Pharo is a pure object-oriented, dynamically typed, and reflective language. The stated project goal 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.
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
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 during 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
#[1234]
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 one double quote character that is part of the content of the comment
The Pharo language syntax is supposed to be very simple and minimalist. The basic language elements are often presented on one postcard as a showcase for the language's brevity. 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 serializing format.
History
Pharo emerged as a fork of Squeak, an open-source Smalltalk environment created by the original 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].
The Pharo consortium[29] was created for companies wishing to support the Pharo project. The Pharo association[30] was created in 2011[31] 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. Beginning in 2008, a new virtual machine (Cog) for Squeak, Pharo and Newspeak has been developed that performs nearly as well as the fastest Smalltalk virtual machine.[32] 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.[33]