desc =
                Pexp_apply (gb, [lbl, map_expr_list loc (map_select st) args]) }
 
   (* group_by Expr.[...] ~having:... *)
   | { pexp_desc =
       Pexp_apply (({ pexp_desc =
-                     Pexp_ident { txt = Lident "group_by"; loc } } as gb),
-                  [(lbl, args); (Labelled "having", hav)]) } as e ->
+                     Pexp_ident { txt = Lident "group_by"; loc; _ }; _ } as gb),
+                  [(lbl, args); (Labelled "having", hav)]); _ } as e ->
       { e with pexp_desc =
                Pexp_apply
                  (gb,
@@ -239,8 +237,8 @@ let rec map_query st loc = function
   (* group_by ~having:... Expr.[...] *)
   | { pexp_desc =
       Pexp_apply (({ pexp_desc =
-                     Pexp_ident { txt = Lident "group_by"; loc } } as gb),
-                  [(Labelled "having", hav); (lbl, args)]) } as e ->
+                     Pexp_ident { txt = Lident "group_by"; loc; _ }; _ } as gb),
+                  [(Labelled "having", hav); (lbl, args)]); _ } as e ->
       { e with pexp_desc =
                Pexp_apply
                  (gb,
@@ -251,46 +249,46 @@ let rec map_query st loc = function
   (* order_by Expr.[...] *)
   | { pexp_desc =
       Pexp_apply (({ pexp_desc =
-                     Pexp_ident { txt = Lident "order_by"; loc } } as ob), [lbl, args]) } as e ->
+                     Pexp_ident { txt = Lident "order_by"; loc; _ }; _ } as ob), [lbl, args]); _ } as e ->
       { e with pexp_desc =
                Pexp_apply (ob, [lbl, map_expr_list loc (map_select st) args]) }
 
   (* field Table.field *)
   | { pexp_desc =
       Pexp_apply (({ pexp_desc =
-                     Pexp_ident { txt = Lident fn; loc } } as fld),
+                     Pexp_ident { txt = Lident fn; loc; _ }; _ } as fld),
                   ([ (Nolabel,
                       { pexp_desc =
-                        Pexp_ident { txt = Ldot (Lident table, field) } })
-                  ] as args)) } as e
-        when fn = "field"|| fn = "foreign_key" ->
+                        Pexp_ident { txt = Ldot (Lident table, _field);_ };_ })
+                  ] as args));_ } as e
+       when fn = "field"|| fn = "foreign_key" ->
       let steps = build_steps (index loc table !(st.tables)) in
       { e with pexp_desc = Pexp_apply (fld, snoc (Nolabel, steps) args) }
 
-  | { pexp_desc = Pexp_apply (({ pexp_loc } as e), args) } as expr ->
+  | { pexp_desc = Pexp_apply (({ pexp_loc;_ } as e), args);_ } as expr ->
       let args =
         List.map
-          (fun (lbl, ({ pexp_loc } as e)) ->
+          (fun (lbl, ({ pexp_loc; _ } as e)) ->
             (lbl, map_query st pexp_loc e))
           args in
       let e = map_query st pexp_loc e in
       { expr with pexp_desc = Pexp_apply (e, args) }
 
-  | { pexp_desc = Pexp_open (ovr, loc, ({ pexp_loc } as e)) } as expr ->
+  | { pexp_desc = Pexp_open (ovr, ({ pexp_loc;_ } as e));_ } as expr ->
       let e = map_query st pexp_loc e in
-      { expr with pexp_desc = Pexp_open (ovr, loc, e) }
+      { expr with pexp_desc = Pexp_open (ovr, e) }
 
   | e ->
       e
 
-and map_select st loc = function
+and map_select st _loc = function
   (* select [...; field|foreign_key|unwrap Table.field; ...] *)
   | { pexp_desc =
       Pexp_apply
         (({ pexp_desc =
-            Pexp_ident { txt = Lident fn; loc } } as fld),
+            Pexp_ident { txt = Lident fn; loc; _ };_ } as fld),
          ([(_, { pexp_desc =
-                 Pexp_ident { txt = Ldot (Lident t, _) } })] as args)) } as e
+                 Pexp_ident { txt = Ldot (Lident t, _); _ }; _ })] as args)); _ } as e
         when fn = "field" || fn = "foreign_key" || fn = "unwrap" ->
       let steps = build_steps (index loc t !(st.tables)) in
       { e with pexp_desc = Pexp_apply (fld, snoc (Nolabel, steps) args) }
@@ -298,20 +296,20 @@ and map_select st loc = function
   (* select [...; subquery (from ...); ...] *)
   | { pexp_desc =
       Pexp_apply (({ pexp_desc =
-                     Pexp_ident { txt = Lident "subquery"; loc } } as sub),
-                  [(lbl, expr)]) } as e ->
+                     Pexp_ident { txt = Lident "subquery"; _ }; _ } as sub),
+                  [(lbl, expr)]); _ } as e ->
 
       let st' = { st with tables = ref [] } in
       let expr = map_query st' expr.pexp_loc expr in
       { e with pexp_desc = Pexp_apply (sub, [(lbl, expr)]) }
 
-  | { pexp_desc = Pexp_apply (fn, args) } as e ->
+  | { pexp_desc = Pexp_apply (fn, args); _ } as e ->
       let args =
         List.map
           (fun (lbl, arg_expr) ->
             match arg_expr with
             (* List argument: map each expression *)
-            | { pexp_desc = Pexp_construct ({ txt = Lident "::" }, _) } ->
+            | { pexp_desc = Pexp_construct ({ txt = Lident "::"; _ }, _); _ } ->
                 (lbl, map_expr_list arg_expr.pexp_loc (map_select st) arg_expr)
             | _ ->
                 (lbl, map_select st arg_expr.pexp_loc arg_expr))
@@ -321,111 +319,120 @@ and map_select st loc = function
   | e ->
       e
 
-let rec map_module table references loc = function
+let rec map_module table references _loc = function
   | [] -> ()
 
   (* Field.foreign_key name ~references:Some.field *)
   | { pstr_desc =
       Pstr_value (_,
-        [{ pvb_pat  = { ppat_desc = Ppat_var { txt = field } }
+        [{ pvb_pat  = { ppat_desc = Ppat_var { txt = field; _ }; _ }
          ; pvb_expr =
            { pexp_desc =
              Pexp_apply ({
                pexp_desc =
-               Pexp_ident { txt = Ldot (Lident "Field", "foreign_key") } },
+               Pexp_ident { txt = Ldot (Lident "Field", "foreign_key"); _ };_ },
                  [ (Nolabel,
-                     { pexp_desc = Pexp_constant (Pconst_string (_, None)) })
+                     { pexp_desc = Pexp_constant (Pconst_string (_, _, None)); _ })
                  ; (Labelled "references",
                      { pexp_desc =
                        Pexp_ident
-                        { txt = Ldot (Lident ref_table, ref_field) } })
-                 ]) }
-             }])
-    ; pstr_loc } :: rest ->
+                        { txt = Ldot (Lident ref_table, ref_field); _ };_ })
+                 ]); _ }; _ }])
+    ; pstr_loc; _ } :: rest ->
       Hashtbl.add references (table, field) (ref_table, ref_field);
       map_module table references pstr_loc rest
 
   (* Field.foreign_key ~references:Some.field name *)
   | { pstr_desc =
       Pstr_value (_,
-        [{ pvb_pat  = { ppat_desc = Ppat_var { txt = field } }
+        [{ pvb_pat  = { ppat_desc = Ppat_var { txt = field;_ };_ }
          ; pvb_expr =
            { pexp_desc =
              Pexp_apply ({
                pexp_desc =
-               Pexp_ident { txt = Ldot (Lident "Field", "foreign_key") } },
+               Pexp_ident { txt = Ldot (Lident "Field", "foreign_key");_ };_ },
                  [ (Labelled "references",
                      { pexp_desc =
                        Pexp_ident
-                        { txt = Ldot (Lident ref_table, ref_field) } })
+                        { txt = Ldot (Lident ref_table, ref_field);_ };_ })
                  ; (Nolabel,
-                     { pexp_desc = Pexp_constant (Pconst_string (_, None)) })
-                 ]) }
-             }])
-    ; pstr_loc } :: rest ->
+                     { pexp_desc = Pexp_constant (Pconst_string (_, _, None));_ })
+                 ]); _ }; _  }])
+    ; pstr_loc; _ } :: rest ->
       Hashtbl.add references (table, field) (ref_table, ref_field);
       map_module table references pstr_loc rest
 
-  | { pstr_loc } :: rest ->
+  | { pstr_loc; _ } :: rest ->
       map_module table references pstr_loc rest
 
-let sql_mapper references _config _cookies =
-  { default_mapper with
-    expr =
-      (fun mapper expr ->
-        match expr with
-        (* let%sql = ... *)
-        | { pexp_desc = Pexp_extension ({ txt = "sql"; loc }, pstr) } ->
-            begin match pstr with
-            | PStr [{ pstr_desc = Pstr_eval (expr, _) }] ->
-                let expr =
-                  match load_state () with
-                  | Some st -> map_query st loc expr
-                  | None -> expr in
-                Ast_helper.with_default_loc loc (fun () -> expr)
-            | _ ->
-                error loc "invalid sql"
-            end
-        | x -> default_mapper.expr mapper x)
-
-  ; structure_item =
-      (fun mapper str ->
-        match str with
-        (* module%sql ... = struct ... end *)
-        | { pstr_desc = Pstr_extension (({ txt = "sql"; loc }, pstr), _) } ->
-            begin match pstr with
-            | PStr
-                [{ pstr_desc =
-                   Pstr_module
-                    ({ pmb_name = { txt = name }
-                     ; pmb_expr = { pmod_desc = Pmod_structure strs }
-                     ; pmb_loc } as m) }] ->
-                map_module name references pmb_loc strs;
-                global_references := Some references;
-                let str = Str.module_ m in
-                Ast_helper.with_default_loc loc (fun () -> str)
-            | PStr
-                [{ pstr_desc =
-                  Pstr_value (rec_flag, [{ pvb_expr } as b]) }] ->
-                let str =
-                  match load_state () with
-                  | Some st ->
-                      let expr = map_query st loc pvb_expr in
-                      let binding = { b with pvb_expr = expr } in
-                      Str.value rec_flag [binding]
-                  | None ->
-                      Str.value rec_flag [b] in
-                Ast_helper.with_default_loc loc (fun () -> str)
-            | _ ->
-                error loc "invalid sql"
-            end
-        | x -> default_mapper.structure_item mapper x)
-  }
-
-let migration =
-  Versions.migrate Versions.ocaml_404 Versions.ocaml_current
+let map_expr _references expr =
+  (* let%sql = ... *)
+  match load_state () with
+  | Some st -> map_query st expr.pexp_loc expr
+  | None -> expr
+
+let map_str references pstr =
+     match pstr with
+    { pstr_desc =
+            Pstr_module
+              ({ pmb_name = { txt = Some name; _ }
+               ; pmb_expr = { pmod_desc = Pmod_structure strs; _ }
+               ; pmb_loc; _ } as m); pstr_loc;  _ } ->
+        map_module name references pmb_loc strs;
+        global_references := Some references;
+        let str = Str.module_ m in
+        Ast_helper.with_default_loc pstr_loc (fun () -> str)
+     | { pstr_desc =
+                Pstr_value (rec_flag, [{ pvb_expr; _ } as b]); pstr_loc; _ } ->
+        let str =
+          match load_state () with
+          | Some st ->
+             let expr = map_query st pstr_loc pvb_expr in
+             let binding = { b with pvb_expr = expr } in
+             Str.value rec_flag [binding]
+          | None ->
+             Str.value rec_flag [b] in
+        Ast_helper.with_default_loc pstr_loc (fun () -> str)
+     | s -> s
+
+let references = Hashtbl.create 16
+
+let map_all = object
+    inherit Ast_traverse.map as super
+
+    method! expression e =
+      super#expression (map_expr references e)
+
+    method! structure_item =
+      (fun i -> super#structure_item (map_str references i))
+  end
+
+let rule_expr =
+  let ctx = Extension.Context.expression in
+  let pat = Ast_pattern.(single_expr_payload __) in
+  let ext = Extension.declare "sql" ctx pat
+              (fun ~loc:_ ~path:_ -> map_all#expression) in
+  Context_free.Rule.extension ext
+
+(* transform a list of structure_items in one *)
+let flatten_str items =
+  match items with
+  | [x] -> x
+  | _ ->
+     Str.include_ { pincl_mod = Mod.structure items
+                  ; pincl_loc = Location.none
+                  ; pincl_attributes = [] }
+
+(* TODO: why is flatten_str needed ? *)
+let rule_str_item =
+  let ctx = Extension.Context.structure_item in
+  let pat = Ast_pattern.(pstr __) in
+  let ext = Extension.declare "sql" ctx pat
+              (fun ~loc:_ ~path:_ l ->
+                flatten_str (List.map map_all#structure_item l)) in
+  Context_free.Rule.extension ext
 
 let () =
-  let references = Hashtbl.create 16 in
-  Driver.register ~name:"ppx_sequoia"
-    Versions.ocaml_404 (sql_mapper references)
+  Driver.register_transformation
+    ~rules:[rule_expr; rule_str_item]
+    "ppx_sequoia"
diff --git a/sequoia-mysql.opam b/sequoia-mysql.opam
index 7b6d648..042354a 100644
--- a/sequoia-mysql.opam
+++ b/sequoia-mysql.opam
@@ -1,12 +1,12 @@
 opam-version: "1.2"
-version: "0.1.0"
+version: "0.2.0"
 maintainer: "Andre Nathan <andrenth@gmail.com>"
 authors: "Andre Nathan <andrenth@gmail.com>"
 homepage: "https://github.com/andrenth/sequoia"
 bug-reports: "https://github.com/andrenth/sequoia"
 license: "MIT"
 dev-repo: "https://github.com/andrenth/sequoia"
-available: [ ocaml-version >= "4.04.0" ]
+available: [ ocaml-version >= "4.12.0" ]
 build: [
   ["jbuilder" "subst" "-n" name] {pinned}
   ["jbuilder" "build" "-p" name "-j" jobs]
diff --git a/sequoia-postgresql.opam b/sequoia-postgresql.opam
index 2c94539..ab7dea7 100644
--- a/sequoia-postgresql.opam
+++ b/sequoia-postgresql.opam
@@ -1,18 +1,28 @@
 opam-version: "1.2"
-version: "0.1.0"
+version: "0.2.0"
 maintainer: "Andre Nathan <andrenth@gmail.com>"
 authors: "Andre Nathan <andrenth@gmail.com>"
 homepage: "https://github.com/andrenth/sequoia"
 bug-reports: "https://github.com/andrenth/sequoia"
 license: "MIT"
 dev-repo: "https://github.com/andrenth/sequoia"
-available: [ ocaml-version >= "4.04.0" ]
+available: [ ocaml-version >= "4.12.0" ]
 build: [
-  ["jbuilder" "build" "-p" name "-j" jobs]
+  ["dune" "subst"] {dev}
+  [
+    "dune"
+    "build"
+    "-p"
+    name
+    "-j"
+    jobs
+    "@install"
+    "@runtest" {with-test}
+    "@doc" {with-doc}
+  ]
 ]
-build-test: [["jbuilder" "runtest" "-p" name "-j" jobs]]
 depends: [
-  "jbuilder" {build}
+  "dune" {build}
   "base-unix"
   "sequoia"
 ]
diff --git a/sequoia-ppx.opam b/sequoia-ppx.opam
index dece24c..d236c65 100644
--- a/sequoia-ppx.opam
+++ b/sequoia-ppx.opam
@@ -1,18 +1,28 @@
 opam-version: "1.2"
-version: "0.1.0"
+version: "0.2.0"
 maintainer: "Andre Nathan <andrenth@gmail.com>"
 authors: "Andre Nathan <andrenth@gmail.com>"
 homepage: "https://github.com/andrenth/sequoia"
 bug-reports: "https://github.com/andrenth/sequoia"
 license: "MIT"
 dev-repo: "https://github.com/andrenth/sequoia"
-available: [ ocaml-version >= "4.04.0" ]
+available: [ ocaml-version >= "4.12.0" ]
 build: [
-  ["jbuilder" "build" "-p" name "-j" jobs]
+  ["dune" "subst"] {dev}
+  [
+    "dune"
+    "build"
+    "-p"
+    name
+    "-j"
+    jobs
+    "@install"
+    "@runtest" {with-test}
+    "@doc" {with-doc}
+  ]
 ]
-build-test: [["jbuilder" "runtest" "-p" name "-j" jobs]]
 depends: [
-  "jbuilder" {build}
+  "dune" {build}
   "sequoia"
   "ppx_tools_versioned"
   "ocaml-migrate-parsetree"
diff --git a/sequoia-sqlite.opam b/sequoia-sqlite.opam
index 61ab0d6..e89cd5e 100644
--- a/sequoia-sqlite.opam
+++ b/sequoia-sqlite.opam
@@ -1,12 +1,12 @@
 opam-version: "1.2"
-version: "0.1.0"
+version: "0.2.0"
 maintainer: "Andre Nathan <andrenth@gmail.com>"
 authors: "Andre Nathan <andrenth@gmail.com>"
 homepage: "https://github.com/andrenth/sequoia"
 bug-reports: "https://github.com/andrenth/sequoia"
 license: "MIT"
 dev-repo: "https://github.com/andrenth/sequoia"
-available: [ ocaml-version >= "4.04.0" ]
+available: [ ocaml-version >= "4.12.0" ]
 build: [
   ["jbuilder" "subst" "-n" name] {pinned}
 ]
diff --git a/sequoia.opam b/sequoia.opam
index c540f65..8e9db57 100644
--- a/sequoia.opam
+++ b/sequoia.opam
@@ -1,16 +1,27 @@
 opam-version: "1.2"
-version: "0.1.0"
+version: "0.2.0"
 maintainer: "Andre Nathan <andrenth@gmail.com>"
 authors: "Andre Nathan <andrenth@gmail.com>"
 homepage: "https://github.com/andrenth/sequoia"
 bug-reports: "https://github.com/andrenth/sequoia"
 license: "MIT"
 dev-repo: "https://github.com/andrenth/sequoia"
-available: [ ocaml-version >= "4.04.0" ]
+available: [ ocaml-version >= "4.12.0" ]
 build: [
-  ["jbuilder" "build" "-p" name "-j" jobs]
+  ["dune" "subst"] {dev}
+  [
+    "dune"
+    "build"
+    "-p"
+    name
+    "-j"
+    jobs
+    "@install"
+    "@runtest" {with-test}
+    "@doc" {with-doc}
+  ]
 ]
 build-test: [["jbuilder" "runtest" "-p" name "-j" jobs]]
 depends: [
-  "jbuilder" {build}
+  "dune" {build}
 ]
diff --git a/sqlite/dune b/sqlite/dune
new file mode 100644
index 0000000..a3e94d2
--- /dev/null
+++ b/sqlite/dune
@@ -0,0 +1,4 @@
+(library
+ (name sequoia_sqlite)
+ (public_name sequoia-sqlite)
+ (libraries sequoia))
diff --git a/sqlite/jbuild b/sqlite/jbuild
deleted file mode 100644
index de54a37..0000000
--- a/sqlite/jbuild
+++ /dev/null
@@ -1,6 +0,0 @@
-(jbuild_version 1)
-
-(library
- ((name sequoia_sqlite)
-   (public_name sequoia-sqlite)
-   (libraries (sequoia))))
diff --git a/sqlite/sqlite.ml b/sqlite/sqlite.ml
index 29805bc..1003e78 100644
--- a/sqlite/sqlite.ml
+++ b/sqlite/sqlite.ml
@@ -62,8 +62,7 @@ module Expr = struct
     | Sum : int t -> int t
     | Total : int t -> int t
 
-  let avg f = fun src -> Avg (f src)
-  let changes () = fun src -> Changes
+  let changes () = fun _ -> Changes
   let char f = fun src -> Char (f src)
   let coalesce f = fun src -> Coalesce (f src)
   let glob pat f = fun src -> Glob (pat, f src)
@@ -78,7 +77,7 @@ module Expr = struct
   let max f = fun src -> Max (f src)
   let min f = fun src -> Min (f src)
   let nullif f g = fun src -> Nullif (f src, g src)
-  let random () = fun src -> Random
+  let random () = fun _ -> Random
   let randomblob f = fun src -> Randomblob (f src)
   let replace f s1 s2 = fun src -> Replace (f src, s1, s2)
   let round f ?digits = fun src -> Round (f src, digits)
@@ -102,7 +101,7 @@ module Expr = struct
   let sum f = fun src -> Sum (f src)
   let total f = fun src -> Total (f src)
 
-  let rec build
+  let build
     : type a. handover:handover -> build_step -> a t -> build_step =
     fun ~handover st e ->
       let fn ?(st = st) =
diff --git a/src/delete.ml b/src/delete.ml
index baf79ca..e207bbb 100644
--- a/src/delete.ml
+++ b/src/delete.ml
@@ -4,7 +4,7 @@ open Common
 module type S = sig
   type _ t
 
-  val delete : ?where:('t Table.t -> bool Expr.t) -> from:'t Table.t -> 't t
+  val delete : ?where:('t Table.t -> bool Expr.t) -> from:'t Table.t -> unit -> 't t
   val seal : handover:Expr.handover -> 't t -> string * Param.t list
 
   module Expr : module type of Query_common.UpdateDeleteExpr
@@ -16,7 +16,7 @@ module Make (D : Driver.S) : S = struct
   type 't t =
     | D : { table : 't Table.t; where : 'a Expr.t option } -> 't t
 
-  let delete ?where ~from =
+  let delete ?where ~from () =
     let where =
       match where with
       | Some expr -> Some (expr from)
diff --git a/src/delete.mli b/src/delete.mli
index e0f2497..31c26de 100644
--- a/src/delete.mli
+++ b/src/delete.mli
@@ -4,7 +4,7 @@ module type S = sig
 		(** The type of [DELETE] queries. *)
 
   val delete : ?where:('t Table.t -> bool Expr.t)
-            -> from:'t Table.t
+            -> from:'t Table.t -> unit
             -> 't t
 		(** Define a [DELETE] query on the table given by [from] and conditions
         specified by [where]. *)
diff --git a/src/dune b/src/dune
new file mode 100644
index 0000000..9089f7b
--- /dev/null
+++ b/src/dune
@@ -0,0 +1,6 @@
+(include_subdirs unqualified)
+
+(library
+  (name sequoia)
+  (public_name sequoia)
+  (modules :standard))
diff --git a/src/expr.mli b/src/expr.mli
index b5f481f..525d1a5 100644
--- a/src/expr.mli
+++ b/src/expr.mli
@@ -5,6 +5,7 @@ type 'a t = ..
 	(** The type of expressions. It is extended by the query modules (i.e.
 			[Select], [Insert], etc.) to account for expressions that are only
       valid for the respective query types. *)
+
 type 'a cast = ..
 	(** The type that represents an SQL [CAST()]. *)
 
@@ -49,51 +50,73 @@ module Base : sig
 
   val (=)    : ('a -> 'b t) -> ('a -> 'b t) -> 'a -> bool t
 		(** The [=] operator. *)
+
   val (=%)   : ('a -> string t) -> string -> 'a -> bool t
 		(** The [LIKE] operator. *)
+
   val (<>)   : ('a -> 'b t) -> ('a -> 'b t) -> 'a -> bool t
 		(** The [<>] operator. *)
+
   val (<>%)  : ('a -> string t) -> string -> 'a -> bool t
 		(** The [NOT LIKE] operator. *)
+
   val (>)    : ('a -> 'b t) -> ('a -> 'b t) -> 'a -> bool t
 		(** The [>] operator. *)
+
   val (>=)   : ('a -> 'b t) -> ('a -> 'b t) -> 'a -> bool t
 		(** The [>=] operator. *)
+
   val (<)    : ('a -> 'b t) -> ('a -> 'b t) -> 'a -> bool t
 		(** The [<] operator. *)
+
   val (<=)   : ('a -> 'b t) -> ('a -> 'b t) -> 'a -> bool t
 		(** The [<=] operator. *)
+
   val (&&)   : ('a -> bool t) -> ('a -> bool t) -> 'a -> bool t
 		(** The [AND] operator. *)
+
   val (||)   : ('a -> bool t) -> ('a -> bool t) -> 'a -> bool t
 		(** The [OR] operator. *)
+
   val (+)    : ('a -> int t) -> ('a -> int t) -> 'a -> int t
 		(** The [+] operator for integers. *)
+
   val (-)    : ('a -> int t) -> ('a -> int t) -> 'a -> int t
 		(** The [-] operator for integers. *)
+
   val ( * )  : ('a -> int t) -> ('a -> int t) -> 'a -> int t
 		(** The [*] operator for integers. *)
+
   val (/)    : ('a -> int t) -> ('a -> int t) -> 'a -> int t
 		(** The [/] operator for integers. *)
+
   val (+.)   : ('a -> float t) -> ('a -> float t) -> 'a -> float t
 		(** The [+] operator for floats. *)
+
   val (-.)   : ('a -> float t) -> ('a -> float t) -> 'a -> float t
 		(** The [-] operator for floats. *)
+
   val ( *. ) : ('a -> float t) -> ('a -> float t) -> 'a -> float t
 		(** The [*] operator for floats. *)
+
   val (/.)   : ('a -> float t) -> ('a -> float t) -> 'a -> float t
 		(** The [/] operator for floats. *)
+
   val (<<)   : ('a -> int t) -> int -> 'a -> int t
 		(** The [<<] operator. *)
+
   val (>>)   : ('a -> int t) -> int -> 'a -> int t
 		(** The [>>] operator. *)
+
   val (=?)   : ('a -> 'b t) -> ('a -> 'b t) list -> 'a -> bool t
 		(** The [IN] operator. *)
+
   val (<>?)  : ('a -> 'b t) -> ('a -> 'b t) list -> 'a -> bool t
 		(** The [NOT IN] operator. *)
 
   val is_null : ('a -> 'b option t) -> 'a -> bool t
 		(** The [IS NULL] operator. *)
+
   val is_not_null : ('a -> 'b option t) -> 'a -> bool t
 		(** The [IS NOT NULL] operator. *)
 
@@ -101,12 +124,16 @@ module Base : sig
 
   val bool   : bool -> 'a -> bool t
 		(** A boolean value expression. *)
+
   val int    : int -> 'a -> int t
 		(** An int value expression. *)
+
   val float  : float -> 'a -> float t
 		(** A float value expression. *)
+
   val string : string -> 'a -> string t
 		(** A string value expression. *)
+
   val blob   : bytes -> 'a -> bytes t
 		(** A blob value expression. *)
 
@@ -114,12 +141,16 @@ module Base : sig
 
   val as_bool   : ('a -> 'b t) -> 'a -> bool t
 		(** Cast to bool. *)
+
   val as_int    : ('a -> 'b t) -> 'a -> int t
 		(** Cast to int. *)
+
   val as_float  : ('a -> 'b t) -> 'a -> float t
 		(** Cast to float. *)
+
   val as_string : ('a -> 'b t) -> 'a -> string t
 		(** Cast to string. *)
+
   val as_blob   : ('a -> 'b t) -> 'a -> bytes t
 		(** Cast to blob. *)
 
@@ -127,12 +158,16 @@ module Base : sig
   module Null : sig
     val bool   : bool -> 'a -> bool option t
 			(** A nullable boolean value expression. *)
+
     val int    : int -> 'a -> int option t
 			(** A nullable int value expression. *)
+
     val float  : float -> 'a -> float option t
 			(** A nullable float value expression. *)
+
     val string : string -> 'a -> string option t
 			(** A nullable string value expression. *)
+
     val blob   : bytes -> 'a -> bytes option t
 			(** A nullable blob value expression. *)
   end
diff --git a/src/field.mli b/src/field.mli
index 7c8bee5..bfb1cee 100644
--- a/src/field.mli
+++ b/src/field.mli
@@ -17,19 +17,25 @@ type ('t1, 't2) foreign_key = ('t1, int) t * ('t2, int) t
 
 val name : ('t, 'a) t -> string
 	(** The name of a field. *)
+
 val table : ('t, 'a) t -> 't Table.t
 	(** The table a field belongs to. *)
+
 val to_string : ('t, 'a) t -> string
 	(** The string representation of a field, i.e. [table].[name]. *)
 
 val bool : 't Table.t -> string -> ('t, bool) t
 	(** A boolean field. *)
+
 val int : 't Table.t -> string -> ('t, int) t
 	(** An integer field. *)
+
 val float : 't Table.t -> string -> ('t, float) t
 	(** A float field. *)
+
 val string : 't Table.t -> string -> ('t, string) t
 	(** A string field. *)
+
 val blob : 't Table.t -> string -> ('t, bytes) t
 	(** A blob field. *)
 
@@ -48,12 +54,16 @@ module Null : sig
 
   val bool : 't Table.t -> string -> ('t, bool option) t
 		(** A nullable boolean field. *)
+
   val int : 't Table.t -> string -> ('t, int option) t
 		(** A nullable int field. *)
+
   val float : 't Table.t -> string -> ('t, float option) t
 		(** A nullable float field. *)
+
   val string : 't Table.t -> string -> ('t, string option) t
 		(** A nullable string field. *)
+
   val blob : 't Table.t -> string -> ('t, bytes option) t
 		(** A nullable blob field. *)
 end
diff --git a/src/jbuild b/src/jbuild
deleted file mode 100644
index 5f479cf..0000000
--- a/src/jbuild
+++ /dev/null
@@ -1,5 +0,0 @@
-(jbuild_version 1)
-
-(library
- ((name sequoia)
-  (public_name sequoia)))
diff --git a/src/query_common.ml b/src/query_common.ml
index c5bfc5a..1d18e5f 100644
--- a/src/query_common.ml
+++ b/src/query_common.ml
@@ -42,7 +42,7 @@ module UpdateDeleteExpr = struct
   let field fld = fun table -> Field (fld, table)
   let foreign_key fk = fun table -> Foreign (fk, table)
 
-  let rec build
+  let build
     : type a. placeholder:(int -> string)
            -> handover:Expr.handover
            -> build_step
@@ -92,7 +92,6 @@ module InsertReplace = struct
       | f::fs -> Field.name f ^ ", " ^ join_fields fs
 
   let expr_placeholders ~placeholder i vs =
-    let open Lit in
     let rec eps
       : type t a n. int -> (t, a, n) Lit.Vector.t -> string list =
       fun i exprs ->
diff --git a/src/select.ml b/src/select.ml
index 075c5db..a55f81f 100644
--- a/src/select.ml
+++ b/src/select.ml
@@ -224,10 +224,10 @@ module Make (D : Driver.S) : S = struct
     type 'a t = 'a Expr.t
 
     let (-->) expr alias = fun src -> As (expr src, alias)
-    let alias name = fun src -> Alias name
+    let alias name = fun _src -> Alias name
     let field fld steps = fun src -> Field (fld, src, steps)
     let foreign_key fk steps = fun src -> Foreign (fk, src, steps)
-    let subquery sel = fun src -> Select sel
+    let subquery sel = fun _src -> Select sel
 
     (* XXX is there a better name for this? *)
     let unwrap
diff --git a/src/sequoia.ml b/src/sequoia.ml
index fef89aa..7ea2135 100644
--- a/src/sequoia.ml
+++ b/src/sequoia.ml
@@ -1,5 +1,3 @@
-open Printf
-open Common
 
 module type NAMED = sig
   type t
diff --git a/src/sequoia.mli b/src/sequoia.mli
index e26d26e..c8b233f 100644
--- a/src/sequoia.mli
+++ b/src/sequoia.mli
@@ -13,25 +13,34 @@ module type S = sig
 
   module Param  : module type of Param
     (** Query parameters. *)
+
   module Lit    : module type of Lit
     (** Literal values. *)
+
   module Expr   : module type of Expr
     (** Expressions. *)
+
   module Table  : module type of Table
     (** SQL tables. *)
+
   module Field  : module type of Field
     (** Field definitions. *)
+
   module Vector : module type of Vector
     (** Heterogeneous lists with type-encoded length. *)
 
   module Select  : Select.S
     (** [SELECT] queries. *)
+
   module Insert  : Insert.S
     (** [INSERT] queries. *)
+
   module Replace : Replace.S
     (** [REPLACE] queries. *)
+
   module Update  : Update.S
     (** [UPDATE] queries. *)
+
   module Delete  : Delete.S
     (** [DELETE] queries. *)
 
diff --git a/src/update.ml b/src/update.ml
index 45c6a86..f2e7ada 100644
--- a/src/update.ml
+++ b/src/update.ml
@@ -20,6 +20,7 @@ module type S = sig
 
       val asc : ('t Table.t -> 'a Expr.t) -> 't Table.t -> ('t, 'a) expr
       val desc : ('t Table.t -> 'a Expr.t) -> 't Table.t -> ('t, 'a) expr
+
     end
 
     module Vector : Vector.S with type ('t, 'a) elem := ('t, 'a) expr
@@ -37,7 +38,14 @@ module type S = sig
 
     type ('t, 'a) mk = 't Table.t -> ('t, 'a) Expr.expr
 
+    module Vec    : Vector.S with type ('t, 'a) elem := ('t, 'a) Expr.expr
     module Vector : Vector.S with type ('t, 'a) elem := ('t, 'a) mk
+
+    val vectormk_to_vector : 't Table.t
+                             -> ('t, 'a, 'n) Vector.t
+                             -> ('t, 'a, 'n) Vec.t
+
+
   end
 
   module Vector : Vector.S with type ('t, 'a) elem := ('t, 'a) mk
@@ -167,7 +175,7 @@ module Make (D : Driver.S) : S = struct
       let vec = OrderBy.vectormk_to_vector stmt.table bl in
       U { stmt with order_by = Some vec }
 
-  let build_updates ~handover st table updates =
+  let build_updates ~handover st _table updates =
     let fold
       : type t a b. build_step * int
                  -> (t, a) Field.t * (b, a) Expr.expr
diff --git a/src/update.mli b/src/update.mli
index 1cfe26e..cbf946e 100644
--- a/src/update.mli
+++ b/src/update.mli
@@ -67,8 +67,14 @@ module type S = sig
     type ('t, 'a) mk = 't Table.t -> ('t, 'a) Expr.expr
       (** The type of [UPDATE] expression builders. *)
 
+    module Vec    : Vector.S with type ('t, 'a) elem := ('t, 'a) Expr.expr
     module Vector : Vector.S with type ('t, 'a) elem := ('t, 'a) mk
       (** Vector of [UPDATE] expression builders. *)
+
+    val vectormk_to_vector : 't Table.t
+                             -> ('t, 'a, 'n) Vector.t
+                             -> ('t, 'a, 'n) Vec.t
+
   end
 
   module Vector : Vector.S with type ('t, 'a) elem := ('t, 'a) mk
diff --git a/src/vector.ml b/src/vector.ml
index 3dba920..4f68f96 100644
--- a/src/vector.ml
+++ b/src/vector.ml
@@ -46,7 +46,7 @@ struct
     | (::) : ('a, 'b, 'n) t * ('a, 'b, 'm, 'n) matrix
           -> ('a, 'b, 'm Nat.s, 'n) matrix
 
-  type 'z matrix_folder = { mf : 'a 'b. 'z -> ('a, 'b) E.elem -> 'z }
+  (*type 'z matrix_folder = { mf : 'a 'b. 'z -> ('a, 'b) E.elem -> 'z }*)
 
   let rec matrix_fold_left
     : type a b m n. 'z folder -> 'z -> (a, b, m, n) matrix -> 'z =
diff --git a/test/dune b/test/dune
new file mode 100644
index 0000000..7a665b1
--- /dev/null
+++ b/test/dune
@@ -0,0 +1,8 @@
+(alias
+ (name runtest)
+ (deps t.exe))
+
+(executable
+ (name t)
+ (libraries sequoia sequoia-mysql)
+ (preprocess (pps sequoia-ppx)))
diff --git a/test/jbuild b/test/jbuild
deleted file mode 100644
index 08e5a00..0000000
--- a/test/jbuild
+++ /dev/null
@@ -1,12 +0,0 @@
-(jbuild_version 1)
-
-(alias
- ((name runtest)
-  (deps (t.exe))))
-
-(executable
- ((name t)
-  (libraries
-   (sequoia
-    sequoia-mysql))
-  (preprocess (pps (sequoia-ppx)))))
diff --git a/test/ppx/dune b/test/ppx/dune
new file mode 100644
index 0000000..af5e3e2
--- /dev/null
+++ b/test/ppx/dune
@@ -0,0 +1,20 @@
+(alias
+ (name runtest)
+ (deps t.exe))
+
+(rule
+ (target t.ml)
+ (deps
+    (:t t.cppo.ml)
+    (glob_files tables/*.ml)
+    (glob_files queries/*.ml))
+  (action
+     (chdir ${ROOT} (run cppo %{t} -o %{target}))))
+
+(executable
+ (name t)
+ (libraries
+   sequoia
+    sequoia-mysql
+    sequoia-ppx)
+  (preprocess (pps sequoia-ppx)))
diff --git a/test/ppx/jbuild b/test/ppx/jbuild
deleted file mode 100644
index c876b6b..0000000
--- a/test/ppx/jbuild
+++ /dev/null
@@ -1,22 +0,0 @@
-(jbuild_version 1)
-
-(alias
- ((name runtest)
-  (deps (t.exe))))
-
-(rule
- ((targets (t.ml))
-   (deps
-    (t.cppo.ml
-     (glob_files tables/*.ml)
-     (glob_files queries/*.ml)))
-    (action
-     (chdir ${ROOT} (run ${bin:cppo} -V OCAML:${ocaml_version} ${<} -o ${@})))))
-
-(executable
- ((name t)
-  (libraries
-   (sequoia
-    sequoia-mysql
-    sequoia-ppx))
-  (preprocess (pps (sequoia-ppx)))))
diff --git a/test/ppx/queries/q8.ml b/test/ppx/queries/q8.ml
index b7056cc..8777ac8 100644
--- a/test/ppx/queries/q8.ml
+++ b/test/ppx/queries/q8.ml
@@ -1,6 +1,6 @@
 let q8 =
   let query, params =
-    Mysql.(Expr.(Update.(Vector.(Expr.(Vector.(OrderBy.Expr.(Vector.(
+    Mysql.(Expr.(Update.(Vector.(Expr.(OrderBy.(Expr.(Vector.(
       update User.table
         ~set:
           [ User.name, string "John Doe"
diff --git a/test/ppx/queries/q9.ml b/test/ppx/queries/q9.ml
index 075287d..a224029 100644
--- a/test/ppx/queries/q9.ml
+++ b/test/ppx/queries/q9.ml
@@ -1,6 +1,6 @@
 let q9 =
   let query, params = Mysql.(Expr.(Delete.(Expr.(
-    delete ~from:User.table ~where:(field User.name = string "john doe")
+    delete ~from:User.table ~where:(field User.name = string "john doe") ()
       |> seal
   )))) in
   query, params
diff --git a/test/ppx/readme/jbuild b/test/ppx/readme/jbuild
deleted file mode 100644
index 634d225..0000000
--- a/test/ppx/readme/jbuild
+++ /dev/null
@@ -1,13 +0,0 @@
-(jbuild_version 1)
-
-(alias
- ((name runtest)
-  (deps (readme.exe))))
-
-(executable
- ((name readme)
-  (libraries
-   (sequoia
-    sequoia-mysql
-    sequoia-ppx))
-  (preprocess (pps (sequoia-ppx)))))
diff --git a/test/ppx/t.cppo.ml b/test/ppx/t.cppo.ml
index 229ba33..d06ab96 100644
--- a/test/ppx/t.cppo.ml
+++ b/test/ppx/t.cppo.ml
@@ -10,12 +10,15 @@ module Bool = struct
         (module struct
           type t = True
           let to_string = "TRUE"
+          let _ = True (* avoid warning *)
         end : Mysql.Enum.Instance)
     | False ->
         (module struct
           type t = False
           let to_string = "FALSE"
-        end : Mysql.Enum.Instance)
+	  let _ = False
+          end : Mysql.Enum.Instance)
+
 end
 
 module Tables = struct
diff --git a/test/t.ml b/test/t.ml
index e23cfc3..c6fbf85 100644
--- a/test/t.ml
+++ b/test/t.ml
@@ -20,6 +20,9 @@ module Tables = struct
     let team = Field.foreign_key "team_id" ~references:Team.id
     let user = Field.foreign_key "user_id" ~references:User.id
   end
+  let _ = TeamUser.id   (* avoid unused warning *)
+  let _ = TeamUser.team (* avoid unused warning *)
+  let _ = TeamUser.user (* avoid unused warning *)
 
   module Project = struct
     include (val Mysql.table "projects")
@@ -27,6 +30,8 @@ module Tables = struct
     let leader = Field.foreign_key "leader_id" ~references:User.id
     let title = Field.string "title"
   end
+  let _ = Project.id
+  let _ = Project.title
 end
 
 let () =