2 * Copyright 2016 Facebook, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 #ifndef FOLLY_DYNAMIC_INL_H_
18 #define FOLLY_DYNAMIC_INL_H_
21 #include <boost/iterator/iterator_adaptor.hpp>
22 #include <boost/iterator/iterator_facade.hpp>
23 #include <folly/Likely.h>
24 #include <folly/Conv.h>
25 #include <folly/Format.h>
27 //////////////////////////////////////////////////////////////////////
32 struct hash< ::folly::dynamic> {
33 size_t operator()(::folly::dynamic const& d) const {
40 //////////////////////////////////////////////////////////////////////
42 // This is a higher-order preprocessor macro to aid going from runtime
43 // types to the compile time type system.
44 #define FB_DYNAMIC_APPLY(type, apply) do { \
46 case NULLT: apply(void*); break; \
47 case ARRAY: apply(Array); break; \
48 case BOOL: apply(bool); break; \
49 case DOUBLE: apply(double); break; \
50 case INT64: apply(int64_t); break; \
51 case OBJECT: apply(ObjectImpl); break; \
52 case STRING: apply(fbstring); break; \
53 default: CHECK(0); abort(); \
57 //////////////////////////////////////////////////////////////////////
61 struct TypeError : std::runtime_error {
62 explicit TypeError(const std::string& expected, dynamic::Type actual);
63 explicit TypeError(const std::string& expected,
64 dynamic::Type actual1, dynamic::Type actual2);
69 //////////////////////////////////////////////////////////////////////
73 // This helper is used in destroy() to be able to run destructors on
74 // types like "int64_t" without a compiler error.
76 template<class T> static void destroy(T* t) { t->~T(); }
80 * The enable_if junk here is necessary to avoid ambiguous
81 * conversions relating to bool and double when you implicitly
82 * convert an int or long to a dynamic.
84 template<class T, class Enable = void> struct ConversionHelper;
86 struct ConversionHelper<
88 typename std::enable_if<
89 std::is_integral<T>::value && !std::is_same<T,bool>::value
95 struct ConversionHelper<
97 typename std::enable_if<
98 (!std::is_integral<T>::value || std::is_same<T,bool>::value) &&
99 !std::is_same<T,std::nullptr_t>::value
105 struct ConversionHelper<
107 typename std::enable_if<
108 std::is_same<T,std::nullptr_t>::value
115 * Helper for implementing numeric conversions in operators on
116 * numbers. Just promotes to double when one of the arguments is
117 * double, or throws if either is not a numeric type.
119 template<template<class> class Op>
120 dynamic numericOp(dynamic const& a, dynamic const& b) {
121 if (!a.isNumber() || !b.isNumber()) {
122 throw TypeError("numeric", a.type(), b.type());
124 if (a.type() != b.type()) {
125 auto& integ = a.isInt() ? a : b;
126 auto& nonint = a.isInt() ? b : a;
127 return Op<double>()(to<double>(integ.asInt()), nonint.asDouble());
130 return Op<double>()(a.asDouble(), b.asDouble());
132 return Op<int64_t>()(a.asInt(), b.asInt());
137 //////////////////////////////////////////////////////////////////////
140 * We're doing this instead of a simple member typedef to avoid the
141 * undefined behavior of parameterizing std::unordered_map<> with an
144 * Note: Later we may add separate order tracking here (a multi-index
147 struct dynamic::ObjectImpl : std::unordered_map<dynamic, dynamic> {};
149 //////////////////////////////////////////////////////////////////////
151 // Helper object for creating objects conveniently. See object and
152 // the dynamic::dynamic(ObjectMaker&&) ctor.
153 struct dynamic::ObjectMaker {
154 friend struct dynamic;
156 explicit ObjectMaker() : val_(dynamic::object) {}
157 explicit ObjectMaker(dynamic const& key, dynamic val)
158 : val_(dynamic::object)
160 val_.insert(key, std::move(val));
162 explicit ObjectMaker(dynamic&& key, dynamic val)
163 : val_(dynamic::object)
165 val_.insert(std::move(key), std::move(val));
168 // Make sure no one tries to save one of these into an lvalue with
169 // auto or anything like that.
170 ObjectMaker(ObjectMaker&&) = default;
171 ObjectMaker(ObjectMaker const&) = delete;
172 ObjectMaker& operator=(ObjectMaker const&) = delete;
173 ObjectMaker& operator=(ObjectMaker&&) = delete;
175 // These return rvalue-references instead of lvalue-references to allow
176 // constructs like this to moved instead of copied:
177 // dynamic a = dynamic::object("a", "b")("c", "d")
178 ObjectMaker&& operator()(dynamic const& key, dynamic val) {
179 val_.insert(key, std::move(val));
180 return std::move(*this);
183 ObjectMaker&& operator()(dynamic&& key, dynamic val) {
184 val_.insert(std::move(key), std::move(val));
185 return std::move(*this);
192 inline void dynamic::array(EmptyArrayTag) {}
194 template <class... Args>
195 inline dynamic dynamic::array(Args&& ...args) {
196 return dynamic(std::initializer_list<dynamic>{std::forward<Args>(args)...},
200 // This looks like a case for perfect forwarding, but our use of
201 // std::initializer_list for constructing dynamic arrays makes it less
202 // functional than doing this manually.
204 // TODO(ott, 10300209): When the initializer_list constructor is gone,
206 inline dynamic::ObjectMaker dynamic::object() { return ObjectMaker(); }
207 inline dynamic::ObjectMaker dynamic::object(dynamic&& a, dynamic&& b) {
208 return ObjectMaker(std::move(a), std::move(b));
210 inline dynamic::ObjectMaker dynamic::object(dynamic const& a, dynamic&& b) {
211 return ObjectMaker(a, std::move(b));
213 inline dynamic::ObjectMaker dynamic::object(dynamic&& a, dynamic const& b) {
214 return ObjectMaker(std::move(a), b);
216 inline dynamic::ObjectMaker
217 dynamic::object(dynamic const& a, dynamic const& b) {
218 return ObjectMaker(a, b);
221 //////////////////////////////////////////////////////////////////////
223 struct dynamic::const_item_iterator
224 : boost::iterator_adaptor<dynamic::const_item_iterator,
225 dynamic::ObjectImpl::const_iterator> {
226 /* implicit */ const_item_iterator(base_type b) : iterator_adaptor_(b) { }
229 friend class boost::iterator_core_access;
232 struct dynamic::const_key_iterator
233 : boost::iterator_adaptor<dynamic::const_key_iterator,
234 dynamic::ObjectImpl::const_iterator,
236 /* implicit */ const_key_iterator(base_type b) : iterator_adaptor_(b) { }
239 dynamic const& dereference() const {
240 return base_reference()->first;
242 friend class boost::iterator_core_access;
245 struct dynamic::const_value_iterator
246 : boost::iterator_adaptor<dynamic::const_value_iterator,
247 dynamic::ObjectImpl::const_iterator,
249 /* implicit */ const_value_iterator(base_type b) : iterator_adaptor_(b) { }
252 dynamic const& dereference() const {
253 return base_reference()->second;
255 friend class boost::iterator_core_access;
258 //////////////////////////////////////////////////////////////////////
260 inline dynamic::dynamic(void (*)(EmptyArrayTag))
263 new (&u_.array) Array();
266 inline dynamic::dynamic(ObjectMaker (*)())
269 new (getAddress<ObjectImpl>()) ObjectImpl();
272 inline dynamic::dynamic(StringPiece s)
275 new (&u_.string) fbstring(s.data(), s.size());
278 inline dynamic::dynamic(char const* s)
281 new (&u_.string) fbstring(s);
284 inline dynamic::dynamic(std::string const& s)
287 new (&u_.string) fbstring(s);
290 inline dynamic::dynamic(fbstring const& s)
293 new (&u_.string) fbstring(s);
296 inline dynamic::dynamic(fbstring&& s)
299 new (&u_.string) fbstring(std::move(s));
302 inline dynamic::dynamic(std::initializer_list<dynamic> il)
303 : dynamic(std::move(il), PrivateTag()) {
306 inline dynamic::dynamic(std::initializer_list<dynamic> il, PrivateTag)
309 new (&u_.array) Array(il.begin(), il.end());
312 inline dynamic& dynamic::operator=(std::initializer_list<dynamic> il) {
313 (*this) = dynamic(il, PrivateTag());
317 inline dynamic::dynamic(ObjectMaker&& maker)
320 new (getAddress<ObjectImpl>())
321 ObjectImpl(std::move(*maker.val_.getAddress<ObjectImpl>()));
324 inline dynamic::dynamic(dynamic const& o)
330 inline dynamic::dynamic(dynamic&& o) noexcept
333 *this = std::move(o);
336 inline dynamic::~dynamic() noexcept { destroy(); }
339 dynamic::dynamic(T t) {
340 typedef typename detail::ConversionHelper<T>::type U;
341 type_ = TypeInfo<U>::type;
342 new (getAddress<U>()) U(std::move(t));
345 template<class Iterator>
346 dynamic::dynamic(Iterator first, Iterator last)
349 new (&u_.array) Array(first, last);
352 //////////////////////////////////////////////////////////////////////
354 inline dynamic::const_iterator dynamic::begin() const {
355 return get<Array>().begin();
357 inline dynamic::const_iterator dynamic::end() const {
358 return get<Array>().end();
362 struct dynamic::IterableProxy {
363 typedef It const_iterator;
364 typedef typename It::value_type value_type;
366 /* implicit */ IterableProxy(const dynamic::ObjectImpl* o) : o_(o) { }
377 const dynamic::ObjectImpl* o_;
380 inline dynamic::IterableProxy<dynamic::const_key_iterator> dynamic::keys()
382 return &(get<ObjectImpl>());
385 inline dynamic::IterableProxy<dynamic::const_value_iterator> dynamic::values()
387 return &(get<ObjectImpl>());
390 inline dynamic::IterableProxy<dynamic::const_item_iterator> dynamic::items()
392 return &(get<ObjectImpl>());
395 inline bool dynamic::isString() const { return get_nothrow<fbstring>(); }
396 inline bool dynamic::isObject() const { return get_nothrow<ObjectImpl>(); }
397 inline bool dynamic::isBool() const { return get_nothrow<bool>(); }
398 inline bool dynamic::isArray() const { return get_nothrow<Array>(); }
399 inline bool dynamic::isDouble() const { return get_nothrow<double>(); }
400 inline bool dynamic::isInt() const { return get_nothrow<int64_t>(); }
401 inline bool dynamic::isNull() const { return get_nothrow<void*>(); }
402 inline bool dynamic::isNumber() const { return isInt() || isDouble(); }
404 inline dynamic::Type dynamic::type() const {
408 inline fbstring dynamic::asString() const { return asImpl<fbstring>(); }
409 inline double dynamic::asDouble() const { return asImpl<double>(); }
410 inline int64_t dynamic::asInt() const { return asImpl<int64_t>(); }
411 inline bool dynamic::asBool() const { return asImpl<bool>(); }
413 inline const fbstring& dynamic::getString() const& { return get<fbstring>(); }
414 inline double dynamic::getDouble() const& { return get<double>(); }
415 inline int64_t dynamic::getInt() const& { return get<int64_t>(); }
416 inline bool dynamic::getBool() const& { return get<bool>(); }
418 inline fbstring& dynamic::getString() & { return get<fbstring>(); }
419 inline double& dynamic::getDouble() & { return get<double>(); }
420 inline int64_t& dynamic::getInt() & { return get<int64_t>(); }
421 inline bool& dynamic::getBool() & { return get<bool>(); }
423 inline fbstring dynamic::getString() && { return std::move(get<fbstring>()); }
424 inline double dynamic::getDouble() && { return get<double>(); }
425 inline int64_t dynamic::getInt() && { return get<int64_t>(); }
426 inline bool dynamic::getBool() && { return get<bool>(); }
428 inline const char* dynamic::data() const& { return get<fbstring>().data(); }
429 inline const char* dynamic::c_str() const& { return get<fbstring>().c_str(); }
430 inline StringPiece dynamic::stringPiece() const { return get<fbstring>(); }
433 struct dynamic::CompareOp {
434 static bool comp(T const& a, T const& b) { return a < b; }
437 struct dynamic::CompareOp<dynamic::ObjectImpl> {
438 static bool comp(ObjectImpl const&, ObjectImpl const&) {
439 // This code never executes; it is just here for the compiler.
444 inline dynamic& dynamic::operator+=(dynamic const& o) {
445 if (type() == STRING && o.type() == STRING) {
446 *getAddress<fbstring>() += *o.getAddress<fbstring>();
449 *this = detail::numericOp<std::plus>(*this, o);
453 inline dynamic& dynamic::operator-=(dynamic const& o) {
454 *this = detail::numericOp<std::minus>(*this, o);
458 inline dynamic& dynamic::operator*=(dynamic const& o) {
459 *this = detail::numericOp<std::multiplies>(*this, o);
463 inline dynamic& dynamic::operator/=(dynamic const& o) {
464 *this = detail::numericOp<std::divides>(*this, o);
468 #define FB_DYNAMIC_INTEGER_OP(op) \
469 inline dynamic& dynamic::operator op(dynamic const& o) { \
470 if (!isInt() || !o.isInt()) { \
471 throw TypeError("int64", type(), o.type()); \
473 *getAddress<int64_t>() op o.asInt(); \
477 FB_DYNAMIC_INTEGER_OP(%=)
478 FB_DYNAMIC_INTEGER_OP(|=)
479 FB_DYNAMIC_INTEGER_OP(&=)
480 FB_DYNAMIC_INTEGER_OP(^=)
482 #undef FB_DYNAMIC_INTEGER_OP
484 inline dynamic& dynamic::operator++() {
489 inline dynamic& dynamic::operator--() {
494 inline dynamic const& dynamic::operator[](dynamic const& idx) const& {
498 inline dynamic dynamic::operator[](dynamic const& idx) && {
499 return std::move((*this)[idx]);
502 template<class K, class V> inline dynamic& dynamic::setDefault(K&& k, V&& v) {
503 auto& obj = get<ObjectImpl>();
504 return obj.insert(std::make_pair(std::forward<K>(k),
505 std::forward<V>(v))).first->second;
508 inline dynamic* dynamic::get_ptr(dynamic const& idx) & {
509 return const_cast<dynamic*>(const_cast<dynamic const*>(this)->get_ptr(idx));
512 inline dynamic& dynamic::at(dynamic const& idx) & {
513 return const_cast<dynamic&>(const_cast<dynamic const*>(this)->at(idx));
516 inline dynamic dynamic::at(dynamic const& idx) && {
517 return std::move(at(idx));
520 inline bool dynamic::empty() const {
527 inline std::size_t dynamic::count(dynamic const& key) const {
528 return find(key) != items().end();
531 inline dynamic::const_item_iterator dynamic::find(dynamic const& key) const {
532 return get<ObjectImpl>().find(key);
535 template<class K, class V> inline void dynamic::insert(K&& key, V&& val) {
536 auto& obj = get<ObjectImpl>();
537 auto rv = obj.insert({ std::forward<K>(key), nullptr });
538 rv.first->second = std::forward<V>(val);
541 inline void dynamic::update(const dynamic& mergeObj) {
542 if (!isObject() || !mergeObj.isObject()) {
543 throw TypeError("object", type(), mergeObj.type());
546 for (const auto& pair : mergeObj.items()) {
547 (*this)[pair.first] = pair.second;
551 inline void dynamic::update_missing(const dynamic& mergeObj1) {
552 if (!isObject() || !mergeObj1.isObject()) {
553 throw TypeError("object", type(), mergeObj1.type());
556 // Only add if not already there
557 for (const auto& pair : mergeObj1.items()) {
558 if ((*this).find(pair.first) == (*this).items().end()) {
559 (*this)[pair.first] = pair.second;
564 inline dynamic dynamic::merge(
565 const dynamic& mergeObj1,
566 const dynamic& mergeObj2) {
568 // No checks on type needed here because they are done in update_missing
569 // Note that we do update_missing here instead of update() because
570 // it will prevent the extra writes that would occur with update()
571 auto ret = mergeObj2;
572 ret.update_missing(mergeObj1);
576 inline std::size_t dynamic::erase(dynamic const& key) {
577 auto& obj = get<ObjectImpl>();
578 return obj.erase(key);
581 inline dynamic::const_iterator dynamic::erase(const_iterator it) {
582 auto& arr = get<Array>();
583 // std::vector doesn't have an erase method that works on const iterators,
584 // even though the standard says it should, so this hack converts to a
585 // non-const iterator before calling erase.
586 return get<Array>().erase(arr.begin() + (it - arr.begin()));
589 inline dynamic::const_key_iterator dynamic::erase(const_key_iterator it) {
590 return const_key_iterator(get<ObjectImpl>().erase(it.base()));
593 inline dynamic::const_key_iterator dynamic::erase(const_key_iterator first,
594 const_key_iterator last) {
595 return const_key_iterator(get<ObjectImpl>().erase(first.base(),
599 inline dynamic::const_value_iterator dynamic::erase(const_value_iterator it) {
600 return const_value_iterator(get<ObjectImpl>().erase(it.base()));
603 inline dynamic::const_value_iterator dynamic::erase(const_value_iterator first,
604 const_value_iterator last) {
605 return const_value_iterator(get<ObjectImpl>().erase(first.base(),
609 inline dynamic::const_item_iterator dynamic::erase(const_item_iterator it) {
610 return const_item_iterator(get<ObjectImpl>().erase(it.base()));
613 inline dynamic::const_item_iterator dynamic::erase(const_item_iterator first,
614 const_item_iterator last) {
615 return const_item_iterator(get<ObjectImpl>().erase(first.base(),
619 inline void dynamic::resize(std::size_t sz, dynamic const& c) {
620 auto& arr = get<Array>();
624 inline void dynamic::push_back(dynamic const& v) {
625 auto& arr = get<Array>();
629 inline void dynamic::push_back(dynamic&& v) {
630 auto& arr = get<Array>();
631 arr.push_back(std::move(v));
634 inline void dynamic::pop_back() {
635 auto& arr = get<Array>();
639 //////////////////////////////////////////////////////////////////////
641 #define FOLLY_DYNAMIC_DEC_TYPEINFO(T, str, val) \
642 template <> struct dynamic::TypeInfo<T> { \
643 static constexpr const char* name = str; \
644 static constexpr dynamic::Type type = val; \
648 FOLLY_DYNAMIC_DEC_TYPEINFO(void*, "null", dynamic::NULLT)
649 FOLLY_DYNAMIC_DEC_TYPEINFO(bool, "boolean", dynamic::BOOL)
650 FOLLY_DYNAMIC_DEC_TYPEINFO(fbstring, "string", dynamic::STRING)
651 FOLLY_DYNAMIC_DEC_TYPEINFO(dynamic::Array, "array", dynamic::ARRAY)
652 FOLLY_DYNAMIC_DEC_TYPEINFO(double, "double", dynamic::DOUBLE)
653 FOLLY_DYNAMIC_DEC_TYPEINFO(int64_t, "int64", dynamic::INT64)
654 FOLLY_DYNAMIC_DEC_TYPEINFO(dynamic::ObjectImpl, "object", dynamic::OBJECT)
656 #undef FOLLY_DYNAMIC_DEC_TYPEINFO
659 T dynamic::asImpl() const {
661 case INT64: return to<T>(*get_nothrow<int64_t>());
662 case DOUBLE: return to<T>(*get_nothrow<double>());
663 case BOOL: return to<T>(*get_nothrow<bool>());
664 case STRING: return to<T>(*get_nothrow<fbstring>());
666 throw TypeError("int/double/bool/string", type());
670 // Return a T* to our type, or null if we're not that type.
672 T* dynamic::get_nothrow() & noexcept {
673 if (type_ != TypeInfo<T>::type) {
676 return getAddress<T>();
680 T const* dynamic::get_nothrow() const& noexcept {
681 return const_cast<dynamic*>(this)->get_nothrow<T>();
684 // Return T* for where we can put a T, without type checking. (Memory
685 // might be uninitialized, even.)
687 T* dynamic::getAddress() noexcept {
688 return GetAddrImpl<T>::get(u_);
692 T const* dynamic::getAddress() const noexcept {
693 return const_cast<dynamic*>(this)->getAddress<T>();
696 template<class T> struct dynamic::GetAddrImpl {};
697 template<> struct dynamic::GetAddrImpl<void*> {
698 static void** get(Data& d) noexcept { return &d.nul; }
700 template<> struct dynamic::GetAddrImpl<dynamic::Array> {
701 static Array* get(Data& d) noexcept { return &d.array; }
703 template<> struct dynamic::GetAddrImpl<bool> {
704 static bool* get(Data& d) noexcept { return &d.boolean; }
706 template<> struct dynamic::GetAddrImpl<int64_t> {
707 static int64_t* get(Data& d) noexcept { return &d.integer; }
709 template<> struct dynamic::GetAddrImpl<double> {
710 static double* get(Data& d) noexcept { return &d.doubl; }
712 template<> struct dynamic::GetAddrImpl<fbstring> {
713 static fbstring* get(Data& d) noexcept { return &d.string; }
715 template<> struct dynamic::GetAddrImpl<dynamic::ObjectImpl> {
716 static_assert(sizeof(ObjectImpl) <= sizeof(Data::objectBuffer),
717 "In your implementation, std::unordered_map<> apparently takes different"
718 " amount of space depending on its template parameters. This is "
719 "weird. Make objectBuffer bigger if you want to compile dynamic.");
721 static ObjectImpl* get(Data& d) noexcept {
722 void* data = &d.objectBuffer;
723 return static_cast<ObjectImpl*>(data);
729 if (auto* p = get_nothrow<T>()) {
732 throw TypeError(TypeInfo<T>::name, type());
736 T const& dynamic::get() const {
737 return const_cast<dynamic*>(this)->get<T>();
740 //////////////////////////////////////////////////////////////////////
743 * Helper for implementing operator<<. Throws if the type shouldn't
747 struct dynamic::PrintImpl {
748 static void print(dynamic const&, std::ostream& out, T const& t) {
752 // Otherwise, null, being (void*)0, would print as 0.
754 struct dynamic::PrintImpl<void*> {
755 static void print(dynamic const& /* d */,
758 DCHECK_EQ((void*)0, nul);
763 struct dynamic::PrintImpl<dynamic::ObjectImpl> {
764 static void print(dynamic const& d,
766 dynamic::ObjectImpl const&) {
767 d.print_as_pseudo_json(out);
771 struct dynamic::PrintImpl<dynamic::Array> {
772 static void print(dynamic const& d,
774 dynamic::Array const&) {
775 d.print_as_pseudo_json(out);
779 inline void dynamic::print(std::ostream& out) const {
780 #define FB_X(T) PrintImpl<T>::print(*this, out, *getAddress<T>())
781 FB_DYNAMIC_APPLY(type_, FB_X);
785 inline std::ostream& operator<<(std::ostream& out, dynamic const& d) {
790 //////////////////////////////////////////////////////////////////////
792 // Secialization of FormatValue so dynamic objects can be formatted
794 class FormatValue<dynamic> {
796 explicit FormatValue(const dynamic& val) : val_(val) { }
798 template <class FormatCallback>
799 void format(FormatArg& arg, FormatCallback& cb) const {
800 switch (val_.type()) {
802 FormatValue<std::nullptr_t>(nullptr).format(arg, cb);
805 FormatValue<bool>(val_.asBool()).format(arg, cb);
808 FormatValue<int64_t>(val_.asInt()).format(arg, cb);
810 case dynamic::STRING:
811 FormatValue<fbstring>(val_.asString()).format(arg, cb);
813 case dynamic::DOUBLE:
814 FormatValue<double>(val_.asDouble()).format(arg, cb);
817 FormatValue(val_.at(arg.splitIntKey())).format(arg, cb);
819 case dynamic::OBJECT:
820 FormatValue(val_.at(arg.splitKey().toFbstring())).format(arg, cb);
830 class FormatValue<detail::DefaultValueWrapper<dynamic, V>> {
832 explicit FormatValue(
833 const detail::DefaultValueWrapper<dynamic, V>& val)
836 template <class FormatCallback>
837 void format(FormatArg& arg, FormatCallback& cb) const {
838 auto& c = val_.container;
843 case dynamic::STRING:
844 case dynamic::DOUBLE:
845 FormatValue<dynamic>(c).format(arg, cb);
849 int key = arg.splitIntKey();
850 if (key >= 0 && size_t(key) < c.size()) {
851 FormatValue<dynamic>(c.at(key)).format(arg, cb);
853 FormatValue<V>(val_.defaultValue).format(arg, cb);
857 case dynamic::OBJECT:
859 auto pos = c.find(arg.splitKey());
860 if (pos != c.items().end()) {
861 FormatValue<dynamic>(pos->second).format(arg, cb);
863 FormatValue<V>(val_.defaultValue).format(arg, cb);
871 const detail::DefaultValueWrapper<dynamic, V>& val_;
876 #undef FB_DYNAMIC_APPLY