Merge pull request #37 from ToruNiina/to-toml-deprecated

feat: mark to_toml as deprecated

.travis.yml

@@ -12,8 +12,39 @@ matrix:
         - ubuntu-toolchain-r-test
         packages:
         - g++-5
-        - build-essential
-        - cmake
+        - libboost-all-dev
+  - os: linux
+    language: cpp
+    compiler: gcc
+    env: COMPILER="g++-6"
+    addons:
+      apt:
+        sources:
+        - ubuntu-toolchain-r-test
+        packages:
+        - g++-6
+        - libboost-all-dev
+  - os: linux
+    language: cpp
+    compiler: gcc
+    env: COMPILER="g++-7"
+    addons:
+      apt:
+        sources:
+        - ubuntu-toolchain-r-test
+        packages:
+        - g++-7
+        - libboost-all-dev
+  - os: linux
+    language: cpp
+    compiler: gcc
+    env: COMPILER="g++-8"
+    addons:
+      apt:
+        sources:
+        - ubuntu-toolchain-r-test
+        packages:
+        - g++-8
         - libboost-all-dev
   - os: linux
     language: cpp
@@ -26,8 +57,66 @@ matrix:
         - llvm-toolchain-precise-3.7
         packages:
         - clang-3.7
-        - build-essential
-        - cmake
+        - libboost-all-dev
+  - os: linux
+    language: cpp
+    compiler: clang
+    env: COMPILER="clang++-4.0"
+    addons:
+      apt:
+        sources:
+        - ubuntu-toolchain-r-test
+        - llvm-toolchain-trusty-4.0
+        packages:
+        - clang-4.0
+        - libboost-all-dev
+  - os: linux
+    language: cpp
+    compiler: clang
+    env: COMPILER="clang++-5.0"
+    addons:
+      apt:
+        sources:
+        - ubuntu-toolchain-r-test
+        - llvm-toolchain-trusty-5.0
+        packages:
+        - clang-5.0
+        - libboost-all-dev
+  - os: linux
+    language: cpp
+    compiler: clang
+    env: COMPILER="clang++-6.0"
+    addons:
+      apt:
+        sources:
+        - ubuntu-toolchain-r-test
+        - llvm-toolchain-trusty-6.0
+        packages:
+        - clang-6.0
+        - libboost-all-dev
+  - os: linux
+    language: cpp
+    compiler: clang
+    env: COMPILER="clang++-7"
+    addons:
+      apt:
+        sources:
+        - ubuntu-toolchain-r-test
+        - llvm-toolchain-trusty-7
+        packages:
+        - clang-7
+        - libboost-all-dev
+  - os: linux
+    language: cpp
+    compiler: clang
+    env: COMPILER="clang++-8"
+    addons:
+      apt:
+        sources:
+        - ubuntu-toolchain-r-test
+        - llvm-toolchain-trusty-8
+        packages:
+        - clang-8
         - libboost-all-dev
   - os: osx
     language: cpp

README.md

@@ -2,12 +2,12 @@ toml11
 ======
 
 [![Build Status](https://travis-ci.org/ToruNiina/toml11.svg?branch=master)](https://travis-ci.org/ToruNiina/toml11)
-[![Build status](https://ci.appveyor.com/api/projects/status/m2n08a926asvg5mg?svg=true)](https://ci.appveyor.com/project/ToruNiina/toml11)
+[![Build status](https://ci.appveyor.com/api/projects/status/m2n08a926asvg5mg/branch/master?svg=true)](https://ci.appveyor.com/project/ToruNiina/toml11/branch/master)
 [![Version](https://img.shields.io/github/release/ToruNiina/toml11.svg?style=flat)](https://github.com/ToruNiina/toml11/releases)
 [![License](https://img.shields.io/github/license/ToruNiina/toml11.svg?style=flat)](LICENSE)
 [![DOI](https://zenodo.org/badge/DOI/10.5281/zenodo.1209136.svg)](https://doi.org/10.5281/zenodo.1209136)
 
-C++11 header-only toml parser depending only on C++ standard library.
+C++11 header-only toml parser/encoder depending only on C++ standard library.
 
 compatible to the latest version of
 [TOML v0.5.0](https://github.com/toml-lang/toml/blob/master/versions/en/toml-v0.5.0.md)
@@ -642,6 +642,7 @@ I thank the contributor for providing great feature to this repository.
   - Intel Compiler support
 - Quentin Khan (@xaxousis)
   - Found & Fixed a bug around ODR
+  - Improved error message to show the location where the parser fails
 
 ## Licensing terms
 

tests/CMakeLists.txt

@@ -28,6 +28,7 @@ set(TEST_NAMES
     test_serialize_file
     test_parse_unicode
     test_error_detection
+    test_format_error
 )
 
 CHECK_CXX_COMPILER_FLAG("-Wall" COMPILER_SUPPORTS_WALL)

tests/test_format_error.cpp

@@ -0,0 +1,75 @@
+#define BOOST_TEST_MODULE "test_value"
+#ifdef UNITTEST_FRAMEWORK_LIBRARY_EXIST
+#include <boost/test/unit_test.hpp>
+#else
+#define BOOST_TEST_NO_LIB
+#include <boost/test/included/unit_test.hpp>
+#endif
+#include <toml.hpp>
+
+// to check it successfully compiles. it does not check the formatted string.
+
+BOOST_AUTO_TEST_CASE(test_1_value)
+{
+    toml::value val(42);
+
+    {
+        const std::string pretty_error =
+            toml::format_error("[error] test error", val, "this is a value");
+        std::cout << pretty_error << std::endl;
+    }
+
+    {
+        const std::string pretty_error =
+            toml::format_error("[error] test error", val, "this is a value",
+                               std::vector<std::string>{"this is a hint"});
+        std::cout << pretty_error << std::endl;
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_2_values)
+{
+    toml::value v1(42);
+    toml::value v2(3.14);
+    {
+        const std::string pretty_error =
+            toml::format_error("[error] test error with two values",
+                               v1, "this is the answer",
+                               v2, "this is the pi");
+        std::cout << pretty_error << std::endl;
+    }
+
+    {
+        const std::string pretty_error =
+            toml::format_error("[error] test error with two values",
+                               v1, "this is the answer",
+                               v2, "this is the pi",
+                               std::vector<std::string>{"hint"});
+        std::cout << pretty_error << std::endl;
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_3_values)
+{
+    toml::value v1(42);
+    toml::value v2(3.14);
+    toml::value v3("foo");
+    {
+        const std::string pretty_error =
+            toml::format_error("[error] test error with two values",
+                               v1, "this is the answer",
+                               v2, "this is the pi",
+                               v3, "this is a meta-syntactic variable");
+        std::cout << pretty_error << std::endl;
+    }
+
+    {
+        const std::string pretty_error =
+            toml::format_error("[error] test error with two values",
+                               v1, "this is the answer",
+                               v2, "this is the pi",
+                               v3, "this is a meta-syntactic variable",
+                               std::vector<std::string>{"hint 1", "hint 2"});
+        std::cout << pretty_error << std::endl;
+    }
+}

tests/test_parse_key.cpp

@@ -13,23 +13,23 @@ using namespace detail;
 
 BOOST_AUTO_TEST_CASE(test_bare_key)
 {
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_key, "barekey",  std::vector<key>(1, "barekey"));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_key, "bare-key", std::vector<key>(1, "bare-key"));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_key, "bare_key", std::vector<key>(1, "bare_key"));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_key, "1234",     std::vector<key>(1, "1234"));
+    TOML11_TEST_PARSE_EQUAL(parse_key, "barekey",  std::vector<key>(1, "barekey"));
+    TOML11_TEST_PARSE_EQUAL(parse_key, "bare-key", std::vector<key>(1, "bare-key"));
+    TOML11_TEST_PARSE_EQUAL(parse_key, "bare_key", std::vector<key>(1, "bare_key"));
+    TOML11_TEST_PARSE_EQUAL(parse_key, "1234",     std::vector<key>(1, "1234"));
 }
 
 BOOST_AUTO_TEST_CASE(test_quoted_key)
 {
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_key, "\"127.0.0.1\"",          std::vector<key>(1, "127.0.0.1"         ));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_key, "\"character encoding\"", std::vector<key>(1, "character encoding"));
+    TOML11_TEST_PARSE_EQUAL(parse_key, "\"127.0.0.1\"",          std::vector<key>(1, "127.0.0.1"         ));
+    TOML11_TEST_PARSE_EQUAL(parse_key, "\"character encoding\"", std::vector<key>(1, "character encoding"));
 #if defined(_MSC_VER) || defined(__INTEL_COMPILER)
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_key, "\"\xCA\x8E\xC7\x9D\xCA\x9E\"", std::vector<key>(1, "\xCA\x8E\xC7\x9D\xCA\x9E"));
+    TOML11_TEST_PARSE_EQUAL(parse_key, "\"\xCA\x8E\xC7\x9D\xCA\x9E\"", std::vector<key>(1, "\xCA\x8E\xC7\x9D\xCA\x9E"));
 #else
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_key, "\"ʎǝʞ\"",                std::vector<key>(1, "ʎǝʞ"               ));
+    TOML11_TEST_PARSE_EQUAL(parse_key, "\"ʎǝʞ\"",                std::vector<key>(1, "ʎǝʞ"               ));
 #endif
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_key, "'key2'",                 std::vector<key>(1, "key2"              ));
-    TOML11_TEST_PARSE_EQUAL_VALUE(parse_key, "'quoted \"value\"'",     std::vector<key>(1, "quoted \"value\""  ));
+    TOML11_TEST_PARSE_EQUAL(parse_key, "'key2'",                 std::vector<key>(1, "key2"              ));
+    TOML11_TEST_PARSE_EQUAL(parse_key, "'quoted \"value\"'",     std::vector<key>(1, "quoted \"value\""  ));
 }
 
 BOOST_AUTO_TEST_CASE(test_dotted_key)
@@ -38,13 +38,13 @@ BOOST_AUTO_TEST_CASE(test_dotted_key)
         std::vector<key> keys(2);
         keys[0] = "physical";
         keys[1] = "color";
-        TOML11_TEST_PARSE_EQUAL_VALUE(parse_key, "physical.color", keys);
+        TOML11_TEST_PARSE_EQUAL(parse_key, "physical.color", keys);
     }
     {
         std::vector<key> keys(2);
         keys[0] = "physical";
         keys[1] = "shape";
-        TOML11_TEST_PARSE_EQUAL_VALUE(parse_key, "physical.shape", keys);
+        TOML11_TEST_PARSE_EQUAL(parse_key, "physical.shape", keys);
     }
     {
         std::vector<key> keys(4);
@@ -52,12 +52,12 @@ BOOST_AUTO_TEST_CASE(test_dotted_key)
         keys[1] = "y";
         keys[2] = "z";
         keys[3] = "w";
-        TOML11_TEST_PARSE_EQUAL_VALUE(parse_key, "x.y.z.w", keys);
+        TOML11_TEST_PARSE_EQUAL(parse_key, "x.y.z.w", keys);
     }
     {
         std::vector<key> keys(2);
         keys[0] = "site";
         keys[1] = "google.com";
-        TOML11_TEST_PARSE_EQUAL_VALUE(parse_key, "site.\"google.com\"", keys);
+        TOML11_TEST_PARSE_EQUAL(parse_key, "site.\"google.com\"", keys);
     }
 }

toml/combinator.hpp

@@ -39,7 +39,7 @@ inline std::string show_char(const char c)
     else
     {
         std::ostringstream oss;
-        oss << std::hex << std::setfill('0') << std::setw(2) << "0x"
+        oss << "0x" << std::hex << std::setfill('0') << std::setw(2)
             << static_cast<int>(c);
         return oss.str();
     }

toml/get.hpp

@@ -210,8 +210,9 @@ T get(const value& v)
     {
         throw std::out_of_range(detail::format_underline(concat_to_string(
             "[erorr] toml::get specified container size is ", container.size(),
-            " but there are ", ar.size(), " elements in toml array."),
-            detail::get_region(v), "here"));
+            " but there are ", ar.size(), " elements in toml array."), {
+                {std::addressof(detail::get_region(v)), "here"}
+            }));
     }
     std::transform(ar.cbegin(), ar.cend(), container.begin(),
                    [](const value& x){return ::toml::get<value_type>(x);});
@@ -233,7 +234,9 @@ T get(const value& v)
     {
         throw std::out_of_range(detail::format_underline(concat_to_string(
             "[erorr] toml::get specified std::pair but there are ", ar.size(),
-            " elements in toml array."), detail::get_region(v), "here"));
+            " elements in toml array."), {
+                {std::addressof(detail::get_region(v)), "here"}
+            }));
     }
     return std::make_pair(::toml::get<first_type >(ar.at(0)),
                           ::toml::get<second_type>(ar.at(1)));
@@ -264,7 +267,9 @@ T get(const value& v)
         throw std::out_of_range(detail::format_underline(concat_to_string(
             "[erorr] toml::get specified std::tuple with ",
             std::tuple_size<T>::value, "elements, but there are ", ar.size(),
-            " elements in toml array."), detail::get_region(v), "here"));
+            " elements in toml array."), {
+                {std::addressof(detail::get_region(v)), "here"}
+            }));
     }
     return detail::get_tuple_impl<T>(ar,
             detail::make_index_sequence<std::tuple_size<T>::value>{});
@@ -340,8 +345,9 @@ find(const toml::value& v, const toml::key& ky)
     if(tab.count(ky) == 0)
     {
         throw std::out_of_range(detail::format_underline(concat_to_string(
-            "[error] key \"", ky, "\" not found"), detail::get_region(v),
-            "in this table"));
+            "[error] key \"", ky, "\" not found"), {
+                {std::addressof(detail::get_region(v)), "in this table"}
+            }));
     }
     return ::toml::get<T>(tab.at(ky));
 }
@@ -353,8 +359,9 @@ find(toml::value& v, const toml::key& ky)
     if(tab.count(ky) == 0)
     {
         throw std::out_of_range(detail::format_underline(concat_to_string(
-            "[error] key \"", ky, "\" not found"), detail::get_region(v),
-            "in this table"));
+            "[error] key \"", ky, "\" not found"), {
+                {std::addressof(detail::get_region(v)), "in this table"}
+            }));
     }
     return ::toml::get<T>(tab.at(ky));
 }
@@ -366,8 +373,9 @@ find(toml::value&& v, const toml::key& ky)
     if(tab.count(ky) == 0)
     {
         throw std::out_of_range(detail::format_underline(concat_to_string(
-            "[error] key \"", ky, "\" not found"), detail::get_region(v),
-            "in this table"));
+            "[error] key \"", ky, "\" not found"), {
+                {std::addressof(detail::get_region(v)), "in this table"}
+            }));
     }
     return ::toml::get<T>(std::move(tab[ky]));
 }

toml/lexer.hpp

@@ -124,9 +124,9 @@ using lex_escape_unicode_short = sequence<character<'u'>,
 using lex_escape_unicode_long  = sequence<character<'U'>,
                                           repeat<lex_hex_dig, exactly<8>>>;
 using lex_escape_seq_char = either<character<'"'>, character<'\\'>,
-                                   character<'/'>, character<'b'>,
-                                   character<'f'>, character<'n'>,
-                                   character<'r'>, character<'t'>,
+                                   character<'b'>, character<'f'>,
+                                   character<'n'>, character<'r'>,
+                                   character<'t'>,
                                    lex_escape_unicode_short,
                                    lex_escape_unicode_long
                                    >;

toml/region.hpp

@@ -28,44 +28,6 @@ inline std::string make_string(std::size_t len, char c)
     return std::string(len, c);
 }
 
-// location in a container, normally in a file content.
-// shared_ptr points the resource that the iter points.
-// it can be used not only for resource handling, but also error message.
-template<typename Container>
-struct location
-{
-    static_assert(std::is_same<char, typename Container::value_type>::value,"");
-    using const_iterator = typename Container::const_iterator;
-    using source_ptr     = std::shared_ptr<const Container>;
-
-    location(std::string name, Container cont)
-      : source_(std::make_shared<Container>(std::move(cont))),
-        source_name_(std::move(name)), iter_(source_->cbegin())
-    {}
-    location(const location&) = default;
-    location(location&&)      = default;
-    location& operator=(const location&) = default;
-    location& operator=(location&&)      = default;
-    ~location() = default;
-
-    const_iterator& iter()       noexcept {return iter_;}
-    const_iterator  iter() const noexcept {return iter_;}
-
-    const_iterator  begin() const noexcept {return source_->cbegin();}
-    const_iterator  end()   const noexcept {return source_->cend();}
-
-    source_ptr const& source() const& noexcept {return source_;}
-    source_ptr&&      source() &&     noexcept {return std::move(source_);}
-
-    std::string const& name() const noexcept {return source_name_;}
-
-  private:
-
-    source_ptr     source_;
-    std::string    source_name_;
-    const_iterator iter_;
-};
-
 // region in a container, normally in a file content.
 // shared_ptr points the resource that the iter points.
 // combinators returns this.
@@ -86,12 +48,89 @@ struct region_base
     virtual std::string line()     const {return std::string("unknown line");}
     virtual std::string line_num() const {return std::string("?");}
 
-
     virtual std::size_t before()   const noexcept {return 0;}
     virtual std::size_t size()     const noexcept {return 0;}
     virtual std::size_t after()    const noexcept {return 0;}
 };
 
+// location in a container, normally in a file content.
+// shared_ptr points the resource that the iter points.
+// it can be used not only for resource handling, but also error message.
+//
+// it can be considered as a region that contains only one character.
+template<typename Container>
+struct location final : public region_base
+{
+    static_assert(std::is_same<char, typename Container::value_type>::value,"");
+    using const_iterator = typename Container::const_iterator;
+    using source_ptr     = std::shared_ptr<const Container>;
+
+    location(std::string name, Container cont)
+      : source_(std::make_shared<Container>(std::move(cont))),
+        source_name_(std::move(name)), iter_(source_->cbegin())
+    {}
+    location(const location&) = default;
+    location(location&&)      = default;
+    location& operator=(const location&) = default;
+    location& operator=(location&&)      = default;
+    ~location() = default;
+
+    bool is_ok() const noexcept override {return static_cast<bool>(source_);}
+
+    const_iterator& iter()       noexcept {return iter_;}
+    const_iterator  iter() const noexcept {return iter_;}
+
+    const_iterator  begin() const noexcept {return source_->cbegin();}
+    const_iterator  end()   const noexcept {return source_->cend();}
+
+    std::string str()  const override {return make_string(1, *this->iter());}
+    std::string name() const override {return source_name_;}
+
+    std::string line_num() const override
+    {
+        return std::to_string(1+std::count(this->begin(), this->iter(), '\n'));
+    }
+
+    std::string line() const override
+    {
+        return make_string(this->line_begin(), this->line_end());
+    }
+
+    const_iterator line_begin() const noexcept
+    {
+        using reverse_iterator = std::reverse_iterator<const_iterator>;
+        return std::find(reverse_iterator(this->iter()),
+                         reverse_iterator(this->begin()), '\n').base();
+    }
+    const_iterator line_end() const noexcept
+    {
+        return std::find(this->iter(), this->end(), '\n');
+    }
+
+    // location is always points a character. so the size is 1.
+    std::size_t size() const noexcept override
+    {
+        return 1u;
+    }
+    std::size_t before() const noexcept override
+    {
+        return std::distance(this->line_begin(), this->iter());
+    }
+    std::size_t after() const noexcept override
+    {
+        return std::distance(this->iter(), this->line_end());
+    }
+
+    source_ptr const& source() const& noexcept {return source_;}
+    source_ptr&&      source() &&     noexcept {return std::move(source_);}
+
+  private:
+
+    source_ptr     source_;
+    std::string    source_name_;
+    const_iterator iter_;
+};
+
 template<typename Container>
 struct region final : public region_base
 {
@@ -200,96 +239,67 @@ struct region final : public region_base
 
 // to show a better error message.
 inline std::string format_underline(const std::string& message,
-        const region_base& reg, const std::string& comment_for_underline,
+        std::vector<std::pair<region_base const*, std::string>> reg_com,
         std::vector<std::string> helps = {})
 {
+    assert(!reg_com.empty());
+
 #ifdef _WIN32
     const auto newline = "\r\n";
 #else
     const char newline = '\n';
 #endif
-    const auto line        = reg.line();
-    const auto line_number = reg.line_num();
 
-    std::string retval;
-    retval += message;
-    retval += newline;
-    retval += " --> ";
-    retval += reg.name();
-    retval += newline;
-    retval += ' ';
-    retval += line_number;
-    retval += " | ";
-    retval += line;
-    retval += newline;
-    retval += make_string(line_number.size() + 1, ' ');
-    retval += " | ";
-    retval += make_string(reg.before(), ' ');
-    retval += make_string(reg.size(),   '~');
-    retval += ' ';
-    retval += comment_for_underline;
-    if(helps.size() != 0)
-    {
-        retval += newline;
-        retval += make_string(line_number.size() + 1, ' ');
-        retval += " | ";
-        for(const auto help : helps)
+    const auto line_num_width = std::max_element(reg_com.begin(), reg_com.end(),
+        [](std::pair<region_base const*, std::string> const& lhs,
+           std::pair<region_base const*, std::string> const& rhs)
         {
-            retval += newline;
-            retval += "Hint: ";
-            retval += help;
+            return lhs.first->line_num().size() < rhs.first->line_num().size();
         }
-    }
-    return retval;
-}
-
-// to show a better error message.
-inline std::string format_underline(const std::string& message,
-        const region_base& reg1, const std::string& comment_for_underline1,
-        const region_base& reg2, const std::string& comment_for_underline2,
-        std::vector<std::string> helps = {})
-{
-#ifdef _WIN32
-    const auto newline = "\r\n";
-#else
-    const char newline = '\n';
-#endif
-    const auto line1        = reg1.line();
-    const auto line_number1 = reg1.line_num();
-    const auto line2        = reg2.line();
-    const auto line_number2 = reg2.line_num();
-    const auto line_num_width =
-        std::max(line_number1.size(), line_number2.size());
+    )->first->line_num().size();
 
     std::ostringstream retval;
     retval << message << newline;
-    retval << " --> " << reg1.name() << newline;
-//  ---------------------------------------
-    retval << ' ' << std::setw(line_num_width) << line_number1;
-    retval << " | " << line1 << newline;
-    retval << make_string(line_num_width + 1, ' ');
-    retval << " | ";
-    retval << make_string(reg1.before(), ' ');
-    retval << make_string(reg1.size(),   '~');
-    retval << ' ';
-    retval << comment_for_underline1 << newline;
-//  ---------------------------------------
-    if(reg2.name() != reg1.name())
+
+    for(std::size_t i=0; i<reg_com.size(); ++i)
     {
-        retval << " --> " << reg2.name() << newline;
+        if(i!=0 && reg_com.at(i-1).first->name() == reg_com.at(i).first->name())
+        {
+            retval << newline << " ..." << newline;
+        }
+        else
+        {
+            if(i != 0) {retval << newline;}
+            retval << " --> " << reg_com.at(i).first->name() << newline;
+        }
+
+        const region_base* const reg = reg_com.at(i).first;
+        const std::string&   comment = reg_com.at(i).second;
+
+
+        retval << ' ' << std::setw(line_num_width) << reg->line_num();
+        retval << " | " << reg->line() << newline;
+        retval << make_string(line_num_width + 1, ' ');
+        retval << " | " << make_string(reg->before(), ' ');
+
+        if(reg->size() == 1)
+        {
+            // invalid
+            // ^------
+            retval << '^';
+            retval << make_string(reg->after(), '-');
+        }
+        else
+        {
+            // invalid
+            // ~~~~~~~
+            retval << make_string(reg->size(), '~');
+        }
+
+        retval << ' ';
+        retval << comment;
     }
-    else
-    {
-        retval << " ..." << newline;
-    }
-    retval << ' ' << std::setw(line_num_width) << line_number2;
-    retval << " | " << line2 << newline;
-    retval << make_string(line_num_width + 1, ' ');
-    retval << " | ";
-    retval << make_string(reg2.before(), ' ');
-    retval << make_string(reg2.size(),   '~');
-    retval << ' ';
-    retval << comment_for_underline2;
+
     if(helps.size() != 0)
     {
         retval << newline;
@@ -305,62 +315,6 @@ inline std::string format_underline(const std::string& message,
     return retval.str();
 }
 
-
-// to show a better error message.
-template<typename Container>
-std::string
-format_underline(const std::string& message, const location<Container>& loc,
-                 const std::string& comment_for_underline,
-                 std::vector<std::string> helps = {})
-{
-#ifdef _WIN32
-    const auto newline = "\r\n";
-#else
-    const char newline = '\n';
-#endif
-    using const_iterator   = typename location<Container>::const_iterator;
-    using reverse_iterator = std::reverse_iterator<const_iterator>;
-    const auto line_begin  = std::find(reverse_iterator(loc.iter()),
-                                       reverse_iterator(loc.begin()),
-                                       '\n').base();
-    const auto line_end    = std::find(loc.iter(), loc.end(), '\n');
-
-    const auto line_number = std::to_string(
-            1 + std::count(loc.begin(), loc.iter(), '\n'));
-
-    std::string retval;
-    retval += message;
-    retval += newline;
-    retval += " --> ";
-    retval += loc.name();
-    retval += newline;
-    retval += ' ';
-    retval += line_number;
-    retval += " | ";
-    retval += make_string(line_begin, line_end);
-    retval += newline;
-    retval += make_string(line_number.size() + 1, ' ');
-    retval += " | ";
-    retval += make_string(std::distance(line_begin, loc.iter()),' ');
-    retval += '^';
-    retval += make_string(std::distance(loc.iter(), line_end), '-');
-    retval += ' ';
-    retval += comment_for_underline;
-    if(helps.size() != 0)
-    {
-        retval += newline;
-        retval += make_string(line_number.size() + 1, ' ');
-        retval += " | ";
-        for(const auto help : helps)
-        {
-            retval += newline;
-            retval += "Hint: ";
-            retval += help;
-        }
-    }
-    return retval;
-}
-
 } // detail
 } // toml
 #endif// TOML11_REGION_H

toml/serializer.hpp

@@ -5,6 +5,7 @@
 #include "value.hpp"
 #include "lexer.hpp"
 #include <limits>
+#include <cstdio>
 
 namespace toml
 {
@@ -30,13 +31,12 @@ struct serializer
     }
     std::string operator()(const toml::floating f) const
     {
-        std::string token = [=] {
-            // every float value needs decimal point (or exponent).
-            std::ostringstream oss;
-            oss << std::setprecision(float_prec_) << std::showpoint << f;
-            return oss.str();
-        }();
+        const auto fmt = "%.*g";
+        const auto bsz = std::snprintf(nullptr, 0, fmt, this->float_prec_, f);
+        std::vector<char> buf(bsz + 1, '\0'); // +1 for null character(\0)
+        std::snprintf(buf.data(), buf.size(), fmt, this->float_prec_, f);
 
+        std::string token(buf.begin(), buf.end());
         if(token.back() == '.') // 1. => 1.0
         {
             token += '0';

toml/to_toml.hpp

@@ -8,32 +8,38 @@ namespace toml
 {
 
 template<typename T>
+TOML11_MARK_AS_DEPRECATED
 inline value to_toml(T&& x)
 {
     return value(std::forward<T>(x));
 }
 
 template<typename T>
+TOML11_MARK_AS_DEPRECATED
 inline value to_toml(T&& x, string_t kind)
 {
     return value(std::forward<T>(x), kind);
 }
 
+TOML11_MARK_AS_DEPRECATED
 inline value to_toml(local_date d, local_time t)
 {
     return value(local_datetime(d, t));
 }
+TOML11_MARK_AS_DEPRECATED
 inline value to_toml(local_date d, local_time t, time_offset ofs)
 {
     return value(offset_datetime(d, t, ofs));
 }
 
 template<typename ... Ts>
+TOML11_MARK_AS_DEPRECATED
 inline value to_toml(Ts&& ... xs)
 {
     return value(toml::array{toml::value(std::forward<Ts>(xs)) ... });
 }
 
+TOML11_MARK_AS_DEPRECATED
 inline value to_toml(std::initializer_list<std::pair<std::string, toml::value>> xs)
 {
     return value(toml::table(xs.begin(), xs.end()));

toml/utility.hpp

@@ -7,6 +7,16 @@
 #include <memory>
 #include <sstream>
 
+#if __cplusplus >= 201402L
+#  define TOML11_MARK_AS_DEPRECATED [[deprecated]]
+#elif defined(__GNUC__)
+#  define TOML11_MARK_AS_DEPRECATED __attribute__((deprecated))
+#elif defined(_MSC_VER)
+#  define TOML11_MARK_AS_DEPRECATED __declspec(deprecated)
+#else
+#  define TOML11_MARK_AS_DEPRECATED
+#endif
+
 namespace toml
 {
 
@@ -29,8 +39,9 @@ inline void resize_impl(T& container, std::size_t N, std::true_type)
 template<typename T>
 inline void resize_impl(T& container, std::size_t N, std::false_type)
 {
-    if(container.size() >= N) return;
-    else throw std::invalid_argument("not resizable type");
+    if(container.size() >= N) {return;}
+
+    throw std::invalid_argument("not resizable type");
 }
 
 } // detail
@@ -38,8 +49,9 @@ inline void resize_impl(T& container, std::size_t N, std::false_type)
 template<typename T>
 inline void resize(T& container, std::size_t N)
 {
-    if(container.size() == N) return;
-    else return detail::resize_impl(container, N, detail::has_resize_method<T>());
+    if(container.size() == N) {return;}
+
+    return detail::resize_impl(container, N, detail::has_resize_method<T>());
 }
 
 namespace detail
@@ -73,7 +85,5 @@ T from_string(const std::string& str, U&& opt)
     return v;
 }
 
-
-
 }// toml
 #endif // TOML11_UTILITY

toml/value.hpp

@@ -21,8 +21,8 @@ namespace detail
 {
 // to show error messages. not recommended for users.
 region_base const& get_region(const value&);
-// ditto.
-void assign_keeping_region(value&, value);
+template<typename Region>
+void change_region(value&, Region&&);
 }// detail
 
 template<typename T>
@@ -562,8 +562,8 @@ class value
     // for error messages
     friend region_base const& detail::get_region(const value&);
 
-    // to see why it's here, see detail::insert_nested_key.
-    friend void detail::assign_keeping_region(value&, value);
+    template<typename Region>
+    friend void detail::change_region(value&, Region&&);
 
     template<value_t T>
     struct switch_cast;
@@ -599,35 +599,21 @@ inline region_base const& get_region(const value& v)
 {
     return *(v.region_info_);
 }
-// If we keep region information after assigning another toml::* types, the
-// error message become different from the actual value contained.
-// To avoid this kind of confusing phenomena, the default assigners clear the
-// old region_info_. But this functionality is actually needed deep inside of
-// parser, so if you want to see the usecase, see toml::detail::insert_nested_key
-// defined in toml/parser.hpp.
-inline void assign_keeping_region(value& v, value other)
+
+template<typename Region>
+void change_region(value& v, Region&& reg)
 {
-    v.cleanup(); // this keeps region info
-    // keep region_info_ intact
-    v.type_ = other.type();
-    switch(v.type())
-    {
-        case value_t::Boolean       : ::toml::value::assigner(v.boolean_        , other.boolean_        ); break;
-        case value_t::Integer       : ::toml::value::assigner(v.integer_        , other.integer_        ); break;
-        case value_t::Float         : ::toml::value::assigner(v.floating_       , other.floating_       ); break;
-        case value_t::String        : ::toml::value::assigner(v.string_         , other.string_         ); break;
-        case value_t::OffsetDatetime: ::toml::value::assigner(v.offset_datetime_, other.offset_datetime_); break;
-        case value_t::LocalDatetime : ::toml::value::assigner(v.local_datetime_ , other.local_datetime_ ); break;
-        case value_t::LocalDate     : ::toml::value::assigner(v.local_date_     , other.local_date_     ); break;
-        case value_t::LocalTime     : ::toml::value::assigner(v.local_time_     , other.local_time_     ); break;
-        case value_t::Array         : ::toml::value::assigner(v.array_          , other.array_          ); break;
-        case value_t::Table         : ::toml::value::assigner(v.table_          , other.table_          ); break;
-        default: break;
-    }
+    using region_type = typename std::remove_reference<
+        typename std::remove_cv<Region>::type
+        >::type;
+
+    std::shared_ptr<region_base> new_reg =
+        std::make_shared<region_type>(std::forward<region_type>(reg));
+    v.region_info_ = new_reg;
     return;
 }
-}// detail
 
+}// detail
 
 template<> struct value::switch_cast<value_t::Boolean>
 {
@@ -695,9 +681,11 @@ typename detail::toml_default_type<T>::type& value::cast() &
 {
     if(T != this->type_)
     {
-        throw type_error(format_underline(concat_to_string(
-            "[error] toml::value bad_cast to ", T), *region_info_,
-            concat_to_string("the actual type is ", this->type_)));
+        throw type_error(detail::format_underline(concat_to_string(
+            "[error] toml::value bad_cast to ", T), {
+                {this->region_info_.get(),
+                 concat_to_string("the actual type is ", this->type_)}
+            }));
     }
     return switch_cast<T>::invoke(*this);
 }
@@ -706,9 +694,11 @@ typename detail::toml_default_type<T>::type const& value::cast() const&
 {
     if(T != this->type_)
     {
-        throw type_error(format_underline(concat_to_string(
-            "[error] toml::value bad_cast to ", T), *region_info_,
-            concat_to_string("the actual type is ", this->type_)));
+        throw type_error(detail::format_underline(concat_to_string(
+            "[error] toml::value bad_cast to ", T), {
+                {this->region_info_.get(),
+                 concat_to_string("the actual type is ", this->type_)}
+            }));
     }
     return switch_cast<T>::invoke(*this);
 }
@@ -717,9 +707,11 @@ typename detail::toml_default_type<T>::type&&      value::cast() &&
 {
     if(T != this->type_)
     {
-        throw type_error(format_underline(concat_to_string(
-            "[error] toml::value bad_cast to ", T), *region_info_,
-            concat_to_string("the actual type is ", this->type_)));
+        throw type_error(detail::format_underline(concat_to_string(
+            "[error] toml::value bad_cast to ", T), {
+                {this->region_info_.get(),
+                 concat_to_string("the actual type is ", this->type_)}
+             }));
     }
     return switch_cast<T>::invoke(std::move(*this));
 }
@@ -802,22 +794,38 @@ inline bool operator>=(const toml::value& lhs, const toml::value& rhs)
     return !(lhs < rhs);
 }
 
-inline std::string format_error(const std::string& err_msg,
-        const toml::value& v, const std::string& comment,
-        std::vector<std::string> hints = {})
+namespace detail
 {
-    return detail::format_underline(err_msg, detail::get_region(v), comment,
-                                    std::move(hints));
+inline std::string format_error_impl(const std::string& err_msg,
+        std::vector<std::pair<region_base const*, std::string>> val,
+        std::vector<std::string> hints)
+{
+    return format_underline(err_msg, std::move(val), std::move(hints));
+}
+inline std::string format_error_impl(const std::string& err_msg,
+        std::vector<std::pair<region_base const*, std::string>> val)
+{
+    return format_underline(err_msg, std::move(val));
 }
 
-inline std::string format_error(const std::string& err_msg,
-        const toml::value& v1, const std::string& comment1,
-        const toml::value& v2, const std::string& comment2,
-        std::vector<std::string> hints = {})
+template<typename ... Ts>
+std::string format_error_impl(const std::string& err_msg,
+        std::vector<std::pair<region_base const*, std::string>> val,
+        const toml::value& v, const std::string& comment,
+        Ts&& ... args)
 {
-    return detail::format_underline(err_msg, detail::get_region(v1), comment1,
-                                             detail::get_region(v2), comment2,
-                                             std::move(hints));
+    val.push_back(std::make_pair(std::addressof(get_region(v)), comment));
+    return format_error_impl(err_msg, std::move(val), std::forward<Ts>(args)...);
+}
+} // detail
+
+template<typename ... Ts>
+std::string format_error(const std::string& err_msg, Ts&& ... args)
+{
+    std::vector<std::pair<detail::region_base const*, std::string>> val;
+    val.reserve(sizeof...(args) / 2);
+    return detail::format_error_impl(err_msg, std::move(val),
+                                     std::forward<Ts>(args)...);
 }
 
 template<typename Visitor>