Template is behavior-based

本文所要表达的思想是: 在使用template的时候，应该谨记: template is behavior-based。

关于behavior-based，参见:

1) Theory\Programming-paradigm\Abstraction-and-polymorphism\Polymorphism\Implementation

2) Theory\Programming-paradigm\Generic-programming\Type-requirement

drdobbs-Templates-and-Duck-Typing

参见drdobbs-Templates-and-Duck-Typing章节。

wikipedia Generic programming # Templates in C++

This works whether the arguments x and y are integers, strings, or any other type for which the expression x < y is sensible, or more specifically, for any type for which operator< is defined. Common inheritance is not needed for the set of types that can be used, and so it is very similar to duck typing.

wikipedia Duck typing # Templates or generic types

Template, or generic functions or methods apply the duck test in a static typing context; this brings all the advantages and disadvantages of static versus dynamic type checking in general. Duck typing can also be more flexible in that only the methods actually called at runtime need to be implemented, while templates require implementations of all methods that can not be proven unreachable at compile time.

NOTE: 上面这段话从static versus dynamic type的角度来进行比较

Languages like Python, Java and Objective-C are examples of duck typing because it is possible in them to construct new types in runtime via reflection and inspect whether these objects implement certain methods. On the other hand, there are languages that rely on compile-time metaprogramming techniques (like C++ and its template system) and thus do not fit into the category of duck typing; instead, at some point in the compilation pipeline, all placeholder types become substituted with some concrete types specified in a particular instantiation. Even though certain type erasure is possible in them, runtime inspection is limited.

cppreference Named requirement

参见 ./Named-requirements，其中有关于这个话题的讨论。