principles:rule_of_explicitness
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principles:rule_of_explicitness [2013-02-28 22:43] – created christian | principles:rule_of_explicitness [2021-10-18 22:06] (current) – +++ restored +++ christian | ||
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===== Context ===== | ===== Context ===== | ||
/* fill in contexts here: */ | /* fill in contexts here: */ | ||
- | * [[contexts: | + | * [[contexts: |
+ | * [[contexts: | ||
+ | * [[contexts: | ||
===== Principle Statement ===== | ===== Principle Statement ===== | ||
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===== Description ===== | ===== Description ===== | ||
+ | Solutions often differ in the level of explicitness. A feature can be implemented explicitly or it can be a side-effect of the implementation of another feature or a more general functionality. The same applies to module communication. A module can invoke another module directly or there can be various forms of indirections like events or observers. | ||
+ | RoE states that explicit solutions are better than implicit ones. Indirection, | ||
===== Rationale ===== | ===== Rationale ===== | ||
+ | If something is realized explicitly, it is easier to understand. Implicit solutions require the developer to have a deeper understanding of the module as it is necessary to "read between the lines" | ||
===== Strategies ===== | ===== Strategies ===== | ||
+ | |||
+ | * Avoid indirection (but keep [[Low Coupling|LC]] in mind) | ||
+ | * Avoid indirection though events/ | ||
+ | * Avoid indirecting middleware like messaging middleware in favor of direct communication. Explicit communication paths are easier to grasp and debug. | ||
+ | * Avoid configurability (but keep [[Generalization Principle|GP]] in mind) | ||
+ | * Avoid using configuration files for specifying behavior. Instead implement varying behavior explicitly. | ||
+ | * Avoid highly configurable modules. Instead implement varying behavior explicitly. | ||
+ | * Explicitly state which module to use | ||
+ | * Avoid importing all classes of a given package/ | ||
+ | * Avoid '' | ||
+ | * Explicitly name parameters | ||
+ | * In Python and other languages that allow this use named parameters. | ||
+ | * Avoid long parameter lists and use objects with explicit attribute assignments instead. (see [[Option-Operand Separation]]) | ||
+ | * Use parameter types that explicitly state what the input is. Rather use specific types for parameters like customers, articles, URLs, colors, money, etc. instead of using strings or integers for these values (see [[anti-patterns: | ||
+ | * Avoid implicit type conversions. | ||
+ | * In C# do not to specify implicit cast operations | ||
+ | * In C++ use the '' | ||
+ | * In PHP use the '' | ||
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* [[More Is More Complex]] (MIMC): Stating something explicitly requires more code. | * [[More Is More Complex]] (MIMC): Stating something explicitly requires more code. | ||
* [[Generalization Principle]] (GP): RoE often results in specific solutions. Generality often requires stating something implicitly. | * [[Generalization Principle]] (GP): RoE often results in specific solutions. Generality often requires stating something implicitly. | ||
+ | * [[Low Coupling]] (LC): Direct communication typically has the disadvantage of a higher coupling. Indirection reduces coupling but creates implicit/ | ||
+ | * [[Don' | ||
==== Complementary Principles ==== | ==== Complementary Principles ==== | ||
* [[Keep It Simple Stupid]] (KISS): Explicit solutions are often also simpler. | * [[Keep It Simple Stupid]] (KISS): Explicit solutions are often also simpler. | ||
+ | * [[Murphy' | ||
+ | * [[Model Principle]] (MP): RoE states that [[anti-patterns: | ||
+ | * [[Law of Leaky Abstractions]] (LLA): Often abstractions create a level of implicitness. Abstraction leaks are one reason why explicit solutions can be considered preferable. | ||
==== Principle Collections ==== | ==== Principle Collections ==== | ||
+ | {{page> | ||
- | ===== Example | + | |
+ | ===== Examples | ||
===== Description Status ===== | ===== Description Status ===== | ||
/* Choose one of the following and comment out the rest: */ | /* Choose one of the following and comment out the rest: */ | ||
- | [[wiki: | + | /*[[wiki: |
- | /*[[wiki: | + | [[wiki: |
/ | / | ||
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* Martin Fowler: // | * Martin Fowler: // | ||
* Tim Peters: // | * Tim Peters: // | ||
+ | |||
+ | ===== Discussion ===== | ||
+ | |||
+ | Discuss this wiki article and the principle on the corresponding [[talk: | ||
principles/rule_of_explicitness.1362087785.txt.gz · Last modified: 2013-05-20 12:46 (external edit)