Squirrel (programming language)

This article may be in need of reorganization to comply with Wikipedia's layout guidelines. Please help by to make improvements to the overall structure. (March 2018) (Learn how and when to remove this template message)

This article needs to be updated. Please help update this article to reflect recent events or newly available information. (March 2018)

Squirrel

Paradigm	Multi-paradigm: scripting, imperative, functional, object-oriented
Designed by	Alberto Demichelis
First appeared	September 6, 2003; 18 years ago (2003-09-06)
Stable release	3.1 / March 27, 2016; 5 years ago (2016-03-27)
Typing discipline	Dynamic
OS	Cross-platform
License	MIT license
Filename extensions	.nut
Website	squirrel-lang.org
Influenced by
C++, JavaScript, Lua, Python
Influenced
MiniD

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 and embedded systems.

MirthKit, a simple toolkit for making and distributing open source, cross-platform 2D games, uses Squirrel for its platform.^[1] It is used extensively by Code::Blocks for scripting and was also used in Final Fantasy Crystal Chronicles: My Life as a King.^[2][3] 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.^[4]

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 == 0) {
      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[]

• Enduro/X, cluster application server
• , an end-to-end IoT platform^[5]

Games using Squirrel[]

History[]

The language was made public in 2003 under the zlib/libpng license.^[19] In November 2010, the license was changed to the MIT license to enable the project to be hosted on Google Code.^[20][21] It is developed and maintained by Alberto Demichelis.

See also[]

• Lua
• AngelScript
• Python
• ECMAScript
• Ruby

References[]

External links[]

• Official website