Revert "libmstch: Remove boost dependency"

This reverts commit cb78291982. The buildbots have GCC6. GCC7 is needed for C++17. Signed-off-by: Rosen Penev <rosenp@gmail.com>
5 years ago · bfb89d058b
--- a/libs/libmstch/Makefile
+++ b/libs/libmstch/Makefile
@ -2,7 +2,7 @@ include $(TOPDIR)/rules.mk
 PKG_NAME:=libmstch
 PKG_VERSION:=1.0.2
 PKG_RELEASE:=3
 PKG_RELEASE:=2
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION).tar.gz
 PKG_SOURCE_URL:=https://codeload.github.com/no1msd/mstch/tar.gz/$(PKG_VERSION)?
@ -14,6 +14,7 @@ PKG_MAINTAINER:=Amol Bhave <ambhave@fb.com>
 PKG_LICENSE:=MIT
 PKG_LICENSE_FILES:=LICENSE
 HOST_BUILD_DEPENDS:=boost/host
 PKG_BUILD_PARALLEL:=1
 CMAKE_INSTALL:=1
@ -25,7 +26,7 @@ define Package/libmstch
 	SECTION:=libs
 	CATEGORY:=Libraries
 	TITLE:=Complete implementation of {{mustache}} templates using modern C++
 	DEPENDS:=+libstdcpp
 	DEPENDS:=+boost +boost-container
 	URL:=https://github.com/no1msd/mstch
 endef
--- a/libs/libmstch/patches/010-wrench-fix-build-in-c-17-on-GCC-libstdc-and-on-clang.patch
+++ b/libs/libmstch/patches/010-wrench-fix-build-in-c-17-on-GCC-libstdc-and-on-clang.patch
@ -1,138 +0,0 @@
 From ee63b2717de7261c95733bc1742d8dfc3317429e Mon Sep 17 00:00:00 2001
 From: "Damien Buhl (alias daminetreg)" <damien.buhl@lecbna.org>
 Date: Thu, 6 Sep 2018 05:07:03 +0200
 Subject: [PATCH] :wrench: fix build in c++17 on GCC libstdc++ and on
 clang+libc++.
 ---
 CMakeLists.txt                 | 3 +--
 include/mstch/mstch.hpp        | 4 ++--
 src/render_context.cpp         | 4 ++--
 src/state/in_section.cpp       | 6 +++---
 src/state/outside_section.cpp  | 4 ++--
 src/visitor/render_node.hpp    | 2 +-
 src/visitor/render_section.hpp | 4 ++--
 7 files changed, 13 insertions(+), 14 deletions(-)
 diff --git a/CMakeLists.txt b/CMakeLists.txt
 index 8d8e0c7..7ee9f01 100644
 --- a/CMakeLists.txt
 +++ b/CMakeLists.txt
@@ -6,12 +6,11 @@ option(WITH_BENCHMARK "enable building benchmark executable" OFF)
 set(CMAKE_INCLUDE_CURRENT_DIR ON)
 set(CMAKE_INCLUDE_CURRENT_DIR_IN_INTERFACE ON)
 -set(CMAKE_BUILD_TYPE Release)
 set(mstch_VERSION 1.0.1)
 if(NOT MSVC)
 -  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -Wall -Wextra -O3")
 +  add_compile_options(-Wall -Wextra)
 endif()
 add_subdirectory(src)
 diff --git a/include/mstch/mstch.hpp b/include/mstch/mstch.hpp
 index 58d3330..0af9e4d 100644
 --- a/include/mstch/mstch.hpp
 +++ b/include/mstch/mstch.hpp
@@ -97,11 +97,11 @@ using node = boost::make_recursive_variant<
     std::nullptr_t, std::string, int, double, bool,
     internal::lambda_t<boost::recursive_variant_>,
     std::shared_ptr<internal::object_t<boost::recursive_variant_>>,
 -    std::map<const std::string, boost::recursive_variant_>,
 +    std::map<std::string, boost::recursive_variant_>,
     std::vector<boost::recursive_variant_>>::type;
 using object = internal::object_t<node>;
 using lambda = internal::lambda_t<node>;
 -using map = std::map<const std::string, node>;
 +using map = std::map<std::string, node>;
 using array = std::vector<node>;
 std::string render(
 diff --git a/src/render_context.cpp b/src/render_context.cpp
 index 90b2ffc..756114d 100644
 --- a/src/render_context.cpp
 +++ b/src/render_context.cpp
@@ -41,8 +41,8 @@ const mstch::node& render_context::find_node(
         {&find_node(token.substr(0, token.rfind('.')), current_nodes)});
   else
     for (auto& node: current_nodes)
 -      if (visit(has_token(token), *node))
 -        return visit(get_token(token, *node), *node);
 +      if (mstch::visit(has_token(token), *node))
 +        return mstch::visit(get_token(token, *node), *node);
   return null_node;
 }
 diff --git a/src/state/in_section.cpp b/src/state/in_section.cpp
 index a139913..0062493 100644
 --- a/src/state/in_section.cpp
 +++ b/src/state/in_section.cpp
@@ -16,9 +16,9 @@ std::string in_section::render(render_context& ctx, const token& token) {
       auto& node = ctx.get_node(m_start_token.name());
       std::string out;
 -      if (m_type == type::normal && !visit(is_node_empty(), node))
 -        out = visit(render_section(ctx, m_section, m_start_token.delims()), node);
 -      else if (m_type == type::inverted && visit(is_node_empty(), node))
 +      if (m_type == type::normal && !mstch::visit(is_node_empty(), node))
 +        out = mstch::visit(render_section(ctx, m_section, m_start_token.delims()), node);
 +      else if (m_type == type::inverted && mstch::visit(is_node_empty(), node))
         out = render_context::push(ctx).render(m_section);
       ctx.set_state<outside_section>();
 diff --git a/src/state/outside_section.cpp b/src/state/outside_section.cpp
 index c9817b1..46e204b 100644
 --- a/src/state/outside_section.cpp
 +++ b/src/state/outside_section.cpp
@@ -18,9 +18,9 @@ std::string outside_section::render(
       ctx.set_state<in_section>(in_section::type::inverted, token);
       break;
     case token::type::variable:
 -      return visit(render_node(ctx, flag::escape_html), ctx.get_node(token.name()));
 +      return mstch::visit(render_node(ctx, flag::escape_html), ctx.get_node(token.name()));
     case token::type::unescaped_variable:
 -      return visit(render_node(ctx, flag::none), ctx.get_node(token.name()));
 +      return mstch::visit(render_node(ctx, flag::none), ctx.get_node(token.name()));
     case token::type::text:
       return token.raw();
     case token::type::partial:
 diff --git a/src/visitor/render_node.hpp b/src/visitor/render_node.hpp
 index 633dd4d..d5d5b40 100644
 --- a/src/visitor/render_node.hpp
 +++ b/src/visitor/render_node.hpp
@@ -38,7 +38,7 @@ class render_node: public boost::static_visitor<std::string> {
   std::string operator()(const lambda& value) const {
     template_type interpreted{value([this](const mstch::node& n) {
 -      return visit(render_node(m_ctx), n);
 +      return mstch::visit(render_node(m_ctx), n);
     })};
     auto rendered = render_context::push(m_ctx).render(interpreted);
     return (m_flag == flag::escape_html) ? html_escape(rendered) : rendered;
 diff --git a/src/visitor/render_section.hpp b/src/visitor/render_section.hpp
 index f2d5259..ac753e3 100644
 --- a/src/visitor/render_section.hpp
 +++ b/src/visitor/render_section.hpp
@@ -31,7 +31,7 @@ class render_section: public boost::static_visitor<std::string> {
     for (auto& token: m_section)
       section_str += token.raw();
     template_type interpreted{fun([this](const mstch::node& n) {
 -      return visit(render_node(m_ctx), n);
 +      return mstch::visit(render_node(m_ctx), n);
     }, section_str), m_delims};
     return render_context::push(m_ctx).render(interpreted);
   }
@@ -42,7 +42,7 @@ class render_section: public boost::static_visitor<std::string> {
       return render_context::push(m_ctx, array).render(m_section);
     else
       for (auto& item: array)
 -        out += visit(render_section(
 +        out += mstch::visit(render_section(
             m_ctx, m_section, m_delims, flag::keep_array), item);
     return out;
   }
 -- 
 2.17.1
--- a/libs/libmstch/patches/020-switch-boost-variant-to-std-variant-and-to-C-17.patch
+++ b/libs/libmstch/patches/020-switch-boost-variant-to-std-variant-and-to-C-17.patch
@ -1,442 +0,0 @@
 From 8e9679af05f0132e2934f8d7e1bfbaf36dc57cd7 Mon Sep 17 00:00:00 2001
 From: =?UTF-8?q?Torbj=C3=B6rn=20Klatt?= <t.klatt.oss@mailbox.org>
 Date: Tue, 27 Nov 2018 20:56:02 +0100
 Subject: [PATCH] switch boost::variant to std::variant and to C++17
 This is based on work by @mbits-libs as published on Github:
 mbits-libs/libmstch@747c5eed3ddbff94a0354f1b1d217f547867ef27
 The `is_node_empty` type had to be extended to detect the std::variant's
 default type `std::monostate` as an empty value. This change made all
 the unit tests pass.
 ---
 CMakeLists.txt                 |  6 ++-
 include/mstch/mstch.hpp        | 41 ++++++++++++++++----
 src/CMakeLists.txt             |  6 +--
 src/utils.hpp                  | 13 ++++---
 src/visitor/get_token.hpp      |  4 +-
 src/visitor/has_token.hpp      |  4 +-
 src/visitor/is_node_empty.hpp  | 16 +++++---
 src/visitor/render_node.hpp    | 69 +++++++++++++++-------------------
 src/visitor/render_section.hpp | 48 ++++++++++++-----------
 test/CMakeLists.txt            |  3 --
 test/test_main.cpp             |  2 +-
 11 files changed, 115 insertions(+), 97 deletions(-)
 diff --git a/CMakeLists.txt b/CMakeLists.txt
 index 7ee9f01..9df666f 100644
 --- a/CMakeLists.txt
 +++ b/CMakeLists.txt
@@ -7,10 +7,12 @@ option(WITH_BENCHMARK "enable building benchmark executable" OFF)
 set(CMAKE_INCLUDE_CURRENT_DIR ON)
 set(CMAKE_INCLUDE_CURRENT_DIR_IN_INTERFACE ON)
 -set(mstch_VERSION 1.0.1)
 +set(mstch_VERSION 1.0.2)
 if(NOT MSVC)
 -  add_compile_options(-Wall -Wextra)
 +  add_compile_options(-std=c++17 -Wall -Wextra -O3)
 +else()
 +  add_compile_options(/std:c++latest)
 endif()
 add_subdirectory(src)
 diff --git a/include/mstch/mstch.hpp b/include/mstch/mstch.hpp
 index 0af9e4d..2ea9855 100644
 --- a/include/mstch/mstch.hpp
 +++ b/include/mstch/mstch.hpp
@@ -5,8 +5,7 @@
 #include <string>
 #include <memory>
 #include <functional>
 -
 -#include <boost/variant.hpp>
 +#include <variant>
 namespace mstch {
@@ -93,12 +92,38 @@ class lambda_t {
 }
 -using node = boost::make_recursive_variant<
 -    std::nullptr_t, std::string, int, double, bool,
 -    internal::lambda_t<boost::recursive_variant_>,
 -    std::shared_ptr<internal::object_t<boost::recursive_variant_>>,
 -    std::map<std::string, boost::recursive_variant_>,
 -    std::vector<boost::recursive_variant_>>::type;
 +struct node : std::variant<
 +    std::monostate, std::nullptr_t, std::string, int, unsigned int, double, bool,
 +    internal::lambda_t<node>,
 +    std::shared_ptr<internal::object_t<node>>,
 +    std::map<const std::string, node>,
 +    std::vector<node>
 +> {
 +  using empty_type = std::monostate;
 +  using lambda_type = internal::lambda_t<node>;
 +  using shared_ptr_type = std::shared_ptr<internal::object_t<node>>;
 +  using map_type = std::map<const std::string, node>;
 +  using vector_type = std::vector<node>;
 +
 +  using base_type = std::variant<
 +    std::monostate, std::nullptr_t, std::string, int, unsigned int, double, bool,
 +    internal::lambda_t<node>,
 +    std::shared_ptr<internal::object_t<node>>,
 +    std::map<const std::string, node>,
 +    std::vector<node>
 +  >;
 +
 +  using base_type::base_type;
 +
 +  node() : base_type(std::in_place_type<std::monostate>) {}
 +
 +  explicit node(const char* value) : base_type(std::in_place_type<std::string>, value) {}
 +
 +  base_type& base() { return *this; }
 +  base_type const& base() const { return *this; }
 +};
 +
 +using empty = std::monostate;
 using object = internal::object_t<node>;
 using lambda = internal::lambda_t<node>;
 using map = std::map<std::string, node>;
 diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
 index 6517fc4..22d4f41 100644
 --- a/src/CMakeLists.txt
 +++ b/src/CMakeLists.txt
@@ -1,11 +1,8 @@
 -find_package(Boost 1.54 REQUIRED)
 -
 set(mstch_INCLUDE_DIR
     ${PROJECT_SOURCE_DIR}/include CACHE STRING "mstch include directory")
 include_directories(
 -    ${mstch_INCLUDE_DIR}
 -    ${Boost_INCLUDE_DIR})
 +    ${mstch_INCLUDE_DIR})
 set(SRC
     state/in_section.cpp
@@ -62,3 +59,4 @@ install(FILES
     "${CMAKE_CURRENT_BINARY_DIR}/mstch/mstch-config-version.cmake"
     DESTINATION lib/cmake/mstch
     COMPONENT Devel)
 +
 diff --git a/src/utils.hpp b/src/utils.hpp
 index 9041a3e..ea19029 100644
 --- a/src/utils.hpp
 +++ b/src/utils.hpp
@@ -1,7 +1,8 @@
 #pragma once
 #include <string>
 -#include <boost/variant/apply_visitor.hpp>
 +#include <vector>
 +#include <variant>
 namespace mstch {
@@ -13,11 +14,13 @@ citer first_not_ws(criter begin, criter end);
 std::string html_escape(const std::string& str);
 criter reverse(citer it);
 -template<class... Args>
 -auto visit(Args&&... args) -> decltype(boost::apply_visitor(
 -    std::forward<Args>(args)...))
 +template<class Visitor, class... Visited>
 +decltype(auto) visit(Visitor&& visitor, Visited&&... nodes)
 {
 -  return boost::apply_visitor(std::forward<Args>(args)...);
 +  return std::visit(std::forward<Visitor>(visitor), nodes.base()...);
 }
 +template <typename T, typename U>
 +constexpr bool is_v = std::is_same_v<T, U>;
 +
 }
 diff --git a/src/visitor/get_token.hpp b/src/visitor/get_token.hpp
 index d41ab6e..f7b1714 100644
 --- a/src/visitor/get_token.hpp
 +++ b/src/visitor/get_token.hpp
@@ -1,13 +1,11 @@
 #pragma once
 -#include <boost/variant/static_visitor.hpp>
 -
 #include "mstch/mstch.hpp"
 #include "has_token.hpp"
 namespace mstch {
 -class get_token: public boost::static_visitor<const mstch::node&> {
 +class get_token {
  public:
   get_token(const std::string& token, const mstch::node& node):
       m_token(token), m_node(node)
 diff --git a/src/visitor/has_token.hpp b/src/visitor/has_token.hpp
 index 5ab30d4..0076f97 100644
 --- a/src/visitor/has_token.hpp
 +++ b/src/visitor/has_token.hpp
@@ -1,12 +1,10 @@
 #pragma once
 -#include <boost/variant/static_visitor.hpp>
 -
 #include "mstch/mstch.hpp"
 namespace mstch {
 -class has_token: public boost::static_visitor<bool> {
 +class has_token {
  public:
   has_token(const std::string& token): m_token(token) {
   }
 diff --git a/src/visitor/is_node_empty.hpp b/src/visitor/is_node_empty.hpp
 index a0ae432..d7434e7 100644
 --- a/src/visitor/is_node_empty.hpp
 +++ b/src/visitor/is_node_empty.hpp
@@ -1,18 +1,20 @@
 #pragma once
 -#include <boost/variant/static_visitor.hpp>
 -
 #include "mstch/mstch.hpp"
 namespace mstch {
 -class is_node_empty: public boost::static_visitor<bool> {
 +class is_node_empty {
  public:
   template<class T>
   bool operator()(const T&) const {
     return false;
   }
 +  bool operator()(const empty&) const {
 +    return true;
 +  }
 +
   bool operator()(const std::nullptr_t&) const {
     return true;
   }
@@ -21,6 +23,10 @@ class is_node_empty: public boost::static_visitor<bool> {
     return value == 0;
   }
 +  bool operator()(const unsigned int& value) const {
 +    return value == 0;
 +  }
 +
   bool operator()(const double& value) const {
     return value == 0;
   }
@@ -30,11 +36,11 @@ class is_node_empty: public boost::static_visitor<bool> {
   }
   bool operator()(const std::string& value) const {
 -    return value == "";
 +    return value.empty();
   }
   bool operator()(const array& array) const {
 -    return array.size() == 0;
 +    return array.empty();
   }
 };
 diff --git a/src/visitor/render_node.hpp b/src/visitor/render_node.hpp
 index d5d5b40..d8f5315 100644
 --- a/src/visitor/render_node.hpp
 +++ b/src/visitor/render_node.hpp
@@ -1,7 +1,6 @@
 #pragma once
 #include <sstream>
 -#include <boost/variant/static_visitor.hpp>
 #include "render_context.hpp"
 #include "mstch/mstch.hpp"
@@ -9,47 +8,41 @@
 namespace mstch {
 -class render_node: public boost::static_visitor<std::string> {
 - public:
 +class render_node {
 +public:
   enum class flag { none, escape_html };
 -  render_node(render_context& ctx, flag p_flag = flag::none):
 -      m_ctx(ctx), m_flag(p_flag)
 +  render_node(render_context& ctx, flag p_flag = flag::none) :
 +    m_ctx(ctx), m_flag(p_flag)
   {
   }
 -  template<class T>
 -  std::string operator()(const T&) const {
 -    return "";
 -  }
 -
 -  std::string operator()(const int& value) const {
 -    return std::to_string(value);
 -  }
 -
 -  std::string operator()(const double& value) const {
 -    std::stringstream ss;
 -    ss << value;
 -    return ss.str();
 -  }
 -
 -  std::string operator()(const bool& value) const {
 -    return value ? "true" : "false";
 -  }
 -
 -  std::string operator()(const lambda& value) const {
 -    template_type interpreted{value([this](const mstch::node& n) {
 -      return mstch::visit(render_node(m_ctx), n);
 -    })};
 -    auto rendered = render_context::push(m_ctx).render(interpreted);
 -    return (m_flag == flag::escape_html) ? html_escape(rendered) : rendered;
 -  }
 -
 -  std::string operator()(const std::string& value) const {
 -    return (m_flag == flag::escape_html) ? html_escape(value) : value;
 -  }
 -
 - private:
 -  render_context& m_ctx;
 +  template <typename T>
 +  std::string operator()(const T& value) const {
 +    if constexpr(is_v<T, int>) {
 +      return std::to_string(value);
 +    } else if constexpr(is_v<T, unsigned int>) {
 +      return std::to_string(value);
 +    } else if constexpr(is_v<T, double>) {
 +      std::stringstream ss;
 +      ss << value;
 +      return ss.str();
 +    } else if constexpr(is_v<T, bool>) {
 +      return value ? "true" : "false";
 +    } else if constexpr(is_v<T, lambda>) {
 +      template_type interpreted{ value([this](const mstch::node& n) {
 +        return mstch::visit(render_node(m_ctx), n);
 +      }) };
 +      auto rendered = render_context::push(m_ctx).render(interpreted);
 +      return (m_flag == flag::escape_html) ? html_escape(rendered) : rendered;
 +    } else if constexpr(is_v<T, std::string>) {
 +      return (m_flag == flag::escape_html) ? html_escape(value) : value;
 +    }
 +
 +    return {};
 +  };
 +
 +private:
 +  render_context & m_ctx;
   flag m_flag;
 };
 diff --git a/src/visitor/render_section.hpp b/src/visitor/render_section.hpp
 index ac753e3..0c08c17 100644
 --- a/src/visitor/render_section.hpp
 +++ b/src/visitor/render_section.hpp
@@ -1,7 +1,5 @@
 #pragma once
 -#include <boost/variant/static_visitor.hpp>
 -
 #include "render_context.hpp"
 #include "mstch/mstch.hpp"
 #include "utils.hpp"
@@ -9,7 +7,7 @@
 namespace mstch {
 -class render_section: public boost::static_visitor<std::string> {
 +class render_section {
  public:
   enum class flag { none, keep_array };
   render_section(
@@ -22,29 +20,29 @@ class render_section: public boost::static_visitor<std::string> {
   }
   template<class T>
 -  std::string operator()(const T& t) const {
 -    return render_context::push(m_ctx, t).render(m_section);
 -  }
 -
 -  std::string operator()(const lambda& fun) const {
 -    std::string section_str;
 -    for (auto& token: m_section)
 -      section_str += token.raw();
 -    template_type interpreted{fun([this](const mstch::node& n) {
 -      return mstch::visit(render_node(m_ctx), n);
 -    }, section_str), m_delims};
 -    return render_context::push(m_ctx).render(interpreted);
 -  }
 -
 -  std::string operator()(const array& array) const {
 -    std::string out;
 -    if (m_flag == flag::keep_array)
 -      return render_context::push(m_ctx, array).render(m_section);
 -    else
 -      for (auto& item: array)
 -        out += mstch::visit(render_section(
 +  std::string operator()(const T& value) const {
 +    if constexpr(is_v<T, lambda>) {
 +      std::string section_str;
 +      for (auto& token : m_section) {
 +        section_str += token.raw();
 +      }
 +      template_type interpreted{ value([this](const mstch::node& n) {
 +        return mstch::visit(render_node(m_ctx), n);
 +      }, section_str), m_delims };
 +      return render_context::push(m_ctx).render(interpreted);
 +    } else if constexpr(is_v<T, array>) {
 +      std::string out;
 +      if (m_flag == flag::keep_array) {
 +        return render_context::push(m_ctx, value).render(m_section);
 +      } else {
 +        for (auto& item: value) {
 +          out += mstch::visit(render_section(
             m_ctx, m_section, m_delims, flag::keep_array), item);
 -    return out;
 +        }
 +      }
 +      return out;
 +    }
 +    return render_context::push(m_ctx, value).render(m_section);
   }
  private:
 diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
 index 061bc2e..b290b65 100644
 --- a/test/CMakeLists.txt
 +++ b/test/CMakeLists.txt
@@ -1,10 +1,7 @@
 -find_package(Boost 1.54 REQUIRED)
 -
 include_directories(
   ${CMAKE_SOURCE_DIR}/include
   ${CMAKE_SOURCE_DIR}/vendor/Catch/single_include
   ${CMAKE_SOURCE_DIR}/vendor/rapidjson/include
 -  ${Boost_INCLUDE_DIR})
 file(GLOB data_files RELATIVE
   "${CMAKE_SOURCE_DIR}/test/data"
 diff --git a/test/test_main.cpp b/test/test_main.cpp
 index a52fe3c..d823a24 100644
 --- a/test/test_main.cpp
 +++ b/test/test_main.cpp
@@ -65,7 +65,7 @@ mstch::node parse_with_rapidjson(const std::string& str) {
 }
 #define SPECS_TEST(x) TEST_CASE("specs_" #x) { \
 -  using boost::get; \
 +  using std::get; \
   auto data = parse_with_rapidjson(x ## _json); \
   for (auto& test_item: get<mstch::array>(get<mstch::map>(data)["tests"])) {\
     auto test = get<mstch::map>(test_item); \
 -- 
 2.17.1
--- a/libs/libmstch/patches/030-Fix-assignment-of-string-literals-to-node-conversion.patch
+++ b/libs/libmstch/patches/030-Fix-assignment-of-string-literals-to-node-conversion.patch
@ -1,26 +0,0 @@
 From 6dd1986dc8b713c212def7f8eab7f38e705f17a5 Mon Sep 17 00:00:00 2001
 From: Kira Backes <home_kira@kira-game.home.kirab.de>
 Date: Wed, 6 Feb 2019 16:56:47 +0100
 Subject: [PATCH] Fix assignment of string literals to node (conversion to
 bool)
 ---
 include/mstch/mstch.hpp | 2 ++
 1 file changed, 2 insertions(+)
 diff --git a/include/mstch/mstch.hpp b/include/mstch/mstch.hpp
 index 2ea9855..bb86e78 100644
 --- a/include/mstch/mstch.hpp
 +++ b/include/mstch/mstch.hpp
@@ -118,6 +118,8 @@ struct node : std::variant<
   node() : base_type(std::in_place_type<std::monostate>) {}
   explicit node(const char* value) : base_type(std::in_place_type<std::string>, value) {}
 +  
 +  node& operator=(const char* value) { return *this = std::string{value}; }
   base_type& base() { return *this; }
   base_type const& base() const { return *this; }
 -- 
 2.17.1