Editing Logical disjunction (section)

==Applications in computer science==
{{Expand section|date=February 2021}}
[[File:Or-gate-en.svg|thumb|150px|OR [[logic gate]]]]
[[Operator (programming)|Operators]] corresponding to logical disjunction exist in most [[programming language]]s.

===Bitwise operation===
Disjunction is often used for [[bitwise operation]]s. Examples:
* 0 or 0 = 0
* 0 or 1 = 1
* 1 or 0 = 1
* 1 or 1 = 1
* 1010 or 1100 = 1110

The <code>or</code> operator can be used to set bits in a [[bit field]] to 1, by <code>or</code>-ing the field with a constant field with the relevant bits set to 1. For example, <code>x = x | 0b00000001</code> will force the final bit to 1, while leaving other bits unchanged.{{citation needed|date=February 2021}}

===Logical operation===
Many languages distinguish between bitwise and logical disjunction by providing two distinct operators; in languages following [[C (programming language)|C]], [[bitwise disjunction]] is performed with the single pipe operator (<code>|</code>), and logical disjunction with the double pipe (<code>||</code>) operator.

Logical disjunction is usually [[Short-circuit evaluation|short-circuited]]; that is, if the first (left) operand evaluates to <code>true</code>, then the second (right) operand is not evaluated. The logical disjunction operator thus usually constitutes a [[sequence point]].

{{anchor|parallel-or}}In a parallel (concurrent) language, it is possible to short-circuit both sides: they are evaluated in parallel, and if one terminates with value true, the other is interrupted. This operator is thus called the ''parallel or''.

Although the type of a logical disjunction expression is Boolean in most languages (and thus can only have the value <code>true</code> or <code>false</code>), in some languages (such as [[Python programming language|Python]] and [[JavaScript]]), the logical disjunction operator returns one of its operands: the first operand if it evaluates to a true value, and the second operand otherwise.<ref>{{cite web |title=Python 3.12.1 Documentation - The Python Language Reference - 6.11 Boolean operations |url=https://docs.python.org/3/reference/expressions.html#boolean-operations |access-date=25 Dec 2023}}</ref><ref>{{cite web |title=JavaScript References - Expressions & Operators - Logical AND (&&) |date=25 September 2023 |url=https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Operators/Logical_AND |access-date=25 Dec 2023}}</ref> This allows it to fulfill the role of the [[Elvis operator]].

===Constructive disjunction===
The [[Curry–Howard correspondence]] relates a [[constructivism (mathematics)|constructivist]] form of disjunction to [[tagged union]] types.{{citation needed|date=February 2021}}<ref>{{Cite journal |title=Context-Free Language Theory Formalization |journal=Universidade Federal de Pernambuco |pages=6|arxiv=1505.00061 |author1=Marcus Vinícius Midena Ramos |last2=de Queiroz |first2=Ruy J. G. B. |year=2015 }}</ref>