v3.0.0

This release is a major version bump, so it's ABI breaks all around.
Any changes that are likely to cause migration issues (API changes, build system breakage, etc.) are indicated with ⚠️.

Fixes:

• ⚠️ fixed toml::table init-list constructor requiring double-brackets
• ⚠️ fixed TOML_API + extern templates causing linker errors in some circumstances
• ⚠️ fixed incorrect noexcept specifications on many functions
• ⚠️ fixed missing TOML_API on some interfaces
• fixed toml::json_formatter not formatting inf and nan incorrectly
• fixed a number of spec conformance issues (#127, #128, #129, #130, #131, #132, #135) (@moorereason)
• fixed an illegal table redefinition edge case (#112) (@python36)
• fixed documentation issues
• fixed GCC bug causing memory leak during parse failures (#123, #124) (@rsmmr, @ronalabraham)
• fixed incorrect handling of vertical whitespace in keys when printing TOML to streams
• fixed incorrect source position in redefinition error messages
• fixed missing includes <initializer_list>, <utility>
• fixed parser not correctly round-tripping the format of binary and octal integers in some cases
• fixed some incorrect unicode scalar sequence transformations (#125)
• fixed strong exception guarantee edge-cases in toml::table and toml::array

Additions:

• added value flags to array + table insert methods (#44) (@levicki)
• added support for Unicode 14.0
• added support for ref categories and cv-qualifiers in toml::node::ref()
• added magic toml::value_flags constant toml::preserve_source_value_flags
• added clang's enum annotation attributes to all enums
• added TOML_ENABLE_FORMATTERS option
• added toml::yaml_formatter
• added toml::value copy+move constructor overloads with flags override
• added toml::table::prune()
• added toml::table::lower_bound() (same semantics as std::map::lower_bound())
• added toml::table::emplace_hint() (same semantics as std::map::emplace_hint())
• added toml::table::at() (same semantics as std::map::at())
• added toml::node_view::operator==
• added toml::key - provides a facility to access the source_regions of parsed keys (#82) (@vaartis)
• added toml::is_key<> and toml::is_key_or_convertible<> metafunctions
• added toml::format_flags::relaxed_float_precision (#89) (@vaartis)
• added toml::format_flags::quote_infinities_and_nans
• added toml::format_flags::indent_sub_tables (#120) (@W4RH4WK)
• added toml::format_flags::indent_array_elements (#120) (@W4RH4WK)
• added toml::format_flags::allow_unicode_strings
• added toml::format_flags::allow_real_tabs_in_strings
• added toml::format_flags::allow_octal_integers
• added toml::format_flags::allow_hexadecimal_integers
• added toml::format_flags::allow_binary_integers
• added toml::date_time converting constructors from toml::date and toml::time
• added toml::at_path(), toml::node::at_path() and toml::node_view::at_path() for qualified path-based lookups (#118) (@ben-crowhurst)
• added toml::array::resize() param default_init_flags
• added toml::array::replace() (#109) (@LebJe)
• added toml::array::prune()
• added toml::array::at() (same semantics as std::vector::at())
• added parse_benchmark example
• added operator-> to toml::value for class types

Changes:

• ⚠️ toml::format_flags is now backed by uint64_t (was previously uint8_t)
• ⚠️ toml::source_index is now an alias for uint32_t unconditionally (was previously dependent on TOML_LARGE_FILES)
• ⚠️ toml::table now uses toml::key as the key type (was previously std::string)
• ⚠️ toml::value_flags is now backed by uint16_t (was previously uint8_t)
• ⚠️ made all overloaded operators 'hidden friends' where possible
• ⚠️ renamed toml::default_formatter to toml::toml_formatter (toml::default_formatter is now an alias)
• ⚠️ renamed TOML_PARSER option to TOML_ENABLE_PARSER (TOML_PARSER will continue to work but is deprecated)
• ⚠️ renamed TOML_UNRELEASED_FEATURES to TOML_ENABLE_UNRELEASED_FEATURES (TOML_UNRELEASED_FEATURES will continue to work but is deprecated)
• ⚠️ renamed TOML_WINDOWS_COMPAT to TOML_ENABLE_WINDOWS_COMPAT (TOML_WINDOWS_COMPAT will continue to work but is deprecated)
• applied clang-format to all the things 🎉️
• exposed TOML_NAMESPACE_START and TOML_NAMESPACE_END macros to help with ADL specialization scenarios
• improved performance of parser
• made date/time constructors accept any integral types
• moved all implementation headers to /impl
• renamed all implementation headers to .h and 'source' headers to .inl
• updated conformance tests

Removals:

• ⚠️ removed toml::format_flags::allow_value_format_flags
• ⚠️ removed TOML_LARGE_FILES (it is now default - explicitly setting TOML_LARGE_FILES to 0 will invoke an #error)
• ⚠️ removed unnecessary template machinery (esp. where ostreams were involved)
• removed unnecessary uses of final

Build system:

• ⚠️ increased minimum required meson version to 0.54.0
• disabled 'install' path when being used as a meson subproject (#114) (@Tachi107)
• fixed builds failing with meson 0.6.0 (#117) (@Tachi107)
• general meson improvements and fixes (#115) (@Tachi107)
• used override_dependency where supported (#116) (@Tachi107)