Pure function

<p>In <a href="/facts/Computer_programming/QmSsFnu0">computer programming</a>, a pure function is a <a href="/facts/Subroutine/9vFJrg0A">function</a> that has the following properties:
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<ol><li>the function <a href="/facts/Return_statement/lK7c71aa">return values</a> are <a href="/facts/Relational_operator/nTXrhxN2">identical</a> for identical <a href="/facts/Argument_of_a_function/QkuPc28I">arguments</a> (no variation with local <a href="/facts/Static_variable/dYIs2E5p">static variables</a>, <a href="/facts/Non-local_variable/vNoF8Bn4">non-local variables</a>, mutable <a href="/facts/Value_type_and_reference_type/0xLHHokA">reference arguments</a> or <a href="/facts/Input%2foutput/WQTE8Jas">input streams</a>, i.e., <a href="/facts/Referential_transparency/g0zARbAD">referential transparency</a>), and</li>
<li>the function has no <a href="/facts/Side_effect_(computer_science)/AU3GlLzG">side effects</a> (no mutation of local static variables, non-local variables, mutable reference arguments or input/output streams).</li></ol>

Pure function open-in-new

Pure function