21.4 Afternotes

Ru-Brd

Tuple construction is one of those template applications that appears to have been independently attempted by many programmers. The details of these attempts vary widely, but many are based on the idea of a recursive pair structure (such as our recursive duos). One interesting alternative was developed by Andrei Alexandrescu in [AlexandrescuDesign]. He cleanly separates the list of types from the list of fields in the tuple. This leads to the concept of a type list that has various applications of its own (one of which is the construction of a tuple with the encapsulated types).

Section 13.13 on page 222 discusses the concept of template list parameters , which are a language extension that makes the implementation of tuples almost trivial.

Ru-Brd