Thinking in C++ Vol 2 - Practical Programming
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Summary

Templates go far beyond simple type parameterization. When you combine argument type deduction, custom specialization, and template metaprogramming, C++ templates emerge as a powerful code generation mechanism.

One of the weaknesses of C++ templates that we did not mention is the difficulty in interpreting compile-time error messages. The quantity of inscrutable text spewed out by the compiler can be quite overwhelming. C++ compilers have improved their template error messages, and Leor Zolman has written a tool called STLFilt that renders these error messages much more readable by extracting the useful information and throwing away the rest.[85]

Another important idea to take away from this chapter is that a template implies an interface. That is, even though the template keyword says I ll take any type, the code in a template definition requires that certain operators and member functions be supported that s the interface. So in reality, a template definition is saying, I ll take any type that supports this interface. Things would be much nicer if the compiler could simply say, Hey, this type that you re trying to instantiate the template with doesn t support that interface can t do it. Using templates constitutes a sort of latent type checking that is more flexible than the pure object-oriented practice of requiring all types to derive from certain base classes.

In Chapters 6 and 7 we explore in depth the most famous application of templates, the subset of the Standard C++ library commonly known as the Standard Template Library (STL). Chapters 9 and 10 also use template techniques not found in this chapter.

Thinking in C++ Vol 2 - Practical Programming
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