fix gcc-5 build

[folly.git] / folly / dynamic.h

diff --git a/folly/dynamic.h b/folly/dynamic.h
index 2dc49434cbf32c386e7bf734533efacf3e7ec1b4..47a40d991e3e3d5ce52933d1f9cbfd3789919613 100644 (file)
--- a/folly/dynamic.h
+++ b/folly/dynamic.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2016 Facebook, Inc.
+ * Copyright 2017 Facebook, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -45,16 +45,6 @@
  * Also see folly/json.h for the serialization and deserialization
  * functions for JSON.
  *
- * Note: dynamic is not DefaultConstructible.  Rationale:
- *
- *   - The intuitive thing to initialize a defaulted dynamic to would
- *     be nullptr.
- *
- *   - However, the expression dynamic d = {} is required to call the
- *     default constructor by the standard, which is confusing
- *     behavior for dynamic unless the default constructor creates an
- *     empty array.
- *
  * Additional documentation is in folly/docs/Dynamic.md.
  *
  * @author Jordan DeLong <delong.j@fb.com>
@@ -95,6 +85,7 @@ struct dynamic : private boost::operators<dynamic> {
     OBJECT,
     STRING,
   };
+  template<class T, class Enable = void> struct NumericTypeHelper;
 
   /*
    * We support direct iteration of arrays, and indirect iteration of objects.
@@ -143,18 +134,20 @@ public:
   static dynamic array(Args&& ...args);
 
   static ObjectMaker object();
-  static ObjectMaker object(dynamic&&, dynamic&&);
-  static ObjectMaker object(dynamic const&, dynamic&&);
-  static ObjectMaker object(dynamic&&, dynamic const&);
-  static ObjectMaker object(dynamic const&, dynamic const&);
+  static ObjectMaker object(dynamic, dynamic);
+
+  /**
+   * Default constructor, initializes with nullptr.
+   */
+  dynamic();
 
   /*
    * String compatibility constructors.
    */
+  /* implicit */ dynamic(std::nullptr_t);
   /* implicit */ dynamic(StringPiece val);
   /* implicit */ dynamic(char const* val);
-  /* implicit */ dynamic(std::string const& val);
-  /* implicit */ dynamic(std::string&& val);
+  /* implicit */ dynamic(std::string val);
 
   /*
    * This is part of the plumbing for array() and object(), above.
@@ -166,15 +159,18 @@ public:
   /* implicit */ dynamic(ObjectMaker&&);
 
   /*
-   * Conversion constructors from most of the other types.
+   * Constructors for integral and float types.
+   * Other types are SFINAEd out with NumericTypeHelper.
    */
-  template<class T> /* implicit */ dynamic(T t);
+  template<class T, class NumericType = typename NumericTypeHelper<T>::type>
+  /* implicit */ dynamic(T t);
 
   /*
    * Create a dynamic that is an array of the values from the supplied
    * iterator range.
    */
-  template<class Iterator> dynamic(Iterator first, Iterator last);
+  template<class Iterator>
+  explicit dynamic(Iterator first, Iterator last);
 
   dynamic(dynamic const&);
   dynamic(dynamic&&) noexcept;