Language binding

{{Short description|Software library that allows using another library coded in another programming language}}

In programming and software design, a '''binding''' is an application programming interface (API) that provides glue code specifically made to allow a programming language to use a foreign library or operating system service (one that is not native to that language).

==Characteristics== Binding generally refers to a mapping of one thing to another. In the context of software libraries, bindings are wrapper libraries that bridge two programming languages, so that a library written for one language can be used in another language.<ref>{{cite web|url=http://www.cairographics.org/manual/language-bindings.html |title=Appendix A. Creating a language binding for cairo |publisher=Cairographics.org |access-date=2014-04-02}}</ref> Many software libraries are written in system programming languages such as C or C++. To use such libraries from another language, usually of higher-level, such as Java, Common Lisp, Scheme, Python, or Lua, a binding to the library must be created in that language, possibly requiring recompiling the language's code, depending on the amount of modification needed.<ref>{{cite web |url=http://www.acm.org/tsc/apis.html |title=Standards, APIs, Interfaces and Bindings |publisher=Acm.org |access-date=2014-04-02 |archive-url=https://web.archive.org/web/20150116081559/http://www.acm.org/tsc/apis.html |archive-date=2015-01-16 |url-status=dead }}</ref> However, most languages offer a foreign function interface, such as Python's and OCaml's <code>ctypes</code>, and Embeddable Common Lisp's <code>cffi</code> and <code>uffi</code>.<ref>{{cite web|url=https://docs.python.org/3/library/ctypes.html |title=ctypes – A foreign function library for Python |work=Python v3.8.3 documentation |publisher=Docs.python.org |access-date=2020-06-04}}</ref><ref>{{cite web |url= https://realworldocaml.org/v1/en/html/foreign-function-interface.html |title= Real World OCaml, Chapter 19. Foreign Function Interface |year= 2013 |access-date= 2015-07-19 |last= Hickey |first= Jason |last2= Madhavapeddy |first2= Anil |last3= Minsky |first3= Yaron |website= realworldocaml.org |archive-date= 2015-07-18 |archive-url= https://web.archive.org/web/20150718235806/https://realworldocaml.org/v1/en/html/foreign-function-interface.html |url-status= dead }}</ref><ref>{{cite web|url=http://common-lisp.net/project/cffi/manual/html_node/Introduction.html#Introduction |title=Introduction – CFFI User Manual |publisher=Common-lisp.net |access-date=2014-04-02}}</ref>

For example, Python bindings are used when an extant C library, written for some purpose, is to be used from Python. Another example is <code>libsvn</code> which is written in C to provide an API to access the Subversion software repository. To access Subversion from within Java code, <code>libsvnjavahl</code> can be used, which depends on <code>libsvn</code> being installed and acts as a bridge between the language Java and <code>libsvn</code>, thus providing an API that invokes functions from <code>libsvn</code> to do the work.<ref>{{cite web |url=http://subclipse.tigris.org/wiki/JavaHL |title=Subversion JavaHL FAQ |publisher=Subclipse.tigris.org |date=2013-06-18 |access-date=2014-04-02 |archive-date=2014-12-27 |archive-url=https://web.archive.org/web/20141227185536/http://subclipse.tigris.org/wiki/JavaHL |url-status=dead }}</ref>

Major motives to create library bindings include software reuse, to reduce reimplementing a library in several languages, and the difficulty of implementing some algorithms efficiently in some high-level languages.

==Runtime environment== {{expand section|date=November 2016}}

===Object models=== {{Further|Object model}} * Common Object Request Broker Architecture (CORBA) – cross-platform-language model * Component Object Model (COM) – Microsoft Windows only cross-language model ** Distributed Component Object Model (DCOM) – extension enabling COM to work over networks ** Cross Platform Component Object Model (XPCOM) – Mozilla applications cross-platform model * Common Language Infrastructure – .NET Framework cross-platform-language model * Freedesktop.org D-Bus – open cross-platform-language model

===Virtual machines=== {{Further|Virtual machine}} * Comparison of application virtual machines

==Porting== {{Further|Porting}} * Portable object – cross-platform-language object model definition

==See also== {{prose|date=November 2016}} {{Portal|Computer programming}}

{{Div col|colwidth=50em}} * Application programming interface (API) * Application binary interface (ABI) * Calling convention * Embedded SQL * Name mangling * Simplified Wrapper and Interface Generator (SWIG) – interface binding generator from many languages to many languages, open-source * Wrapper function {{div col end}}

==References== {{Reflist|30em}}

==External links== *[http://www.open-std.org/JTC1/SC22/WG11/ JTC1/SC22/WG11 - Binding Techniques], an ISO standard for language bindings *[https://stackoverflow.com/questions/25865/what-is-a-language-binding What is a language binding?]

Category:Compilers Category:Computer libraries