[common.string] added some meaningfull error messages

dune/stuff/common/string.hh

@@ -174,17 +174,19 @@ private:
   template <class S>
   static S convert_from_string_safely(const std::string& str_in)
   {
-    S s_out;
     try {
-      s_out = Choose<S>::fromString(str_in);
+      return Choose<S>::fromString(str_in);
     } catch (boost::bad_lexical_cast& e) {
       DUNE_THROW(Exceptions::external_error,
-                 "Error " << e.what() << " in boost while parsing the value " << str_in << ". \n");
+                 "Error in boost while converting the string '" << str_in << "' to type '" << Typename<T>::value()
+                                                                << "':\n"
+                                                                << e.what());
     } catch (std::exception& e) {
       DUNE_THROW(Exceptions::external_error,
-                 "Error " << e.what() << " in the stl while parsing the value " << str_in << ". \n");
+                 "Error in the stl while converting the string '" << str_in << "' to type '" << Typename<T>::value()
+                                                                  << "':\n"
+                                                                  << e.what());
     }
-    return s_out;
   } // ... convert_from_string_safely(...)
 
 protected:
@@ -244,7 +246,6 @@ protected:
     }
   } // ... get_matrix_from_string(...)
 
-
   template <class VectorType, class S>
   static VectorType get_vector_from_string(std::string vector_str, const size_t size)
   {
@@ -289,7 +290,19 @@ public:
   {
     assert(rows == 0);
     assert(cols == 0);
-    return boost::lexical_cast<ReturnType, std::string>(s);
+    try {
+      return boost::lexical_cast<ReturnType, std::string>(s);
+    } catch (boost::bad_lexical_cast& e) {
+      DUNE_THROW(Exceptions::external_error,
+                 "Error in boost while converting the string '" << s << "' to type '" << Typename<ReturnType>::value()
+                                                                << "':\n"
+                                                                << e.what());
+    } catch (std::exception& e) {
+      DUNE_THROW(Exceptions::external_error,
+                 "Error in the stl while converting the string '" << s << "' to type '" << Typename<ReturnType>::value()
+                                                                  << "':\n"
+                                                                  << e.what());
+    }
   }
 }; // ... Choose < ReturnType >
 
@@ -311,8 +324,11 @@ public:
     else {
       try {
         return char(stoi(s));
-      } catch (std::invalid_argument) {
-        DUNE_THROW(Stuff::Exceptions::wrong_input_given, "Failed to convert string to char");
+      } catch (std::invalid_argument& e) {
+        DUNE_THROW(Stuff::Exceptions::wrong_input_given,
+                   "Error in the stl while converting the string '" << s << "' to type '" << Typename<char>::value()
+                                                                    << "':\n"
+                                                                    << e.what());
       }
     }
   } // ... fromString(...)