The standard containers all return references from their iterator (note, however, that some “containers aren’t really container, e.g., std::vector<bool> which returns a proxy). Other iterators might return proxies or values although this isn’t strictly supported. Of course, the standard doesn’t make any guarantees with respect to performance. Any sort of performance related feature (beyond complexity … Read more
I suspect the answer is “you cannot do this”. Yes, that is the case, you cannot pass a function template as a template argument. From 14.3.3: A template-argument for a template template-parameter shall be the name of a class template or an alias template, expressed as id-expression. The template function needs to be instantiated before … Read more
Let’s have a stab at an answer (I marked this community wiki so we get a good response together)… I’m working since a long time with templates and error messages have generally improved in some way or another: Writing a stack of errors creates a lot more text but also typically includes the level the … Read more
GCC is wrong. There is already a bug report. [dcl.type.simple]/2 says: A type-specifier of the form typenameopt nested-name-specifieropt template-name is a placeholder for a deduced class type ([dcl.type.class.deduct]). And [dcl.type.class.deduct]/2 says: A placeholder for a deduced class type can also be used in the type-specifier-seq in the new-type-id or type-id of a new-expression, as the … Read more
I don’t see how you can possibly do better than struct city { string name; int zipcode; }; There’s nothing non-essential there. You need the types of the two members, your whole question is predicated around giving names to the two members, and you want it to be a unique type. You do know about … Read more
Dust.js is a good option. It is better than some of the other templating frameworks because it does not constrain that the data should be in a file, or in a string, etc. Also it is being actively maintained https://github.com/linkedin/dustjs. Has it been successful? Yes, I know at least LinkedIn is using it and also … Read more
As @martin-ghallager said, one needs to use an external function to access those elements. Helpfully, the standard library already provides the index function (which does exactly what Martin’s dotNotation function does). To use it just write: {{ index .Data “core.value” }} The index function will return a default value in case the key is not … Read more
The file will by default be read from disk on every request, so there is no need to restart anything. There is a caching template loader, but it is disabled by default. See the documentation for more info.
VisitedSet is a template, not a class, so you can’t use VisitedSet in a nested name specifier such as VisitedSet::getSize(). Just as you specified the declaration of class VisitedSet<T> for all class T, you must specify the definition of VisitedSet<T>::getSize() for all class T: template<class T> int VisitedSet<T>::getSize() { // ^^^ return vec.size(); } The … Read more
For C++ templates I have a couple of patterns If there is just a single template parameter, I name it T (or U,V for nested templates). When there are multiple parameters and the use is not immediately obvious then I use descriptive names prefixed with T. For example, TKey, TValue, TIdentifiier, etc … This makes … Read more