Squirrel (programming language)
Computer programming language
From Wikipedia, the free encyclopedia
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.
| Squirrel | |
|---|---|
| Paradigm | Multi-paradigm: scripting, imperative, functional, object-oriented |
| Designed by | Alberto Demichelis |
| First appeared | September 6, 2003 |
| 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) | |
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, 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 platform[6]
Games using Squirrel
- Alien Swarm[7]
- Antinomy of Common Flowers[8]
- Apex Legends
- Battle Brothers
- Contagion[7]
- Counter Strike: Global Offensive[7]
- CRSED: F.O.A.D.
- Final Fantasy Crystal Chronicles: My Life as a King[3]
- Gothic Online,[9] a mod for Gothic II
- GTA IV's IV-MP[10]
- Left 4 Dead 2[7]
- Liberty Unleashed[11]
- Mafia II's M2-Multiplayer[12]
- Melty Blood: Type Lumina[13]
- Nuclear Dawn[7]
- OpenTTD[14]
- Portal 2[7]
- Tom Clancy's Rainbow Six Siege's Heated Metal[15]
- Shadow Warrior
- Simutrans[16]
- Sonic Unleashed (PS2/Wii)[17]
- SuperTux
- Team Fortress 2[18]
- Thimbleweed Park[19]
- Thief II (unofficial NewDark engine update)[20]
- Titanfall[7]
- Vice City Multiplayer,[21] a mod for Grand Theft Auto: Vice City[22]
- Under Night In-Birth[23]
- 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.[25][26] It is developed and maintained by Alberto Demichelis.