“Regular Types and Why Do I Care ?”
summary
Explains why STL expects value-like types, shows std::sort actually requires a strict weak ordering (example: a naive 2D point comparator yields unordered pairs and breaks sort), and demonstrates correct lexicographic and distance-based comparators. Covers Concepts Lite / C++20 three-way comparison (three-way comparison / spaceship) and how std::optional and string_view as borrow type interact with equality and ordering. Recommends designing types as SemiRegular/Regular when possible and treating non-owning spans and views with contextual care.
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chapters (20)
- 0:00Intro
- 0:55Why Regular Types
- 2:40Terminology
- 4:53YOP
- 6:52Mathematics Really Does Matter
- 8:16Algorithmic Journeys
- 9:06Fundamentals of Genetic Programming
- 10:47Simplicity
- 13:07STL Design Principles
- 18:46Why Do I Care
- 20:16stdssort
- 25:23strict weak ordering
- 26:07equivalence relations and equivalence classes
- 27:31dictionary order
- 29:41equality comparable
- 33:25wholepart semantics
- 36:53STD optional
- 39:57StringView
- 43:31Span
- 46:01Questions
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