feat: remove deprecated functions

Merge pull request #61 from ToruNiina/as-something
feat: add as_something functions for convenience
2025-12-16 03:08:52 +08:00 · 2019-04-28 15:59:09 +09:00 · 2019-04-28 15:02:19 +09:00 · 2019-04-27 19:04:44 +09:00 · 2019-04-27 18:33:59 +09:00 · 2019-04-27 17:42:12 +09:00
17 changed files with 952 additions and 187 deletions
--- a/.travis.yml
+++ b/.travis.yml
@@ -5,7 +5,7 @@ matrix:
  - os: linux
    language: cpp
    compiler: gcc
-    env: COMPILER="g++-5"
+    env: COMPILER="g++-5" CXX_STANDARD=11
    addons:
      apt:
        sources:
@@ -16,7 +16,7 @@ matrix:
  - os: linux
    language: cpp
    compiler: gcc
-    env: COMPILER="g++-6"
+    env: COMPILER="g++-6" CXX_STANDARD=11
    addons:
      apt:
        sources:
@@ -27,7 +27,7 @@ matrix:
  - os: linux
    language: cpp
    compiler: gcc
-    env: COMPILER="g++-7"
+    env: COMPILER="g++-7" CXX_STANDARD=11
    addons:
      apt:
        sources:
@@ -38,7 +38,18 @@ matrix:
  - os: linux
    language: cpp
    compiler: gcc
-    env: COMPILER="g++-8"
+    env: COMPILER="g++-8" CXX_STANDARD=11
+    addons:
+      apt:
+        sources:
+        - ubuntu-toolchain-r-test
+        packages:
+        - g++-8
+        - libboost-all-dev
+  - os: linux
+    language: cpp
+    compiler: gcc
+    env: COMPILER="g++-8" CXX_STANDARD=17
    addons:
      apt:
        sources:
@@ -49,7 +60,7 @@ matrix:
  - os: linux
    language: cpp
    compiler: clang
-    env: COMPILER="clang++-3.7"
+    env: COMPILER="clang++-3.7" CXX_STANDARD=11
    addons:
      apt:
        sources:
@@ -61,7 +72,7 @@ matrix:
  - os: linux
    language: cpp
    compiler: clang
-    env: COMPILER="clang++-4.0"
+    env: COMPILER="clang++-4.0" CXX_STANDARD=11
    addons:
      apt:
        sources:
@@ -73,7 +84,7 @@ matrix:
  - os: linux
    language: cpp
    compiler: clang
-    env: COMPILER="clang++-5.0"
+    env: COMPILER="clang++-5.0" CXX_STANDARD=11
    addons:
      apt:
        sources:
@@ -85,7 +96,7 @@ matrix:
  - os: linux
    language: cpp
    compiler: clang
-    env: COMPILER="clang++-6.0"
+    env: COMPILER="clang++-6.0" CXX_STANDARD=11
    addons:
      apt:
        sources:
@@ -97,7 +108,7 @@ matrix:
  - os: linux
    language: cpp
    compiler: clang
-    env: COMPILER="clang++-7"
+    env: COMPILER="clang++-7" CXX_STANDARD=11
    addons:
      apt:
        sources:
@@ -109,7 +120,7 @@ matrix:
  - os: linux
    language: cpp
    compiler: clang
-    env: COMPILER="clang++-8"
+    env: COMPILER="clang++-8" CXX_STANDARD=11
    addons:
      apt:
        sources:
@@ -118,14 +129,38 @@ matrix:
        packages:
        - clang-8
        - libboost-all-dev
+  - os: linux
+    language: cpp
+    compiler: clang
+    env: COMPILER="clang++-8" CXX_STANDARD=17
+    addons:
+      apt:
+        sources:
+        - ubuntu-toolchain-r-test
+        - llvm-toolchain-trusty-8
+        packages:
+        - clang-8
+        - g++-8
+        - libboost-all-dev
  - os: osx
    language: cpp
    compiler: clang
+    env: CXX_STANDARD=11

 script:
+- |
+  if [[ "${TRAVIS_OS_NAME}" == "linux" ]]; then
+    mkdir -p cmake
+    travis_retry wget "https://cmake.org/files/v3.11/cmake-3.11.2-Linux-x86_64.tar.gz"
+    tar xf cmake-3.11.2-Linux-x86_64.tar.gz -C cmake --strip-components=1
+    export PATH=${TRAVIS_BUILD_DIR}/cmake/bin:${PATH}
+  else
+    brew upgrade cmake
+  fi
+- cmake --version
 - mkdir build
 - cd build
 - git clone https://github.com/toml-lang/toml.git
- cmake -DCMAKE_CXX_COMPILER=$COMPILER ..
+- cmake -DCMAKE_CXX_COMPILER=$COMPILER -DCMAKE_CXX_STANDARD=$CXX_STANDARD ..
 - make
 - ctest --output-on-failure
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -4,7 +4,10 @@ project(toml11)

 include(CheckCXXCompilerFlag)
 if("${CMAKE_VERSION}" VERSION_GREATER 3.1)
-    set(CMAKE_CXX_STANDARD 11)
+    set(CMAKE_CXX_EXTENSIONS OFF)
+    if(NOT DEFINED CMAKE_CXX_STANDARD)
+        set(CMAKE_CXX_STANDARD 11)
+    endif()
    set(CXX_STANDARD_REQUIRED ON)
 else()
    # Manually check for C++11 compiler flag.
--- a/README.md
+++ b/README.md
@@ -63,6 +63,7 @@ int main()
 - [Conversion between toml value and arbitrary types](#conversion-between-toml-value-and-arbitrary-types)
 - [Invalid UTF-8 Codepoints](#invalid-utf-8-codepoints)
 - [Formatting user-defined error messages](#formatting-user-defined-error-messages)
+- [Getting comments related to a value](#getting-comments)
 - [Serializing TOML data](#serializing-toml-data)
 - [Underlying types](#underlying-types)
 - [Running Tests](#running-tests)
@@ -187,6 +188,12 @@ See also [underlying types](#underlying-types).

 NOTE: To enable to get a reference, conversions between Float and Integer are not supported.

+After C++17, you can use `std::string_view` to get a string from a `toml::value`.
+
+```cpp
+const auto sv = toml::get<std::string_view>(tab.at("key"));
+```
+
 ### In the case of type error

 If you pass an invalid type to `toml::get`, `toml::type_error` will be thrown.
@@ -500,9 +507,9 @@ You can check what type of value does `toml::value` contains by `is_*` function.

 ```cpp
 toml::value v = /* ... */;
-if(v.is_integer() && toml::get<int>(v) == 42)
+if(v.is_integer())
 {
-    std::cout << "value is 42" << std::endl;
+    std::cout << "value is an integer" << std::endl;
 }
 ```

@@ -546,6 +553,36 @@ toml::value v = /* ... */;
 if(v.is(toml::value_t::Boolean)) // ...
 ```

+## Casting value
+
+So far, `toml::get` is introduced, but if you don't need any type conversion,
+`as_*` is simpler to use.
+
+```cpp
+toml::value v = /* ... */;
+if(v.is_integer() && v.as_integer() == 42)
+{
+    std::cout << "value is 42" << std::endl;
+}
+```
+
+The complete list of the functions is below.
+
+```cpp
+const toml::value v(/*...*/);
+v.as_boolean();
+v.as_integer();
+v.as_float();
+v.as_string();
+v.as_offset_datetime();
+v.as_local_datetime();
+v.as_local_date();
+v.as_local_time();
+v.as_array();
+v.as_table();
+v.as_uninitialized();
+```
+
 ## Visiting a toml::value

 toml11 provides `toml::visit` to apply a function to `toml::value` in the
@@ -603,6 +640,27 @@ toml::value operator""_toml(const char* str, std::size_t len);
 Access to the operator can be gained with `using namespace toml::literals;`,
 `using namespace toml::toml_literals`, and `using namespace toml::literals::toml_literals`.

+Note that a key that is composed only of digits is allowed in TOML.
+And, unlike the file parser, toml-literal allows a bare value without a key.
+Thus it is difficult to distinguish arrays having integers and definitions of
+tables that are named as digits.
+Currently, literal `[1]` becomes a table named "1".
+To ensure a literal to be considered as an array with one element, you need to
+add a comma after the first element (like `[1,]`).
+
+```cpp
+"[1,2,3]"_toml;   // This is an array
+"[table]"_toml;   // This is a table that has an empty table named "table" inside.
+"[[1,2,3]]"_toml; // This is an array of arrays
+"[[table]]"_toml; // This is a table that has an array of tables inside.
+
+"[[1]]"_toml;     // This literal is ambiguous.
+                  // Currently, it becomes a table that has array of table "1".
+"1 = [{}]"_toml;  // This is a table that has an array of table named 1.
+"[[1,]]"_toml;    // This is an array of arrays.
+"[[1],]"_toml;    // ditto.
+```
+
 ## Conversion between toml value and arbitrary types

 You can also use `toml::get` and other related functions with the types you defined
@@ -810,6 +868,53 @@ you will get an error message like this.
   |       ~~ maximum number here
 ```

+## Getting comments
+
+Since toml11 keeps a file data until all the values are destructed, you can
+also extract a comment related to a value by calling `toml::value::comment()`.
+
+If there is a comment just after a value (within the same line), you can get
+the specific comment by `toml::value::comment_inline()`.
+
+If there are comments just before a value (without any newline between them),
+you can get the comments by `toml::value::comment_before()`.
+
+`toml::value::comment()` returns the results of both functions after
+concatenating them.
+
+```toml
+a = 42 # comment for a.
+
+# comment for b.
+# this is also a comment for b.
+b = "foo"
+
+c = [ # comment for c.
+    3.14, # this is not a comment for c, but for 3.14.
+] # this is also a comment for c.
+```
+
+```cpp
+// "# comment for a."
+const std::string com1 = toml::find(data, "a").comment();
+
+// "# comment for b."
+const std::string com2 = toml::find(data, "b").comment();
+
+// "# comment for c.\n# this is also a comment for c."
+const std::string com3 = toml::find(data, "c").comment();
+
+// "# this is not a comment for c, but for 3.14."
+const std::string com3 = toml::find<toml::array>(data, "c").front().comment();
+```
+
+Note that once a data in a value is modified, the related file region
+information would be deleted. Thus after modifying a data, you cannot find any
+comments.
+
+Also note that currently it does not support any way to set a comment to a value.
+And currently, serializer does not take comments into account.
+
 ## Serializing TOML data

 toml11 (after v2.1.0) enables you to serialize data into toml format.
@@ -961,11 +1066,13 @@ I appreciate the help of the contributors who introduced the great feature to th
 - Quentin Khan (@xaxousis)
  - Found & Fixed a bug around ODR
  - Improved error messages for invaild keys to show the location where the parser fails
+- Petr Beneš (@wbenny)
+  - Fixed warnings on MSVC

 ## Licensing terms

 This product is licensed under the terms of the [MIT License](LICENSE).

- Copyright (c) 2017 Toru Niina
+- Copyright (c) 2017-2019 Toru Niina

 All rights reserved.
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -21,6 +21,7 @@ set(TEST_NAMES
    test_parse_key
    test_parse_table_key
    test_literals
+    test_comments
    test_get
    test_get_related_func
    test_from_toml
--- a/tests/test_comments.cpp
+++ b/tests/test_comments.cpp
@@ -0,0 +1,125 @@
+#define BOOST_TEST_MODULE "test_comments"
+#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>
+
+BOOST_AUTO_TEST_CASE(test_comment_before)
+{
+    using namespace toml::literals::toml_literals;
+    {
+        const toml::value v = u8R"(
+            # comment for a.
+            a = 42
+            # comment for b.
+            b = "baz"
+        )"_toml;
+
+        BOOST_CHECK_EQUAL(toml::find(v, "a").comment_before(), u8"# comment for a.");
+        BOOST_CHECK_EQUAL(toml::find(v, "b").comment_before(), u8"# comment for b.");
+        BOOST_CHECK_EQUAL(toml::find(v, "a").comment_inline(), "");
+        BOOST_CHECK_EQUAL(toml::find(v, "b").comment_inline(), "");
+
+        BOOST_CHECK_EQUAL(toml::find(v, "a").comment(), u8"# comment for a.");
+        BOOST_CHECK_EQUAL(toml::find(v, "b").comment(), u8"# comment for b.");
+    }
+
+    {
+        const toml::value v = u8R"(
+            # comment for a.
+            # another comment for a.
+            a = 42
+            # comment for b.
+            # also comment for b.
+            b = "baz"
+        )"_toml;
+
+        BOOST_CHECK_EQUAL(toml::find(v, "a").comment_before(), u8R"(# comment for a.
+# another comment for a.)");
+        BOOST_CHECK_EQUAL(toml::find(v, "b").comment_before(), u8R"(# comment for b.
+# also comment for b.)");
+        BOOST_CHECK_EQUAL(toml::find(v, "a").comment_inline(), u8"");
+        BOOST_CHECK_EQUAL(toml::find(v, "b").comment_inline(), u8"");
+
+        BOOST_CHECK_EQUAL(toml::find(v, "a").comment(), u8R"(# comment for a.
+# another comment for a.)");
+        BOOST_CHECK_EQUAL(toml::find(v, "b").comment(), u8R"(# comment for b.
+# also comment for b.)");
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_comment_inline)
+{
+    using namespace toml::literals::toml_literals;
+    {
+        const toml::value v = u8R"(
+            a = 42    # comment for a.
+            b = "baz" # comment for b.
+        )"_toml;
+
+        BOOST_CHECK_EQUAL(toml::find(v, "a").comment_before(), "");
+        BOOST_CHECK_EQUAL(toml::find(v, "b").comment_before(), "");
+        BOOST_CHECK_EQUAL(toml::find(v, "a").comment_inline(), u8"# comment for a.");
+        BOOST_CHECK_EQUAL(toml::find(v, "b").comment_inline(), u8"# comment for b.");
+
+        BOOST_CHECK_EQUAL(toml::find(v, "a").comment(), u8"# comment for a.");
+        BOOST_CHECK_EQUAL(toml::find(v, "b").comment(), u8"# comment for b.");
+    }
+    {
+        const toml::value v = u8R"(
+            a = [    # comment for a.
+                42,
+            ] # this also.
+            b = [ # comment for b.
+                "bar",
+            ]
+            c = [
+                3.14, # this is not a comment for c, but 3.14.
+            ] # comment for c.
+        )"_toml;
+
+        BOOST_CHECK_EQUAL(toml::find(v, "a").comment_before(), "");
+        BOOST_CHECK_EQUAL(toml::find(v, "b").comment_before(), "");
+        BOOST_CHECK_EQUAL(toml::find(v, "c").comment_before(), "");
+
+        BOOST_CHECK_EQUAL(toml::find(v, "a").comment_inline(), u8R"(# comment for a.
+# this also.)");
+        BOOST_CHECK_EQUAL(toml::find(v, "b").comment_inline(), u8"# comment for b.");
+        BOOST_CHECK_EQUAL(toml::find(v, "c").comment_inline(), u8"# comment for c.");
+
+        BOOST_CHECK_EQUAL(toml::find(v, "a").comment(),  u8R"(# comment for a.
+# this also.)");
+        BOOST_CHECK_EQUAL(toml::find(v, "b").comment(), u8"# comment for b.");
+        BOOST_CHECK_EQUAL(toml::find(v, "c").comment(), u8"# comment for c.");
+
+        const auto& c0 = toml::find<toml::array>(v, "c").at(0);
+        BOOST_CHECK_EQUAL(c0.comment(), u8"# this is not a comment for c, but 3.14.");
+    }
+}
+
+BOOST_AUTO_TEST_CASE(test_comment_both)
+{
+    using namespace toml::literals::toml_literals;
+    {
+        const toml::value v = u8R"(
+            # comment for a.
+            a = 42 # inline comment for a.
+            # comment for b.
+            b = "baz" # inline comment for b.
+        )"_toml;
+
+        BOOST_CHECK_EQUAL(toml::find(v, "a").comment_before(), "# comment for a.");
+        BOOST_CHECK_EQUAL(toml::find(v, "b").comment_before(), "# comment for b.");
+        BOOST_CHECK_EQUAL(toml::find(v, "a").comment_inline(), "# inline comment for a.");
+        BOOST_CHECK_EQUAL(toml::find(v, "b").comment_inline(), "# inline comment for b.");
+
+        BOOST_CHECK_EQUAL(toml::find(v, "a").comment(), u8R"(# comment for a.
+# inline comment for a.)");
+        BOOST_CHECK_EQUAL(toml::find(v, "b").comment(), u8R"(# comment for b.
+# inline comment for b.)");
+    }
+}
--- a/tests/test_get.cpp
+++ b/tests/test_get.cpp
@@ -12,6 +12,9 @@
 #include <list>
 #include <deque>
 #include <array>
+#if __cplusplus >= 201703L
+#include <string_view>
+#endif


 BOOST_AUTO_TEST_CASE(test_get_exact)
@@ -166,6 +169,17 @@ BOOST_AUTO_TEST_CASE(test_get_string_type)
        toml::get<std::string>(v) += "bar";
        BOOST_CHECK_EQUAL("foobar", toml::get<std::string>(v));
    }
+
+#if __cplusplus >= 201703L
+    {
+        toml::value v("foo", toml::string_t::basic);
+        BOOST_CHECK_EQUAL("foo", toml::get<std::string_view>(v));
+    }
+    {
+        toml::value v("foo", toml::string_t::literal);
+        BOOST_CHECK_EQUAL("foo", toml::get<std::string_view>(v));
+    }
+#endif
 }

 BOOST_AUTO_TEST_CASE(test_get_toml_array)
--- a/tests/test_literals.cpp
+++ b/tests/test_literals.cpp
@@ -33,6 +33,18 @@ BOOST_AUTO_TEST_CASE(test_file_as_literal)
            b = "baz"
        )"_toml;

+        BOOST_CHECK_EQUAL(r, v);
+    }
+    {
+        const toml::value r{
+            {"table", toml::table{{"a", 42}, {"b", "baz"}}}
+        };
+        const toml::value v = u8R"(
+            [table]
+            a = 42
+            b = "baz"
+        )"_toml;
+
        BOOST_CHECK_EQUAL(r, v);
    }
 }
@@ -91,6 +103,19 @@ BOOST_AUTO_TEST_CASE(test_value_as_literal)

        BOOST_CHECK(v1.is_array());
        BOOST_CHECK((toml::get<std::vector<int>>(v1) == std::vector<int>{1,2,3}));
+
+        const toml::value v2 = u8R"([1,])"_toml;
+
+        BOOST_CHECK(v2.is_array());
+        BOOST_CHECK((toml::get<std::vector<int>>(v2) == std::vector<int>{1}));
+
+        const toml::value v3 = u8R"([[1,]])"_toml;
+        BOOST_CHECK(v3.is_array());
+        BOOST_CHECK((toml::get<std::vector<int>>(toml::get<toml::array>(v3).front()) == std::vector<int>{1}));
+
+        const toml::value v4 = u8R"([[1],])"_toml;
+        BOOST_CHECK(v4.is_array());
+        BOOST_CHECK((toml::get<std::vector<int>>(toml::get<toml::array>(v4).front()) == std::vector<int>{1}));
    }
    {
        const toml::value v1 = u8R"({a = 42})"_toml;
--- a/tests/test_value.cpp
+++ b/tests/test_value.cpp
@@ -9,6 +9,11 @@
 #include <map>
 #include <list>

+#if __cplusplus >= 201703L
+#include <string_view>
+#endif
+
+
 BOOST_AUTO_TEST_CASE(test_value_boolean)
 {
    toml::value v1(true);
@@ -25,6 +30,8 @@ BOOST_AUTO_TEST_CASE(test_value_boolean)

    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Boolean>(), true);
    BOOST_CHECK_EQUAL(v2.cast<toml::value_t::Boolean>(), false);
+    BOOST_CHECK_EQUAL(v1.as_boolean(), true);
+    BOOST_CHECK_EQUAL(v2.as_boolean(), false);

    v1 = false;
    v2 = true;
@@ -40,6 +47,8 @@ BOOST_AUTO_TEST_CASE(test_value_boolean)

    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Boolean>(), false);
    BOOST_CHECK_EQUAL(v2.cast<toml::value_t::Boolean>(), true);
+    BOOST_CHECK_EQUAL(v1.as_boolean(), false);
+    BOOST_CHECK_EQUAL(v2.as_boolean(), true);

    toml::value v3(v1);
    toml::value v4(v2);
@@ -57,6 +66,8 @@ BOOST_AUTO_TEST_CASE(test_value_boolean)

    BOOST_CHECK_EQUAL(v3.cast<toml::value_t::Boolean>(), false);
    BOOST_CHECK_EQUAL(v4.cast<toml::value_t::Boolean>(), true);
+    BOOST_CHECK_EQUAL(v3.as_boolean(), false);
+    BOOST_CHECK_EQUAL(v4.as_boolean(), true);

    toml::value v5(std::move(v1));
    toml::value v6(std::move(v2));
@@ -72,6 +83,8 @@ BOOST_AUTO_TEST_CASE(test_value_boolean)

    BOOST_CHECK_EQUAL(v5.cast<toml::value_t::Boolean>(), false);
    BOOST_CHECK_EQUAL(v6.cast<toml::value_t::Boolean>(), true);
+    BOOST_CHECK_EQUAL(v5.as_boolean(), false);
+    BOOST_CHECK_EQUAL(v6.as_boolean(), true);

    v1 = 42;
    v2 = 3.14;
@@ -87,6 +100,8 @@ BOOST_AUTO_TEST_CASE(test_value_boolean)

    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Integer>(), 42);
    BOOST_CHECK_EQUAL(v2.cast<toml::value_t::Float>(),   3.14);
+    BOOST_CHECK_EQUAL(v1.as_integer(),  42);
+    BOOST_CHECK_EQUAL(v2.as_float(), 3.14);
 }

 BOOST_AUTO_TEST_CASE(test_value_integer)
@@ -105,6 +120,8 @@ BOOST_AUTO_TEST_CASE(test_value_integer)

    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Integer>(), -42);
    BOOST_CHECK_EQUAL(v2.cast<toml::value_t::Integer>(),  42u);
+    BOOST_CHECK_EQUAL(v1.as_integer(), -42);
+    BOOST_CHECK_EQUAL(v2.as_integer(),  42u);

    v1 = 54;
    v2 = -54;
@@ -120,6 +137,8 @@ BOOST_AUTO_TEST_CASE(test_value_integer)

    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Integer>(),  54);
    BOOST_CHECK_EQUAL(v2.cast<toml::value_t::Integer>(), -54);
+    BOOST_CHECK_EQUAL(v1.as_integer(),  54);
+    BOOST_CHECK_EQUAL(v2.as_integer(), -54);

    toml::value v3(v1);
    toml::value v4(v2);
@@ -137,6 +156,8 @@ BOOST_AUTO_TEST_CASE(test_value_integer)

    BOOST_CHECK_EQUAL(v3.cast<toml::value_t::Integer>(),  54);
    BOOST_CHECK_EQUAL(v4.cast<toml::value_t::Integer>(), -54);
+    BOOST_CHECK_EQUAL(v3.as_integer(),  54);
+    BOOST_CHECK_EQUAL(v4.as_integer(), -54);

    toml::value v5(std::move(v1));
    toml::value v6(std::move(v2));
@@ -152,6 +173,8 @@ BOOST_AUTO_TEST_CASE(test_value_integer)

    BOOST_CHECK_EQUAL(v5.cast<toml::value_t::Integer>(),  54);
    BOOST_CHECK_EQUAL(v6.cast<toml::value_t::Integer>(), -54);
+    BOOST_CHECK_EQUAL(v5.as_integer(),  54);
+    BOOST_CHECK_EQUAL(v6.as_integer(), -54);

    v1 = true;
    v2 = false;
@@ -167,6 +190,8 @@ BOOST_AUTO_TEST_CASE(test_value_integer)

    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Boolean>(), true);
    BOOST_CHECK_EQUAL(v2.cast<toml::value_t::Boolean>(), false);
+    BOOST_CHECK_EQUAL(v1.as_boolean(), true);
+    BOOST_CHECK_EQUAL(v2.as_boolean(), false);
 }

 BOOST_AUTO_TEST_CASE(test_value_float)
@@ -183,8 +208,10 @@ BOOST_AUTO_TEST_CASE(test_value_float)
    BOOST_CHECK(v1.is_float());
    BOOST_CHECK(v2.is_float());

-    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Float>(), 3.14);
+    BOOST_CHECK_EQUAL         (v1.cast<toml::value_t::Float>(), 3.14);
    BOOST_CHECK_CLOSE_FRACTION(v2.cast<toml::value_t::Float>(), 3.14, 1e-2);
+    BOOST_CHECK_EQUAL         (v1.as_float(), 3.14);
+    BOOST_CHECK_CLOSE_FRACTION(v2.as_float(), 3.14, 1e-2);

    v1 = 2.718f;
    v2 = 2.718;
@@ -199,7 +226,9 @@ BOOST_AUTO_TEST_CASE(test_value_float)
    BOOST_CHECK(v2.is_float());

    BOOST_CHECK_CLOSE_FRACTION(v1.cast<toml::value_t::Float>(), 2.718, 1e-3);
-    BOOST_CHECK_EQUAL(v2.cast<toml::value_t::Float>(), 2.718);
+    BOOST_CHECK_EQUAL         (v2.cast<toml::value_t::Float>(), 2.718);
+    BOOST_CHECK_CLOSE_FRACTION(v1.as_float(), 2.718, 1e-3);
+    BOOST_CHECK_EQUAL         (v2.as_float(), 2.718);

    toml::value v3(v1);
    toml::value v4(v2);
@@ -216,7 +245,9 @@ BOOST_AUTO_TEST_CASE(test_value_float)
    BOOST_CHECK(v4.is_float());

    BOOST_CHECK_CLOSE_FRACTION(v3.cast<toml::value_t::Float>(), 2.718, 1e-3);
-    BOOST_CHECK_EQUAL(v4.cast<toml::value_t::Float>(), 2.718);
+    BOOST_CHECK_EQUAL         (v4.cast<toml::value_t::Float>(), 2.718);
+    BOOST_CHECK_CLOSE_FRACTION(v3.as_float(), 2.718, 1e-3);
+    BOOST_CHECK_EQUAL         (v4.as_float(), 2.718);

    toml::value v5(std::move(v1));
    toml::value v6(std::move(v2));
@@ -231,7 +262,9 @@ BOOST_AUTO_TEST_CASE(test_value_float)
    BOOST_CHECK(v6.is_float());

    BOOST_CHECK_CLOSE_FRACTION(v5.cast<toml::value_t::Float>(), 2.718, 1e-3);
-    BOOST_CHECK_EQUAL(v6.cast<toml::value_t::Float>(), 2.718);
+    BOOST_CHECK_EQUAL         (v6.cast<toml::value_t::Float>(), 2.718);
+    BOOST_CHECK_CLOSE_FRACTION(v5.as_float(), 2.718, 1e-3);
+    BOOST_CHECK_EQUAL         (v6.as_float(), 2.718);

    v1 = true;
    v2 = false;
@@ -247,6 +280,8 @@ BOOST_AUTO_TEST_CASE(test_value_float)

    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Boolean>(), true);
    BOOST_CHECK_EQUAL(v2.cast<toml::value_t::Boolean>(), false);
+    BOOST_CHECK_EQUAL(v1.as_boolean(), true);
+    BOOST_CHECK_EQUAL(v2.as_boolean(), false);
 }

 BOOST_AUTO_TEST_CASE(test_value_string)
@@ -271,6 +306,10 @@ BOOST_AUTO_TEST_CASE(test_value_string)
    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::String>(), "foo");
    BOOST_CHECK_EQUAL(v2.cast<toml::value_t::String>(), "foo");
    BOOST_CHECK_EQUAL(v3.cast<toml::value_t::String>(), "foo");
+    BOOST_CHECK_EQUAL(v1.as_string(), "foo");
+    BOOST_CHECK_EQUAL(v2.as_string(), "foo");
+    BOOST_CHECK_EQUAL(v3.as_string(), "foo");
+

    v1 = "bar";
    v2 = "bar";
@@ -289,6 +328,10 @@ BOOST_AUTO_TEST_CASE(test_value_string)
    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::String>(), "bar");
    BOOST_CHECK_EQUAL(v2.cast<toml::value_t::String>(), "bar");
    BOOST_CHECK_EQUAL(v3.cast<toml::value_t::String>(), "bar");
+    BOOST_CHECK_EQUAL(v1.as_string(), "bar");
+    BOOST_CHECK_EQUAL(v2.as_string(), "bar");
+    BOOST_CHECK_EQUAL(v3.as_string(), "bar");
+

    toml::value v4(v1);
    toml::value v5(v2);
@@ -313,6 +356,10 @@ BOOST_AUTO_TEST_CASE(test_value_string)
    BOOST_CHECK_EQUAL(v4.cast<toml::value_t::String>(), "bar");
    BOOST_CHECK_EQUAL(v5.cast<toml::value_t::String>(), "bar");
    BOOST_CHECK_EQUAL(v6.cast<toml::value_t::String>(), "bar");
+    BOOST_CHECK_EQUAL(v4.as_string(), "bar");
+    BOOST_CHECK_EQUAL(v5.as_string(), "bar");
+    BOOST_CHECK_EQUAL(v6.as_string(), "bar");
+

    v4.cast<toml::value_t::String>().str.at(2) = 'z';
    v5.cast<toml::value_t::String>().str.at(2) = 'z';
@@ -331,9 +378,9 @@ BOOST_AUTO_TEST_CASE(test_value_string)
    BOOST_CHECK(v5.is_string());
    BOOST_CHECK(v6.is_string());

-    BOOST_CHECK_EQUAL(v4.cast<toml::value_t::String>(), "baz");
-    BOOST_CHECK_EQUAL(v5.cast<toml::value_t::String>(), "baz");
-    BOOST_CHECK_EQUAL(v6.cast<toml::value_t::String>(), "baz");
+    BOOST_CHECK_EQUAL(v4.as_string(), "baz");
+    BOOST_CHECK_EQUAL(v5.as_string(), "baz");
+    BOOST_CHECK_EQUAL(v6.as_string(), "baz");

    v1 = true;
    v2 = true;
@@ -355,6 +402,28 @@ BOOST_AUTO_TEST_CASE(test_value_string)
    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Boolean>(), true);
    BOOST_CHECK_EQUAL(v2.cast<toml::value_t::Boolean>(), true);
    BOOST_CHECK_EQUAL(v3.cast<toml::value_t::Boolean>(), true);
+    BOOST_CHECK_EQUAL(v1.as_boolean(), true);
+    BOOST_CHECK_EQUAL(v2.as_boolean(), true);
+    BOOST_CHECK_EQUAL(v3.as_boolean(), true);
+
+#if __cplusplus >= 201703L
+    std::string_view sv = "foo";
+
+    toml::value v7(sv);
+    toml::value v8(sv, toml::string_t::literal);
+
+    BOOST_CHECK_EQUAL(v7.type(), toml::value_t::String);
+    BOOST_CHECK_EQUAL(v8.type(), toml::value_t::String);
+    BOOST_CHECK(v7.is(toml::value_t::String));
+    BOOST_CHECK(v8.is(toml::value_t::String));
+    BOOST_CHECK(v7.is<toml::String>());
+    BOOST_CHECK(v8.is<toml::String>());
+    BOOST_CHECK(v7.is_string());
+    BOOST_CHECK(v8.is_string());
+
+    BOOST_CHECK_EQUAL(v7.cast<toml::value_t::String>(), "foo");
+    BOOST_CHECK_EQUAL(v8.cast<toml::value_t::String>(), "foo");
+#endif
 }

 BOOST_AUTO_TEST_CASE(test_value_local_date)
@@ -368,6 +437,8 @@ BOOST_AUTO_TEST_CASE(test_value_local_date)

    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::LocalDate>(),
                      toml::local_date(2018, toml::month_t::Jan, 31));
+    BOOST_CHECK_EQUAL(v1.as_local_date(),
+                      toml::local_date(2018, toml::month_t::Jan, 31));

    v1 = toml::local_date(2018, toml::month_t::Apr, 1);

@@ -378,6 +449,8 @@ BOOST_AUTO_TEST_CASE(test_value_local_date)

    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::LocalDate>(),
                      toml::local_date(2018, toml::month_t::Apr, 1));
+    BOOST_CHECK_EQUAL(v1.as_local_date(),
+                      toml::local_date(2018, toml::month_t::Apr, 1));

    toml::value v2(v1);
    BOOST_CHECK(v2 == v1);
@@ -389,6 +462,8 @@ BOOST_AUTO_TEST_CASE(test_value_local_date)

    BOOST_CHECK_EQUAL(v2.cast<toml::value_t::LocalDate>(),
                      toml::local_date(2018, toml::month_t::Apr, 1));
+    BOOST_CHECK_EQUAL(v2.as_local_date(),
+                      toml::local_date(2018, toml::month_t::Apr, 1));

    v1 = true;
    BOOST_CHECK_EQUAL(v1.type(), toml::value_t::Boolean);
@@ -396,6 +471,7 @@ BOOST_AUTO_TEST_CASE(test_value_local_date)
    BOOST_CHECK(v1.is<toml::Boolean>());
    BOOST_CHECK(v1.is_boolean());
    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Boolean>(), true);
+    BOOST_CHECK_EQUAL(v1.as_boolean(), true);
 }

 BOOST_AUTO_TEST_CASE(test_value_local_time)
@@ -415,10 +491,18 @@ BOOST_AUTO_TEST_CASE(test_value_local_time)

    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::LocalTime>(),
                      toml::local_time(12, 30, 45));
+    BOOST_CHECK_EQUAL(v1.as_local_time(),
+                      toml::local_time(12, 30, 45));
+
    BOOST_CHECK_EQUAL(v2.cast<toml::value_t::LocalTime>(),
                      toml::local_time(12, 30, 45));
+    BOOST_CHECK_EQUAL(v2.as_local_time(),
+                      toml::local_time(12, 30, 45));
+
    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::LocalTime>(),
                      v2.cast<toml::value_t::LocalTime>());
+    BOOST_CHECK_EQUAL(v1.as_local_time(),
+                      v2.as_local_time());

    v1 = toml::local_time(1, 30, 0, /*ms*/ 100, /*us*/ 0);

@@ -428,6 +512,8 @@ BOOST_AUTO_TEST_CASE(test_value_local_time)
    BOOST_CHECK(v1.is_local_time());
    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::LocalTime>(),
                      toml::local_time(1, 30, 0, 100, 0));
+    BOOST_CHECK_EQUAL(v1.as_local_time(),
+                      toml::local_time(1, 30, 0, 100, 0));

    toml::value v3(v1);
    BOOST_CHECK(v3 == v1);
@@ -439,6 +525,8 @@ BOOST_AUTO_TEST_CASE(test_value_local_time)

    BOOST_CHECK_EQUAL(v3.cast<toml::value_t::LocalTime>(),
                      toml::local_time(1, 30, 0, 100, 0));
+    BOOST_CHECK_EQUAL(v3.as_local_time(),
+                      toml::local_time(1, 30, 0, 100, 0));

    v1 = true;
    BOOST_CHECK_EQUAL(v1.type(), toml::value_t::Boolean);
@@ -446,6 +534,7 @@ BOOST_AUTO_TEST_CASE(test_value_local_time)
    BOOST_CHECK(v1.is<toml::Boolean>());
    BOOST_CHECK(v1.is_boolean());
    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Boolean>(), true);
+    BOOST_CHECK_EQUAL(v1.as_boolean(), true);
 }

 BOOST_AUTO_TEST_CASE(test_value_local_datetime)
@@ -464,6 +553,10 @@ BOOST_AUTO_TEST_CASE(test_value_local_datetime)
                      toml::local_datetime(
                          toml::local_date(2018, toml::month_t::Jan, 31),
                          toml::local_time(12, 30, 45)));
+    BOOST_CHECK_EQUAL(v1.as_local_datetime(),
+                      toml::local_datetime(
+                          toml::local_date(2018, toml::month_t::Jan, 31),
+                          toml::local_time(12, 30, 45)));

    v1 = toml::local_datetime(
                toml::local_date(2018, toml::month_t::Apr, 1),
@@ -478,6 +571,10 @@ BOOST_AUTO_TEST_CASE(test_value_local_datetime)
                      toml::local_datetime(
                          toml::local_date(2018, toml::month_t::Apr, 1),
                          toml::local_time(1, 15, 30)));
+    BOOST_CHECK_EQUAL(v1.as_local_datetime(),
+                      toml::local_datetime(
+                          toml::local_date(2018, toml::month_t::Apr, 1),
+                          toml::local_time(1, 15, 30)));

    toml::value v2(v1);
    BOOST_CHECK(v2 == v1);
@@ -491,6 +588,11 @@ BOOST_AUTO_TEST_CASE(test_value_local_datetime)
                      toml::local_datetime(
                          toml::local_date(2018, toml::month_t::Apr, 1),
                          toml::local_time(1, 15, 30)));
+    BOOST_CHECK_EQUAL(v2.as_local_datetime(),
+                      toml::local_datetime(
+                          toml::local_date(2018, toml::month_t::Apr, 1),
+                          toml::local_time(1, 15, 30)));
+

    v1 = true;
    BOOST_CHECK_EQUAL(v1.type(), toml::value_t::Boolean);
@@ -498,6 +600,7 @@ BOOST_AUTO_TEST_CASE(test_value_local_datetime)
    BOOST_CHECK(v1.is<toml::Boolean>());
    BOOST_CHECK(v1.is_boolean());
    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Boolean>(), true);
+    BOOST_CHECK_EQUAL(v1.as_boolean(), true);
 }

 BOOST_AUTO_TEST_CASE(test_value_offset_datetime)
@@ -519,6 +622,12 @@ BOOST_AUTO_TEST_CASE(test_value_offset_datetime)
                toml::local_time(12, 30, 45),
                toml::time_offset(9, 0)
                ));
+    BOOST_CHECK_EQUAL(v1.as_offset_datetime(),
+            toml::offset_datetime(
+                toml::local_date(2018, toml::month_t::Jan, 31),
+                toml::local_time(12, 30, 45),
+                toml::time_offset(9, 0)
+                ));

    v1 = toml::offset_datetime(
                toml::local_date(2018, toml::month_t::Apr, 1),
@@ -535,6 +644,12 @@ BOOST_AUTO_TEST_CASE(test_value_offset_datetime)
                toml::local_date(2018, toml::month_t::Apr, 1),
                toml::local_time(1, 15, 30),
                toml::time_offset(9, 0)));
+    BOOST_CHECK_EQUAL(v1.as_offset_datetime(),
+            toml::offset_datetime(
+                toml::local_date(2018, toml::month_t::Apr, 1),
+                toml::local_time(1, 15, 30),
+                toml::time_offset(9, 0)));
+

    toml::value v2(v1);
    BOOST_CHECK(v2 == v1);
@@ -549,12 +664,19 @@ BOOST_AUTO_TEST_CASE(test_value_offset_datetime)
                toml::local_date(2018, toml::month_t::Apr, 1),
                toml::local_time(1, 15, 30),
                toml::time_offset(9, 0)));
+    BOOST_CHECK_EQUAL(v2.as_offset_datetime(),
+            toml::offset_datetime(
+                toml::local_date(2018, toml::month_t::Apr, 1),
+                toml::local_time(1, 15, 30),
+                toml::time_offset(9, 0)));
+
    v1 = true;
    BOOST_CHECK_EQUAL(v1.type(), toml::value_t::Boolean);
    BOOST_CHECK(v1.is(toml::value_t::Boolean));
    BOOST_CHECK(v1.is<toml::Boolean>());
    BOOST_CHECK(v1.is_boolean());
    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Boolean>(), true);
+    BOOST_CHECK_EQUAL(v1.as_boolean(), true);
 }

 BOOST_AUTO_TEST_CASE(test_value_array)
@@ -578,6 +700,12 @@ BOOST_AUTO_TEST_CASE(test_value_array)
    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Array>().at(2).cast<toml::value_t::Integer>(), 3);
    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Array>().at(3).cast<toml::value_t::Integer>(), 4);
    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Array>().at(4).cast<toml::value_t::Integer>(), 5);
+    BOOST_CHECK_EQUAL(v1.as_array().at(0).as_integer(), 1);
+    BOOST_CHECK_EQUAL(v1.as_array().at(1).as_integer(), 2);
+    BOOST_CHECK_EQUAL(v1.as_array().at(2).as_integer(), 3);
+    BOOST_CHECK_EQUAL(v1.as_array().at(3).as_integer(), 4);
+    BOOST_CHECK_EQUAL(v1.as_array().at(4).as_integer(), 5);
+

    BOOST_CHECK_EQUAL(v2.cast<toml::value_t::Array>().at(0).cast<toml::value_t::Integer>(), 6);
    BOOST_CHECK_EQUAL(v2.cast<toml::value_t::Array>().at(1).cast<toml::value_t::Integer>(), 7);
@@ -603,12 +731,24 @@ BOOST_AUTO_TEST_CASE(test_value_array)
    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Array>().at(2).cast<toml::value_t::Integer>(), 8);
    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Array>().at(3).cast<toml::value_t::Integer>(), 9);
    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Array>().at(4).cast<toml::value_t::Integer>(), 0);
+    BOOST_CHECK_EQUAL(v1.as_array().at(0).as_integer(), 6);
+    BOOST_CHECK_EQUAL(v1.as_array().at(1).as_integer(), 7);
+    BOOST_CHECK_EQUAL(v1.as_array().at(2).as_integer(), 8);
+    BOOST_CHECK_EQUAL(v1.as_array().at(3).as_integer(), 9);
+    BOOST_CHECK_EQUAL(v1.as_array().at(4).as_integer(), 0);
+

    BOOST_CHECK_EQUAL(v2.cast<toml::value_t::Array>().at(0).cast<toml::value_t::Integer>(), 1);
    BOOST_CHECK_EQUAL(v2.cast<toml::value_t::Array>().at(1).cast<toml::value_t::Integer>(), 2);
    BOOST_CHECK_EQUAL(v2.cast<toml::value_t::Array>().at(2).cast<toml::value_t::Integer>(), 3);
    BOOST_CHECK_EQUAL(v2.cast<toml::value_t::Array>().at(3).cast<toml::value_t::Integer>(), 4);
    BOOST_CHECK_EQUAL(v2.cast<toml::value_t::Array>().at(4).cast<toml::value_t::Integer>(), 5);
+    BOOST_CHECK_EQUAL(v2.as_array().at(0).as_integer(), 1);
+    BOOST_CHECK_EQUAL(v2.as_array().at(1).as_integer(), 2);
+    BOOST_CHECK_EQUAL(v2.as_array().at(2).as_integer(), 3);
+    BOOST_CHECK_EQUAL(v2.as_array().at(3).as_integer(), 4);
+    BOOST_CHECK_EQUAL(v2.as_array().at(4).as_integer(), 5);
+

    toml::value v3(v1);
    BOOST_CHECK(v3 == v1);
@@ -623,6 +763,12 @@ BOOST_AUTO_TEST_CASE(test_value_array)
    BOOST_CHECK_EQUAL(v3.cast<toml::value_t::Array>().at(2).cast<toml::value_t::Integer>(), 8);
    BOOST_CHECK_EQUAL(v3.cast<toml::value_t::Array>().at(3).cast<toml::value_t::Integer>(), 9);
    BOOST_CHECK_EQUAL(v3.cast<toml::value_t::Array>().at(4).cast<toml::value_t::Integer>(), 0);
+    BOOST_CHECK_EQUAL(v3.as_array().at(0).as_integer(), 6);
+    BOOST_CHECK_EQUAL(v3.as_array().at(1).as_integer(), 7);
+    BOOST_CHECK_EQUAL(v3.as_array().at(2).as_integer(), 8);
+    BOOST_CHECK_EQUAL(v3.as_array().at(3).as_integer(), 9);
+    BOOST_CHECK_EQUAL(v3.as_array().at(4).as_integer(), 0);
+

    v1 = true;
    BOOST_CHECK_EQUAL(v1.type(), toml::value_t::Boolean);
@@ -630,6 +776,7 @@ BOOST_AUTO_TEST_CASE(test_value_array)
    BOOST_CHECK(v1.is<toml::Boolean>());
    BOOST_CHECK(v1.is_boolean());
    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Boolean>(), true);
+    BOOST_CHECK_EQUAL(v1.as_boolean(), true);
 }

 BOOST_AUTO_TEST_CASE(test_value_table)
@@ -644,6 +791,10 @@ BOOST_AUTO_TEST_CASE(test_value_table)
    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Table>().at("foo").cast<toml::value_t::Integer>(),    42);
    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Table>().at("bar").cast<toml::value_t::Float>(),      3.14);
    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Table>().at("baz").cast<toml::value_t::String>().str, "qux");
+    BOOST_CHECK_EQUAL(v1.as_table().at("foo").as_integer(),    42);
+    BOOST_CHECK_EQUAL(v1.as_table().at("bar").as_float(),   3.14);
+    BOOST_CHECK_EQUAL(v1.as_table().at("baz").as_string().str, "qux");
+

    v1 = toml::table{{"foo", 2.71}, {"bar", 54}, {"baz", "quux"}};

@@ -655,6 +806,10 @@ BOOST_AUTO_TEST_CASE(test_value_table)
    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Table>().at("foo").cast<toml::value_t::Float>(),      2.71);
    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Table>().at("bar").cast<toml::value_t::Integer>(),    54);
    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Table>().at("baz").cast<toml::value_t::String>().str, "quux");
+    BOOST_CHECK_EQUAL(v1.as_table().at("foo").as_float(),   2.71);
+    BOOST_CHECK_EQUAL(v1.as_table().at("bar").as_integer(),    54);
+    BOOST_CHECK_EQUAL(v1.as_table().at("baz").as_string().str, "quux");
+

    toml::value v3(v1);
    BOOST_CHECK(v3 == v1);
@@ -667,6 +822,10 @@ BOOST_AUTO_TEST_CASE(test_value_table)
    BOOST_CHECK_EQUAL(v3.cast<toml::value_t::Table>().at("foo").cast<toml::value_t::Float>(),      2.71);
    BOOST_CHECK_EQUAL(v3.cast<toml::value_t::Table>().at("bar").cast<toml::value_t::Integer>(),    54);
    BOOST_CHECK_EQUAL(v3.cast<toml::value_t::Table>().at("baz").cast<toml::value_t::String>().str, "quux");
+    BOOST_CHECK_EQUAL(v3.as_table().at("foo").as_float(),   2.71);
+    BOOST_CHECK_EQUAL(v3.as_table().at("bar").as_integer(),    54);
+    BOOST_CHECK_EQUAL(v3.as_table().at("baz").as_string().str, "quux");
+

    v1 = true;
    BOOST_CHECK_EQUAL(v1.type(), toml::value_t::Boolean);
@@ -674,6 +833,7 @@ BOOST_AUTO_TEST_CASE(test_value_table)
    BOOST_CHECK(v1.is<toml::Boolean>());
    BOOST_CHECK(v1.is_boolean());
    BOOST_CHECK_EQUAL(v1.cast<toml::value_t::Boolean>(), true);
+    BOOST_CHECK_EQUAL(v1.as_boolean(), true);
 }

 BOOST_AUTO_TEST_CASE(test_value_empty)
--- a/toml/combinator.hpp
+++ b/toml/combinator.hpp
@@ -9,7 +9,10 @@
 #include <type_traits>
 #include <iterator>
 #include <limits>
+#include <array>
 #include <iomanip>
+#include <cstdio>
+#include <cassert>
 #include <cctype>

 // they scans characters and returns region if it matches to the condition.
@@ -38,10 +41,12 @@ inline std::string show_char(const char c)
    }
    else
    {
-        std::ostringstream oss;
-        oss << "0x" << std::hex << std::setfill('0') << std::setw(2)
-            << static_cast<int>(c);
-        return oss.str();
+        std::array<char, 5> buf;
+        buf.fill('\0');
+        const auto r = std::snprintf(
+                buf.data(), buf.size(), "0x%02x", static_cast<int>(c) & 0xFF);
+        assert(r == buf.size() - 1);
+        return std::string(buf.data());
    }
 }

@@ -51,7 +56,8 @@ struct character
    static constexpr char target = C;

    template<typename Cont>
-    static result<region<Cont>, std::string> invoke(location<Cont>& loc)
+    static result<region<Cont>, std::string>
+    invoke(location<Cont>& loc, const bool msg = false)
    {
        static_assert(std::is_same<char, typename Cont::value_type>::value,
                      "internal error: container::value_type should be `char`.");
@@ -62,8 +68,12 @@ struct character
        const char c = *(loc.iter());
        if(c != target)
        {
-            return err(concat_to_string("expected '", show_char(target),
-                                        "' but got '", show_char(c), "'."));
+            if(msg)
+            {
+                return err(concat_to_string("expected '", show_char(target),
+                                            "' but got '", show_char(c), "'."));
+            }
+            return err("");
        }
        loc.advance(); // update location

@@ -86,7 +96,8 @@ struct in_range
    static constexpr char lower = Low;

    template<typename Cont>
-    static result<region<Cont>, std::string> invoke(location<Cont>& loc)
+    static result<region<Cont>, std::string>
+    invoke(location<Cont>& loc, const bool msg = false)
    {
        static_assert(std::is_same<char, typename Cont::value_type>::value,
                      "internal error: container::value_type should be `char`.");
@@ -97,9 +108,13 @@ struct in_range
        const char c = *(loc.iter());
        if(c < lower || upper < c)
        {
-            return err(concat_to_string("expected character in range "
-                "[", show_char(lower), ", ", show_char(upper), "] but got ",
-                "'", show_char(c), "'."));
+            if(msg)
+            {
+                return err(concat_to_string("expected character in range "
+                    "[", show_char(lower), ", ", show_char(upper), "] but got ",
+                    "'", show_char(c), "'."));
+            }
+            return err("");
        }

        loc.advance();
@@ -120,7 +135,8 @@ template<typename Combinator>
 struct exclude
 {
    template<typename Cont>
-    static result<region<Cont>, std::string> invoke(location<Cont>& loc)
+    static result<region<Cont>, std::string>
+    invoke(location<Cont>& loc, const bool msg = false)
    {
        static_assert(std::is_same<char, typename Cont::value_type>::value,
                      "internal error: container::value_type should be `char`.");
@@ -128,13 +144,16 @@ struct exclude
        if(loc.iter() == loc.end()) {return err("not sufficient characters");}
        auto first = loc.iter();

-        auto rslt = Combinator::invoke(loc);
+        auto rslt = Combinator::invoke(loc, msg);
        if(rslt.is_ok())
        {
            loc.reset(first);
-            return err(concat_to_string(
-                "invalid pattern (", Combinator::pattern(), ") appeared ",
-                rslt.unwrap().str()));
+            if(msg)
+            {
+                return err(concat_to_string("invalid pattern (",
+                    Combinator::pattern(), ") appeared ", rslt.unwrap().str()));
+            }
+            return err("");
        }
        loc.reset(std::next(first)); // XXX maybe loc.advance() is okay but...
        return ok(region<Cont>(loc, first, loc.iter()));
@@ -151,12 +170,13 @@ template<typename Combinator>
 struct maybe
 {
    template<typename Cont>
-    static result<region<Cont>, std::string> invoke(location<Cont>& loc)
+    static result<region<Cont>, std::string>
+    invoke(location<Cont>& loc, const bool msg = false)
    {
        static_assert(std::is_same<char, typename Cont::value_type>::value,
                      "internal error: container::value_type should be `char`.");

-        const auto rslt = Combinator::invoke(loc);
+        const auto rslt = Combinator::invoke(loc, msg);
        if(rslt.is_ok())
        {
            return rslt;
@@ -177,34 +197,36 @@ template<typename Head, typename ... Tail>
 struct sequence<Head, Tail...>
 {
    template<typename Cont>
-    static result<region<Cont>, std::string> invoke(location<Cont>& loc)
+    static result<region<Cont>, std::string>
+    invoke(location<Cont>& loc, const bool msg = false)
    {
        static_assert(std::is_same<char, typename Cont::value_type>::value,
                      "internal error: container::value_type should be `char`.");

        const auto first = loc.iter();
-        const auto rslt = Head::invoke(loc);
+        const auto rslt = Head::invoke(loc, msg);
        if(rslt.is_err())
        {
            loc.reset(first);
            return err(rslt.unwrap_err());
        }
-        return sequence<Tail...>::invoke(loc, std::move(rslt.unwrap()), first);
+        return sequence<Tail...>::invoke(loc, std::move(rslt.unwrap()), first, msg);
    }

    // called from the above function only, recursively.
    template<typename Cont, typename Iterator>
    static result<region<Cont>, std::string>
-    invoke(location<Cont>& loc, region<Cont> reg, Iterator first)
+    invoke(location<Cont>& loc, region<Cont> reg, Iterator first,
+           const bool msg = false)
    {
-        const auto rslt = Head::invoke(loc);
+        const auto rslt = Head::invoke(loc, msg);
        if(rslt.is_err())
        {
            loc.reset(first);
            return err(rslt.unwrap_err());
        }
        reg += rslt.unwrap(); // concat regions
-        return sequence<Tail...>::invoke(loc, std::move(reg), first);
+        return sequence<Tail...>::invoke(loc, std::move(reg), first, msg);
    }

    static std::string pattern()
@@ -219,9 +241,10 @@ struct sequence<Head>
    // would be called from sequence<T ...>::invoke only.
    template<typename Cont, typename Iterator>
    static result<region<Cont>, std::string>
-    invoke(location<Cont>& loc, region<Cont> reg, Iterator first)
+    invoke(location<Cont>& loc, region<Cont> reg, Iterator first,
+           const bool msg = false)
    {
-        const auto rslt = Head::invoke(loc);
+        const auto rslt = Head::invoke(loc, msg);
        if(rslt.is_err())
        {
            loc.reset(first);
@@ -240,14 +263,15 @@ template<typename Head, typename ... Tail>
 struct either<Head, Tail...>
 {
    template<typename Cont>
-    static result<region<Cont>, std::string> invoke(location<Cont>& loc)
+    static result<region<Cont>, std::string>
+    invoke(location<Cont>& loc, const bool msg = false)
    {
        static_assert(std::is_same<char, typename Cont::value_type>::value,
                      "internal error: container::value_type should be `char`.");

-        const auto rslt = Head::invoke(loc);
+        const auto rslt = Head::invoke(loc, msg);
        if(rslt.is_ok()) {return rslt;}
-        return either<Tail...>::invoke(loc);
+        return either<Tail...>::invoke(loc, msg);
    }

    static std::string pattern()
@@ -259,11 +283,12 @@ template<typename Head>
 struct either<Head>
 {
    template<typename Cont>
-    static result<region<Cont>, std::string> invoke(location<Cont>& loc)
+    static result<region<Cont>, std::string>
+    invoke(location<Cont>& loc, const bool msg = false)
    {
        static_assert(std::is_same<char, typename Cont::value_type>::value,
                      "internal error: container::value_type should be `char`.");
-        return Head::invoke(loc);
+        return Head::invoke(loc, msg);
    }
    static std::string pattern()
    {
@@ -282,13 +307,14 @@ template<typename T, std::size_t N>
 struct repeat<T, exactly<N>>
 {
    template<typename Cont>
-    static result<region<Cont>, std::string> invoke(location<Cont>& loc)
+    static result<region<Cont>, std::string>
+    invoke(location<Cont>& loc, const bool msg = false)
    {
        region<Cont> retval(loc);
        const auto first = loc.iter();
        for(std::size_t i=0; i<N; ++i)
        {
-            auto rslt = T::invoke(loc);
+            auto rslt = T::invoke(loc, msg);
            if(rslt.is_err())
            {
                loc.reset(first);
@@ -308,14 +334,15 @@ template<typename T, std::size_t N>
 struct repeat<T, at_least<N>>
 {
    template<typename Cont>
-    static result<region<Cont>, std::string> invoke(location<Cont>& loc)
+    static result<region<Cont>, std::string>
+    invoke(location<Cont>& loc, const bool msg = false)
    {
        region<Cont> retval(loc);

        const auto first = loc.iter();
        for(std::size_t i=0; i<N; ++i)
        {
-            auto rslt = T::invoke(loc);
+            auto rslt = T::invoke(loc, msg);
            if(rslt.is_err())
            {
                loc.reset(first);
@@ -325,7 +352,7 @@ struct repeat<T, at_least<N>>
        }
        while(true)
        {
-            auto rslt = T::invoke(loc);
+            auto rslt = T::invoke(loc, msg);
            if(rslt.is_err())
            {
                return ok(std::move(retval));
@@ -343,12 +370,13 @@ template<typename T>
 struct repeat<T, unlimited>
 {
    template<typename Cont>
-    static result<region<Cont>, std::string> invoke(location<Cont>& loc)
+    static result<region<Cont>, std::string>
+    invoke(location<Cont>& loc, const bool msg = false)
    {
        region<Cont> retval(loc);
        while(true)
        {
-            auto rslt = T::invoke(loc);
+            auto rslt = T::invoke(loc, msg);
            if(rslt.is_err())
            {
                return ok(std::move(retval));
--- a/toml/datetime.hpp
+++ b/toml/datetime.hpp
@@ -25,20 +25,22 @@ inline std::tm localtime_s(const std::time_t* src)
 {
    std::tm dst;
    const auto result = ::localtime_r(src, &dst);
-    if(!result)
-    {
-        throw std::runtime_error("localtime_r failed.");
-    }
+    if (!result) { throw std::runtime_error("localtime_r failed."); }
+    return dst;
+}
+#elif _MSC_VER
+inline std::tm localtime_s(const std::time_t* src)
+{
+    std::tm dst;
+    const auto result = ::localtime_s(&dst, src);
+    if (result) { throw std::runtime_error("localtime_s failed."); }
    return dst;
 }
 #else
-// XXX: On Windows, std::localtime is thread-safe because they uses thread-local
-// storage to store the instance of std::tm. On the other platforms, it may not
-// be thread-safe.
 inline std::tm localtime_s(const std::time_t* src)
 {
    const auto result = std::localtime(src);
-    if(!result) {throw std::runtime_error("localtime failed.");}
+    if (!result) { throw std::runtime_error("localtime failed."); }
    return *result;
 }
 #endif
@@ -360,12 +362,12 @@ struct local_datetime
        // can be used to get millisecond & microsecond information.
        const auto t_diff = tp -
            std::chrono::system_clock::from_time_t(std::mktime(&time));
-        this->time.millisecond = std::chrono::duration_cast<
-            std::chrono::milliseconds>(t_diff).count();
-        this->time.microsecond = std::chrono::duration_cast<
-            std::chrono::microseconds>(t_diff).count();
-        this->time.nanosecond = std::chrono::duration_cast<
-            std::chrono::nanoseconds >(t_diff).count();
+        this->time.millisecond = static_cast<std::uint16_t>(
+          std::chrono::duration_cast<std::chrono::milliseconds>(t_diff).count());
+        this->time.microsecond = static_cast<std::uint16_t>(
+          std::chrono::duration_cast<std::chrono::microseconds>(t_diff).count());
+        this->time.nanosecond = static_cast<std::uint16_t>(
+          std::chrono::duration_cast<std::chrono::nanoseconds >(t_diff).count());
    }

    explicit local_datetime(const std::time_t t)
--- a/toml/get.hpp
+++ b/toml/get.hpp
@@ -108,6 +108,18 @@ inline std::string get(value&& v)
    return std::move(v.cast<value_t::String>().str);
 }

+// ============================================================================
+// std::string_view
+
+#if __cplusplus >= 201703L
+template<typename T, typename std::enable_if<
+    std::is_same<T, std::string_view>::value, std::nullptr_t>::type = nullptr>
+inline std::string_view get(const value& v)
+{
+    return std::string_view(v.cast<value_t::String>().str);
+}
+#endif
+
 // ============================================================================
 // std::chrono::duration from toml::local_time.

@@ -546,67 +558,6 @@ T get_or(const toml::value& v, T&& opt)
    }
 }

-// ===========================================================================
-// get_or(table, key, fallback)
-//
-// DEPRECATED: use find_or instead.
-
-template<typename T>
-TOML11_MARK_AS_DEPRECATED("use toml::find_or(table, key, opt) instead.")
-auto get_or(const toml::table& tab, const toml::key& ky, T&& opt)
-    -> decltype(get_or(std::declval<value const&>(), std::forward<T>(opt)))
-{
-    if(tab.count(ky) == 0) {return opt;}
-    return ::toml::get_or(tab.at(ky), std::forward<T>(opt));
-}
-template<typename T>
-TOML11_MARK_AS_DEPRECATED("use toml::find_or(table, key, opt) instead.")
-auto get_or(toml::table& tab, const toml::key& ky, T&& opt)
-    -> decltype(get_or(std::declval<value&>(), std::forward<T>(opt)))
-{
-    if(tab.count(ky) == 0) {return opt;}
-    return ::toml::get_or(tab[ky], std::forward<T>(opt));
-}
-template<typename T>
-TOML11_MARK_AS_DEPRECATED("use toml::find_or(table, key, opt) instead.")
-auto get_or(toml::table&& tab, const toml::key& ky, T&& opt)
-    -> decltype(get_or(std::declval<value&&>(), std::forward<T>(opt)))
-{
-    if(tab.count(ky) == 0) {return opt;}
-    return ::toml::get_or(std::move(tab[ky]), std::forward<T>(opt));
-}
-
-template<typename T>
-TOML11_MARK_AS_DEPRECATED("use toml::find_or(value, key, opt) instead.")
-auto get_or(const toml::value& v, const toml::key& ky, T&& opt)
-    -> decltype(get_or(std::declval<value const&>(), std::forward<T>(opt)))
-{
-    if(!v.is_table()) {return opt;}
-    const auto& tab = toml::get<toml::table>(v);
-    if(tab.count(ky) == 0) {return opt;}
-    return ::toml::get_or(tab.at(ky), std::forward<T>(opt));
-}
-template<typename T>
-TOML11_MARK_AS_DEPRECATED("use toml::find_or(value, key, opt) instead.")
-auto get_or(toml::value& v, const toml::key& ky, T&& opt)
-    -> decltype(get_or(std::declval<value&>(), std::forward<T>(opt)))
-{
-    if(!v.is_table()) {return opt;}
-    auto& tab = toml::get<toml::table>(v);
-    if(tab.count(ky) == 0) {return opt;}
-    return ::toml::get_or(tab[ky], std::forward<T>(opt));
-}
-template<typename T>
-TOML11_MARK_AS_DEPRECATED("use toml::find_or(value, key, opt) instead.")
-auto get_or(toml::value&& v, const toml::key& ky, T&& opt)
-    -> decltype(get_or(std::declval<value&&>(), std::forward<T>(opt)))
-{
-    if(!v.is_table()) {return opt;}
-    auto tab = toml::get<toml::table>(std::move(v));
-    if(tab.count(ky) == 0) {return opt;}
-    return ::toml::get_or(std::move(tab[ky]), std::forward<T>(opt));
-}
-
 // ===========================================================================
 // find_or(value, key, fallback)

--- a/toml/literal.hpp
+++ b/toml/literal.hpp
@@ -30,16 +30,52 @@ inline ::toml::value operator""_toml(const char* str, std::size_t len)
        ::toml::detail::lex_ws, ::toml::detail::at_least<1>>;
    skip_ws::invoke(loc);

-    // literal may be a bare value. try them first.
-    if(auto data = ::toml::detail::parse_value(loc))
+    // to distinguish arrays and tables, first check it is a table or not.
+    //
+    // "[1,2,3]"_toml;   // this is an array
+    // "[table]"_toml;   // a table that has an empty table named "table" inside.
+    // "[[1,2,3]]"_toml; // this is an array of arrays
+    // "[[table]]"_toml; // this is a table that has an array of tables inside.
+    //
+    // "[[1]]"_toml;     // this can be both... (currently it becomes a table)
+    // "1 = [{}]"_toml;  // this is a table that has an array of table named 1.
+    // "[[1,]]"_toml;    // this is an array of arrays.
+    // "[[1],]"_toml;    // this also.
+
+    const auto the_front = loc.iter();
+
+    const bool is_table_key = ::toml::detail::lex_std_table::invoke(loc);
+    loc.reset(the_front);
+
+    const bool is_aots_key  = ::toml::detail::lex_array_table::invoke(loc);
+    loc.reset(the_front);
+
+    // If it is neither a table-key or a array-of-table-key, it may be a value.
+    if(!is_table_key && !is_aots_key)
    {
-        return data.unwrap();
+        if(auto data = ::toml::detail::parse_value(loc))
+        {
+            return data.unwrap();
+        }
    }

-    // literal is a TOML file (i.e. multiline table).
+    // Note that still it can be a table, because the literal might be something
+    // like the following.
+    // ```cpp
+    // R"( // c++11 raw string literals
+    //   key = "value"
+    //   int = 42
+    // )"_toml;
+    // ```
+    // It is a valid toml file.
+    // It should be parsed as if we parse a file with this content.
+
    if(auto data = ::toml::detail::parse_toml_file(loc))
    {
        loc.reset(loc.begin()); // rollback to the top of the literal
+        // skip needless characters for error message
+        skip_line::invoke(loc); // skip the first several needless lines
+        skip_ws::invoke(loc);   // skip the first several needless whitespaces
        return ::toml::value(std::move(data.unwrap()),
                ::toml::detail::region<std::vector<char>>(std::move(loc)));
    }
--- a/toml/parser.hpp
+++ b/toml/parser.hpp
@@ -116,10 +116,28 @@ parse_integer(location<Container>& loc)
    const auto first = loc.iter();
    if(first != loc.end() && *first == '0')
    {
-        if(const auto bin = parse_binary_integer     (loc)) {return bin;}
-        if(const auto oct = parse_octal_integer      (loc)) {return oct;}
-        if(const auto hex = parse_hexadecimal_integer(loc)) {return hex;}
-        // else, maybe just zero.
+        const auto second = std::next(first);
+        if(second == loc.end()) // the token is just zero.
+        {
+            return ok(std::make_pair(0, region<Container>(loc, first, second)));
+        }
+
+        if(*second == 'b') {return parse_binary_integer     (loc);} // 0b1100
+        if(*second == 'o') {return parse_octal_integer      (loc);} // 0o775
+        if(*second == 'x') {return parse_hexadecimal_integer(loc);} // 0xC0FFEE
+
+        if(std::isdigit(*second))
+        {
+            return err(format_underline("[error] toml::parse_integer: "
+                "leading zero in an Integer is not allowed.",
+                {{std::addressof(loc), "leading zero"}}));
+        }
+        else if(std::isalpha(*second))
+        {
+             return err(format_underline("[error] toml::parse_integer: "
+                "unknown integer prefix appeared.",
+                {{std::addressof(loc), "none of 0x, 0o, 0b"}}));
+        }
    }

    if(const auto token = lex_dec_int::invoke(loc))
@@ -308,7 +326,7 @@ result<std::string, std::string> parse_escape_sequence(location<Container>& loc)
            {
                return err(format_underline("[error] parse_escape_sequence: "
                           "invalid token found in UTF-8 codepoint uXXXX.",
-                           {{std::addressof(loc), token.unwrap_err()}}));
+                           {{std::addressof(loc), "here"}}));
            }
        }
        case 'U':
@@ -321,7 +339,7 @@ result<std::string, std::string> parse_escape_sequence(location<Container>& loc)
            {
                return err(format_underline("[error] parse_escape_sequence: "
                           "invalid token found in UTF-8 codepoint Uxxxxxxxx",
-                           {{std::addressof(loc), token.unwrap_err()}}));
+                           {{std::addressof(loc), "here"}}));
            }
        }
    }
@@ -388,7 +406,9 @@ parse_ml_basic_string(location<Container>& loc)
    else
    {
        loc.reset(first);
-        return err(token.unwrap_err());
+        return err(format_underline("[error] toml::parse_ml_basic_string: "
+                   "the next token is not a multiline string",
+                   {{std::addressof(loc), "here"}}));
    }
 }

@@ -437,7 +457,9 @@ parse_basic_string(location<Container>& loc)
    else
    {
        loc.reset(first); // rollback
-        return err(token.unwrap_err());
+        return err(format_underline("[error] toml::parse_basic_string: "
+                   "the next token is not a string",
+                   {{std::addressof(loc), "here"}}));
    }
 }

@@ -476,7 +498,9 @@ parse_ml_literal_string(location<Container>& loc)
    else
    {
        loc.reset(first); // rollback
-        return err(token.unwrap_err());
+        return err(format_underline("[error] toml::parse_ml_literal_string: "
+                   "the next token is not a multiline literal string",
+                   {{std::addressof(loc), "here"}}));
    }
 }

@@ -513,7 +537,9 @@ parse_literal_string(location<Container>& loc)
    else
    {
        loc.reset(first); // rollback
-        return err(token.unwrap_err());
+        return err(format_underline("[error] toml::parse_literal_string: "
+                   "the next token is not a literal string",
+                   {{std::addressof(loc), "here"}}));
    }
 }

@@ -521,10 +547,30 @@ template<typename Container>
 result<std::pair<toml::string, region<Container>>, std::string>
 parse_string(location<Container>& loc)
 {
-    if(const auto rslt = parse_ml_basic_string(loc))   {return rslt;}
-    if(const auto rslt = parse_ml_literal_string(loc)) {return rslt;}
-    if(const auto rslt = parse_basic_string(loc))      {return rslt;}
-    if(const auto rslt = parse_literal_string(loc))    {return rslt;}
+    if(loc.iter() != loc.end() && *(loc.iter()) == '"')
+    {
+        if(loc.iter() + 1 != loc.end() && *(loc.iter() + 1) == '"' &&
+           loc.iter() + 2 != loc.end() && *(loc.iter() + 2) == '"')
+        {
+            return parse_ml_basic_string(loc);
+        }
+        else
+        {
+            return parse_basic_string(loc);
+        }
+    }
+    else if(loc.iter() != loc.end() && *(loc.iter()) == '\'')
+    {
+        if(loc.iter() + 1 != loc.end() && *(loc.iter() + 1) == '\'' &&
+           loc.iter() + 2 != loc.end() && *(loc.iter() + 2) == '\'')
+        {
+            return parse_ml_literal_string(loc);
+        }
+        else
+        {
+            return parse_literal_string(loc);
+        }
+    }
    return err(format_underline("[error] toml::parse_string: ",
                {{std::addressof(loc), "the next token is not a string"}}));
 }
@@ -758,7 +804,7 @@ parse_offset_datetime(location<Container>& loc)
    {
        loc.reset(first);
        return err(format_underline("[error]: toml::parse_offset_datetime: ",
-            {{std::addressof(loc), "the next token is not a local_datetime"}}));
+            {{std::addressof(loc), "the next token is not a offset_datetime"}}));
    }
 }

@@ -1360,10 +1406,16 @@ parse_inline_table(location<Container>& loc)
                return ok(std::make_pair(
                            retval, region<Container>(loc, first, loc.iter())));
            }
+            else if(*loc.iter() == '#' || *loc.iter() == '\r' || *loc.iter() == '\n')
+            {
+                throw syntax_error(format_underline("[error] "
+                    "toml::parse_inline_table: missing curly brace `}`",
+                    {{std::addressof(loc), "should be `}`"}}));
+            }
            else
            {
                throw syntax_error(format_underline("[error] "
-                    "toml:::parse_inline_table: missing table separator `,` ",
+                    "toml::parse_inline_table: missing table separator `,` ",
                    {{std::addressof(loc), "should be `,`"}}));
            }
        }
@@ -1374,6 +1426,46 @@ parse_inline_table(location<Container>& loc)
            {{std::addressof(loc), "should be closed"}}));
 }

+template<typename Container>
+value_t guess_number_type(const location<Container>& l)
+{
+    location<Container> loc = l;
+
+    if(lex_offset_date_time::invoke(loc)) {return value_t::OffsetDatetime;}
+    loc.reset(l.iter());
+
+    if(lex_local_date_time::invoke(loc)) {return value_t::LocalDatetime;}
+    loc.reset(l.iter());
+
+    if(lex_local_date::invoke(loc)) {return value_t::LocalDate;}
+    loc.reset(l.iter());
+
+    if(lex_local_time::invoke(loc)) {return value_t::LocalTime;}
+    loc.reset(l.iter());
+
+    if(lex_float::invoke(loc)) {return value_t::Float;}
+    loc.reset(l.iter());
+
+    return value_t::Integer;
+}
+
+template<typename Container>
+value_t guess_value_type(const location<Container>& loc)
+{
+    switch(*loc.iter())
+    {
+        case '"' : {return value_t::String; }
+        case '\'': {return value_t::String; }
+        case 't' : {return value_t::Boolean;}
+        case 'f' : {return value_t::Boolean;}
+        case '[' : {return value_t::Array;  }
+        case '{' : {return value_t::Table;  }
+        case 'i' : {return value_t::Float;  } // inf.
+        case 'n' : {return value_t::Float;  } // nan.
+        default  : {return guess_number_type(loc);}
+    }
+}
+
 template<typename Container>
 result<value, std::string> parse_value(location<Container>& loc)
 {
@@ -1383,31 +1475,27 @@ result<value, std::string> parse_value(location<Container>& loc)
        return err(format_underline("[error] toml::parse_value: input is empty",
                   {{std::addressof(loc), ""}}));
    }
-    if(auto r = parse_string         (loc))
-    {return ok(value(std::move(r.unwrap().first), std::move(r.unwrap().second)));}
-    if(auto r = parse_array          (loc))
-    {return ok(value(std::move(r.unwrap().first), std::move(r.unwrap().second)));}
-    if(auto r = parse_inline_table   (loc))
-    {return ok(value(std::move(r.unwrap().first), std::move(r.unwrap().second)));}
-    if(auto r = parse_boolean        (loc))
-    {return ok(value(std::move(r.unwrap().first), std::move(r.unwrap().second)));}
-    if(auto r = parse_offset_datetime(loc))
-    {return ok(value(std::move(r.unwrap().first), std::move(r.unwrap().second)));}
-    if(auto r = parse_local_datetime (loc))
-    {return ok(value(std::move(r.unwrap().first), std::move(r.unwrap().second)));}
-    if(auto r = parse_local_date     (loc))
-    {return ok(value(std::move(r.unwrap().first), std::move(r.unwrap().second)));}
-    if(auto r = parse_local_time     (loc))
-    {return ok(value(std::move(r.unwrap().first), std::move(r.unwrap().second)));}
-    if(auto r = parse_floating       (loc))
-    {return ok(value(std::move(r.unwrap().first), std::move(r.unwrap().second)));}
-    if(auto r = parse_integer        (loc))
-    {return ok(value(std::move(r.unwrap().first), std::move(r.unwrap().second)));}

-    const auto msg = format_underline("[error] toml::parse_value: "
-            "unknown token appeared", {{std::addressof(loc), "unknown"}});
-    loc.reset(first);
-    return err(msg);
+    switch(guess_value_type(loc))
+    {
+        case value_t::Boolean        : {return parse_boolean(loc);        }
+        case value_t::Integer        : {return parse_integer(loc);        }
+        case value_t::Float          : {return parse_floating(loc);       }
+        case value_t::String         : {return parse_string(loc);         }
+        case value_t::OffsetDatetime : {return parse_offset_datetime(loc);}
+        case value_t::LocalDatetime  : {return parse_local_datetime(loc); }
+        case value_t::LocalDate      : {return parse_local_date(loc);     }
+        case value_t::LocalTime      : {return parse_local_time(loc);     }
+        case value_t::Array          : {return parse_array(loc);          }
+        case value_t::Table          : {return parse_inline_table(loc);   }
+        default:
+        {
+            const auto msg = format_underline("[error] toml::parse_value: "
+                    "unknown token appeared", {{std::addressof(loc), "unknown"}});
+            loc.reset(first);
+            return err(msg);
+        }
+    }
 }

 template<typename Container>
@@ -1463,7 +1551,8 @@ parse_table_key(location<Container>& loc)
    }
    else
    {
-        return err(token.unwrap_err());
+        return err(format_underline("[error] toml::parse_table_key: "
+            "not a valid table key", {{std::addressof(loc), "here"}}));
    }
 }

@@ -1471,7 +1560,7 @@ template<typename Container>
 result<std::pair<std::vector<key>, region<Container>>, std::string>
 parse_array_table_key(location<Container>& loc)
 {
-    if(auto token = lex_array_table::invoke(loc))
+    if(auto token = lex_array_table::invoke(loc, true))
    {
        location<std::string> inner_loc(loc.name(), token.unwrap().str());

@@ -1516,7 +1605,8 @@ parse_array_table_key(location<Container>& loc)
    }
    else
    {
-        return err(token.unwrap_err());
+        return err(format_underline("[error] toml::parse_array_table_key: "
+            "not a valid table key", {{std::addressof(loc), "here"}}));
    }
 }

--- a/toml/region.hpp
+++ b/toml/region.hpp
@@ -52,6 +52,14 @@ struct region_base
    virtual std::size_t before()   const noexcept {return 0;}
    // number of characters in the line after the region
    virtual std::size_t after()    const noexcept {return 0;}
+
+    virtual std::string comment_before() const {return "";} // just before
+    virtual std::string comment_inline() const {return "";} // in the same line
+    virtual std::string comment()        const {return "";} // concatenate
+    // ```toml
+    // # comment_before
+    // key = "value" # comment_inline
+    // ```
 };

 // location represents a position in a container, which contains a file content.
@@ -71,7 +79,7 @@ struct location final : public region_base
        "container should be randomly accessible");

    location(std::string name, Container cont)
-      : source_(std::make_shared<Container>(std::move(cont))), line_number_(0),
+      : source_(std::make_shared<Container>(std::move(cont))), line_number_(1),
        source_name_(std::move(name)), iter_(source_->cbegin())
    {}
    location(const location&) = default;
@@ -88,7 +96,7 @@ struct location final : public region_base
    const_iterator begin() const noexcept {return source_->cbegin();}
    const_iterator end()   const noexcept {return source_->cend();}

-    // XXX At first, `location::line_num()` is implemented using `std::count` to
+    // XXX `location::line_num()` used to be implemented using `std::count` to
    // count a number of '\n'. But with a long toml file (typically, 10k lines),
    // it becomes intolerably slow because each time it generates error messages,
    // it counts '\n' from thousands of characters. To workaround it, I decided
@@ -110,8 +118,8 @@ struct location final : public region_base
    }
    void reset(const_iterator rollback) noexcept
    {
-        // since c++11, std::distance works in both ways and returns a negative
-        // value if `first` is ahead from `last`.
+        // since c++11, std::distance works in both ways for random-access
+        // iterators and returns a negative value if `first > last`.
        if(0 <= std::distance(rollback, this->iter_)) // rollback < iter
        {
            this->line_number_ -= std::count(rollback, this->iter_, '\n');
@@ -280,6 +288,92 @@ struct region final : public region_base

    std::string name() const override {return source_name_;}

+    std::string comment_before() const override
+    {
+        auto iter = this->line_begin(); // points the first element
+        std::vector<std::pair<decltype(iter), decltype(iter)>> comments;
+        while(iter != this->begin())
+        {
+            iter = std::prev(iter);
+            using rev_iter = std::reverse_iterator<decltype(iter)>;
+            auto line_before = std::find(rev_iter(iter), rev_iter(this->begin()),
+                                         '\n').base();
+            // range [line_before, iter) represents the previous line
+
+            auto comment_found = std::find(line_before, iter, '#');
+            if(iter != comment_found && std::all_of(line_before, comment_found,
+                    [](const char c) noexcept -> bool {
+                        return c == ' ' || c == '\t';
+                    }))
+            {
+                // the line before this range contains only a comment.
+                comments.push_back(std::make_pair(comment_found, iter));
+            }
+            else
+            {
+                break;
+            }
+            iter = line_before;
+        }
+
+        std::string com;
+        for(auto i = comments.crbegin(), e = comments.crend(); i!=e; ++i)
+        {
+            if(i != comments.crbegin()) {com += '\n';}
+            com += std::string(i->first, i->second);
+        }
+        return com;
+    }
+
+    std::string comment_inline() const override
+    {
+        if(this->contain_newline())
+        {
+            std::string com;
+            // check both the first and the last line.
+            const auto first_line_end =
+                std::find(this->line_begin(), this->last(), '\n');
+            const auto first_comment_found =
+                std::find(this->line_begin(), first_line_end, '#');
+
+            if(first_comment_found != first_line_end)
+            {
+                com += std::string(first_comment_found, first_line_end);
+            }
+
+            const auto last_comment_found =
+                std::find(this->last(), this->line_end(), '#');
+            if(last_comment_found != this->line_end())
+            {
+                if(!com.empty()){com += '\n';}
+                com += std::string(last_comment_found, this->line_end());
+            }
+            return com;
+        }
+        const auto comment_found =
+            std::find(this->line_begin(), this->line_end(), '#');
+        return std::string(comment_found, this->line_end());
+    }
+
+    std::string comment() const override
+    {
+        std::string com_bef = this->comment_before();
+        std::string com_inl = this->comment_inline();
+        if(!com_bef.empty() && !com_inl.empty())
+        {
+            com_bef += '\n';
+            return com_bef + com_inl;
+        }
+        else if(com_bef.empty())
+        {
+            return com_inl;
+        }
+        else
+        {
+            return com_bef;
+        }
+    }
+
  private:

    source_ptr     source_;
@@ -343,7 +437,8 @@ inline std::string format_underline(const std::string& message,
        {
            // invalid
            // ~~~~~~~
-            retval << make_string(reg->size(), '~');
+            const auto underline_len = std::min(reg->size(), reg->line().size());
+            retval << make_string(underline_len, '~');
        }

        retval << ' ';
--- a/toml/string.hpp
+++ b/toml/string.hpp
@@ -4,6 +4,11 @@
 #define TOML11_STRING_HPP
 #include <string>
 #include <cstdint>
+#if __cplusplus >= 201703L
+#if __has_include(<string_view>)
+#include <string_view>
+#endif
+#endif

 namespace toml
 {
@@ -40,6 +45,17 @@ struct string
    operator std::string const& () const& noexcept {return str;}
    operator std::string&&      () &&     noexcept {return std::move(str);}

+#if __cplusplus >= 201703L
+    explicit string(std::string_view s): kind(string_t::basic), str(s){}
+    string(std::string_view s, string_t k): kind(k), str(s){}
+
+    string& operator=(std::string_view s)
+    {kind = string_t::basic; str = s; return *this;}
+
+    explicit operator std::string_view() const noexcept
+    {return std::string_view(str);}
+#endif
+
    string_t    kind;
    std::string str;
 };
--- a/toml/types.hpp
+++ b/toml/types.hpp
@@ -7,6 +7,11 @@
 #include "traits.hpp"
 #include <vector>
 #include <unordered_map>
+#if __cplusplus >= 201703L
+#if __has_include(<string_view>)
+#include <string_view>
+#endif
+#endif

 namespace toml
 {
@@ -172,6 +177,9 @@ template<typename T>
 struct is_container : conjunction<
    negation<is_map<T>>,
    negation<std::is_same<T, std::string>>,
+#if __cplusplus >= 201703L
+    negation<std::is_same<T, std::string_view>>,
+#endif
    has_iterator<T>,
    has_value_type<T>
    >{};
--- a/toml/value.hpp
+++ b/toml/value.hpp
@@ -14,6 +14,9 @@
 #include <unordered_map>
 #include <cassert>
 #include <cstdint>
+#if __cplusplus >= 201703L
+#include <string_view>
+#endif

 namespace toml
 {
@@ -293,6 +296,29 @@ class value
        assigner(this->string_, toml::string(std::string(s), kind));
    }

+#if __cplusplus >= 201703L
+    value(std::string_view s)
+        : type_(value_t::String),
+          region_info_(std::make_shared<region_base>(region_base{}))
+    {
+        assigner(this->string_, toml::string(s));
+    }
+    value& operator=(std::string_view s)
+    {
+        this->cleanup();
+        this->type_ = value_t::String;
+        this->region_info_ = std::make_shared<region_base>(region_base{});
+        assigner(this->string_, toml::string(s));
+        return *this;
+    }
+    value(std::string_view s, string_t kind)
+        : type_(value_t::String),
+          region_info_(std::make_shared<region_base>(region_base{}))
+    {
+        assigner(this->string_, toml::string(s, kind));
+    }
+#endif
+
    // local date ===========================================================

    value(const local_date& ld)
@@ -572,6 +598,14 @@ class value
        return *this;
    }

+    // for internal use ------------------------------------------------------
+
+    template<typename T, typename Container, typename std::enable_if<
+        detail::is_exact_toml_type<T>::value, std::nullptr_t>::type = nullptr>
+    value(std::pair<T, detail::region<Container>> parse_result)
+        : value(std::move(parse_result.first), std::move(parse_result.second))
+    {}
+
    // type checking and casting ============================================

    template<typename T>
@@ -599,6 +633,41 @@ class value
    template<value_t T>
    typename detail::toml_default_type<T>::type&&      cast() &&;

+    boolean         const& as_boolean()         const {return this->cast<value_t::Boolean       >();}
+    integer         const& as_integer()         const {return this->cast<value_t::Integer       >();}
+    floating        const& as_float()           const {return this->cast<value_t::Float         >();}
+    string          const& as_string()          const {return this->cast<value_t::String        >();}
+    offset_datetime const& as_offset_datetime() const {return this->cast<value_t::OffsetDatetime>();}
+    local_datetime  const& as_local_datetime()  const {return this->cast<value_t::LocalDatetime >();}
+    local_date      const& as_local_date()      const {return this->cast<value_t::LocalDate     >();}
+    local_time      const& as_local_time()      const {return this->cast<value_t::LocalTime     >();}
+    array           const& as_array()           const {return this->cast<value_t::Array         >();}
+    table           const& as_table()           const {return this->cast<value_t::Table         >();}
+
+    boolean&          as_boolean()         {return this->cast<value_t::Boolean       >();}
+    integer&          as_integer()         {return this->cast<value_t::Integer       >();}
+    floating&         as_float()           {return this->cast<value_t::Float         >();}
+    string&           as_string()          {return this->cast<value_t::String        >();}
+    offset_datetime&  as_offset_datetime() {return this->cast<value_t::OffsetDatetime>();}
+    local_datetime&   as_local_datetime()  {return this->cast<value_t::LocalDatetime >();}
+    local_date&       as_local_date()      {return this->cast<value_t::LocalDate     >();}
+    local_time&       as_local_time()      {return this->cast<value_t::LocalTime     >();}
+    array&            as_array()           {return this->cast<value_t::Array         >();}
+    table&            as_table()           {return this->cast<value_t::Table         >();}
+
+    std::string comment() const
+    {
+        return this->region_info_->comment();
+    }
+    std::string comment_before() const
+    {
+        return this->region_info_->comment_before();
+    }
+    std::string comment_inline() const
+    {
+        return this->region_info_->comment_inline();
+    }
+
  private:

    void cleanup() noexcept
Author	SHA1	Message	Date
ToruNiina	87be890e07	feat: remove deprecated functions	2019-04-28 15:59:09 +09:00
Toru Niina	d72dc706d0	Merge pull request #61 from ToruNiina/as-something feat: add as_something functions for convenience	2019-04-28 15:02:19 +09:00
ToruNiina	4cbbcd8f62	Merge branch 'master' into as-something	2019-04-27 19:04:44 +09:00
Toru Niina	a2631ecacb	Merge pull request #60 from ToruNiina/string-view support std::string_view	2019-04-27 18:33:59 +09:00
ToruNiina	4bcc5e8375	Merge branch 'master' into as-something	2019-04-27 17:42:12 +09:00
Toru Niina	90f84000ba	Merge pull request #59 from ToruNiina/preserve-comments Preserve comments; related to #48	2019-04-27 17:40:26 +09:00
ToruNiina	20a13754a7	chore: update README for as_* functions	2019-04-27 16:50:44 +09:00
ToruNiina	aa7b9a3965	refactor: rename as_floating -> as_float Actually, since `floating` is used for toml::types, `as_floating` seems to be clearer. But currently `is_*` functions uses `float`, not `floating`, so `as_float` is chosen for the consistency. In a future release, possibly v3, those names may need to be re-considered for clarity.	2019-04-27 16:45:25 +09:00
ToruNiina	84ac1d10f3	test: add test for toml::value::as_something	2019-04-27 16:22:50 +09:00
ToruNiina	0d623856a7	feat: add value::as_something() for convenience	2019-04-27 16:22:23 +09:00
ToruNiina	ec0d4e4e8c	chore: update README for comments	2019-04-27 15:50:54 +09:00
ToruNiina	80ea736b3f	ci: try to update standard library on travis	2019-04-27 14:46:40 +09:00
ToruNiina	ebaa5dfb51	chore: fix build settings for OS X on Travis	2019-04-26 21:10:29 +09:00
ToruNiina	f3bdf083fe	fix: fix typo in test code for string_view	2019-04-26 16:51:23 +09:00
ToruNiina	1ce54a9cf9	chore: add auto test with c++17 + latest compilers	2019-04-26 16:35:03 +09:00
ToruNiina	6383a93ce7	chore: check CXX_STANDARD exists or not	2019-04-26 16:33:48 +09:00
ToruNiina	01aa2ef5b2	feat: add ctor to value to init with string_view	2019-04-26 16:33:09 +09:00
ToruNiina	819351f5a4	test: add test for init toml::value by string_view	2019-04-26 16:32:23 +09:00
ToruNiina	2967cebfb3	test: add test to get a toml::value as string_view	2019-04-26 16:31:59 +09:00
ToruNiina	32e9a2c1c7	test: add test for comments in an array	2019-04-26 15:35:41 +09:00
ToruNiina	8e0a40a1aa	test: add test for getting comments	2019-04-25 22:34:12 +09:00
ToruNiina	e460826084	feat: enable to get a comment related to a value - comment_before(): get comments just before a value. - comment_inline(): get a comment in the same line as a value. - comment(): get comment_before() + comment_inline().	2019-04-25 22:32:39 +09:00
ToruNiina	aa3445f38c	feat: add functions to get comments around region	2019-04-25 22:32:18 +09:00
ToruNiina	408b7bf35e	Merge branch 'master' into string-view	2019-04-23 23:32:08 +09:00
ToruNiina	6185dfee14	chore: fix typo in README	2019-04-23 23:31:37 +09:00
ToruNiina	37aa2739a5	chore: add description about string_view to README	2019-04-23 23:27:53 +09:00
ToruNiina	d061c33a16	feat: enable toml::get with std::string_view	2019-04-23 23:24:23 +09:00
ToruNiina	0c7d2d07d4	feat: do not consider string_view as a container it is a kind of string.	2019-04-23 23:23:57 +09:00
ToruNiina	62cf4373bd	feat: conversion toml::string <-> string_view	2019-04-22 23:18:05 +09:00
Toru Niina	a74ad23514	Merge pull request #58 from ToruNiina/improve-err-msg-literal Improve error message from toml literal	2019-04-22 20:50:11 +09:00
ToruNiina	2d9b4992ec	fix: restrict length of underline by size of line in some cases, `region` contains several lines and `region::size` returns the whole size that is a sum of lengthes of all the lines. To avoid too long underlines, restrict the length of underline by the length of the line that is shown in the message.	2019-04-21 16:38:08 +09:00
ToruNiina	82e8c1e68b	fix: skip first ws/newlines in toml literal when ""_toml literal is used with C++11 raw-string literal, it normally starts with newline like the following. ```cpp const auto v = u8R"( [table] key = "value" )"_toml; ``` With this, the error message shows the first empty line that starts just after `u8R"(` and thus the error message shows nothing. To avoid this, skip the first empty lines and whitespaces in literal.	2019-04-21 16:31:24 +09:00
ToruNiina	46be054ce9	fix: improve err msg for multiline inline table show "missing curly brace" instead of "missing table key-value separator"	2019-04-19 13:22:13 +09:00
ToruNiina	789d784769	chore: update README; about literals	2019-04-19 13:18:35 +09:00
ToruNiina	81deb8efde	chore: update README	2019-04-19 12:41:24 +09:00
Toru Niina	072dccd05d	Merge pull request #56 from ToruNiina/optimization Optimization	2019-04-19 01:30:29 +09:00
ToruNiina	637c99d637	refactor: generate error message in parser	2019-04-18 15:09:58 +09:00
ToruNiina	0f48852730	perf: check value type before parsing to avoid needless error message generation	2019-04-18 14:26:27 +09:00
ToruNiina	0499b2907d	Merge branch 'master' into optimization	2019-04-18 14:10:08 +09:00
ToruNiina	61e69c9251	fix: count line number from 1, not 0	2019-04-18 13:56:19 +09:00
ToruNiina	4a560ea1e5	fix: show correct error message	2019-04-18 00:04:33 +09:00
ToruNiina	c5b6ee6f81	feat: add yet another constructor to value to make implementation of parse_value easier	2019-04-17 23:43:42 +09:00
ToruNiina	1a7bf63622	Merge branch 'master' into optimization	2019-04-17 14:58:28 +09:00
Toru Niina	8847cdc0a9	Merge pull request #55 from wbenny/master fix /W4 warnings on MSVC	2019-04-17 13:16:19 +09:00
ToruNiina	c82e76a111	perf: check string type before parsing it to avoid unncessary error message generation, check the first some characters before parsing it. It makes parsing process faster and is also helpful to generate more accurate error messages.	2019-04-16 21:47:24 +09:00
ToruNiina	4db486d76d	perf: check integer prefix before trying to parse all the parsers generate error messages and error message generation is not a lightweight task. It concatenates a lot of strings, it formats many values, etc. To avoid useless error-message generation, first check which prefix is used and then parse special integers. Additionally, by checking that, the quality of the error message can be improved (later).	2019-04-16 21:37:12 +09:00
ToruNiina	91966a6917	perf: do not use concat_string if it is not needed At the earlier stage of the development, I thought that it is useful if lexer-combinators generate error messages, because by doing this, parser would not need to generate an error message. But now it turned out that to show an appropriate error message, parser need to generate according to the context. And almost all the messages from lexer are discarded. So I added another parameter to lexer-combinator to suppress error message generation. In the future, we may want to remove messages completely from lexers, but currently I will keep it. Removing those unused message generation makes the parsing process faster.	2019-04-16 21:09:59 +09:00
ToruNiina	b3917aaadf	refactor: use snprintf to show char in hex instead of std::ostringstream.	2019-04-16 20:54:29 +09:00
Petr Benes	ba307003c4	fix /W4 warnings on MSVC	2019-04-16 13:25:45 +02:00
Toru Niina	21fd1271d9	Merge pull request #54 from ToruNiina/hotfix fix: resolve ambiguity in the `""_toml` literal	2019-04-15 13:34:35 +09:00
ToruNiina	f9ab7d6f56	chore: add note about literals to README.md	2019-04-14 20:08:23 +09:00
ToruNiina	0a3a41a708	test: add test for literals for difficult case	2019-04-14 20:06:11 +09:00
ToruNiina	6c2a536fa5	fix: check literal has a table or an array first The literal like this `"[[table]]"_toml` caused a syntax error. It is because the literal parser first check that it might be a bare value without a key, and parse_array directory throws syntax_error. This change makes the parser first check a literal is a name of table, and then parse the content.	2019-04-14 19:48:43 +09:00