switch to C++14 compilation

* configure.ac: Compile in C++14 by default and rename
--enable-c++14 as c++17.
* doc/org/compile.org, doc/org/concepts.org, doc/org/index.org,
doc/org/install.org, doc/org/tut.org, doc/org/upgrade2.org, HACKING,
NEWS, README: Adjust all mentions of C++11.
* spot/twaalgos/stats.hh: Use std::make_unique.

HACKING

@@ -28,7 +28,7 @@ since the generated files they produce are distributed.)
   GNU Bison >= 3.0
   GNU Emacs (preferably >= 24 but it may work with older versions)
   Groff (a.k.a. GNU troff) >= 1.20
-  SWIG >= 3.0 (for its better C++11 support)
+  SWIG >= 3.0 (for its better C++11/C++14 support)
   Doxygen >= 1.4.0
   Perl, with its Gettext module (it might be called something like
     liblocale-gettext-perl or p5-locale-gettext in your distribution)
@@ -300,16 +300,14 @@ forget guards, and we do not forget to rename them when a file is
 copied into another one.
 
 
-C++11
+C++14
 -----
 
-  Spot uses some C++11 features, and therefore requires a C++11
+  Spot uses some C++14 features, and therefore requires a C++14
-  compiler.  The code relies on features that are not available in
+  compiler.  g++ 5.x or clang++ 3.4 should be enough.
-  version of g++ older than 4.8, so this is our minimum requirement
-  for now.  Avoid features that require 4.9.
 
-  Reasonably recent versions of clang should work as well.  Our
+  We currently avoid C++17 features until C++17 compiler are widely
-  build farm has clang++ 3.5.
+  available.
 
 Encoding
 --------

NEWS

@@ -1,5 +1,16 @@
 New in spot 2.3.5.dev (not yet released)
 
+  Build:
+
+  - Spot is now built in C++14 mode, so you need at least GCC 5 or
+    clang 3.4.  The current version of all major linux distributions
+    ship with at least GCC 6, which defaults to C++14, so this should
+    not be a problem.  In *this* release of Spot, most of the header
+    files are still C++11 compatible, so you should be able to include
+    Spot in a C++11 project in case you do not yet want to upgrade.
+    There is also an --enable-c++17 option to configure in case you
+    want to force a build of Spot in C++17 mode.
+
   Tools:
 
   - genaut is a new binary that produces families of automata defined

README

@@ -2,7 +2,7 @@ Overview
 ========
 
 Spot is a model-checking toolkit comprising:
-  - a C++11 library with data-structures and algorithms for working
+  - a C++14 library with data-structures and algorithms for working
     with linear-time temporal logical formulas and ω-automata with
     any acceptance condition.
   - a set of command-line tools for easy access to those algorithms,
@@ -73,8 +73,8 @@ Installation
 Requirements
 ------------
 
-Spot requires a C++11-compliant compiler.
+Spot requires a C++14-compliant compiler.  G++ 5.x or later, as well
-G++ 4.8 or later, as well as Clang++ 3.5 or later should work.
+as Clang++ 3.5 or later should work.
 
 Spot expects a complete installation of Python (version 3.3 or later).
 Especially, Python's headers files should be installed.  If you don't
@@ -141,6 +141,10 @@ flags specific to Spot:
      client code should be compiled with -D_GLIBCXX_DEBUG as well.  This
      options should normally only be useful to run Spot's test-suite.
 
+   --enable-c++17
+     Build everything in C++17 mode.  We use that in our build farm to
+     ensure that Spot can be used in C++17 projects as well.
+
 Here are the meaning of the fine-tuning options, in case
 --enable/disable-devel is not enough.
 

configure.ac

@@ -47,18 +47,14 @@ adl_CHECK_BISON
 # Decrease verbosity when passing argument V=0
 AM_SILENT_RULES([no])
 
-# Option to activate C/C++14
+# Option to activate C++17
-AC_ARG_ENABLE([c++14],
+AC_ARG_ENABLE([c++17],
-              [AC_HELP_STRING([--enable-c++14],
+              [AC_HELP_STRING([--enable-c++17],
-                              [Use C++14.])],
+                              [Compile in C++17 mode.])],
-              [enable_14=yes], [enable_14=no])
+              [enable_17=yes], [enable_17=no])
 
-# Activate at C11 for gnulib tests
+# Activate C11 for gnulib tests
-if test x"${enable_14}" = xyes; then
+AX_CHECK_COMPILE_FLAG([-std=c11], [CFLAGS="$CFLAGS -std=c11"])
-  AX_CHECK_COMPILE_FLAG([-std=c14], [CFLAGS="$CFLAGS -std=c14"])
-else
-  AX_CHECK_COMPILE_FLAG([-std=c11], [CFLAGS="$CFLAGS -std=c11"])
-fi
 
 gl_INIT
 
@@ -73,46 +69,11 @@ AX_CHECK_COMPILE_FLAG([-Werror -fvisibility=hidden],
     [CXXFLAGS="$CXXFLAGS -fvisibility-inlines-hidden"])])
 CXXFLAGS="$CXXFLAGS -DSPOT_BUILD"
 
-# Turn on C++11 support
-m4_define([_AX_CXX_COMPILE_STDCXX_11_testbody],
-[AC_LANG_SOURCE([#include <memory>
-#include <string>
-#include <chrono>  // fails with some installation of clang
-#include <map>
-
-    template <typename T>
-    struct check
-    {
-      static_assert(sizeof(int) <= sizeof(T), "not big enough");
-    };
-
-    typedef check<check<bool>> right_angle_brackets;
-
-    auto f = std::make_shared<std::string>("shared_ptr");
-
-    int a;
-    decltype(a) b;
-
-    typedef check<int> check_type;
-    check_type c;
-    check_type&& cr = static_cast<check_type&&>(c);
-
-    auto d = a;
-
-    void test_emplace()
-    {
-       std::map<int, int> m;
-       m.emplace(1, 2); // fails with g++ 4.6
-    }
-])])
-
 # Turn on C++14 support
-# This is currently a copy of the above code for C++11, feel free to add
-# further tests here when necessary.
 m4_define([_AX_CXX_COMPILE_STDCXX_14_testbody],
 [AC_LANG_SOURCE([#include <memory>
 #include <string>
-#include <chrono>  // fails with some installation of clang
+#include <chrono>  // used to fail in C++11 with some installation of clang
 #include <map>
 
     template <typename T>
@@ -123,7 +84,7 @@ m4_define([_AX_CXX_COMPILE_STDCXX_14_testbody],
 
     typedef check<check<bool>> right_angle_brackets;
 
-    auto f = std::make_shared<std::string>("shared_ptr");
+    auto f = std::make_unique<std::string>("uniq_ptr");
 
     int a;
     decltype(a) b;
@@ -133,15 +94,19 @@ m4_define([_AX_CXX_COMPILE_STDCXX_14_testbody],
     check_type&& cr = static_cast<check_type&&>(c);
 
     auto d = a;
-
-    void test_emplace()
-    {
-       std::map<int, int> m;
-       m.emplace(1, 2); // fails with g++ 4.6
-    }
 ])])
 
-if test x"${enable_14}" = xyes; then
+if test x"${enable_17}" = xyes; then
+  for f in -std=c++17 '-std=c++17 -stdlib=libc++' -std=c++1z
+  do
+    AX_CHECK_COMPILE_FLAG([$f], [CXXFLAGS="$CXXFLAGS $f" stdpass=true], [], [],
+                          [_AX_CXX_COMPILE_STDCXX_14_testbody])
+    ${stdpass-false} && break
+  done
+  if ! "${stdpass-false}"; then
+    AC_ERROR([unable to turn on C++17 mode with this compiler])
+  fi
+else
   for f in -std=c++14 '-std=c++14 -stdlib=libc++' -std=c++1y
   do
     AX_CHECK_COMPILE_FLAG([$f], [CXXFLAGS="$CXXFLAGS $f" stdpass=true], [], [],
@@ -151,16 +116,6 @@ if test x"${enable_14}" = xyes; then
   if ! "${stdpass-false}"; then
     AC_ERROR([unable to turn on C++14 mode with this compiler])
   fi
-else
-  for f in -std=c++11 '-std=c++11 -stdlib=libc++' -std=c++0x
-  do
-    AX_CHECK_COMPILE_FLAG([$f], [CXXFLAGS="$CXXFLAGS $f" stdpass=true], [], [],
-                          [_AX_CXX_COMPILE_STDCXX_11_testbody])
-    ${stdpass-false} && break
-  done
-  if ! "${stdpass-false}"; then
-    AC_ERROR([unable to turn on C++11 mode with this compiler])
-  fi
 fi
 
 AX_CHECK_BUDDY

doc/org/compile.org

@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 #+TITLE: Compiling against Spot
-#+DESCRIPTION: How to compile C++11 programs using Spot
+#+DESCRIPTION: How to compile C++14 programs using Spot
 #+SETUPFILE: setup.org
 #+HTML_LINK_UP: tut.html
 
@@ -39,10 +39,10 @@ obvisously.  On this page, we are going to assume that you use =g++=
 same user interface.  To successfully build the =hello= program, we
 might need to tell the compiler several things:
 
-1. The language that we use is C++11 (or C++14).  This usually
+1. The language that we use is C++14 (or optionally C++17).  This
-   requires passing an option like =-std=c++11=.  Note that with
+   usually requires passing an option like =-std=c++14=.  Note that
-   version 6 of =g++= the default is now to compile C++14, so this
+   with version 6 of =g++= the default is now to compile C++14, so
-   option is not necessary.
+   this option is not necessary.
 2. The C++ preprocessor should be able to find =spot/misc/version.hh=.
    This might require appending another directory to the include
    search path with =-I location=.
@@ -78,7 +78,7 @@ be able to find everything by default, and you should be able to
 compile =hello.cc= and then execute =hello= with
 
 #+BEGIN_SRC sh
-g++ -std=c++11 hello.cc -lspot -o hello
+g++ -std=c++14 hello.cc -lspot -o hello
 ./hello
 #+END_SRC
 
@@ -101,11 +101,11 @@ This means that all spot headers have been installed in
 
 Usually, these directories are searched by default, so
 #+BEGIN_SRC sh
-g++ -std=c++11 hello.cc -lspot -o hello
+g++ -std=c++14 hello.cc -lspot -o hello
 #+END_SRC
 should still work.  But if that is not the case, add
 #+BEGIN_SRC sh
-g++ -std=c++11 -I/usr/local/include hello.cc -L/usr/local/lib -lspot -o hello
+g++ -std=c++14 -I/usr/local/include hello.cc -L/usr/local/lib -lspot -o hello
 #+END_SRC
 
 If running =./hello= fails with a message about not finding =libspot.so=,
@@ -131,7 +131,7 @@ libraries in =$HOME/usr/lib=.
 
 You would compile =hello.cc= with
 #+BEGIN_SRC sh
-g++ -std=c++11 -I$HOME/usr/include hello.cc -L$HOME/usr/lib -lspot -o hello
+g++ -std=c++14 -I$HOME/usr/include hello.cc -L$HOME/usr/lib -lspot -o hello
 #+END_SRC
 and execute with
 #+BEGIN_SRC sh
@@ -184,7 +184,7 @@ There are at least two traps with this scenario:
 
 So compiling against a non-installed Spot would look like this:
 #+BEGIN_SRC sh
-/dir/spot-X.Y/libtool link g++ -std=c++11 -I/dir/spot-X.Y -I/dir/spot-X.Y/buddy/src hello.cc /dir/spot-X.Y/spot/libspot.la -o hello
+/dir/spot-X.Y/libtool link g++ -std=c++14 -I/dir/spot-X.Y -I/dir/spot-X.Y/buddy/src hello.cc /dir/spot-X.Y/spot/libspot.la -o hello
 #+END_SRC
 
 Using =libtool link g++= instead of =g++= will cause =libtool= to

doc/org/concepts.org

@@ -1022,7 +1022,7 @@ components that are distributed and installed by Spot.
 
   - =libbddx= is a customized version of [[https://sourceforge.net/projects/buddy/][the BuDDy library]], for
     manipulating [[#bdd][BDDs]].
-  - =libspot= is the main library, containing a C++11 implementation of all the
+  - =libspot= is the main library, containing a C++14 implementation of all the
     data structures and algorithms.  This depends on =libddx=.
   - =libspotgen= is an auxiliary library that contains functions to
     generate families of automata, useful for benchmarking and testing
@@ -1034,7 +1034,7 @@ components that are distributed and installed by Spot.
     SpinS or a patched version of DiVinE, but you have to install
     those third-party tools first.  See [[https://gitlab.lrde.epita.fr/spot/spot/blob/next/tests/ltsmin/README][=tests/ltsmin/README=]]
     for details.
-  - In addition to the C++11 API, we also provide Python bindings for
+  - In addition to the C++14 API, we also provide Python bindings for
     =libspotgen=, =libspotltsmin=, =libbddx=, and most of =libspot=.
     These are available by importing =spot.gen=, =spot.ltsmin=, =bdd=,
     and =spot=.  Those Python bindings also includes some additional

doc/org/index.org

@@ -1,11 +1,11 @@
 # -*- coding: utf-8 -*-
 #+TITLE: Spot: a platform for LTL and ω-automata manipulation
 #+DESCRIPTION: Spot is a library and tool suite for LTL and ω-automata
-#+KEYWORDS: Spot,C++11,library,platform,framework,tool-suite,LTL,PSL,omega-automata
+#+KEYWORDS: Spot,C++14,library,platform,framework,tool-suite,LTL,PSL,omega-automata
 #+SETUPFILE: setup.org
 #+HTML_HEAD_EXTRA: <style>#org-div-home-and-up { display: none; }</style>
 
-Spot is a C++11 library for LTL, ω-automata manipulation and model
+Spot is a C++14 library for LTL, ω-automata manipulation and model
 checking.  It has the following notable features:
 
 - Support for [[file:concepts.org::#ltl][LTL]] (several syntaxes supported) and

doc/org/install.org

@@ -16,7 +16,7 @@ successful development build]].
 
 ** Requirements
 
-Spot requires a C++11-compliant compiler.  =g++= 4.8 or later, as well
+Spot requires a C++14-compliant compiler.  =g++= 5.0 or later, as well
 as =clang++= 3.5 or later should work.
 
 Spot expects a complete installation of Python (version 3.3 or later).
@@ -75,7 +75,7 @@ apt-get install spot libspot-dev spot-doc python3-spot # Or a subset of those
 #+END_SRC
 
 The package =spot= contains the [[file:tools.org][command-line tools]]. =libspot-dev=
-contains the header files if you plan to use Spot in a C++11
+contains the header files if you plan to use Spot in a C++14
 program. =spot-doc= contains some html (including these pages) and pdf
 documentation. Finally =python3-spot= contains some Python bindings
 (this package also installs some ipython notebooks that you can use as

doc/org/tut.org

@@ -1,6 +1,6 @@
 # -*- coding: utf-8 -*-
 #+TITLE: Code Examples
-#+DESCRIPTION: Directory of code examples for using Spot in C++11, Python, and shell.
+#+DESCRIPTION: Directory of code examples for using Spot in C++14, Python, and shell.
 #+SETUPFILE: setup.org
 #+HTML_LINK_UP: index.html
 

doc/org/upgrade2.org

@@ -20,7 +20,7 @@ experience of updating a couple of projects that are using Spot.
   Spot 1.2.6 and Spot 2.0, just to get an idea of what will need to be
   updated.
 
-  1. [[#cpp11][Spot now compiles using the C++11 standard]].  Compliant compiler
+  1. [[#cpp14][Spot now compiles using the C++14 standard]].  Compliant compiler
      are sufficiently widespread now that this should not be an issue.
 
   2. The layout of the source-tree and the layout of the installed
@@ -83,23 +83,22 @@ experience of updating a couple of projects that are using Spot.
      numbered.  Many algorithms have been rewritten on top of this
      =twa_graph= class, and this simplified them a lot.
 
-* Upgrading to C++11
+* Upgrading to C++14
   :PROPERTIES:
   :CUSTOM_ID: cpp11
   :END:
 
-  Because Spot now relies on C++11 features, programs that use Spot
+  Because Spot now relies on C++14 features, programs that use Spot
   should at least be compiled using this version (or a later one) of
   the language.
 
   Before the =g++= 6.0, the default C++ standard used was C++98, and
-  enabling C++11 is usually done by passing the option =-std=c++11=.
+  enabling C++14 is usually done by passing the option =-std=c++14=.
   In =g++= 6.0 the default C++ standard used is C++14, so passing
-  =-std=c++11= is only necessary in projects that are incompatible
+  =-std=c++14= is not necessary.
-  with C++14.
 
-  Upgrading from C++98 or C++03 to C++11 should be relatively smooth
+  Upgrading from C++98, C++03 or C++11 to C++14 should be relatively
-  as the language is /mostly/ backward compatible.
+  smooth as the language is /mostly/ backward compatible.
 
 * Upgrading =#include= directives
   :PROPERTIES:
@@ -600,7 +599,6 @@ for (auto i: aut->succ(s))
   automatically unregistered when the automaton is destroyed.
 
 
-
 * Various renamings
 
   :PROPERTIES:

spot/twaalgos/stats.hh

@@ -1,6 +1,6 @@
 // -*- coding: utf-8 -*-
-// Copyright (C) 2008, 2011, 2012, 2013, 2014, 2015, 2016 Laboratoire de
+// Copyright (C) 2008, 2011-2017 Laboratoire de Recherche et
-// Recherche et Développement de l'Epita (LRDE).
+// Développement de l'Epita (LRDE).
 // Copyright (C) 2004 Laboratoire d'Informatique de Paris 6 (LIP6),
 // département Systèmes Répartis Coopératifs (SRC), Université Pierre
 // et Marie Curie.
@@ -77,7 +77,7 @@ namespace spot
   public:
     void automaton(const const_twa_graph_ptr& aut)
     {
-      val_ = std::unique_ptr<scc_info>(new scc_info(aut));
+      val_ = std::make_unique<scc_info>(aut);
     }
 
     void reset()