Add benchmark to chose between S-Expressions and JSON for rc file

Rc files are quite long for their purpose, since its command to be launched
across a session.

Rc files were created, with some random text (from the cecill license in fact),
in two format. We keep .human, human readable files for the futur if necessary.

Here is the result:
┌──────┬──────────┬─────────┬───────────┬──────────┬────────────┐
│ Name │ Time/Run │ mWd/Run │  mjWd/Run │ Prom/Run │ Percentage │
├──────┼──────────┼─────────┼───────────┼──────────┼────────────┤
│ Sexp │ 820.59us │ 934.00w │ 1_029.18w │    0.18w │    100.00% │
│ Json │ 198.46us │ 981.00w │     3.07w │          │     24.19% │
└──────┴──────────┴─────────┴───────────┴──────────┴────────────┘
Json is clearly faster, however we are with very short time, this way Sexp maybe
acceptable (us stand for μs).

Note: Cherry picked from a private branch, with conflict resolution.
Thought it may be useful to have this.

bench/Makefile

@@ -2,3 +2,4 @@ all:
 	corebuild -pkg core_bench sprintf_vs_concat.byte
 	corebuild -pkg core_bench swap.byte
 	corebuild -pkg core_bench,yojson,atdgen biniou_vs_binprot.byte
+	corebuild -pkg core_bench,yojson rc_file_format.byte

bench/rc_file.json.human

@@ -0,0 +1,40 @@
+{
+  "progs": [
+    "This config file should be a machine output, quite long",
+    "The authors of the CeCILL (for Ce[a] C[nrs] I[nria] L[ogiciel] L[ibre])",
+    "license are:",
+    "Commissariat à l'énergie atomique et aux énergies alternatives - CEA, a",
+    "public scientific, technical and industrial research establishment,",
+    "having its principal place of business at 25 rue Leblanc, immeuble Le",
+    "Ponant D, 75015 Paris, France.",
+    "Centre National de la Recherche Scientifique - CNRS, a public scientific",
+    "and technological establishment, having its principal place of business",
+    "at 3 rue Michel-Ange, 75794 Paris cedex 16, France.",
+    "Institut National de Recherche en Informatique et en Automatique -",
+    "Inria, a public scientific and technological establishment, having its",
+    "principal place of business at Domaine de Voluceau, Rocquencourt, BP",
+    "105, 78153 Le Chesnay cedex, France.", "Preamble",
+    "The purpose of this Free Software license agreement is to grant users",
+    "the right to modify and redistribute the software governed by this",
+    "license within the framework of an open source distribution model.",
+    "The exercising of this right is conditional upon certain obligations for",
+    "users so as to preserve this status for all subsequent redistributions.",
+    "In consideration of access to the source code and the rights to copy,",
+    "modify and redistribute granted by the license, users are provided only",
+    "with a limited warranty and the software's author, the holder of the",
+    "economic rights, and the successive licensors only have limited liability.",
+    "In this respect, the risks associated with loading, using, modifying",
+    "and/or developing or reproducing the software by the user are brought to",
+    "the user's attention, given its Free Software status, which may make it",
+    "complicated to use, with the result that its use is reserved for",
+    "developers and experienced professionals having in-depth computer",
+    "knowledge. Users are therefore encouraged to load and test the",
+    "suitability of the software as regards their requirements in conditions",
+    "enabling the security of their systems and/or data to be ensured and,",
+    "more generally, to use and operate it in the same conditions of",
+    "security. This Agreement may be freely reproduced and published,",
+    "provided it is not altered, and that no provisions are either added or",
+    "removed herefrom."
+  ],
+  "settings": []
+}

bench/rc_file.scm.human

@@ -0,0 +1,41 @@
+(
+  ("progs" (
+    "This config file should be a machine output, quite long"
+    "The authors of the CeCILL (for Ce[a] C[nrs] I[nria] L[ogiciel] L[ibre])"
+    "license are:"
+    "Commissariat à l'énergie atomique et aux énergies alternatives - CEA, a"
+    "public scientific, technical and industrial research establishment,"
+    "having its principal place of business at 25 rue Leblanc, immeuble Le"
+    "Ponant D, 75015 Paris, France."
+    "Centre National de la Recherche Scientifique - CNRS, a public scientific"
+    "and technological establishment, having its principal place of business"
+    "at 3 rue Michel-Ange, 75794 Paris cedex 16, France."
+    "Institut National de Recherche en Informatique et en Automatique -"
+    "Inria, a public scientific and technological establishment, having its"
+    "principal place of business at Domaine de Voluceau, Rocquencourt, BP"
+    "105, 78153 Le Chesnay cedex, France."
+    "Preamble"
+    "The purpose of this Free Software license agreement is to grant users"
+    "the right to modify and redistribute the software governed by this"
+    "license within the framework of an open source distribution model."
+    "The exercising of this right is conditional upon certain obligations for"
+    "users so as to preserve this status for all subsequent redistributions."
+    "In consideration of access to the source code and the rights to copy,"
+    "modify and redistribute granted by the license, users are provided only"
+    "with a limited warranty and the software's author, the holder of the"
+    "economic rights, and the successive licensors only have limited liability."
+    "In this respect, the risks associated with loading, using, modifying"
+    "and/or developing or reproducing the software by the user are brought to"
+    "the user's attention, given its Free Software status, which may make it"
+    "complicated to use, with the result that its use is reserved for"
+    "developers and experienced professionals having in-depth computer"
+    "knowledge. Users are therefore encouraged to load and test the"
+    "suitability of the software as regards their requirements in conditions"
+    "enabling the security of their systems and/or data to be ensured and,"
+    "more generally, to use and operate it in the same conditions of"
+    "security. This Agreement may be freely reproduced and published,"
+    "provided it is not altered, and that no provisions are either added or"
+    "removed herefrom."
+  ))
+  ("settings" ())
+)

bench/rc_file_format.ml

@@ -0,0 +1,66 @@
+(******************************************************************************)
+(* Copyright © Joly Clément, 2016                                             *)
+(*                                                                            *)
+(*  leowzukw@vmail.me                                                         *)
+(*                                                                            *)
+(*  Ce logiciel est un programme informatique servant à exécuter              *)
+(*  automatiquement des programmes à l'ouverture du terminal.                 *)
+(*                                                                            *)
+(*  Ce logiciel est régi par la licence CeCILL soumise au droit français et   *)
+(*  respectant les principes de diffusion des logiciels libres. Vous pouvez   *)
+(*  utiliser, modifier et/ou redistribuer ce programme sous les conditions    *)
+(*  de la licence CeCILL telle que diffusée par le CEA, le CNRS et l'INRIA    *)
+(*  sur le site "http://www.cecill.info".                                     *)
+(*                                                                            *)
+(*  En contrepartie de l'accessibilité au code source et des droits de copie, *)
+(*  de modification et de redistribution accordés par cette licence, il n'est *)
+(*  offert aux utilisateurs qu'une garantie limitée.  Pour les mêmes raisons, *)
+(*  seule une responsabilité restreinte pèse sur l'auteur du programme,  le   *)
+(*  titulaire des droits patrimoniaux et les concédants successifs.           *)
+(*                                                                            *)
+(*  A cet égard  l'attention de l'utilisateur est attirée sur les risques     *)
+(*  associés au chargement,  à l'utilisation,  à la modification et/ou au     *)
+(*  développement et à la reproduction du logiciel par l'utilisateur étant    *)
+(*  donné sa spécificité de logiciel libre, qui peut le rendre complexe à     *)
+(*  manipuler et qui le réserve donc à des développeurs et des professionnels *)
+(*  avertis possédant  des  connaissances  informatiques approfondies.  Les   *)
+(*  utilisateurs sont donc invités à charger  et  tester  l'adéquation  du    *)
+(*  logiciel à leurs besoins dans des conditions permettant d'assurer la      *)
+(*  sécurité de leurs systèmes et ou de leurs données et, plus généralement,  *)
+(*  à l'utiliser et l'exploiter dans les mêmes conditions de sécurité.        *)
+(*                                                                            *)
+(*  Le fait que vous puissiez accéder à cet en-tête signifie que vous avez    *)
+(*  pris connaissance de la licence CeCILL, et que vous en avez accepté les   *)
+(*  termes.                                                                   *)
+(******************************************************************************)
+
+open Core.Std;;
+
+(* File to compare speed of the two format, json and sexp *)
+open Core_bench.Std
+
+(* Base file, machine output, see corresponding .human files for a human
+ * friendlier version *)
+let scm = "./rc_file.scm";;
+let json = "./rc_file.json";;
+
+let parse_scm () =
+  Sexp.load_sexp scm
+  |> ignore
+;;
+
+let parse_json () =
+  Yojson.Basic.from_file json
+  |> ignore
+;;
+
+let tests = [
+  "Sexp", parse_scm;
+  "Json", parse_json;
+]
+
+let () =
+  List.map tests ~f:(fun (name,test) -> Bench.Test.create ~name test)
+  |> Bench.make_command
+  |> Command.run
+