[lmi-commits] [lmi] master 32888b1 2/2: Add a static assertion that was not possible before C++11

[Greg Chicares]

branch: master
commit 32888b14c8592e8a671f3f9f4d47b8119eaf0927
Author: Gregory W. Chicares <address@hidden>
Commit: Gregory W. Chicares <address@hidden>

    Add a static assertion that was not possible before C++11
    
    std::numeric_limits<T>::max() now returns constexpr T.
---
 tn_range_test.cpp     |    5 ++++-
 tn_range_test_aux.hpp |   10 +++-------
 2 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/tn_range_test.cpp b/tn_range_test.cpp
index 7dfd349..d070660 100644
--- a/tn_range_test.cpp
+++ b/tn_range_test.cpp
@@ -31,7 +31,10 @@
 #include <sstream>
 
 // This should fail to compile:
-//   template class tn_range<double, std::string>;
+//    template class tn_range<double, std::string>;
+
+// This should fail to compile:
+//    tn_range<bool, percentage_trammel<bool> > boolean_percentage;
 
 template<typename T>
 class nonnegative
diff --git a/tn_range_test_aux.hpp b/tn_range_test_aux.hpp
index cf2aecc..3b28686 100644
--- a/tn_range_test_aux.hpp
+++ b/tn_range_test_aux.hpp
@@ -27,21 +27,17 @@
 #include "tn_range_fwd.hpp"
 
 #include <istream>
+#include <limits>
 #include <ostream>
 
-// The derived trammel class must be defined here so that its size is
+// Each derived trammel class must be defined here so that its size is
 // known to all translation units that might use it.
 
-// An assertion such as
-//    static_assert(100 <= std::numeric_limits<T>::max(), "");
-// cannot work: the macro's argument must be an integral constant
-// expression, so it can't involve a function call and can't perform
-// any non-integer operation.
-
 template<typename T>
 class percentage_trammel
     :public trammel_base<T>
 {
+    static_assert(100 <= std::numeric_limits<T>::max(), "");
     T nominal_minimum() const override {return   0;}
     T default_value()   const override {return   0;}
     T nominal_maximum() const override {return 100;}