Editing Duck typing (section)

===Structural type systems===

Duck typing is similar to, but distinct from, [[Structural type system|structural typing]]. Structural typing is a [[Type system#Static typing|static typing]] system that determines type compatibility and equivalence by a type's structure, whereas duck typing is [[Type system#Dynamic typing|dynamic]] and determines type compatibility by only that part of a type's structure that is accessed during [[Runtime (program lifecycle phase)|runtime]].

The [[TypeScript]],<ref>{{Cite web|url=https://www.se-radio.net/2019/10/episode-384-boris-cherny-on-typescript|title=SE Radio Episode 384: Boris Cherny on TypeScript|website=se-radio.net|access-date=2019-10-25}}</ref> [[Elm (programming language)|Elm]]<ref>{{cite web|url=http://guide.elm-lang.org/core_language.html|title=Core Language · An Introduction to Elm|first=Evan|last=Czaplicki|access-date=30 January 2017}}</ref> and [[Python (programming language)|Python]]<ref>{{Cite web|url=https://peps.python.org/pep-0544/|title=PEP 544 – Protocols: Structural subtyping (static duck typing)}}</ref> languages support structural typing to varying degrees.