From: Mikko Rasa <tdb@tdb.fi>
Date: Sun, 19 Apr 2020 13:24:11 +0000 (+0300)
Subject: Update a SFINAE construct
X-Git-Url: http://git.tdb.fi/?a=commitdiff_plain;h=08ca2d33416e549bd3d071a164ed2a98765dda4b;p=libs%2Fdatafile.git

Update a SFINAE construct
---

diff --git a/source/type.h b/source/type.h
index f40657e..fdd040d 100644
--- a/source/type.h
+++ b/source/type.h
@@ -2,6 +2,7 @@
 #define MSP_DATAFILE_TYPE_H_
 
 #include <msp/core/inttypes.h>
+#include <msp/core/meta.h>
 #include <msp/strings/lexicalcast.h>
 
 namespace Msp {
@@ -64,20 +65,16 @@ const char valid_signatures[] =
 	0
 };
 
-template<typename T>
-struct HasLoadType
+struct CheckLoadType: Sfinae
 {
-	struct Yes { char c[2]; };
-	struct No { char c; };
-
-	template<typename U>
-	static Yes f(typename U::LoadType *);
-	template<typename U>
-	static No f(...);
-
-	enum { value = (sizeof(f<T>(0))==sizeof(Yes)) };
+	template<typename T>
+	static Yes f(typename T::LoadType *);
+	using Sfinae::f;
 };
 
+template<typename T>
+struct HasLoadType: Sfinae::Evaluate<CheckLoadType, T> { };
+
 template<typename T, bool lt = HasLoadType<T>::value>
 struct TypeInfo;