| Squirrel | |
|---|---|
| Paradigm | Multi-paradigm: scripting, imperative, functional, object-oriented |
| Designed by | Alberto Demichelis |
| First appeared | September 6, 2003 (2003-09-06) |
| Stable release | |
| Typing discipline | Dynamic |
| OS | Cross-platform |
| License | MIT license |
| Filename extensions | .nut |
| Website | squirrel-lang |
| Influenced by | |
| C++, JavaScript, Lua, Python | |
| Influenced | |
| MiniD (since renamed Croc) | |
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.34 It is also used in Left 4 Dead 2, Portal 2, Team Fortress 2, Thimbleweed Park, and War Thunder 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 support for UCS-2 wide strings
Syntax
Squirrel uses a C-like syntax, albeit inspired by that of Lua as well.
- Factorial in Squirrel
local function factorial(x) // Getting function which is factorial, then getting value which is x
{
if (x <= 1) { // if x is less than 1
return 1; // then the code will just return 1
}
else { // if that doesn't work
return x * factorial(x-1); // then the code will return x times 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 platform6
Games using Squirrel
- Alien Swarm7
- Antinomy of Common Flowers8
- Apex Legends
- Battle Brothers
- Contagion7
- Counter Strike: Global Offensive7
- CRSED: F.O.A.D.
- Final Fantasy Crystal Chronicles: My Life as a King3
- Gothic Online,9 a mod for Gothic II
- GTA IV's IV-MP10
- Left 4 Dead 27
- Liberty Unleashed11
- Mafia II's M2-Multiplayer12
- Melty Blood: Type Lumina13
- Nuclear Dawn7
- OpenTTD14
- Portal 27
- Tom Clancy's Rainbow Six Siege's Heated Metal15
- Shadow Warrior
- Simutrans16
- Sonic Unleashed (PS2/Wii)17
- SuperTux
- Team Fortress 218
- Thimbleweed Park19
- Thief II (unofficial NewDark engine update)20
- Titanfall7
- Vice City Multiplayer,21 a mod for Grand Theft Auto: Vice City22
- Under Night In-Birth23
- 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.24 In November 2010, the license was changed to the MIT license to enable the project to be hosted on Google Code.2526 It is developed and maintained by Alberto Demichelis.
References
References
- "squirrel/HISTORY at master - albertodemichelis/squirrel - GitHub".
- MirthKit Developer Wiki Archived 2014-02-11 at the Wayback Machine
- Brandon Boyer (21 February 2008). "Gamasutra - GDC 2008 Event Coverage". gamasutra.com. Gamasutra. Archived from the original on May 9, 2010.
- "Exclusive: Behind The Scenes of Final Fantasy's WiiWare Debut". gamasutra.com. Gamasutra. 23 June 2008. Archived from the original on November 10, 2010. Retrieved 22 September 2011.
- "L4D2 Vscripts - Valve Developer Community". developer.valvesoftware.com. Retrieved 2018-07-06.
- "Electric Imp programming guide". electricimp.com.
- "VScript". valvesoftware.com. 2014-08-20. Retrieved 2015-01-17.
- "th155-decomp". GitHub. Retrieved 2020-10-19.
- Gothic 2 Online
- "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.
- "undernightinbirth". GitHub. Retrieved 2024-08-18.
- "AI:Main Page - OpenTTD". wiki.openttd.org. Retrieved 2018-07-06.
- "Heated Metal". Github. Retrieved 2026-01-09.
- "Simutrans-Squirrel-API: Main Page". dwachs.github.io. Retrieved 2018-07-06.
- "The VG Resource Wiki". wiki.vg-resource.com. Retrieved 2021-09-04.
- "Team Fortress 2 Update Released". Retrieved 2026-01-17.
- "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.
- "undernightinbirth". GitHub. Retrieved 2024-08-18.
- "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.