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<ol class="chapter"><li class="chapter-item expanded "><a href="../intro.html"><strong aria-hidden="true">1.</strong> Introduction</a></li><li class="chapter-item expanded "><a href="../idioms/index.html"><strong aria-hidden="true">2.</strong> Idioms</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../idioms/coercion-arguments.html"><strong aria-hidden="true">2.1.</strong> Use borrowed types for arguments</a></li><li class="chapter-item expanded "><a href="../idioms/concat-format.html"><strong aria-hidden="true">2.2.</strong> Concatenating Strings with format!</a></li><li class="chapter-item expanded "><a href="../idioms/ctor.html"><strong aria-hidden="true">2.3.</strong> Constructor</a></li><li class="chapter-item expanded "><a href="../idioms/default.html"><strong aria-hidden="true">2.4.</strong> The Default Trait</a></li><li class="chapter-item expanded "><a href="../idioms/deref.html"><strong aria-hidden="true">2.5.</strong> Collections Are Smart 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href="../patterns/fold.html"><strong aria-hidden="true">3.5.</strong> Fold</a></li><li class="chapter-item expanded "><a href="../patterns/newtype.html"><strong aria-hidden="true">3.6.</strong> Newtype</a></li><li class="chapter-item expanded "><a href="../patterns/RAII.html"><strong aria-hidden="true">3.7.</strong> RAII Guards</a></li><li class="chapter-item expanded "><a href="../patterns/small-crates.html"><strong aria-hidden="true">3.8.</strong> Prefer Small Crates</a></li><li class="chapter-item expanded "><a href="../patterns/strategy.html"><strong aria-hidden="true">3.9.</strong> Strategy</a></li><li class="chapter-item expanded "><a href="../patterns/unsafe-mods.html"><strong aria-hidden="true">3.10.</strong> Contain unsafety in small modules</a></li><li class="chapter-item expanded "><a href="../patterns/visitor.html"><strong aria-hidden="true">3.11.</strong> Visitor</a></li></ol></li><li class="chapter-item expanded "><a href="../anti_patterns/index.html"><strong aria-hidden="true">4.</strong> Anti-patterns</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../anti_patterns/deny-warnings.html"><strong aria-hidden="true">4.1.</strong> #[deny(warnings)]</a></li><li class="chapter-item expanded "><a href="../anti_patterns/deref.html"><strong aria-hidden="true">4.2.</strong> Deref Polymorphism</a></li></ol></li><li class="chapter-item expanded "><a href="../functional/index.html"><strong aria-hidden="true">5.</strong> Functional Programming</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../functional/paradigms.html"><strong aria-hidden="true">5.1.</strong> Programming paradigms</a></li></ol></li><li class="chapter-item expanded "><a href="../additional_resources/index.html"><strong aria-hidden="true">6.</strong> Additional Resources</a></li><li><ol class="section"><li class="chapter-item expanded "><a href="../additional_resources/design-principles.html" class="active"><strong aria-hidden="true">6.1.</strong> Design principles</a></li></ol></li></ol>
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<h1><a class="header" href="#design-principles" id="design-principles">Design principles</a></h1>
<h2><a class="header" href="#a-brief-overview-over-common-design-principles" id="a-brief-overview-over-common-design-principles">A brief overview over common design principles</a></h2>
<hr />
<h2><a class="header" href="#a-hrefhttpsenwikipediaorgwikisolidsolida" id="a-hrefhttpsenwikipediaorgwikisolidsolida"><a href="https://en.wikipedia.org/wiki/SOLID">SOLID</a></a></h2>
<ul>
<li><a href="https://en.wikipedia.org/wiki/Single-responsibility_principle">Single Responsibility Principle (SRP)</a>:
A class should only have a single responsibility, that is, only changes to one part of the software's
specification should be able to affect the specification of the class.</li>
<li><a href="https://en.wikipedia.org/wiki/Open%E2%80%93closed_principle">Open/Closed Principle (OCP)</a>:
&quot;Software entities ... should be open for extension, but closed for modification.&quot;</li>
<li><a href="https://en.wikipedia.org/wiki/Liskov_substitution_principle">Liskov Substitution Principle (LSP)</a>:
&quot;Objects in a program should be replaceable with instances of their subtypes without altering the correctness
of that program.&quot;</li>
<li><a href="https://en.wikipedia.org/wiki/Interface_segregation_principle">Interface Segregation Principle (ISP)</a>:
&quot;Many client-specific interfaces are better than one general-purpose interface.&quot;</li>
<li><a href="https://en.wikipedia.org/wiki/Dependency_inversion_principle">Dependency Inversion Principle (DIP)</a>:
One should &quot;depend upon abstractions, [not] concretions.&quot;</li>
</ul>
<h2><a class="header" href="#a-hrefhttpsenwikipediaorgwikidon27t_repeat_yourselfdry-dont-repeat-yourselfa" id="a-hrefhttpsenwikipediaorgwikidon27t_repeat_yourselfdry-dont-repeat-yourselfa"><a href="https://en.wikipedia.org/wiki/Don%27t_repeat_yourself">DRY (Dont Repeat Yourself)</a></a></h2>
<p>&quot;Every piece of knowledge must have a single, unambiguous, authoritative representation within a system&quot;</p>
<h2><a class="header" href="#a-hrefhttpsenwikipediaorgwikikiss_principlekiss-principlea" id="a-hrefhttpsenwikipediaorgwikikiss_principlekiss-principlea"><a href="https://en.wikipedia.org/wiki/KISS_principle">KISS principle</a></a></h2>
<p>most systems work best if they are kept simple rather than made complicated; therefore,
simplicity should be a key goal in design, and unnecessary complexity should be avoided</p>
<h2><a class="header" href="#a-hrefhttpsenwikipediaorgwikilaw_of_demeterlaw-of-demeter-loda" id="a-hrefhttpsenwikipediaorgwikilaw_of_demeterlaw-of-demeter-loda"><a href="https://en.wikipedia.org/wiki/Law_of_Demeter">Law of Demeter (LoD)</a></a></h2>
<p>a given object should assume as little as possible about the structure or properties of
anything else (including its subcomponents), in accordance with the principle of &quot;information hiding&quot;</p>
<h2><a class="header" href="#a-hrefhttpsenwikipediaorgwikidesign_by_contractdesign-by-contract-dbca" id="a-hrefhttpsenwikipediaorgwikidesign_by_contractdesign-by-contract-dbca"><a href="https://en.wikipedia.org/wiki/Design_by_contract">Design by contract (DbC)</a></a></h2>
<p>software designers should define formal, precise and verifiable interface specifications
for software components, which extend the ordinary definition of abstract data types with
preconditions, postconditions and invariants</p>
<h2><a class="header" href="#a-hrefhttpsenwikipediaorgwikiencapsulation_computer_programmingencapsulationa" id="a-hrefhttpsenwikipediaorgwikiencapsulation_computer_programmingencapsulationa"><a href="https://en.wikipedia.org/wiki/Encapsulation_(computer_programming)">Encapsulation</a></a></h2>
<p>bundling of data with the methods that operate on that data, or the restricting of
direct access to some of an object's components. Encapsulation is used to hide the
values or state of a structured data object inside a class, preventing unauthorized
parties' direct access to them.</p>
<h2><a class="header" href="#a-hrefhttpsenwikipediaorgwikicommande28093query_separationcommand-query-separationcqsa" id="a-hrefhttpsenwikipediaorgwikicommande28093query_separationcommand-query-separationcqsa"><a href="https://en.wikipedia.org/wiki/Command%E2%80%93query_separation">Command-Query-Separation(CQS)</a></a></h2>
<p>“Functions should not produce abstract side effects...only commands (procedures) will
be permitted to produce side effects.” - Bertrand Meyer: Object Oriented Software Construction</p>
<h2><a class="header" href="#a-hrefhttpsenwikipediaorgwikiprinciple_of_least_astonishmentprinciple-of-least-astonishment-polaa" id="a-hrefhttpsenwikipediaorgwikiprinciple_of_least_astonishmentprinciple-of-least-astonishment-polaa"><a href="https://en.wikipedia.org/wiki/Principle_of_least_astonishment">Principle of least astonishment (POLA)</a></a></h2>
<p>a component of a system should behave in a way that most users will expect it to behave.
The behavior should not astonish or surprise users</p>
<h2><a class="header" href="#linguistic-modular-units" id="linguistic-modular-units">Linguistic-Modular-Units</a></h2>
<p>“Modules must correspond to syntactic units in the language used.” - Bertrand Meyer:
Object Oriented Software Construction</p>
<h2><a class="header" href="#self-documentation" id="self-documentation">Self-Documentation</a></h2>
<p>“The designer of a module should strive to make all information about the module part of
the module itself.” - Bertrand Meyer: Object Oriented Software Construction</p>
<h2><a class="header" href="#uniform-access" id="uniform-access">Uniform-Access</a></h2>
<p>“All services offered by a module should be available through a uniform notation,
which does not betray whether they are implemented through storage or through computation.” -
Bertrand Meyer: Object Oriented Software Construction</p>
<h2><a class="header" href="#single-choice" id="single-choice">Single-Choice</a></h2>
<p>“Whenever a software system must support a set of alternatives, one and only one module
in the system should know their exhaustive list.” - Bertrand Meyer: Object Oriented
Software Construction</p>
<h2><a class="header" href="#persistence-closure" id="persistence-closure">Persistence-Closure</a></h2>
<p>“Whenever a storage mechanism stores an object, it must store with it the dependents
of that object. Whenever a retrieval mechanism retrieves a previously stored object,
it must also retrieve any dependent of that object that has not yet been retrieved.” -
Bertrand Meyer: Object Oriented Software Construction</p>
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