Editing Smalltalk (section)

=== <!--If this subsection is renamed, leave an {{anchor|OpenSmalltalk}} to it -->OpenSmalltalk ===
[[OpenSmalltalk VM]] ('''OS VM''') is a relatively high-performance implementation of the Smalltalk virtual machine on which several modern open-source Smalltalk dialects are based.<ref>{{Citation| work=OpenSmalltalk |title=opensmalltalk-vm |date=2020-11-03|url=https://github.com/OpenSmalltalk/opensmalltalk-vm |publisher=Git hub|access-date=2020-11-08}}</ref><ref name="hal-01883380">{{cite report |author=Eliot Miranda |author2=Clément Bera |author3=Elisa Gonzalez Boix |author4=Dan Ingalls |title=Two Decades of Smalltalk VM Development: Live VM development through Simulation Tools; Virtual Machines and Language Implementations VMIL 2018, Boston, United States |publisher=hal.archives-ouvertes.fr |doi=10.1145/3281287.3281295 |date=2018 |url=https://hal.archives-ouvertes.fr/hal-01883380/document|archive-url=https://web.archive.org/web/20221105011044/https://hal.archives-ouvertes.fr/hal-01883380/document |archive-date=2022-11-05}}</ref> The OS VM derives from the original Back-to-the-Future<ref>{{cite journal|first1=Dan |last1=Ingalls |first2=Ted |last2=Kaehler |first3=John |last3=Maloney |first4=Scott |last4=Wallace |first5=Alan |last5=Kay |year=1997 |title=Back to the Future: the story of Squeak, a practical Smalltalk written in itself |journal=ACM SIGPLAN Notices |publisher=ACM Digital Library |volume=32 |issue=10 |pages=318–326 |doi=10.1145/263700.263754 |doi-access=free}}</ref> (BTTF) Squeak interpreter implemented by Dan Ingalls, Ted Khaeler, John Maloney and many other contributors. As with the BTTF VM, OS VM is [[Source-to-source compiler|transpiled]] from the Smalltalk system in which it is developed (using a subset of Smalltalk named Slang) to native [[C (programming language)|C]] language source code,<ref>{{Cite web|title= Slang |url= http://wiki.squeak.org/squeak/slang |access-date=2020-11-08|website= Squeak}}</ref> which is in turn compiled against specific platform and architecture of the hardware practically enabling cross-platform execution of the Smalltalk images. The OS VM differs from the BTTF VM in
* introducing a JIT compiler to native machine code, including sophisticated machine-code method cacheing techniques
* using "context-to-stack-mapping" to vastly reduce the overheads of context objects
* supporting both the original BTTF object representation, and Spur, a much more efficient and native 32-bit and 64-bit scheme with a much improved garbage collector, object pinning, and lazy become
The notable Smalltalk dialects based on the OS VM <ref name="EliotMirand2018">{{Cite web |last1=Miranda |first1=Eliot |last2=Bera |first2=Clément |last3=Gonzalez Boix |first3=Elisa |last4=Dan |first4=Ingalls |date=October 8, 2018 |title=Two Decades of Smalltalk VM Development: Live VM development through Simulation Tools |url=https://hal.archives-ouvertes.fr/hal-01883380/document |format=PDF}}</ref> are:

*[[Squeak]], the original open source Smalltalk that the OpenSmalltalk VM was built for{{R|name=EliotMirand2018|page=2}}, that derives from Xerox PARC's Smalltalk-80 v1
*[[Pharo]] Smalltalk, an open-source [[cross-platform]] language, that derives from Squeak
*[[Croquet Project#Virtual machine|Croquet]], a replicating distributed Smalltalk for the [[Croquet Project]]
*[[Cuis Smalltalk]] that derives from Squeak