Recursive data type
data type that refers to itself in its definition
In computer programming, a recursive data type is a data type whose definition contains values of the same type. It is also known as a recursively defined, inductively defined or inductive data type. Data of recursive types are usually viewed as directed graphs.
An important application of recursion in computer science is in defining dynamic data structures such as Lists and Trees. Recursive data structures can dynamically grow to an arbitrarily large size in response to runtime requirements; in contrast, a static array's size requirements must be set at compile time.
Sometimes the term "inductive data type" is used for algebraic data types which are not necessarily recursive.
Example
An example is the list type, in Haskell:
This indicates that a list of a's is either an empty list or a cons cell containing an 'a' (the "head" of the list) and another list (the "tail").
Another example is a similar singly linked type in Java:
This indicates that non-empty list of type E contains a data member of type E, and a reference to another List object for the rest of the list (or a null reference to indicate that this is the end of the list).
Mutually recursive data types
Data types can also be defined by mutual recursion. The most important basic example of this is a tree, which can be defined mutually recursively in terms of a forest (a list of trees).
The public source identifies “Recursive data type” as data type that refers to itself in its definition. This brief keeps that definition visible, then builds a research path around Recursive, data and type.
Why this record matters
A short description can identify a subject without explaining its stakes. For “Recursive data type”, the useful work is to connect “data type that refers to itself in its definition” to the records capable of establishing context and consequence.
Named sources, stable identifiers and responsible institutions provide the strongest route from overview to verifiable evidence. The source revision retrieved here is dated Nov 3, 2025. The linked authority identifier is Q3098441. None of the 0 selected statements returned an explicit reference.
Overview language is designed for orientation and should not be treated as a substitute for the evidence cited beneath it. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Use the entry as an orientation point, then follow its citations and revision history. Names, dates and institutional relationships should be checked against the original record.
- Subject orientation
- Search vocabulary
- Locating named sources
The closest primary source, responsible institution and strongest cited specialist reference.
Three-step research path
- Establish the record: confirm the title “Recursive data type”, its source revision and the description used here.
- Expand the search: follow Recursive data type primary sources, Recursive data type archive and Recursive research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “Recursive data type”?
- Which cited source is closest to the event, object or claim?
- Which institution is responsible for the underlying evidence?
Search terms from this dossier
This entry incorporates text from “Recursive data type” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.