principles:uniformity_principle
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principles:uniformity_principle [2021-05-19 09:49] – old revision restored (2021-05-11 17:19) 2a04:ac00:4:d29:5054:ff:fe00:d387 | principles:uniformity_principle [2021-09-02 12:50] – old revision restored (2021-05-19 09:48) 65.21.179.175 | ||
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+ | ====== Uniformity Principle (UP) ====== | ||
===== Variants and Alternative Names ===== | ===== Variants and Alternative Names ===== | ||
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===== Principle Statement ===== | ===== Principle Statement ===== | ||
+ | |||
+ | Solve similar problems in the same way. | ||
===== Description ===== | ===== Description ===== | ||
+ | |||
+ | Software design comprises many similar tasks. There are plenty of design decisions that are similar to ones taken before. UP tells that a design is good when similar design problems are solved the same way. UP can be applied to a large variety of problems: naming identifiers, | ||
+ | |||
+ | Striving for consistency and always using the same solutions also means that it can be a good idea to apply a " | ||
===== Rationale ===== | ===== Rationale ===== | ||
+ | |||
+ | Following UP reduces the number of different solutions. There are fewer concepts to learn, fewer problems to solve and fewer kinds of defects that can occur. So the developers, whether the original ones or the maintainers, | ||
===== Strategies ===== | ===== Strategies ===== | ||
+ | |||
+ | * Use the same naming scheme everywhere | ||
+ | * Use the same techniques, mechanisms, libraries, and frameworks everywhere | ||
+ | * In similar methods use the same order of parameters | ||
+ | |||
+ | |||
+ | ===== Caveats ===== | ||
+ | |||
+ | UP demands solving similar problems in the //same way// and not just in a similar way. This is crucial as subtle differences can be dangerous. These small differences are created easily. Sometimes it is impossible to do two things exactly the same way. And also over time two modules may slowly diverge. So it is sometimes better to have two modules work completely differently than to allow for these subtle differences as they easily lead to misconceptions and mistakes (see [[Murphy' | ||
+ | |||
+ | See also section [[#contrary principles]]. | ||
===== Origin ===== | ===== Origin ===== | ||
+ | |||
+ | This principle is newly proposes here. Nevertheless the idea is not new and should be pretty intuitive to every developer. | ||
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==== Generalizations ==== | ==== Generalizations ==== | ||
+ | |||
+ | * [[Murphy' | ||
==== Specializations ==== | ==== Specializations ==== | ||
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==== Contrary Principles ==== | ==== Contrary Principles ==== | ||
- | | + | Note that UP can be contrary to virtually every other principle as it demands neglecting other principles in favor of uniformity. |
+ | |||
+ | | ||
+ | * [[Model Principle]] (MP): UP may demand adhering to a certain naming scheme, which may not be best with respect to MP. See [[#example 1: naming schemes]]. | ||
==== Complementary Principles ==== | ==== Complementary Principles ==== | ||
- | * [[principles: | + | * [[Principle of Least Surprise]] |
- | * [[principles: | + | |
- | * [[principles:Easy to Use and Hard to Misuse]] | + | |
==== Principle Collections ==== | ==== Principle Collections ==== | ||
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{{page> | {{page> | ||
- | ===== Example ===== | + | |
+ | ===== Examples ===== | ||
+ | |||
+ | ==== Example | ||
+ | |||
+ | A typical example of the application of UP is the naming of method identifiers for common container classes like [[glossary: | ||
+ | |||
+ | Stacks typically have the methods '' | ||
+ | |||
+ | Queues on the other hand typically have the methods '' | ||
+ | |||
+ | A third possibility is to find a common abstraction and to apply a very general naming scheme to all descendant classes (stack classes, queue classes and others). This is the way it is done in Eiffel((see Bertrand Meyer: // | ||
principles/uniformity_principle.txt · Last modified: 2021-10-18 22:00 by christian