Squirrel (programming language)

Squirrel is a high level imperative, object-oriented programming language, designed to be a lightweight scripting language that fits in the size, memory bandwidth, and real-time requirements of applications like video games.

MirthKit, a simple toolkit for making and distributing open source, cross-platform 2D games, uses Squirrel for its platform.^[2] It is used extensively by Code::Blocks for scripting and was also used in Final Fantasy Crystal Chronicles: My Life as a King.^[3]^[4] It is also used in Left 4 Dead 2, Portal 2 and Thimbleweed Park for scripted events and in NewDark, an unofficial Thief 2: The Metal Age engine update, to facilitate additional, simplified means of scripting mission events, aside of the regular C scripting.^[5]

Language features

Dynamic typing
Delegation
Classes, inheritance
Higher order functions
Generators
Cooperative threads (coroutines)
Tail recursion
Exception handling
Automatic memory management (mainly reference counting with backup garbage collector)
Weak references
Both compiler and virtual machine fit together in about 7k lines of C++ code
Optional 16-bit character strings

Syntax

Squirrel uses a C-like syntax.

Factorial in Squirrel

function factorial(x){ if (x <= 1) { return 1; } else { return x * factorial(x-1); }}

Generators

function not_a_random_number_generator(max) { local last = 42; local IM = 139968; local IA = 3877; local IC = 29573; for(;;) { // loops forever yield (max * (last = (last * IA + IC) % IM) / IM); }}local randtor = not_a_random_number_generator(100);for(local i = 0; i < 10; i += 1) print(">"+resume randtor+"\n");

Classes and inheritance

class BaseVector { constructor(...) { if(vargv.len() >= 3) { x = vargv[0]; y = vargv[1]; z = vargv[2]; } } x = 0; y = 0; z = 0;}class Vector3 extends BaseVector { function _add(other) { if(other instanceof ::Vector3) return ::Vector3(x+other.x,y+other.y,z+other.z); else throw "wrong parameter"; } function Print() { ::print(x+","+y+","+z+"\n"); }}local v0 = Vector3(1,2,3)local v1 = Vector3(11,12,13)local v2 = v0 + v1;v2.Print();

Applications

Applications using Squirrel

Code::Blocks, integrated development environment
Enduro/X, cluster application server
Electric Imp, an end-to-end IoT platform^[6]

Games using Squirrel

Alien Swarm^[7]
Antinomy of Common Flowers^[8]
Apex Legends^[9]
Battle Brothers
Contagion^[7]
Counter Strike: Global Offensive^[7]
CRSED: F.O.A.D.
Final Fantasy Crystal Chronicles: My Life as a King^[3]
GTA IV's IV-MP^[10]
Left 4 Dead 2^[7]
Liberty Unleashed^[11]
Mafia II's M2-Multiplayer^[12]
Nuclear Dawn^[7]
OpenTTD^[13]
Portal 2^[7]
Shadow Warrior
Simutrans^[14]
Sonic Unleashed (PS2/Wii)^[15]
SuperTux
Team Fortress 2^[7]
Thimbleweed Park^[16]
Thief II (unofficial NewDark engine update)^[17]
Titanfall^[7]
Vice City Multiplayer,^[18] a mod for Grand Theft Auto: Vice City^[19]
War Thunder
Zero no Tsukaima - Maigo no Period to Ikusen no Symphony (PS2)
Zero no Tsukaima - Muma ga Tsumugu Yokaze no Nocturne (PS2)
Zero no Tsukaima - Shou-akuma to Harukaze no Concerto (PS2)

History

The language was made public in 2003 under the zlib/libpng license.^[20]In November 2010, the license was changed to the MIT license to enable the project to be hosted on Google Code.^[21]^[22]It is developed and maintained by Alberto Demichelis.

References

^ "squirrel/HISTORY at master - albertodemichelis/squirrel - GitHub".
^ MirthKit Developer Wiki Archived 2014-02-11 at the Wayback Machine
^ a b Brandon Boyer (21 February 2008). "Gamasutra - GDC 2008 Event Coverage". gamasutra.com. Gamasutra.
^ "Exclusive: Behind The Scenes of Final Fantasy's WiiWare Debut". gamasutra.com. Gamasutra. 23 June 2008. Retrieved 22 September 2011.
^ "L4D2 Vscripts - Valve Developer Community". developer.valvesoftware.com. Retrieved 2018-07-06.
^ "Electric Imp programming guide". electricimp.com.
^ a b c d e f g h "VScript". valvesoftware.com. 2014-08-20. Retrieved 2015-01-17.
^ "th155-decomp". GitHub. Retrieved 2020-10-19.
^ "WHAT in the hell, is consumable nut? Please help this is an error code I got, have any of you got this before?". reddit.com. 2019-03-24. Retrieved 2021-09-04.
^ "iv-multiplayer.com". www.iv-multiplayer.com. Archived from the original on 2012-06-07. Retrieved 2018-07-06.
^ "Liberty Unleashed". Retrieved 2019-12-04.
^ "m2-multiplayer.com". www.m2-multiplayer.com. Archived from the original on 2013-01-02. Retrieved 2018-07-06.
^ "AI:Main Page - OpenTTD". wiki.openttd.org. Retrieved 2018-07-06.
^ "Simutrans-Squirrel-API: Main Page". dwachs.github.io. Retrieved 2018-07-06.
^ "The VG Resource Wiki". wiki.vg-resource.com. Retrieved 2021-09-04.
^ "Thimbleweed Park Blog- Engine". blog.thimbleweedpark.com. Retrieved 2018-07-06.
^ "NewDark 1.25: Squirrel script?". ttlg.com. 2017-03-20. Retrieved 2019-12-25.
^ Vice City Multiplayer
^ "Welcome To VC-MP website!". Archived from the original on 2006-04-05. Retrieved 2014-05-04.
^ "The Squirrel programming language". SourceForge. Retrieved 2018-07-06.
^ "Moving to code.google.com and MIT License - The Language - Squirrel - The Programming Language". forum.squirrel-lang.org. Retrieved 2018-07-06.
^ "Google Code Archive - Long-term storage for Google Code Project Hosting". code.google.com. Retrieved 2018-07-06.

External links

Official website