T.concepts

T.concepts: Concept rules

Concepts is a C++20 facility for specifying requirements for template arguments. They are crucial in the thinking about generic programming and the basis of much work on future C++ libraries (standard and other).

This section assumes concept support

Concept use rule summary:

• T.10: Specify concepts for all template arguments
• T.11: Whenever possible use standard concepts
• T.12: Prefer concept names over auto
• T.13: Prefer the shorthand notation for simple, single-type argument concepts
• ???

Concept definition rule summary:

• T.20: Avoid "concepts" without meaningful semantics
• T.21: Require a complete set of operations for a concept
• T.22: Specify axioms for concepts
• T.23: Differentiate a refined concept from its more general case by adding new use patterns
• T.24: Use tag classes or traits to differentiate concepts that differ only in semantics
• T.25: Avoid complimentary constraints
• T.26: Prefer to define concepts in terms of use-patterns rather than simple syntax
• ???