Merge branch 'master' into merge-key-support

Merge keys are specified here[1] for YAML 1.1. While not part of
the YAML 1.2 specification, they're very useful and are supported
in other implementations[2][3][4][5][6][7][8][9][10] that target 1.2.

Support for merge keys is optional and disabled by default. It can
be enabled by defining YAML_CPP_SUPPORT_MERGE_KEYS, either directly
or by setting the CMake option YAML_CPP_SUPPORT_MERGE_KEYS=ON.

[1]: http://yaml.org/type/merge.html
[2]: https://github.com/go-yaml/yaml
[3]: https://github.com/ruby/psych
[4]: https://pypi.org/project/ruamel.yaml/
[5]: https://github.com/pantoniou/libfyaml
[6]: https://github.com/aaubry/YamlDotNet
[7]: https://github.com/goccy/go-yaml
[8]: https://github.com/nodeca/js-yaml
[9]: https://github.com/eemeli/yaml
[10]: https://symfony.com/doc/current/components/yaml.html

.github/workflows/build.yml

@@ -1,7 +1,7 @@
 name: Github PR
 on:
   push:
-    branches: [ master ]
+    branches: [ master, merge-key-support ]
   pull_request:
     branches: [ master ]
   workflow_dispatch:
@@ -20,9 +20,6 @@ jobs:
           googletest: [build, system]
           generator: ["Default Generator", "MinGW Makefiles"]
           exclude:
-          - os: ubuntu-latest
-            cxx_standard: 11
-            googletest: system
           - os: macos-latest
             build: shared
           - os: macos-latest
@@ -40,7 +37,7 @@ jobs:
           ${{format(matrix.generator != 'Default Generator' && '-G "{0}"' || '', matrix.generator)}}
         CMAKE_INSTALL_PREFIX: "${{ github.workspace }}/install-prefix"
         CMAKE_BUILD_TYPE: Debug
-        CMAKE_CXX_FLAGS_DEBUG: ${{ matrix.googletest == 'build' && '-g -D_GLIBCXX_DEBUG -D_GLIBCXX_DEBUG_PEDANTIC' || '-g' }} 
+        CMAKE_CXX_FLAGS_DEBUG: ${{ matrix.googletest == 'build' && '-g -D_GLIBCXX_DEBUG -D_GLIBCXX_DEBUG_PEDANTIC' || '-g' }}
       runs-on: ${{ matrix.os }}
       steps:
 
@@ -64,7 +61,8 @@ jobs:
               -D CMAKE_CXX_FLAGS_DEBUG="${{ env.CMAKE_CXX_FLAGS_DEBUG }}" \
               -D YAML_BUILD_SHARED_LIBS=${{ env.YAML_BUILD_SHARED_LIBS }} \
               -D YAML_USE_SYSTEM_GTEST=${{ env.YAML_USE_SYSTEM_GTEST }} \
-              -D YAML_CPP_BUILD_TESTS=ON
+              -D YAML_CPP_BUILD_TESTS=ON \
+              -DYAML_CPP_SUPPORT_MERGE_KEYS=ON
 
         - name: Build
           run: |

CMakeLists.txt

@@ -29,6 +29,7 @@ option(YAML_CPP_FORMAT_SOURCE "Format source" ${YAML_CPP_MAIN_PROJECT})
 option(YAML_CPP_DISABLE_UNINSTALL  "Disable uninstallation of yaml-cpp" OFF)
 option(YAML_USE_SYSTEM_GTEST "Use system googletest if found" OFF)
 option(YAML_ENABLE_PIC "Use Position-Independent Code " ON)
+option(YAML_CPP_SUPPORT_MERGE_KEYS "Support YAML merge keys ('<<') in yaml-cpp's executable targets. Use '#define YAML_CPP_SUPPORT_MERGE_KEYS' instead when linking from another project." OFF)
 
 cmake_dependent_option(YAML_CPP_BUILD_TESTS
   "Enable yaml-cpp tests" OFF
@@ -38,7 +39,7 @@ cmake_dependent_option(YAML_MSVC_SHARED_RT
   "CMAKE_SYSTEM_NAME MATCHES Windows" OFF)
 set(YAML_CPP_INSTALL_CMAKEDIR "${CMAKE_INSTALL_LIBDIR}/cmake/yaml-cpp"
   CACHE STRING "Path to install the CMake package to")
- 
+
 if (YAML_CPP_FORMAT_SOURCE)
     find_program(YAML_CPP_CLANG_FORMAT_EXE NAMES clang-format)
 endif()
@@ -133,7 +134,8 @@ target_compile_definitions(yaml-cpp
     $<$<NOT:$<BOOL:${YAML_BUILD_SHARED_LIBS}>>:YAML_CPP_STATIC_DEFINE>
   PRIVATE
     $<${build-windows-dll}:${PROJECT_NAME}_DLL>
-    $<$<NOT:$<BOOL:${YAML_CPP_BUILD_CONTRIB}>>:YAML_CPP_NO_CONTRIB>)
+    $<$<NOT:$<BOOL:${YAML_CPP_BUILD_CONTRIB}>>:YAML_CPP_NO_CONTRIB>
+    $<$<BOOL:${YAML_CPP_SUPPORT_MERGE_KEYS}>:YAML_CPP_SUPPORT_MERGE_KEYS>)
 
 target_sources(yaml-cpp
   PRIVATE
@@ -197,7 +199,6 @@ if (YAML_CPP_FORMAT_SOURCE AND YAML_CPP_CLANG_FORMAT_EXE)
     COMMAND clang-format --style=file -i $<TARGET_PROPERTY:yaml-cpp,SOURCES>
     COMMAND_EXPAND_LISTS
     COMMENT "Running clang-format"
-    WORKING_DIRECTORY "${PROJECT_SOURCE_DIR}"
     VERBATIM)
 endif()
 

CONTRIBUTING.md

@@ -17,9 +17,9 @@ Commit messages should be in the imperative mood, as described in the [Git contr
 
 # Tests
 
-Please verify the tests pass by configuring CMake with `-D YAML_CPP_BUILD_TESTS=ON` and running the target `test/yaml-cpp-tests`.
+Please verify the tests pass by running the target `test/yaml-cpp-tests`.
 
-If you are adding functionality, add tests accordingly. Note that the "spec tests" are reserved for examples directly from the YAML spec, so if you have new examples, put them in other test files.
+If you are adding functionality, add tests accordingly.
 
 # Pull request process
 

MODULE.bazel.lock

@@ -1,114 +0,0 @@
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README.md

@@ -61,18 +61,24 @@ FetchContent_Declare(
   GIT_REPOSITORY https://github.com/jbeder/yaml-cpp.git
   GIT_TAG <tag_name> # Can be a tag (yaml-cpp-x.x.x), a commit hash, or a branch name (master)
 )
-FetchContent_MakeAvailable(yaml-cpp)
+FetchContent_GetProperties(yaml-cpp)
+
+if(NOT yaml-cpp_POPULATED)
+  message(STATUS "Fetching yaml-cpp...")
+  FetchContent_Populate(yaml-cpp)
+  add_subdirectory(${yaml-cpp_SOURCE_DIR} ${yaml-cpp_BINARY_DIR})
+endif()
 
 target_link_libraries(YOUR_LIBRARY PUBLIC yaml-cpp::yaml-cpp) # The library or executable that require yaml-cpp library
 ```
 
 ## Recent Releases
 
-[yaml-cpp 0.8.0](https://github.com/jbeder/yaml-cpp/releases/tag/0.8.0) released!
+[yaml-cpp 0.6.0](https://github.com/jbeder/yaml-cpp/releases/tag/yaml-cpp-0.6.0) released! This release requires C++11, and no longer depends on Boost.
 
 [yaml-cpp 0.3.0](https://github.com/jbeder/yaml-cpp/releases/tag/release-0.3.0) is still available if you want the old API.
 
-**The old API will stop receiving bugfixes in 2026.** The 0.3.x versions provide the old API, and 0.5.x and above all provide the new API.
+**The old API will continue to be supported, and will still receive bugfixes!** The 0.3.x and 0.4.x versions will be old API releases, and 0.5.x and above will all be new API releases.
 
 # API Documentation 
 

WORKSPACE

@@ -0,0 +1,10 @@
+workspace(name = "com_github_jbeder_yaml_cpp")
+
+load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
+
+http_archive(
+    name = "com_google_googletest",
+    strip_prefix = "googletest-release-1.8.1",
+    url = "https://github.com/google/googletest/archive/release-1.8.1.tar.gz",
+    sha256 = "9bf1fe5182a604b4135edc1a425ae356c9ad15e9b23f9f12a02e80184c3a249c",
+)

docs/How-To-Emit-YAML.md

@@ -154,7 +154,6 @@ produces
 # STL Containers, and Other Overloads #
 We overload `operator <<` for `std::vector`, `std::list`, and `std::map`, so you can write stuff like:
 
-{% raw %}
 ```cpp
 std::vector <int> squares = {1, 4, 9, 16};
 
@@ -166,7 +165,6 @@ out << YAML::Flow << squares;
 out << ages;
 out << YAML::EndSeq;
 ```
-{% endraw %}
 
 produces
 

include/yaml-cpp/dll.h

@@ -15,9 +15,11 @@
 #    ifndef YAML_CPP_API
 #      ifdef yaml_cpp_EXPORTS
          /* We are building this library */
+#        pragma message( "Defining YAML_CPP_API for DLL export" )
 #        define YAML_CPP_API __declspec(dllexport)
 #      else
          /* We are using this library */
+#        pragma message( "Defining YAML_CPP_API for DLL import" )
 #        define YAML_CPP_API __declspec(dllimport)
 #      endif
 #    endif

include/yaml-cpp/emitter.h

@@ -9,24 +9,18 @@
 
 #include <cmath>
 #include <cstddef>
-#include <cstring>
 #include <limits>
 #include <memory>
 #include <sstream>
 #include <string>
 #include <type_traits>
 
-#if ((defined(_MSVC_LANG) && _MSVC_LANG >= 201703L) || __cplusplus >= 201703L)
-#include <string_view>
-#endif
-
 #include "yaml-cpp/binary.h"
 #include "yaml-cpp/dll.h"
 #include "yaml-cpp/emitterdef.h"
 #include "yaml-cpp/emittermanip.h"
 #include "yaml-cpp/null.h"
 #include "yaml-cpp/ostream_wrapper.h"
-#include "yaml-cpp/fptostring.h"
 
 namespace YAML {
 class Binary;
@@ -73,7 +67,6 @@ class YAML_CPP_API Emitter {
   Emitter& SetLocalPrecision(const _Precision& precision);
 
   // overloads of write
-  Emitter& Write(const char* str, std::size_t size);
   Emitter& Write(const std::string& str);
   Emitter& Write(bool b);
   Emitter& Write(char ch);
@@ -148,7 +141,6 @@ inline Emitter& Emitter::WriteIntegralType(T value) {
   PrepareNode(EmitterNodeType::Scalar);
 
   std::stringstream stream;
-  stream.imbue(std::locale("C"));
   PrepareIntegralStream(stream);
   stream << value;
   m_stream << stream.str();
@@ -166,7 +158,6 @@ inline Emitter& Emitter::WriteStreamable(T value) {
   PrepareNode(EmitterNodeType::Scalar);
 
   std::stringstream stream;
-  stream.imbue(std::locale("C"));
   SetStreamablePrecision<T>(stream);
 
   bool special = false;
@@ -187,7 +178,7 @@ inline Emitter& Emitter::WriteStreamable(T value) {
   }
 
   if (!special) {
-    stream << FpToString(value, stream.precision());
+    stream << value;
   }
   m_stream << stream.str();
 
@@ -207,13 +198,8 @@ inline void Emitter::SetStreamablePrecision<double>(std::stringstream& stream) {
 }
 
 // overloads of insertion
-#if ((defined(_MSVC_LANG) && _MSVC_LANG >= 201703L) || __cplusplus >= 201703L)
-inline Emitter& operator<<(Emitter& emitter, const std::string_view& v) {
-  return emitter.Write(v.data(), v.size());
-}
-#endif
 inline Emitter& operator<<(Emitter& emitter, const std::string& v) {
-  return emitter.Write(v.data(), v.size());
+  return emitter.Write(v);
 }
 inline Emitter& operator<<(Emitter& emitter, bool v) {
   return emitter.Write(v);
@@ -244,7 +230,7 @@ inline Emitter& operator<<(Emitter& emitter, const Binary& b) {
 }
 
 inline Emitter& operator<<(Emitter& emitter, const char* v) {
-  return emitter.Write(v, std::strlen(v));
+  return emitter.Write(std::string(v));
 }
 
 inline Emitter& operator<<(Emitter& emitter, int v) {

include/yaml-cpp/emitterstyle.h

@@ -8,10 +8,9 @@
 #endif
 
 namespace YAML {
-namespace EmitterStyle {
-enum value { Default, Block, Flow };
-}
-
+struct EmitterStyle {
+  enum value { Default, Block, Flow };
+};
 }
 
 #endif  // EMITTERSTYLE_H_62B23520_7C8E_11DE_8A39_0800200C9A66

include/yaml-cpp/exceptions.h

@@ -48,8 +48,6 @@ const char* const UNKNOWN_TOKEN = "unknown token";
 const char* const DOC_IN_SCALAR = "illegal document indicator in scalar";
 const char* const EOF_IN_SCALAR = "illegal EOF in scalar";
 const char* const CHAR_IN_SCALAR = "illegal character in scalar";
-const char* const UNEXPECTED_SCALAR = "unexpected scalar";
-const char* const UNEXPECTED_FLOW = "plain value cannot start with flow indicator character";
 const char* const TAB_IN_INDENTATION =
     "illegal tab when looking for indentation";
 const char* const FLOW_END = "illegal flow end";

include/yaml-cpp/fptostring.h

@@ -1,15 +0,0 @@
-#ifndef YAML_H_FPTOSTRING
-#define YAML_H_FPTOSTRING
-
-#include "yaml-cpp/dll.h"
-
-#include <string>
-
-namespace YAML {
-// "precision = 0" refers to shortest known unique representation of the value
-YAML_CPP_API std::string FpToString(float v, size_t precision = 0);
-YAML_CPP_API std::string FpToString(double v, size_t precision = 0);
-YAML_CPP_API std::string FpToString(long double v, size_t precision = 0);
-}
-
-#endif

include/yaml-cpp/node/convert.h

@@ -28,7 +28,6 @@
 #include "yaml-cpp/node/node.h"
 #include "yaml-cpp/node/type.h"
 #include "yaml-cpp/null.h"
-#include "yaml-cpp/fptostring.h"
 
 
 namespace YAML {
@@ -130,7 +129,7 @@ inner_encode(const T& rhs, std::stringstream& stream){
       stream << ".inf";
     }
   } else {
-    stream << FpToString(rhs, stream.precision());
+    stream << rhs;
   }
 }
 
@@ -172,7 +171,6 @@ ConvertStreamTo(std::stringstream& stream, T& rhs) {
                                                                            \
     static Node encode(const type& rhs) {                                  \
       std::stringstream stream;                                            \
-      stream.imbue(std::locale("C"));                                       \
       stream.precision(std::numeric_limits<type>::max_digits10);           \
       conversion::inner_encode(rhs, stream);                               \
       return Node(stream.str());                                           \
@@ -184,7 +182,6 @@ ConvertStreamTo(std::stringstream& stream, T& rhs) {
       }                                                                    \
       const std::string& input = node.Scalar();                            \
       std::stringstream stream(input);                                     \
-      stream.imbue(std::locale("C"));                                       \
       stream.unsetf(std::ios::dec);                                        \
       if ((stream.peek() == '-') && std::is_unsigned<type>::value) {       \
         return false;                                                      \

include/yaml-cpp/node/detail/iterator.h

@@ -41,7 +41,7 @@ class iterator_base {
   using value_type = V;
   using difference_type = std::ptrdiff_t;
   using pointer = V*;
-  using reference = V&;
+  using reference = V;
 
  public:
   iterator_base() : m_iterator(), m_pMemory() {}

include/yaml-cpp/node/detail/node.h

@@ -128,12 +128,23 @@ class node {
     // NOTE: this returns a non-const node so that the top-level Node can wrap
     // it, and returns a pointer so that it can be nullptr (if there is no such
     // key).
-    return static_cast<const node_ref&>(*m_pRef).get(key, pMemory);
+    node* value = static_cast<const node_ref&>(*m_pRef).get(key, pMemory);
+#ifdef YAML_CPP_SUPPORT_MERGE_KEYS
+    if (!value || value->type() == NodeType::Undefined) {
+      return get_value_from_merge_key(key, value, pMemory);
+    }
+#endif
+    return value;
   }
   template <typename Key>
   node& get(const Key& key, shared_memory_holder pMemory) {
     node& value = m_pRef->get(key, pMemory);
     value.add_dependency(*this);
+#ifdef YAML_CPP_SUPPORT_MERGE_KEYS
+    if (value.type() == NodeType::Undefined) {
+      return *get_value_from_merge_key(key, &value, pMemory);
+    }
+#endif
     return value;
   }
   template <typename Key>
@@ -165,6 +176,33 @@ class node {
   }
 
  private:
+#ifdef YAML_CPP_SUPPORT_MERGE_KEYS
+  template <typename Key>
+  inline node* get_value_from_merge_key(const Key& key, node* currentValue,
+                                        shared_memory_holder pMemory) const {
+    node* mergeValue =
+      static_cast<const node_ref&>(*m_pRef).get(std::string("<<"), pMemory);
+    if (!mergeValue) {
+      return currentValue;
+    }
+    if (mergeValue->type() == NodeType::Map) {
+      return &mergeValue->get(key, pMemory);
+    }
+    if (mergeValue->type() == NodeType::Sequence) {
+      for (const_node_iterator it = mergeValue->begin();
+            it != mergeValue->end(); ++it) {
+        if (it->pNode && it->pNode->type() == NodeType::Map) {
+          node* value = it->pNode->get(key, pMemory);
+          if (value && value->type() != NodeType::Undefined) {
+            return value;
+          }
+        }
+      }
+    }
+    return currentValue;
+  }
+#endif
+
   shared_node_ref m_pRef;
   using nodes = std::set<node*, less>;
   nodes m_dependencies;

include/yaml-cpp/node/detail/node_iterator.h

@@ -69,7 +69,7 @@ class node_iterator_base {
   using value_type = node_iterator_value<V>;
   using difference_type = std::ptrdiff_t;
   using pointer = node_iterator_value<V>*;
-  using reference = node_iterator_value<V>&;
+  using reference = node_iterator_value<V>;
   using SeqIter = typename node_iterator_type<V>::seq;
   using MapIter = typename node_iterator_type<V>::map;
 

include/yaml-cpp/node/impl.h

@@ -124,8 +124,8 @@ struct as_if<T, void> {
   const Node& node;
 
   T operator()() const {
-    if (!node.m_pNode) // no fallback
-      throw InvalidNode(node.m_invalidKey);
+    if (!node.m_pNode)
+      throw TypedBadConversion<T>(node.Mark());
 
     T t;
     if (convert<T>::decode(node, t))
@@ -140,8 +140,6 @@ struct as_if<std::string, void> {
   const Node& node;
 
   std::string operator()() const {
-    if (node.Type() == NodeType::Undefined) // no fallback
-      throw InvalidNode(node.m_invalidKey);
     if (node.Type() == NodeType::Null)
       return "null";
     if (node.Type() != NodeType::Scalar)

include/yaml-cpp/node/type.h

@@ -8,10 +8,9 @@
 #endif
 
 namespace YAML {
-namespace NodeType {
-enum value { Undefined, Null, Scalar, Sequence, Map };
-}
-
+struct NodeType {
+  enum value { Undefined, Null, Scalar, Sequence, Map };
+};
 }
 
 #endif  // VALUE_TYPE_H_62B23520_7C8E_11DE_8A39_0800200C9A66

include/yaml-cpp/null.h

@@ -8,7 +8,7 @@
 #endif
 
 #include "yaml-cpp/dll.h"
-#include <cstddef>
+#include <string>
 
 namespace YAML {
 class Node;
@@ -18,7 +18,7 @@ inline bool operator==(const _Null&, const _Null&) { return true; }
 inline bool operator!=(const _Null&, const _Null&) { return false; }
 
 YAML_CPP_API bool IsNull(const Node& node);  // old API only
-YAML_CPP_API bool IsNullString(const char* str, std::size_t size);
+YAML_CPP_API bool IsNullString(const std::string& str);
 
 extern YAML_CPP_API _Null Null;
 }

include/yaml-cpp/traits.h

@@ -121,7 +121,6 @@ template<typename Key, bool Streamable>
 struct streamable_to_string {
   static std::string impl(const Key& key) {
     std::stringstream ss;
-    ss.imbue(std::locale("C"));
     ss << key;
     return ss.str();
   }