Jump to content

Pharo: Difference between revisions

From Wikipedia, the free encyclopedia
Browse history interactively
← Previous editNext edit →
Content deleted Content added
VisualWikitext
No edit summary
Remove advertisement template: this page has changed a fair bit since 2019
Line 1: Line 1:
{{multiple issues|
{{Advert|date=April 2019}}
{{More citations needed|date=April 2019}}
}}
{{Use mdy dates|date=April 2013}}
{{Use mdy dates|date=April 2013}}
{{other uses}}
{{other uses}}

Revision as of 23:42, 26 February 2022

For other uses, see Pharo (disambiguation).
Not to be confused with the similar term Pharaoh (disambiguation).
Pharo
ParadigmObject-oriented
DeveloperPharo community
First appeared2008; 16 years ago (2008)
Stable release
9.0 / July 15, 2021; 3 years ago (2021-07-15)
Typing disciplineDynamic
Implementation languageSmalltalk
OSWindows, Linux, macOS, others
LicenseMIT license, partly Apache License 2.0[1]
Websitepharo.org
Influenced by
Smalltalk (Squeak)

Pharo is an open source, cross-platform implementation of the classic Smalltalk-80 programming language and runtime.[3] It's based on the OpenSmalltalk virtual machine called Cog (VM), [4][5][6][7]: 16  which evaluates a dynamic, reflective, and object-oriented programming language with a syntax closely resembling Smalltalk-80.

Pharo is shipped with a source code compiled into a system image that contains all software necessary to run Pharo system.[7]: 16  Like the original Smalltalk-80, Pharo provides several live programming features such as immediate object manipulation, live updates, and just-in-time compilation. The image includes an IDE-like software to modify its components.

Pharo was forked from Squeak v3.9 in March of 2008.[8][3][7][7]: 10 [9]

Overview

Pharo is a pure object-oriented dynamically typed and reflective language. The stated goal of Pharo is to revisit Smalltalk design and enhance it.

The name Pharo comes from the French word "phare" (French pronunciation: [faʁ]) which means lighthouse. This is why the Pharo logo shows a drawing of a lighthouse inside the final letter O of the name.

Key features

Virtual machine

  • Multiplatform virtual machine with JIT, combined generational garbage collector, ephemerons, forwarders
  • Fast object enumeration
  • Easy call stack manipulation
  • AST metalinks
  • Relatively low memory consumption
  • Customizable compiler
  • Optional complete object memory persistence
  • Resumable exceptions
  • Fast object serialization

Built-in software

Language features

  • Simple syntax
  • Object-oriented programming
  • Immediate object identity swapping
  • Dynamic inheritance
  • Objects as methods
  • Optional Green threads
  • Customizable metaclasses
  • Easy to use proxy objects

Relation to Smalltalk

Pharo is based on general concepts of Smalltalk but seeks to improve on them so does not limit itself to them. The basic syntax of the language has a close resemblance to Smalltalk. However, the way classes are defined in Pharo differs from other Smalltalk dialects.[how?]

Language syntax

Pharo syntax postcard

The Pharo syntax is based on Smalltalk-80 language syntax with several extensions. Some of these are common among modern Smalltalk dialects.

  • literals for dynamic arrays. The expressions that specify the array content are evaluated in time of the program execution
{1. 2. 1+2}
  • literals for byte arrays that can be composed only of integer numbers in the range from 0 to 255
#[1 2 3 4]
  • literals for scaled decimals, a representation of fixed point decimal numbers able to accurately represent decimal fractions
3.14s2
  • pragmas. In Smalltalk-80 the pragmas are used only for primitive methods. In Pharo they are fully capable method annotations
<gtInspectorPresentationOrder: 30>
  • two double quotes inside a comment are interpreted as a single double quotes character that is part of the content of the comment

The Pharo language syntax is supposed to be very simple and minimalistic. The basic language elements are often presented on a single postcard. The grammar is classified as LL(1).

The language grammar does not specify directly how the code should be stored in files. Pharo uses Tonel as the preferred code serialization format.

History

Pharo emerged as a fork of Squeak, an open-source Smalltalk environment created by the Smalltalk-80 team (Dan Ingalls and Alan Kay). Pharo was created by S. Ducasse [1] and M. Denker in March 2008. It focuses on modern software engineering and development techniques.[citation needed] Pharo is supported by the Pharo consortium (for legal entities) [2] and the Pharo association for physical persons [3].


Version Release date Major features
March 16, 2008 [10] Fork of Squeak environment
Pharo 1.0 April 15, 2010 real closures, EToys and MVC removed
Pharo 1.1 July 26, 2010 Cog JIT VM, Settings framework
Pharo 1.2 March 29, 2011 new Finder, Recent changes tool, improved Help, better themes
Pharo 1.3 August 2011 Zinc, headless images
Pharo 1.4 April 2012[11] Ring metamodel, better code simulator
Pharo 2.0 March 18, 2013.[12] browser improvements, QA tools, Fuel serializer, better files API
Pharo 3.0 April 2014.[13] new modular compiler (Opal) and debugger, continuations
Pharo 4.0 April 2015.[14] GTools, slots
Pharo 5.0 May 2016. [15] Spur VM, UFFI, improved reflectivity
Pharo 6.0 6 June, 2017. [16] 64-bit and Git support
Pharo 6.1 24 July, 2017. [17] improved Git support
Pharo 7.0 22 January, 2019. [18] bootstrapping, new code browser (Calypso), stateful traits
Pharo 8.0 20 January, 2020. [19] improved support of Git, testing, refactoring and Windows
Current stable version: Pharo 9.0 15 July, 2021. [20] GTK3 support, object-centric debugger and inspector, refactorings, official ARM VMs


Use of Pharo

Companies and consultants

Some companies use Pharo for their development projects.[21] In particular, they use:

  • Seaside for dynamic web development[22]
  • Zinc for server architectures[23]
  • Moose[24] to analyse data and software from all programming languages
  • Graphic libraries for evolved user interfaces
  • Roassal to visualize data[25]

The Pharo consortium[26] was created for companies wishing to support the Pharo project. The Pharo association[27] was recently[when?] created for users wishing to support the project.

Performance and virtual machine (VM)

Pharo relies on a virtual machine that is written almost entirely in Smalltalk itself. Beginning in 2008, a new virtual machine (Cog) for Squeak, Pharo and Newspeak has been developed that has a level of performance close to the fastest Smalltalk virtual machine.[28] In 2014/2015 the VM community is working on Spur, a new Memory Manager for Cog that should again increase performance and provide better 64-bit VM support.[29]

See also

References

  1. ^ Pharo license information
  2. ^ The Pharo board
  3. ^ a b Pharo by example. Andrew P. Black, Stéphane Ducasse, Oscar Nierstrasz, Damien Pollet, Damien Cassou, Marcus Denker. [Kehrsatz] Switzerland. October 28, 2009. ISBN 978-3-9523341-4-0. OCLC 957555627.{{cite book}}: CS1 maint: location missing publisher (link) CS1 maint: others (link)
  4. ^ "OpenSmalltalk". opensmalltalk.org. Retrieved November 24, 2021.
  5. ^ OpenSmalltalk/opensmalltalk-vm, OpenSmalltalk, November 23, 2021, retrieved November 24, 2021
  6. ^ "Cog Blog :: About Cog". Retrieved November 24, 2021.
  7. ^ a b c d Black, Andrew P.; Ducasse, Stéphane; Nierstrasz, Oscar; Pollet, Damien (October 28, 2009). "Pharo by Example". Samuel Morello. ResearchGate. ISBN 978-3-9523341-4-0.
  8. ^ "DevelopOnTheWeb". developontheweb.co.uk. Retrieved November 24, 2021.
  9. ^ "The Rise and Fall of Commercial Smalltalk". www.wirfs-brock.com. Retrieved November 24, 2021.
  10. ^ "Pharo got 10 years". Pharo-project.org. Retrieved May 31, 2018.
  11. ^ "Pharo Open Source Smalltalk — Release 1.4". Pharo-project.org. April 17, 2012. Retrieved April 5, 2013.
  12. ^ "Pharo Open Source Smalltalk — Release 2.0". Pharo-project.org. March 18, 2013. Retrieved April 5, 2013.
  13. ^ "Pharo Open Source Smalltalk — Release 3.0". pharo.org. April 30, 2014. Archived from the original on August 23, 2017. Retrieved May 1, 2014.
  14. ^ "Pharo Open Source Smalltalk — Release 4.0". pharo.org. April 15, 2015. Archived from the original on August 23, 2017. Retrieved April 16, 2015.
  15. ^ "Pharo Open Source Smalltalk — Release 5.0". pharo.org. May 12, 2016. Archived from the original on December 29, 2017. Retrieved May 13, 2016.
  16. ^ "Pharo Open Source Smalltalk - Release 6.0". pharo.org. June 6, 2017.
  17. ^ "Pharo 6.1 released". pharo.org. July 24, 2017.
  18. ^ "Pharo 7.0 released". pharo.org. January 22, 2019.
  19. ^ "Pharo 8.0 Released!". pharo.org. January 20, 2020.
  20. ^ "Pharo 9.0 Released!". pharo.org. July 15, 2020.
  21. ^ "(Press Release) Pharo Open Source Smalltalk — Success stories". Pharo-project.org. Retrieved April 5, 2013.
  22. ^ "Home". seaside.st. March 18, 2007. Retrieved April 5, 2013.
  23. ^ "Zinc HTTP Components". Zn.stfx.eu. Retrieved April 5, 2013.
  24. ^ Girba, Tudor. "Home". Moose technology. Retrieved April 5, 2013.
  25. ^ "Agile Visualization". Object Profile. Retrieved May 31, 2018.
  26. ^ "web: Pharo Consortium". Consortium.pharo.org. March 31, 2013. Retrieved April 5, 2013.
  27. ^ Ducasse, Stephane. "association: Pharo Association". Association.pharo.org. Retrieved April 5, 2013.
  28. ^ "Cog Blog". Mirandabanda.org. Retrieved April 5, 2013.
  29. ^ "7-point summary of the Spur memory manager". Clément Béra. Retrieved April 17, 2015.
Retrieved from "https://en.wikipedia.org/enwiki/w/index.php?title=Pharo&oldid=1074195190"