Squirrel (programming language)

Squirrel

Paradigm	Multi-paradigm: scripting, imperative, functional, object-oriented
Appeared in	2003
Designed by	Alberto Demichelis
Stable release	2.2.3 (30, 2009 (2009-06-30))
Typing discipline	Dynamic
Influenced by	Lua, Python, C++, Javascript
Influenced	Dao, MiniD
OS	Cross-platform
License	zlib/libpng license
Website	squirrel-lang.org

This article is about the programming language. For other uses, see Squirrel (disambiguation).

Squirrel is a high level imperative/OO programming language, designed to be a light-weight 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. It is used extensively by Code::Blocks for scripting.

Language features

• Dynamic typing
• Delegation
• Classes & inheritance
• Higher order functions
• Generators
• Cooperative threads (coroutines)
• Tail recursion
• Exception handling
• Automatic memory management (primarily reference counting with backup garbage collector)
• Weak references
• Both compiler and virtual machine fit together in about 6k lines of C++ code.
• Optional 16-bit characters strings

Syntax

Squirrel uses a C-like syntax

Factorial in Squirrel:

 function factorial(x)
 {      
   if (x == 0) {                      
     return 1;                   
   }
   else {
     return x * factorial(x-1);
   }
 }
 

Random numbers using generators:

 function gen_random(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 = gen_random(100);
 
 for(local i = 0; i < 10; i += 1)
    print(">"+resume randtor+"\n");

Classes and inheritance:

 class BaseVector {
   constructor(...)
   {
     if(vargc >= 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 this.getclass())
       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();

History

The language was made public in 2003 under the zlib/libpng license. It is developed and maintained by Alberto Demichelis.

See also

• Lua
• Python
• Ruby

External links

• Squirrel Home Page
• SquirrelWiki
• MirthKit Home Page