Functional and non-functional composition

[peerreynders]

C++ Coding Standards - 101 Rules, Guidelines, and Best Practices

6. Correctness, simplicity, and clarity come first
Summary
KISS (Keep It Simple Software): Correct is better than fast. Simple is better than complex. Clear is better than cute. Safe is better than insecure (see Items 83 and 99).

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8. Don’t optimize prematurely
Summary
Spur not a willing horse (Latin proverb): Premature optimization is as addictive as it is unproductive. The first rule of optimization is: Don’t do it. The second rule of optimization (for experts only) is: Don’t do it yet. Measure twice, optimize once.

Discussion
As [Stroustrup00] §6’s introduction quotes so deliciously:

Premature optimization is the root of all evil.

—Donald Knuth [quoting Hoare]

On the other hand, we cannot ignore efficiency.

—Jon Bentley

Hoare and Knuth are, of course and as always, completely correct (see Item 6 and this Item). So is Bentley (see Item 9).

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9. Don’t pessimize prematurely
Summary
Easy on yourself, easy on the code: All other things being equal, notably code complexity and readability, certain efficient design patterns and coding idioms should just flow naturally from your fingertips and are no harder to write than the pessimized alternatives. This is not premature optimization; it is avoiding gratuitous pessimization.

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