Simplify the SFINAE construct a bit

[libs/core.git] / source / core / meta.h

diff --git a/source/core/meta.h b/source/core/meta.h
index 923096517dba8132a873de68a79344ab6e2910b1..d6ca35935543049d8026b842ecca40785a92ecae 100644 (file)
--- a/source/core/meta.h
+++ b/source/core/meta.h
@@ -1,6 +1,8 @@
 #ifndef MSP_CORE_META_H_
 #define MSP_CORE_META_H_
 
+#include <cstddef>
+
 namespace Msp {
 
 template<typename T>
@@ -41,10 +43,13 @@ struct Sfinae
        struct Yes { char c[2]; };
        struct No { char c; };
 
-       template<size_t s>
+       template<typename T>
+       static No f(...);
+
+       template<typename C, typename T>
        struct Evaluate
        {
-               enum { value = (s==sizeof(Yes)) };
+               enum { value = (sizeof(C::template f<T>(0))==sizeof(Yes)) };
        };
 };