feat: support parse(std::filesystem::path) #113

toml/parser.hpp

@@ -12,6 +12,13 @@
 #include <sstream>
 #include <cstring>
 
+#if __cplusplus >= 201703L
+#if __has_include(<filesystem>)
+#define TOML11_HAS_STD_FILESYSTEM
+#include <filesystem>
+#endif // has_include(<string_view>)
+#endif // cplusplus   >= C++17
+
 namespace toml
 {
 namespace detail
@@ -2102,5 +2109,39 @@ basic_value<Comment, Table, Array> parse(const std::string& fname)
     return parse<Comment, Table, Array>(ifs, fname);
 }
 
+#ifdef TOML11_HAS_STD_FILESYSTEM
+// This function just forwards `parse("filename.toml")` to std::string version
+// to avoid the ambiguity in overload resolution.
+//
+// Both std::string and std::filesystem::path are convertible from const char[].
+// Without this, both parse(std::string) and parse(std::filesystem::path)
+// matches to parse("filename.toml"). This breaks the existing code.
+//
+// This function exactly matches to the invokation with string literal.
+// So this function is preferred than others and the ambiguity disappears.
+template<typename                     Comment = ::toml::discard_comments,
+         template<typename ...> class Table   = std::unordered_map,
+         template<typename ...> class Array   = std::vector,
+         std::size_t N>
+basic_value<Comment, Table, Array> parse(const char (&fname)[N])
+{
+    return parse<Comment, Table, Array>(std::string(fname));
+}
+
+template<typename                     Comment = ::toml::discard_comments,
+         template<typename ...> class Table   = std::unordered_map,
+         template<typename ...> class Array   = std::vector>
+basic_value<Comment, Table, Array> parse(const std::filesystem::path& fpath)
+{
+    std::ifstream ifs(fpath, std::ios_base::binary);
+    if(!ifs.good())
+    {
+        throw std::runtime_error("toml::parse: file open error -> " +
+                                 fpath.string());
+    }
+    return parse<Comment, Table, Array>(ifs, fpath.string());
+}
+#endif // TOML11_HAS_STD_FILESYSTEM
+
 } // toml
 #endif// TOML11_PARSER_HPP