Changed the type of [with_poss] to take a pair of positions.

This allows its implementation to be simplified.
Also, renamed it to [with_loc].
Updated [fancy_parser] to use [with_loc $loc] everywhere.

src/fancy-parser.mly

@@ -85,7 +85,7 @@ grammar:
 declaration:
 
 | h = HEADER /* lexically delimited by %{ ... %} */
-    { [ with_poss $startpos $endpos (DCode h) ] }
+    { [ with_loc $loc (DCode h) ] }
 
 | TOKEN ty = OCAMLTYPE? ts = clist(terminal)
     { List.map (Positions.map (fun (terminal, attrs) -> DToken (ty, terminal, attrs))) ts }
@@ -110,13 +110,13 @@ declaration:
       List.map (Positions.map (fun symbol -> DTokenProperties (symbol, k, prec))) ss }
 
 | PARAMETER t = OCAMLTYPE
-    { [ with_poss $startpos $endpos (DParameter t) ] }
+    { [ with_loc $loc (DParameter t) ] }
 
 | attr = GRAMMARATTRIBUTE
-    { [ with_poss $startpos $endpos (DGrammarAttribute attr) ] }
+    { [ with_loc $loc (DGrammarAttribute attr) ] }
 
 | PERCENTATTRIBUTE actuals = clist(strict_actual) attrs = ATTRIBUTE+
-    { [ with_poss $startpos $endpos (DSymbolAttributes (actuals, attrs)) ] }
+    { [ with_loc $loc (DSymbolAttributes (actuals, attrs)) ] }
 
 | ON_ERROR_REDUCE ss = clist(strict_actual)
     { let prec = ParserAux.new_on_error_reduce_level() in
@@ -289,7 +289,7 @@ production:
 
 producer:
 | id = ioption(terminated(LID, EQUAL)) p = actual attrs = ATTRIBUTE*
-    { position (with_poss $startpos $endpos ()), id, p, attrs }
+    { position (with_loc $loc ()), id, p, attrs }
 
 /* ------------------------------------------------------------------------- */
 /* The ideal syntax of actual parameters includes:
@@ -335,7 +335,7 @@ lax_actual:
 (* 3- *)
 | /* leading bar disallowed */
   branches = branches
-    { ParameterAnonymous (with_poss $startpos $endpos branches) }
+    { ParameterAnonymous (with_loc $loc branches) }
     (* 2016/05/18: we used to eliminate anonymous rules on the fly during
        parsing. However, when an anonymous rule appears in a parameterized
        definition, the fresh nonterminal symbol that is created should be
@@ -357,11 +357,11 @@ lax_actual:
 
 modifier:
   QUESTION
-    { with_poss $startpos $endpos "option" }
+    { with_loc $loc "option" }
 | PLUS
-    { with_poss $startpos $endpos "nonempty_list" }
+    { with_loc $loc "nonempty_list" }
 | STAR
-    { with_poss $startpos $endpos "list" }
+    { with_loc $loc "list" }
 
 /* ------------------------------------------------------------------------- */
 /* A postlude is announced by %%, but is optional. */

src/positions.ml

@@ -35,8 +35,10 @@ let with_pos p v =
     position  = p;
   }
 
-let with_poss p1 p2 v =
-  with_pos (p1, p2) v
+let with_loc =
+  (* The location is converted from the type [position * position]
+     to the type [t]. *)
+  with_pos
 
 let map f v =
   {

src/positions.mli

@@ -38,7 +38,7 @@ val position: 'a located -> t
 (** [with_pos p v] decorates [v] with a position [p]. *)
 val with_pos : t -> 'a -> 'a located
 val with_cpos: Lexing.lexbuf -> 'a -> 'a located
-val with_poss : Lexing.position -> Lexing.position -> 'a -> 'a located
+val with_loc : (Lexing.position * Lexing.position) -> 'a -> 'a located
 
 val unknown_pos : 'a -> 'a located