Move part of write API (spec factories) to a separate header

fmt/CMakeLists.txt

 # Define the fmt library, its includes and the needed defines.
 # format.cc is added to FMT_HEADERS for the header-only configuration.
 set(FMT_HEADERS format.h format.cc ostream.h ostream.cc printf.h printf.cc
-                string.h time.h)
+                string.h time.h write.h)
 if (HAVE_OPEN)
   set(FMT_HEADERS ${FMT_HEADERS} posix.h)
   set(FMT_SOURCES ${FMT_SOURCES} posix.cc)

fmt/format.h

@@ -1747,30 +1747,6 @@ class fill_spec : public format_spec<Char, fill_tag> {
 typedef format_spec<unsigned, width_tag> width_spec;
 typedef format_spec<char, type_tag> type_spec;
 
-class fill_spec_factory {
- public:
-  constexpr fill_spec_factory() {}
-
-  template <typename Char>
-  fill_spec<Char> operator=(Char value) const {
-    return fill_spec<Char>(value);
-  }
-};
-
-template <typename FormatSpec>
-class format_spec_factory {
- public:
-  constexpr format_spec_factory() {}
-
-  FormatSpec operator=(typename FormatSpec::value_type value) const {
-    return FormatSpec(value);
-  }
-};
-
-constexpr fill_spec_factory fill;
-constexpr format_spec_factory<width_spec> width;
-constexpr format_spec_factory<type_spec> type;
-
 // An empty format specifier.
 struct empty_spec {};
 
@@ -2225,17 +2201,6 @@ class system_error : public std::runtime_error {
 FMT_API void format_system_error(fmt::buffer &out, int error_code,
                                  fmt::string_view message) FMT_NOEXCEPT;
 
-namespace internal {
-// Named format specifier.
-template <typename T>
-class named_format_spec {
- public:
-  constexpr named_format_spec() {}
-};
-
-constexpr named_format_spec<unsigned> width;
-}
-
 /**
   \rst
   This template provides operations for formatting and writing data into a

fmt/write.h

+/*
+ Formatting library for C++
+
+ Copyright (c) 2012 - 2016, Victor Zverovich
+ All rights reserved.
+
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions are met:
+
+ 1. Redistributions of source code must retain the above copyright notice, this
+    list of conditions and the following disclaimer.
+ 2. Redistributions in binary form must reproduce the above copyright notice,
+    this list of conditions and the following disclaimer in the documentation
+    and/or other materials provided with the distribution.
+
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef FMT_WRITE_H_
+#define FMT_WRITE_H_
+
+#include "fmt/format.h"
+
+namespace fmt {
+
+class fill_spec_factory {
+ public:
+  constexpr fill_spec_factory() {}
+
+  template <typename Char>
+  fill_spec<Char> operator=(Char value) const {
+    return fill_spec<Char>(value);
+  }
+};
+
+template <typename FormatSpec>
+class format_spec_factory {
+ public:
+  constexpr format_spec_factory() {}
+
+  FormatSpec operator=(typename FormatSpec::value_type value) const {
+    return FormatSpec(value);
+  }
+};
+
+constexpr fill_spec_factory fill;
+constexpr format_spec_factory<width_spec> width;
+constexpr format_spec_factory<type_spec> type;
+
+}  // namespace fmt
+
+#endif  // FMT_WRITE_H_

test/format-test.cc

@@ -43,6 +43,7 @@
 #define None 0
 
 #include "fmt/format.h"
+#include "fmt/write.h"
 
 #include "util.h"
 #include "mock-allocator.h"