X-Git-Url: https://git.hcoop.net/bpt/coccinelle.git/blobdiff_plain/113803cf8147c1b5332cc7d9ac43febcc197e4f0..9bc82bae75129fec4d981ebf245f2f7d7ca73a41:/parsing_cocci/context_neg.ml
diff --git a/parsing_cocci/context_neg.ml b/parsing_cocci/context_neg.ml
index 67b3317..6423d16 100644
--- a/parsing_cocci/context_neg.ml
+++ b/parsing_cocci/context_neg.ml
@@ -1,23 +1,49 @@
(*
-* Copyright 2005-2009, Ecole des Mines de Nantes, University of Copenhagen
-* Yoann Padioleau, Julia Lawall, Rene Rydhof Hansen, Henrik Stuart, Gilles Muller
-* This file is part of Coccinelle.
-*
-* Coccinelle is free software: you can redistribute it and/or modify
-* it under the terms of the GNU General Public License as published by
-* the Free Software Foundation, according to version 2 of the License.
-*
-* Coccinelle is distributed in the hope that it will be useful,
-* but WITHOUT ANY WARRANTY; without even the implied warranty of
-* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-* GNU General Public License for more details.
-*
-* You should have received a copy of the GNU General Public License
-* along with Coccinelle. If not, see .
-*
-* The authors reserve the right to distribute this or future versions of
-* Coccinelle under other licenses.
-*)
+ * Copyright 2010, INRIA, University of Copenhagen
+ * Julia Lawall, Rene Rydhof Hansen, Gilles Muller, Nicolas Palix
+ * Copyright 2005-2009, Ecole des Mines de Nantes, University of Copenhagen
+ * Yoann Padioleau, Julia Lawall, Rene Rydhof Hansen, Henrik Stuart, Gilles Muller, Nicolas Palix
+ * This file is part of Coccinelle.
+ *
+ * Coccinelle is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, according to version 2 of the License.
+ *
+ * Coccinelle is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Coccinelle. If not, see .
+ *
+ * The authors reserve the right to distribute this or future versions of
+ * Coccinelle under other licenses.
+ *)
+
+
+(*
+ * Copyright 2010, INRIA, University of Copenhagen
+ * Julia Lawall, Rene Rydhof Hansen, Gilles Muller, Nicolas Palix
+ * Copyright 2005-2009, Ecole des Mines de Nantes, University of Copenhagen
+ * Yoann Padioleau, Julia Lawall, Rene Rydhof Hansen, Henrik Stuart, Gilles Muller, Nicolas Palix
+ * This file is part of Coccinelle.
+ *
+ * Coccinelle is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, according to version 2 of the License.
+ *
+ * Coccinelle is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Coccinelle. If not, see .
+ *
+ * The authors reserve the right to distribute this or future versions of
+ * Coccinelle under other licenses.
+ *)
(* Detects subtrees that are all minus/plus and nodes that are "binding
@@ -29,6 +55,7 @@ plus subtrees. *)
module Ast = Ast_cocci
module Ast0 = Ast0_cocci
module V0 = Visitor_ast0
+module VT0 = Visitor_ast0_types
module U = Unparse_ast0
(* --------------------------------------------------------------------- *)
@@ -138,21 +165,22 @@ let collect_plus_lines top =
let bind x y = () in
let option_default = () in
let donothing r k e = k e in
- let mcode (_,_,info,mcodekind,_) =
+ let mcode (_,_,info,mcodekind,_,_) =
match mcodekind with
- Ast0.PLUS -> insert info.Ast0.line_start
+ Ast0.PLUS _ -> insert info.Ast0.pos_info.Ast0.line_start
| _ -> () in
let fn =
- V0.combiner bind option_default
+ V0.flat_combiner bind option_default
mcode mcode mcode mcode mcode mcode mcode mcode mcode mcode mcode mcode
donothing donothing donothing donothing donothing donothing
donothing donothing donothing donothing donothing donothing donothing
donothing donothing in
- fn.V0.combiner_top_level top
+ fn.VT0.combiner_rec_top_level top
(* --------------------------------------------------------------------- *)
-type kind = Neutral | AllMarked | NotAllMarked (* marked means + or - *)
+type kind =
+ Neutral | AllMarked of Ast.count | NotAllMarked (* marked means + or - *)
(* --------------------------------------------------------------------- *)
(* The first part analyzes each of the minus tree and the plus tree
@@ -175,7 +203,7 @@ type node =
let kind2c = function
Neutral -> "neutral"
- | AllMarked -> "allmarked"
+ | AllMarked _ -> "allmarked"
| NotAllMarked -> "notallmarked"
let node2c = function
@@ -188,8 +216,8 @@ tokens *)
let bind c1 c2 =
let lub = function
(k1,k2) when k1 = k2 -> k1
- | (Neutral,AllMarked) -> AllMarked
- | (AllMarked,Neutral) -> AllMarked
+ | (Neutral,AllMarked c) -> AllMarked c
+ | (AllMarked c,Neutral) -> AllMarked c
| _ -> NotAllMarked in
match (c1,c2) with
(* token/token *)
@@ -227,22 +255,39 @@ let bind c1 c2 =
let option_default = (*Bind(Neutral,[],[],[],[],[])*)
Recursor(Neutral,[],[],[])
-let mcode (_,_,info,mcodekind,pos) =
- let offset = info.Ast0.offset in
+let mcode (_,_,info,mcodekind,pos,_) =
+ let offset = info.Ast0.pos_info.Ast0.offset in
match mcodekind with
- Ast0.MINUS(_) -> Token(AllMarked,offset,mcodekind,[])
- | Ast0.PLUS -> Token(AllMarked,offset,mcodekind,[])
+ Ast0.MINUS(_) -> Token(AllMarked Ast.ONE,offset,mcodekind,[])
+ | Ast0.PLUS c -> Token(AllMarked c,offset,mcodekind,[])
| Ast0.CONTEXT(_) -> Token(NotAllMarked,offset,mcodekind,[offset])
| _ -> failwith "not possible"
-let neutral_mcode (_,_,info,mcodekind,pos) =
- let offset = info.Ast0.offset in
+let neutral_mcode (_,_,info,mcodekind,pos,_) =
+ let offset = info.Ast0.pos_info.Ast0.offset in
match mcodekind with
Ast0.MINUS(_) -> Token(Neutral,offset,mcodekind,[])
- | Ast0.PLUS -> Token(Neutral,offset,mcodekind,[])
+ | Ast0.PLUS _ -> Token(Neutral,offset,mcodekind,[])
| Ast0.CONTEXT(_) -> Token(Neutral,offset,mcodekind,[offset])
| _ -> failwith "not possible"
+(* neutral for context; used for mcode in bef aft nodes that don't represent
+anything if they don't contain some information *)
+let nc_mcode (_,_,info,mcodekind,pos,_) =
+ (* distinguish from the offset of some real token *)
+ let offset = (-1) * info.Ast0.pos_info.Ast0.offset in
+ match mcodekind with
+ Ast0.MINUS(_) -> Token(AllMarked Ast.ONE,offset,mcodekind,[])
+ | Ast0.PLUS c -> Token(AllMarked c,offset,mcodekind,[])
+ | Ast0.CONTEXT(_) ->
+ (* Unlike the other mcode cases, we drop the offset from the context
+ offsets. This is because we don't know whether the term this is
+ associated with is - or context. In any case, the context offsets are
+ used for identification, and this invisible node should not be needed
+ for this purpose. *)
+ Token(Neutral,offset,mcodekind,[])
+ | _ -> failwith "not possible"
+
let is_context = function Ast0.CONTEXT(_) -> true | _ -> false
let union_all l = List.fold_left Common.union_set [] l
@@ -251,9 +296,10 @@ let union_all l = List.fold_left Common.union_set [] l
intermingled with plus code. it is used in disj_cases *)
let classify is_minus all_marked table code =
let mkres builder k il tl bil btl l e =
- (if k = AllMarked
- then Ast0.set_mcodekind e (all_marked()) (* definitive *)
- else
+ (match k with
+ AllMarked count ->
+ Ast0.set_mcodekind e (all_marked count) (* definitive *)
+ | _ ->
let check_index il tl =
if List.for_all is_context tl
then
@@ -263,7 +309,7 @@ let classify is_minus all_marked table code =
let _ = Hashtbl.find table index in
failwith
(Printf.sprintf "line %d: index %s already used\n"
- (Ast0.get_info e).Ast0.line_start
+ (Ast0.get_info e).Ast0.pos_info.Ast0.line_start
(String.concat " " (List.map string_of_int index)))
with Not_found -> Hashtbl.add table index (e1,l)) in
if il = [] then check_index bil btl else check_index il tl);
@@ -320,7 +366,7 @@ let classify is_minus all_marked table code =
| Ast0.Estars(dots,whencode) ->
k (Ast0.rewrap e (Ast0.Estars(dots,None)))
| Ast0.DisjExpr(starter,expr_list,_,ender) ->
- disj_cases e starter expr_list r.V0.combiner_expression ender
+ disj_cases e starter expr_list r.VT0.combiner_rec_expression ender
| _ -> k e) in
(* not clear why we have the next two cases, since DisjDecl and
@@ -329,7 +375,7 @@ let classify is_minus all_marked table code =
compute_result Ast0.decl e
(match Ast0.unwrap e with
Ast0.DisjDecl(starter,decls,_,ender) ->
- disj_cases e starter decls r.V0.combiner_declaration ender
+ disj_cases e starter decls r.VT0.combiner_rec_declaration ender
| Ast0.Ddots(dots,whencode) ->
k (Ast0.rewrap e (Ast0.Ddots(dots,None)))
(* Need special cases for the following so that the type will be
@@ -343,14 +389,14 @@ let classify is_minus all_marked table code =
reordering their components. *)
| Ast0.Init(stg,ty,id,eq,ini,sem) ->
bind (match stg with Some stg -> mcode stg | _ -> option_default)
- (bind (r.V0.combiner_typeC ty)
- (bind (r.V0.combiner_ident id)
+ (bind (r.VT0.combiner_rec_typeC ty)
+ (bind (r.VT0.combiner_rec_ident id)
(bind (mcode eq)
- (bind (r.V0.combiner_initialiser ini) (mcode sem)))))
+ (bind (r.VT0.combiner_rec_initialiser ini) (mcode sem)))))
| Ast0.UnInit(stg,ty,id,sem) ->
bind (match stg with Some stg -> mcode stg | _ -> option_default)
- (bind (r.V0.combiner_typeC ty)
- (bind (r.V0.combiner_ident id) (mcode sem)))
+ (bind (r.VT0.combiner_rec_typeC ty)
+ (bind (r.VT0.combiner_rec_ident id) (mcode sem)))
| _ -> k e) in
let param r k e =
@@ -358,14 +404,14 @@ let classify is_minus all_marked table code =
(match Ast0.unwrap e with
Ast0.Param(ty,Some id) ->
(* needed for the same reason as in the Init and UnInit cases *)
- bind (r.V0.combiner_typeC ty) (r.V0.combiner_ident id)
+ bind (r.VT0.combiner_rec_typeC ty) (r.VT0.combiner_rec_ident id)
| _ -> k e) in
let typeC r k e =
compute_result Ast0.typeC e
(match Ast0.unwrap e with
Ast0.DisjType(starter,types,_,ender) ->
- disj_cases e starter types r.V0.combiner_typeC ender
+ disj_cases e starter types r.VT0.combiner_rec_typeC ender
| _ -> k e) in
let initialiser r k i =
@@ -375,6 +421,13 @@ let classify is_minus all_marked table code =
k (Ast0.rewrap i (Ast0.Idots(dots,None)))
| _ -> k i) in
+ let case_line r k e =
+ compute_result Ast0.case_line e
+ (match Ast0.unwrap e with
+ Ast0.DisjCase(starter,case_list,_,ender) ->
+ disj_cases e starter case_list r.VT0.combiner_rec_case_line ender
+ | _ -> k e) in
+
let statement r k s =
compute_result Ast0.stmt s
(match Ast0.unwrap s with
@@ -387,20 +440,18 @@ let classify is_minus all_marked table code =
| Ast0.Stars(dots,whencode) ->
k (Ast0.rewrap s (Ast0.Stars(dots,[])))
| Ast0.Disj(starter,statement_dots_list,_,ender) ->
- disj_cases s starter statement_dots_list r.V0.combiner_statement_dots
+ disj_cases s starter statement_dots_list r.VT0.combiner_rec_statement_dots
ender
-(* Why? There is nothing there
(* cases for everything with extra mcode *)
| Ast0.FunDecl((info,bef),_,_,_,_,_,_,_,_)
| Ast0.Decl((info,bef),_) ->
- bind (mcode ((),(),info,bef)) (k s)
+ bind (nc_mcode ((),(),info,bef,(),-1)) (k s)
| Ast0.IfThen(_,_,_,_,_,(info,aft))
| Ast0.IfThenElse(_,_,_,_,_,_,_,(info,aft))
- | Ast0.While(_,_,_,_,_,(info,aft)) ->
- | Ast0.For(_,_,_,_,_,_,_,_,_,(info,aft)) ->
- bind (k s) (mcode ((),(),info,aft))
| Ast0.Iterator(_,_,_,_,_,(info,aft))
-*)
+ | Ast0.While(_,_,_,_,_,(info,aft))
+ | Ast0.For(_,_,_,_,_,_,_,_,_,(info,aft)) ->
+ bind (k s) (nc_mcode ((),(),info,aft,(),-1))
| _ -> k s
) in
@@ -408,14 +459,14 @@ let classify is_minus all_marked table code =
let do_top builder r k e = compute_result builder e (k e) in
let combiner =
- V0.combiner bind option_default
+ V0.flat_combiner bind option_default
mcode mcode mcode mcode mcode mcode mcode mcode mcode mcode mcode mcode
(do_nothing Ast0.dotsExpr) (do_nothing Ast0.dotsInit)
(do_nothing Ast0.dotsParam) (do_nothing Ast0.dotsStmt)
(do_nothing Ast0.dotsDecl) (do_nothing Ast0.dotsCase)
(do_nothing Ast0.ident) expression typeC initialiser param declaration
- statement (do_nothing Ast0.case_line) (do_top Ast0.top) in
- combiner.V0.combiner_top_level code
+ statement case_line (do_top Ast0.top) in
+ combiner.VT0.combiner_rec_top_level code
(* --------------------------------------------------------------------- *)
(* Traverse the hash tables and find corresponding context nodes that have
@@ -423,8 +474,8 @@ the same context children *)
(* this is just a sanity check - really only need to look at the top-level
structure *)
-let equal_mcode (_,_,info1,_,_) (_,_,info2,_,_) =
- info1.Ast0.offset = info2.Ast0.offset
+let equal_mcode (_,_,info1,_,_,_) (_,_,info2,_,_,_) =
+ info1.Ast0.pos_info.Ast0.offset = info2.Ast0.pos_info.Ast0.offset
let equal_option e1 e2 =
match (e1,e2) with
@@ -514,6 +565,8 @@ let rec equal_typeC t1 t2 =
equal_mcode lb1 lb2 && equal_mcode rb1 rb2
| (Ast0.EnumName(kind1,_),Ast0.EnumName(kind2,_)) ->
equal_mcode kind1 kind2
+ | (Ast0.EnumDef(_,lb1,_,rb1),Ast0.EnumDef(_,lb2,_,rb2)) ->
+ equal_mcode lb1 lb2 && equal_mcode rb1 rb2
| (Ast0.StructUnionName(kind1,_),Ast0.StructUnionName(kind2,_)) ->
equal_mcode kind1 kind2
| (Ast0.FunctionType(ty1,lp1,p1,rp1),Ast0.FunctionType(ty2,lp2,p2,rp2)) ->
@@ -535,7 +588,10 @@ let rec equal_typeC t1 t2 =
let equal_declaration d1 d2 =
match (Ast0.unwrap d1,Ast0.unwrap d2) with
- (Ast0.Init(stg1,_,_,eq1,_,sem1),Ast0.Init(stg2,_,_,eq2,_,sem2)) ->
+ (Ast0.MetaDecl(name1,_),Ast0.MetaDecl(name2,_))
+ | (Ast0.MetaField(name1,_),Ast0.MetaField(name2,_)) ->
+ equal_mcode name1 name2
+ | (Ast0.Init(stg1,_,_,eq1,_,sem1),Ast0.Init(stg2,_,_,eq2,_,sem2)) ->
equal_option stg1 stg2 && equal_mcode eq1 eq2 && equal_mcode sem1 sem2
| (Ast0.UnInit(stg1,_,_,sem1),Ast0.UnInit(stg2,_,_,sem2)) ->
equal_option stg1 stg2 && equal_mcode sem1 sem2
@@ -566,7 +622,9 @@ let equal_initialiser i1 i2 =
(Ast0.MetaInit(name1,_),Ast0.MetaInit(name2,_)) ->
equal_mcode name1 name2
| (Ast0.InitExpr(_),Ast0.InitExpr(_)) -> true
- | (Ast0.InitList(lb1,_,rb1),Ast0.InitList(lb2,_,rb2)) ->
+ | (Ast0.InitList(lb1,_,rb1,o1),Ast0.InitList(lb2,_,rb2,o2)) ->
+ (* can't compare orderedness, because this can differ between -
+ and + code *)
(equal_mcode lb1 lb2) && (equal_mcode rb1 rb2)
| (Ast0.InitGccExt(designators1,eq1,_),
Ast0.InitGccExt(designators2,eq2,_)) ->
@@ -625,8 +683,8 @@ let rec equal_statement s1 s2 =
equal_mcode rp1 rp2
| (Ast0.Iterator(nm1,lp1,_,rp1,_,_),Ast0.Iterator(nm2,lp2,_,rp2,_,_)) ->
equal_mcode lp1 lp2 && equal_mcode rp1 rp2
- | (Ast0.Switch(switch1,lp1,_,rp1,lb1,case1,rb1),
- Ast0.Switch(switch2,lp2,_,rp2,lb2,case2,rb2)) ->
+ | (Ast0.Switch(switch1,lp1,_,rp1,lb1,_,_,rb1),
+ Ast0.Switch(switch2,lp2,_,rp2,lb2,_,_,rb2)) ->
equal_mcode switch1 switch2 && equal_mcode lp1 lp2 &&
equal_mcode rp1 rp2 && equal_mcode lb1 lb2 &&
equal_mcode rb1 rb2
@@ -680,6 +738,11 @@ let equal_case_line c1 c2 =
equal_mcode def1 def2 && equal_mcode colon1 colon2
| (Ast0.Case(case1,_,colon1,_),Ast0.Case(case2,_,colon2,_)) ->
equal_mcode case1 case2 && equal_mcode colon1 colon2
+ | (Ast0.DisjCase(starter1,_,mids1,ender1),
+ Ast0.DisjCase(starter2,_,mids2,ender2)) ->
+ equal_mcode starter1 starter2 &&
+ List.for_all2 equal_mcode mids1 mids2 &&
+ equal_mcode ender1 ender2
| (Ast0.OptCase(_),Ast0.OptCase(_)) -> true
| _ -> false
@@ -745,7 +808,7 @@ let contextify_all =
let mcode x = () in
let do_nothing r k e = Ast0.set_mcodekind e (default_context()); k e in
- V0.combiner bind option_default
+ V0.flat_combiner bind option_default
mcode mcode mcode mcode mcode mcode mcode mcode mcode mcode mcode mcode
do_nothing do_nothing do_nothing do_nothing do_nothing do_nothing
do_nothing do_nothing do_nothing do_nothing do_nothing do_nothing
@@ -754,8 +817,6 @@ let contextify_all =
let contextify_whencode =
let bind x y = () in
let option_default = () in
- let mcode x = () in
- let do_nothing r k e = k e in
let expression r k e =
k e;
@@ -764,21 +825,21 @@ let contextify_whencode =
| Ast0.Edots(_,Some whencode)
| Ast0.Ecircles(_,Some whencode)
| Ast0.Estars(_,Some whencode) ->
- contextify_all.V0.combiner_expression whencode
+ contextify_all.VT0.combiner_rec_expression whencode
| _ -> () in
let initialiser r k i =
match Ast0.unwrap i with
Ast0.Idots(dots,Some whencode) ->
- contextify_all.V0.combiner_initialiser whencode
+ contextify_all.VT0.combiner_rec_initialiser whencode
| _ -> k i in
let whencode = function
- Ast0.WhenNot sd -> contextify_all.V0.combiner_statement_dots sd
- | Ast0.WhenAlways s -> contextify_all.V0.combiner_statement s
+ Ast0.WhenNot sd -> contextify_all.VT0.combiner_rec_statement_dots sd
+ | Ast0.WhenAlways s -> contextify_all.VT0.combiner_rec_statement s
| Ast0.WhenModifier(_) -> ()
- | Ast0.WhenNotTrue(e) -> contextify_all.V0.combiner_expression e
- | Ast0.WhenNotFalse(e) -> contextify_all.V0.combiner_expression e in
+ | Ast0.WhenNotTrue(e) -> contextify_all.VT0.combiner_rec_expression e
+ | Ast0.WhenNotFalse(e) -> contextify_all.VT0.combiner_rec_expression e in
let statement r k (s : Ast0.statement) =
k s;
@@ -790,13 +851,11 @@ let contextify_whencode =
let combiner =
V0.combiner bind option_default
- mcode mcode mcode mcode mcode mcode mcode mcode mcode mcode mcode mcode
- do_nothing do_nothing do_nothing do_nothing do_nothing do_nothing
- do_nothing
- expression
- do_nothing initialiser do_nothing do_nothing statement do_nothing
- do_nothing in
- combiner.V0.combiner_top_level
+ {V0.combiner_functions with
+ VT0.combiner_exprfn = expression;
+ VT0.combiner_initfn = initialiser;
+ VT0.combiner_stmtfn = statement} in
+ combiner.VT0.combiner_rec_top_level
(* --------------------------------------------------------------------- *)
@@ -834,18 +893,18 @@ let concat = function
| _ -> failwith "no dots allowed in pure plus code")
| _ -> failwith "plus code is being discarded") in
let res =
- Compute_lines.statement_dots
+ Compute_lines.compute_statement_dots_lines false
(Ast0.rewrap (List.hd l) (Ast0.DOTS (loop l))) in
[Ast0.rewrap res (Ast0.CODE res)]
let collect_up_to m plus =
let minfo = Ast0.get_info m in
- let mend = minfo.Ast0.logical_end in
+ let mend = minfo.Ast0.pos_info.Ast0.logical_end in
let rec loop = function
[] -> ([],[])
| p::plus ->
let pinfo = Ast0.get_info p in
- let pstart = pinfo.Ast0.logical_start in
+ let pstart = pinfo.Ast0.pos_info.Ast0.logical_start in
if pstart > mend
then ([],p::plus)
else let (plus,rest) = loop plus in (p::plus,rest) in
@@ -980,10 +1039,10 @@ let context_neg minus plus =
| (((m::minus) as mall),((p::plus) as pall)) ->
let minfo = Ast0.get_info m in
let pinfo = Ast0.get_info p in
- let mstart = minfo.Ast0.logical_start in
- let mend = minfo.Ast0.logical_end in
- let pstart = pinfo.Ast0.logical_start in
- let pend = pinfo.Ast0.logical_end in
+ let mstart = minfo.Ast0.pos_info.Ast0.logical_start in
+ let mend = minfo.Ast0.pos_info.Ast0.logical_end in
+ let pstart = pinfo.Ast0.pos_info.Ast0.logical_start in
+ let pend = pinfo.Ast0.pos_info.Ast0.logical_end in
if (iscode m or iscode p) &&
(mend + 1 = pstart or pend + 1 = mstart or (* adjacent *)
(mstart <= pstart && mend >= pstart) or
@@ -1001,7 +1060,7 @@ let context_neg minus plus =
classify true
(function _ -> Ast0.MINUS(ref([],Ast0.default_token_info)))
minus_table m in
- let _ = classify false (function _ -> Ast0.PLUS) plus_table p in
+ let _ = classify false (function c -> Ast0.PLUS c) plus_table p in
traverse minus_table plus_table;
(m,p)::loop(minus,plus)
end