🔧 gcc-4.8.5 support

- fix missing initializer for member [-Werror=missing-field-initializers]
 - fix ISO C++ forbids casting between pointer-to-function and pointer-to-object [-Werror=pedantic]
 - add gcc-4.8 tests
 - ubuntu has less patches than CentOS7 on gcc, some old bugs are not
   - https://gcc.gnu.org/bugzilla/show_bug.cgi?id=55971
   - https://sourceware.org/bugzilla/show_bug.cgi?id=25399
 - compat.cmake
   - disable some features with old compilers

.github/reqs.sh

@@ -187,6 +187,7 @@ function _c4_gather_compilers()
         g++-7      ) _c4_addgcc 7  ;;
         g++-6      ) _c4_addgcc 6  ;;
         g++-5      ) _c4_addgcc 5  ;;
+        g++-4.8    ) _c4_addgcc 4.8 ;;
         #g++-4.9    ) _c4_addgcc 4.9 ;;  # https://askubuntu.com/questions/1036108/install-gcc-4-9-at-ubuntu-18-04
         clang++-12 ) _c4_addclang 12  ;;
         clang++-11 ) _c4_addclang 11  ;;

.github/workflows/gcc.yml

@@ -42,6 +42,8 @@ jobs:
           - {std: 20, cxx: g++-10     , bt: Release, os: ubuntu-18.04, bitlinks: shared64 static32}
           - {std: 11, cxx: g++-5      , bt: Debug  , os: ubuntu-18.04, bitlinks: shared64 static32}
           - {std: 11, cxx: g++-5      , bt: Release, os: ubuntu-18.04, bitlinks: shared64 static32}
+          - {std: 11, cxx: g++-4.8    , bt: Debug,   os: ubuntu-18.04, bitlinks: shared64 static32}
+          - {std: 11, cxx: g++-4.8    , bt: Release, os: ubuntu-18.04, bitlinks: shared64 static32}
     env: {STD: "${{matrix.std}}", CXX_: "${{matrix.cxx}}", BT: "${{matrix.bt}}", BITLINKS: "${{matrix.bitlinks}}", VG: "${{matrix.vg}}", SAN: "${{matrix.san}}", LINT: "${{matrix.lint}}", OS: "${{matrix.os}}"}
     steps:
       - {name: checkout, uses: actions/checkout@v2, with: {submodules: recursive}}
@@ -137,6 +139,8 @@ jobs:
           - {std: 17, cxx: g++-10, bt: Release, vg: ON, os: ubuntu-18.04}
           - {std: 20, cxx: g++-10, bt: Debug  , vg: ON, os: ubuntu-18.04}
           - {std: 20, cxx: g++-10, bt: Release, vg: ON, os: ubuntu-18.04}
+          - {std: 11, cxx: g++-4.8, bt: Debug,   vg: ON, os: ubuntu-18.04}
+          - {std: 11, cxx: g++-4.8, bt: Release, vg: ON, os: ubuntu-18.04}
     env: {STD: "${{matrix.std}}", CXX_: "${{matrix.cxx}}", BT: "${{matrix.bt}}", BITLINKS: "${{matrix.bitlinks}}", VG: "${{matrix.vg}}", SAN: "${{matrix.san}}", LINT: "${{matrix.lint}}", OS: "${{matrix.os}}"}
     steps:
       - {name: checkout, uses: actions/checkout@v2, with: {submodules: recursive}}

CMakeLists.txt

@@ -4,6 +4,8 @@ project(ryml
     DESCRIPTION "Rapid YAML parsing and emitting"
     HOMEPAGE_URL "https://github.com/biojppm/rapidyaml"
     LANGUAGES CXX)
+include(./compat.cmake)
+
 c4_project(VERSION 0.3.0 STANDALONE
     AUTHOR "Joao Paulo Magalhaes <dev@jpmag.me>")
 

compat.cmake

@@ -0,0 +1,11 @@
+
+# old gcc-4.8 support
+if((CMAKE_CXX_COMPILER_ID STREQUAL "GNU") AND
+  (CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 4.8) AND
+  (CMAKE_CXX_COMPILER_VERSION VERSION_LESS 5.0))
+
+  # c++17 compiler required
+  set(C4RYML_BUILD_BENCHMARKS OFF CACHE BOOL "" FORCE)
+  # LLVM required
+  set(C4RYML_SANITIZE OFF CACHE BOOL "" FORCE)
+endif()

samples/quickstart.cpp

@@ -128,11 +128,25 @@ int main()
 
 namespace sample {
 
+bool report_check(const char *file, int line, const char *predicate, bool result);
+#ifdef __GNUC__
+#if __GNUC__ == 4 && __GNUC_MINOR__ >= 8
+struct CheckPredicate {
+    const char *file;
+    const int line;
+
+    void operator ()(bool predicate) const {
+        if (!report_check(file, line, nullptr, predicate)) { C4_DEBUG_BREAK(); }
+    }
+};
+#define CHECK CheckPredicate{__FILE__, __LINE__}
+#endif
+#endif
+
+#if !defined(CHECK)
 /// a quick'n'dirty assertion to verify a predicate
 #define CHECK(predicate) do { if(!report_check(__FILE__, __LINE__, #predicate, (predicate))) { C4_DEBUG_BREAK(); } } while(0)
-
+#endif
-bool report_check(const char *file, int line, const char *predicate, bool result);
-
 
 //-----------------------------------------------------------------------------
 
@@ -2492,7 +2506,7 @@ void sample_base64()
         tree.rootref().append_child() << ryml::key(ryml::fmt::base64(c.text)) << c.text;
         CHECK(tree[c.base64].val() == c.text);
     }
-    C4_CHECK(ryml::emitrs<std::string>(tree) == R"('Love all, trust a few, do wrong to none.': TG92ZSBhbGwsIHRydXN0IGEgZmV3LCBkbyB3cm9uZyB0byBub25lLg==
+    CHECK(ryml::emitrs<std::string>(tree) == R"('Love all, trust a few, do wrong to none.': TG92ZSBhbGwsIHRydXN0IGEgZmV3LCBkbyB3cm9uZyB0byBub25lLg==
 'The fool doth think he is wise, but the wise man knows himself to be a fool.': VGhlIGZvb2wgZG90aCB0aGluayBoZSBpcyB3aXNlLCBidXQgdGhlIHdpc2UgbWFuIGtub3dzIGhpbXNlbGYgdG8gYmUgYSBmb29sLg==
 Brevity is the soul of wit.: QnJldml0eSBpcyB0aGUgc291bCBvZiB3aXQu
 All that glitters is not gold.: QWxsIHRoYXQgZ2xpdHRlcnMgaXMgbm90IGdvbGQu
@@ -3963,13 +3977,13 @@ static int num_failed_checks = 0;
 bool report_check(const char *file, int line, const char *predicate, bool result)
 {
     ++num_checks;
-    const char *msg = "OK! ";
+    const char *msg = predicate ? "OK! " : "OK!";
     if(!result)
     {
         ++num_failed_checks;
-        msg = "ERROR: ";
+        msg = predicate ?  "ERROR: " : "ERROR";
     }
-    std::cout << file << ':' << line << ": " << msg << predicate << std::endl;
+    std::cout << file << ':' << line << ": " << msg << (predicate ? predicate : "") << std::endl;
     return result;
 }
 

test/test_case.hpp

@@ -41,11 +41,17 @@ namespace yml {
 
 inline void PrintTo(Callbacks const& cb, ::std::ostream* os)
 {
+#ifdef __GNUC__
+#define RYML_GNUC_EXTENSION __extension__
+#else
+#define RYML_GNUC_EXTENSION
+#endif
     *os << '{'
         << "userdata." << (void*)cb.m_user_data << ','
-        << "allocate." << (void*)cb.m_allocate << ','
+        << "allocate." << RYML_GNUC_EXTENSION (void*)cb.m_allocate << ','
-        << "free." << (void*)cb.m_free << ','
+        << "free." << RYML_GNUC_EXTENSION (void*)cb.m_free << ','
-        << "error." << (void*)cb.m_error << '}';
+        << "error." << RYML_GNUC_EXTENSION (void*)cb.m_error << '}';
+#undef RYML_GNUC_EXTENSION
 }
 
 struct Case;
@@ -443,12 +449,11 @@ struct Case
     Location expected_location;
 
     //! create a standard test case: name, source and expected CaseNode structure
-    template<size_t N, class... Args> Case(csubstr file, int line, csubstr name_,         const char (&src_)[N], Args&& ...args) : filelinebuf(catrs<std::string>(file, ':', line)), fileline(to_csubstr(filelinebuf)), name(name_), src(src_), root(std::forward<Args>(args)...), flags(), expected_location() {}
+    template<class... Args> Case(csubstr file, int line, const char *name_,         const char *src_, Args&& ...args) : filelinebuf(catrs<std::string>(file, ':', line)), fileline(to_csubstr(filelinebuf)), name(to_csubstr(name_)), src(to_csubstr(src_)), root(std::forward<Args>(args)...), flags(), expected_location() {}
     //! create a test case with explicit flags: name, source flags, and expected CaseNode structure
-    template<size_t N, class... Args> Case(csubstr file, int line, csubstr name_, int f_, const char (&src_)[N], Args&& ...args) : filelinebuf(catrs<std::string>(file, ':', line)), fileline(to_csubstr(filelinebuf)), name(name_), src(src_), root(std::forward<Args>(args)...), flags((TestCaseFlags_e)f_), expected_location()  {}
+    template<class... Args> Case(csubstr file, int line, const char *name_, int f_, const char *src_, Args&& ...args) : filelinebuf(catrs<std::string>(file, ':', line)), fileline(to_csubstr(filelinebuf)), name(to_csubstr(name_)), src(to_csubstr(src_)), root(std::forward<Args>(args)...), flags((TestCaseFlags_e)f_), expected_location()  {}
     //! create a test case with an error on an expected location
-    template<size_t N>                Case(csubstr file, int line, csubstr name_, int f_, const char (&src_)[N], LineCol loc) : filelinebuf(catrs<std::string>(file, ':', line)), fileline(to_csubstr(filelinebuf)), name(name_), src(src_), root(), flags((TestCaseFlags_e)f_), expected_location(name, loc.line, loc.col) {}
+                            Case(csubstr file, int line, const char *name_, int f_, const char *src_, LineCol loc) : filelinebuf(catrs<std::string>(file, ':', line)), fileline(to_csubstr(filelinebuf)), name(to_csubstr(name_)), src(to_csubstr(src_)), root(), flags((TestCaseFlags_e)f_), expected_location(name, loc.line, loc.col) {}
-
 };
 
 //-----------------------------------------------------------------------------

test/test_group.hpp

@@ -75,12 +75,28 @@ constexpr const NodeType_e QK = (NodeType_e)(VAL | KEYQUO);
 constexpr const NodeType_e QV = (NodeType_e)(VAL | VALQUO);
 constexpr const NodeType_e QKV = (NodeType_e)(VAL | KEYQUO | VALQUO);
 
+#ifdef __GNUC__
+#if __GNUC__ == 4 && __GNUC_MINOR__ >= 8
+struct CaseAdder {
+    std::vector<Case> *group_cases;
+    const csubstr file;
+    const int line;
 
+    template<typename... Args>
+    void operator ()(Args... parameters) const {
+        group_cases->emplace_back(csubstr(file), line, parameters...);
+    }
+};
 
 /* all arguments are to the constructor of Case */
+#define ADD_CASE_TO_GROUP CaseAdder{group_cases__, csubstr(__FILE__), __LINE__+1}
+#endif
+#endif
+
+#ifndef ADD_CASE_TO_GROUP
 #define ADD_CASE_TO_GROUP(...)                  \
     group_cases__->emplace_back(csubstr(__FILE__), __LINE__+1, __VA_ARGS__)
-
+#endif
 
 #define CASE_GROUP(group_name)                                          \
                                                                         \