add remove clause + tests

src/API.ml

@@ -1381,6 +1381,7 @@ module Utils = struct
         | Some (`After,x) -> [After x]
         | Some (`Before,x) -> [Before x]
         | Some (`Replace,x) -> [Replace x]
+        | Some (`Remove,x) -> [Remove x]
         | None -> []) in
     [Program.Clause {
       Clause.loc = loc;

src/API.mli

@@ -1243,7 +1243,7 @@ module Utils : sig
 
   (** Hackish, in particular the output should be a compiled program *)
   val clause_of_term :
-    ?name:string -> ?graft:([`After | `Before | `Replace] * string) ->
+    ?name:string -> ?graft:([`After | `Before | `Replace | `Remove] * string) ->
     depth:int -> Ast.Loc.t -> Data.term -> Ast.program
 
   (** Lifting/restriction/beta (LOW LEVEL, don't use) *)

src/bl.ml

@@ -88,6 +88,13 @@ module Array = struct
     in
       shift t (i+len-1)
 
+  let shift_left t i len =
+    let rec shift t j =
+      if j = len then t
+      else shift (set t j (get t (j+1))) (j + 1)
+    in
+      shift t i
+
   let rec length t = match !t with Diff(_,_,x) -> length x | Array a -> Array.length a
 
   let of_list l = ref @@ Array (Array.of_list l)
@@ -147,6 +154,18 @@ let rec replace f x = function
           a (* bleah *)
       in
         aux 0
+let rec remove f = function
+  | BCons (head,tail) when f head -> tail
+  | BCons (head, tail) -> BCons (head, remove f tail)
+  | BArray { len; data } as a ->
+      let rec aux i =
+        if i < len then
+          if f data.(i) then BArray { len = len-1; data = Array.shift_left data i len }
+          else aux (i+1)
+        else 
+          a (* bleah *)
+      in
+        aux 0
 
 let rec insert f x = function
   | BCons (head, tail) when f head <= 0 -> BCons (head, BCons(x,tail))

src/bl.mli

@@ -19,8 +19,9 @@ val rcons : 'a -> 'a t -> 'a t
 (* O(n) space and time *)
 val copy : 'a t -> 'a t
 
-(* These 2 are O(n) time, O(1) space. The test must succeed once *)
+(* These 3 are O(n) time, O(1) space. The test must succeed once *)
 val replace : ('a -> bool) -> 'a -> 'a t -> 'a t
+val remove : ('a -> bool) -> 'a t -> 'a t
 val insert : ('a -> int) -> 'a -> 'a t -> 'a t
 
 type 'a scan

src/compiler.ml

@@ -668,6 +668,9 @@ end = struct (* {{{ *)
       | Replace s :: rest ->
           if r.insertion <> None then duplicate_err "insertion";
           aux_attrs { r with insertion = Some (Replace s) } rest
+      | Remove s :: rest ->
+          if r.insertion <> None then duplicate_err "insertion";
+          aux_attrs { r with insertion = Some (Remove s) } rest
       | If s :: rest ->
          if r.ifexpr <> None then duplicate_err "if";
          aux_attrs { r with ifexpr = Some s } rest
@@ -693,7 +696,7 @@ end = struct (* {{{ *)
       | If s :: rest ->
          if r.cifexpr <> None then duplicate_err "if";
          aux_chr { r with cifexpr = Some s } rest
-      | (Before _ | After _ | Replace _ | External | Index _) as a :: _ -> illegal_err a 
+      | (Before _ | After _ | Replace _ | Remove _ | External | Index _) as a :: _ -> illegal_err a 
     in
     let cid = Loc.show loc in 
     { c with Chr.attributes = aux_chr { cid; cifexpr = None } attributes }
@@ -724,7 +727,7 @@ end = struct (* {{{ *)
            | Some (Structured.Index _) -> duplicate_err "index"
            | Some _ -> error ~loc "external predicates cannot be indexed"
          end
-      | (Before _ | After _ | Replace _ | Name _ | If _) as a :: _ -> illegal_err a 
+      | (Before _ | After _ | Replace _ | Remove _ | Name _ | If _) as a :: _ -> illegal_err a 
     in
     let attributes = aux_tatt None attributes in
     let attributes =
@@ -2080,7 +2083,7 @@ module Assemble : sig
 end = struct (* {{{ *)
 
 let compile_clause_attributes ({ Ast.Clause.attributes = { Ast.Structured.id }} as c) =
-  { c with Ast.Clause.attributes = { Assembled.id }}
+  { c with attributes = { Assembled.id }}
 
   let sort_insertion ~old_rev ~extra:l =
     let add s { Ast.Clause.attributes = { Assembled.id }; loc } =
@@ -2096,18 +2099,19 @@ let compile_clause_attributes ({ Ast.Clause.attributes = { Ast.Structured.id }}
       match l, loc_name with
       | [],_ -> error ~loc:c.Ast.Clause.loc ("unable to graft this clause: no clause named " ^
              match loc_name with
-             | Ast.Structured.Replace x -> x
-             | Ast.Structured.After x -> x
-             | Ast.Structured.Before x -> x)
-      | { Ast.Clause.attributes = { Assembled.id = Some n }} :: xs,
-        Ast.Structured.Replace name when n = name ->
-           c :: xs
-      | { Ast.Clause.attributes = { Assembled.id = Some n }} as x :: xs,
+             | Replace x | After x | Before x | Remove x -> x)
+      | { Ast.Clause.attributes = { Assembled.id = Some n }} as x :: xs, (* AFTER   *)
         Ast.Structured.After name when n = name ->
            c :: x :: xs
-      | { Ast.Clause.attributes = { Assembled.id = Some n }} as x :: xs,
-        Ast.Structured.Before name when n = name ->
+      | { attributes = { Assembled.id = Some n }} as x :: xs,            (* BEFORE  *)
+        Before name when n = name ->
            x :: c :: xs
+      | { attributes = { id = Some n }} :: xs,                           (* REPLACE *)
+        Replace name when n = name ->
+           c :: xs
+      | { attributes = { id = Some n }} :: xs,                           (* REMOVE  *)
+        Remove name when n = name ->
+           c :: xs
       | x :: xs, _ -> x :: insert loc_name c xs in
     let rec aux_sort seen acc = function
       | [] -> acc
@@ -2264,7 +2268,7 @@ let rec constants_of acc = function
 let w_symbol_table s f x =
   let table = Symbols.compile_table @@ State.get Symbols.table s in
   let pp_ctx = { table; uv_names = ref (IntMap.empty,0) } in
-  Util.set_spaghetti_printer Util.pp_const (R.Pp.pp_constant ~pp_ctx);
+  Util.set_spaghetti_printer pp_const (R.Pp.pp_constant ~pp_ctx);
   f x
 
 (* Compiler passes *)

src/discrimination_tree.ml

@@ -174,6 +174,15 @@ module Trie = struct
           map = map |> Ptmap.map (replace p x);
         }
 
+  let rec remove f = function
+    | Node { data; other; listTailVariable; map } ->
+        Node {
+          data = data |> List.filter (fun x -> not (f x));
+          other = other |> Option.map (remove f);
+          listTailVariable = listTailVariable |> Option.map (remove f);
+          map = map |> Ptmap.map (remove f);
+        }
+
   let add (a : Path.t) v t =
     let max = ref 0 in
     let rec ins ~pos = let x = Path.get a pos in function
@@ -392,6 +401,7 @@ let retrieve cmp_data path { t } =
   Bl.of_list @@ List.sort cmp_data r
 
 let replace p x i = { i with t = Trie.replace p x i.t }
+let remove keep dt = { dt with t = Trie.remove keep dt.t}
 
 module Internal = struct
   let kConstant = kConstant

src/discrimination_tree.mli

@@ -52,6 +52,7 @@ val empty_dt : 'b list -> 'a t
 val retrieve : ('a -> 'a -> int) -> Path.t -> 'a t -> 'a Bl.scan
 
 val replace : ('a -> bool) -> 'a -> 'a t -> 'a t
+val remove  : ('a -> bool) -> 'a t -> 'a t
 
 (***********************************************************)
 (* Printers                                                *)

src/parser/ast.ml

@@ -143,6 +143,7 @@ type raw_attribute =
   | After of string
   | Before of string
   | Replace of string
+  | Remove of string
   | External
   | Index of int list * string option
 [@@deriving show]
@@ -318,7 +319,7 @@ and attribute = {
   id : string option;
   ifexpr : string option;
 }
-and insertion = Before of string | After of string | Replace of string
+and insertion = Before of string | After of string | Replace of string | Remove of string
 and tattribute =
   | External
   | Index of int list * tindex option

src/parser/ast.mli

@@ -73,6 +73,7 @@ type raw_attribute =
   | After of string
   | Before of string
   | Replace of string
+  | Remove of string
   | External
   | Index of int list * string option
 [@@ deriving show]
@@ -213,7 +214,7 @@ and attribute = {
   id : string option;
   ifexpr : string option;
 }
-and insertion = Before of string | After of string | Replace of string
+and insertion = Before of string | After of string | Replace of string | Remove of string
 and cattribute = {
   cid : string;
   cifexpr : string option

src/parser/grammar.mly

@@ -300,6 +300,7 @@ attribute:
 | AFTER; s = STRING { After s }
 | BEFORE; s = STRING { Before s }
 | REPLACE; s = STRING { Replace s }
+| REMOVE; s = STRING { Remove s }
 | EXTERNAL { External }
 | INDEX; LPAREN; l = nonempty_list(indexing) ; RPAREN; o = option(STRING) { Index (l,o) }
 
@@ -400,6 +401,7 @@ constant:
 | BEFORE { Func.from_string "before" }
 | AFTER { Func.from_string "after" }
 | REPLACE { Func.from_string "replace" }
+| REMOVE { Func.from_string "remove" }
 | INDEX { Func.from_string "index" }
 | c = IO { Func.from_string @@ String.make 1 c }
 | CUT { Func.cutf }

src/parser/lexer.mll.in

@@ -165,6 +165,7 @@ and token = parse
 | "after" { AFTER }
 | "before" { BEFORE }
 | "replace" { REPLACE }
+| "remove" { REMOVE }
 | "name" { NAME }
 | "if" { IF }
 | "index" { INDEX }

src/parser/test_lexer.ml

@@ -15,6 +15,7 @@ type t = Tokens.token =
   | RULE
   | RPAREN
   | REPLACE
+  | REMOVE
   | RCURLY
   | RBRACKET
   | QUOTED of ( string )

src/parser/tokens.mly

@@ -58,6 +58,7 @@
 %token BEFORE
 %token AFTER
 %token REPLACE
+%token REMOVE
 %token NAME 
 %token INDEX 
 %token CONS

src/runtime.ml

@@ -2625,17 +2625,20 @@ let timestamp_clause clause times time graft =
   match graft with
   | None -> clause.timestamp <- [time]; []
   | Some (Elpi_parser.Ast.Structured.Before  x) -> let reference = reference x in clause.timestamp <- reference @ [-time]; reference
-  | Some (Elpi_parser.Ast.Structured.After   x) -> let reference = reference x in clause.timestamp <- reference @ [time]; reference
-  | Some (Elpi_parser.Ast.Structured.Replace x) -> clause.timestamp <- [time]; let reference = reference x in reference
+  | Some (After   x) -> let reference = reference x in clause.timestamp <- reference @ [time]; reference
+  | Some (Replace x) -> clause.timestamp <- [time]; let reference = reference x in reference
+  | Some (Remove x) -> let reference = reference x in reference
 
 let postpend graft reference clause clauses =
   match graft with
   | None -> Bl.rcons clause clauses
   | Some (Elpi_parser.Ast.Structured.Before _)
-  | Some (Elpi_parser.Ast.Structured.After _)   ->
+  | Some (After _)   ->
       Bl.insert (fun x -> lex_insertion x.timestamp clause.timestamp) clause clauses
-  | Some (Elpi_parser.Ast.Structured.Replace _) ->
+  | Some (Replace _) ->
       Bl.replace (fun x -> x.timestamp = reference) clause clauses
+  | Some (Remove _) -> (* TODO: in this case the clause is ignored... *)
+      Bl.remove (fun x -> x.timestamp = reference) clauses
 
 let add1clause2 ~depth ~insert ~empty ~copy m graft reference predicate clause = function
   | TwoLevelIndex { all_clauses; argno; mode; flex_arg_clauses; arg_idx; } ->
@@ -2697,7 +2700,7 @@ let add1clause ~depth { idx; time; times } ~time_dir ~insert ~empty ~cons ~copy
   let grafting_reference = timestamp_clause clause times time graft in
   let times = (* TODO: do this only at compile time *)
       match graft with
-      | Some (Elpi_parser.Ast.Structured.Replace oid) -> StrMap.remove oid times
+      | Some (Replace oid) -> StrMap.remove oid times
       | _ -> times
   in
   let times =
@@ -2712,7 +2715,7 @@ let add1clause ~depth { idx; time; times } ~time_dir ~insert ~empty ~cons ~copy
     try
       (* TODO: do this only at compile time *)
       match graft with
-      | Some (Elpi_parser.Ast.Structured.Replace _) ->
+      | Some (Replace _) ->
           Ptmap.map (function
           | TwoLevelIndex {
             argno; mode;
@@ -2725,8 +2728,24 @@ let add1clause ~depth { idx; time; times } ~time_dir ~insert ~empty ~cons ~copy
               flex_arg_clauses = insert graft grafting_reference clause flex_arg_clauses;
               arg_idx = Ptmap.map (fun l -> insert graft grafting_reference clause l) arg_idx;
               }
-          | BitHash { mode; args; args_idx } -> BitHash { mode; args; args_idx = Ptmap.map (fun l -> insert graft grafting_reference clause l) args_idx }
-          | IndexWithDiscriminationTree {mode; arg_depths; args_idx; } -> IndexWithDiscriminationTree {mode; arg_depths; args_idx = Discrimination_tree.replace (fun x -> x.timestamp = grafting_reference) clause args_idx; }
+          | BitHash hash -> BitHash { hash with args_idx = Ptmap.map (fun l -> insert graft grafting_reference clause l) hash.args_idx }
+          | IndexWithDiscriminationTree dt -> IndexWithDiscriminationTree {dt with args_idx = Discrimination_tree.replace (fun x -> x.timestamp = grafting_reference) clause dt.args_idx; }
+          ) idx
+      | Some (Remove _) ->
+          Ptmap.map (function
+          | TwoLevelIndex {
+            argno; mode;
+            all_clauses;
+            flex_arg_clauses;
+            arg_idx;
+            } -> TwoLevelIndex {
+              argno; mode;
+              all_clauses = insert graft grafting_reference clause all_clauses;
+              flex_arg_clauses = insert graft grafting_reference clause flex_arg_clauses;
+              arg_idx = Ptmap.map (fun l -> insert graft grafting_reference clause l) arg_idx;
+              }
+          | BitHash hash -> BitHash { hash with args_idx = Ptmap.map (fun l -> insert graft grafting_reference clause l) hash.args_idx }
+          | IndexWithDiscriminationTree dt -> IndexWithDiscriminationTree {dt with args_idx = Discrimination_tree.remove (fun x -> x.timestamp = grafting_reference) dt.args_idx; }
           ) idx
       | _ -> add1clause2 ~depth idx ~insert ~empty ~copy graft grafting_reference predicate clause (Ptmap.find predicate idx);
     with

src/test_discrimination_tree.ml

@@ -1,6 +1,11 @@
 open Elpi.Internal.Discrimination_tree
+module DT = Elpi.Internal.Discrimination_tree
 open Internal
 
+let test ~expected found = 
+  if expected <> found then failwith (Format.asprintf "Test DT error: Expected %d, but found %d" expected found)
+
+
 let () = assert (k_of (mkConstant ~safe:false ~data:~-17 ~arity:0) == kConstant)
 let () = assert (k_of mkVariable == kVariable)
 let () = assert (k_of mkLam == kOther)
@@ -54,7 +59,7 @@ let () =
     Format.printf " Retrived clause number is %d\n%!" retrived_nb;
     (* let pp_sep = fun f _ -> Format.pp_print_string f " " in *)
     (* Format.printf " Found instances are %a\n%!" (Format.pp_print_list ~pp_sep Format.pp_print_int) retrived; *)
-    if retrived_nb <> nb then failwith (Format.asprintf "Test DT error: Expected %d clauses, %d found" nb retrived_nb);
+    test retrived_nb nb;
     if (Elpi.Internal.Bl.to_list retrived |> List.sort Int.compare |> List.rev) <> (retrived |> Elpi.Internal.Bl.to_list) then failwith "Test DT error: resultin list is not correctly ordered"
   in
 
@@ -70,4 +75,40 @@ let () =
   test [p2; p3; p4; p5; p6] p1 mkOutputMode 3;
   test [p2; p3; p4; p5; p6] p1 mkInputMode 1;
   test [p1; p2; p3; p4; p5; p6; p8] p7 mkOutputMode 3;
-  test [p1; p2; p3; p4; p5; p6; p8] p7 mkInputMode 2;
+  test [p1; p2; p3; p4; p5; p6; p8] p7 mkInputMode 2
+
+let () =  
+  let get_length dt path = DT.retrieve compare path !dt |> Elpi.Internal.Bl.length in
+  let remove dt e = dt := DT.remove (fun x -> x = e) !dt in
+  let index dt path v = dt := DT.index !dt path v in 
+
+  let constA = mkConstant ~safe:false ~data:~-1 ~arity:~-0 in (* a *)
+  let p1 = [mkListHead; constA; mkListTailVariable; constA] in
+  let p2 = [mkListHead; constA; mkListTailVariable; constA; constA] in
+
+  let p1Index = Path.of_list p1 in (* path for indexing *)
+  let p1Retr = mkInputMode :: p1 |> Path.of_list in (* path for retrival *)
+
+  let p2Index = Path.of_list p2 in (* path for indexing *)
+  let p2Retr = mkInputMode :: p2 |> Path.of_list in (* path for retrival *)
+
+  let dt = DT.empty_dt (List.init 0 Fun.id) |> ref in
+  index dt p1Index 100; index dt p1Index 200;
+  index dt p2Index 200; index dt p2Index 200;
+
+  Printf.printf "Test remove 1\n";
+  test ~expected:2 (get_length dt p1Retr);
+  test ~expected:2 (get_length dt p2Retr);
+
+  Printf.printf "Test remove 2\n";
+  remove dt 100;
+  test ~expected:1 (get_length dt p1Retr);
+  test ~expected:2 (get_length dt p2Retr);
+
+  Printf.printf "Test remove 3\n";
+  remove dt 100;
+  test ~expected:1 (get_length dt p1Retr);
+
+  Printf.printf "Test remove 4\n";
+  remove dt 200;
+  test ~expected:0 (get_length dt p1Retr)