Data structure used to hold a value that could take on several different, but fixed, types
In computer science, a tagged union, also called a variant, variant record, choice type, discriminated union, disjoint union, sum type, or coproduct, is a data structure used to hold a value that could take on several different, but fixed, types. Only one of the types can be in use at any one time, and a tag field explicitly indicates which type is in use. It can be thought of as a type that has several "cases", each of which should be handled correctly when that type is manipulated. This is critical in defining recursive datatypes, in which some component of a value may have the same type as that value, for example in defining a type for representing trees, where it is necessary to distinguish multi-node subtrees and leaves. Like ordinary unions, tagged unions can save storage by overlapping storage areas for each type, since only one is in use at a time.
the taggedunion type, given a tag and a value of the corresponding type. Mathematically, taggedunions correspond to disjoint or discriminated unions, usually...
variables must match.: pp.289–293 Rust implements both tagged and untagged unions. In Rust, taggedunions are implemented using the enum keyword. Unlike enumerated...
computer science, a tagged architecture is a type of computer architecture where every word of memory constitutes a taggedunion, being divided into a...
The term discriminated union may refer to: Disjoint union in set theory. Taggedunion in computer science. This disambiguation page lists articles associated...
constants in the language. An enumerated type can be seen as a degenerate taggedunion of unit type. A variable that has been declared as having an enumerated...
exactly one of two sets Taggedunion – Data structure used to hold a value that could take on several different, but fixed, types Union (computer science) –...
programming by the fact that in languages having taggedunions, option types can be expressed as the taggedunion of the encapsulated type plus a unit type....
type, which has only one failure value, Nothing. The second case is a taggedunion: a result is either some string with a descriptive error message or a...
text Union, a datum which may be one of a set of types Taggedunion (also called a variant, discriminated union or sum type), a union with a tag specifying...
animals are tagged for private purposes, usually one ear is tagged. Australian sheep and goats are required to have visually readable ear tags printed with...
integer, a union may only contain one subtype at a time. A taggedunion (also called a variant, variant record, discriminated union, or disjoint union) contains...
the nil vector. In languages with a tagged architecture, a possibly null pointer can be replaced with a taggedunion which enforces explicit handling of...
contents of a C or C++ struct) As encapsulated metadata and data, using a taggedunion convention to describe the types of nested netstrings, thereby establishing...
product types (i.e., tuples and records) and sum types (i.e., tagged or disjoint unions, coproduct types or variant types). The values of a product type...
is threaded binary tree. In languages with taggedunions such as ML, a tree node is often a taggedunion of two types of nodes, one of which is a 3-tuple...
avoid listing their religions on their ID tags. Medical tattoo, also known as a meat tag "U.S. Soldiers "tagged" for blood transfusion". Popular Science...
rugby union communities. Tag rugby comes in several forms with OzTag, Try Tag Rugby (UK) and Mini Tag being some of the better known variations. Tag rugby...
pattern matching used to implement language dialects Symbolic integration Taggedunion Tom (pattern matching language) SNOBOL for a programming language based...
EU stars or any other symbol. So does Turkey (TR) (which is in a customs union with the EU), Montenegro (MNE), North Macedonia (NMK) and Serbia (SRB)....
constructivist form of disjunction to taggedunion types.[citation needed] The membership of an element of a union set in set theory is defined in terms...
Special Protection Group) are tagged in red, while journalists in the press pool are tagged in yellow. Both red and yellow-tagged passengers sit in economy...
code for the extinct Erre language err, a particular constructor in taggedunion data structures Estrogen related receptor and particular members of the...
Church encoding – a related concept from functional programming, in which taggedunion/sum types may be modeled using the behaviors of "visitors" on such types...
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