Introduction

Squirrel is a high level imperative, object-oriented programming language used in Titanfall to script large amounts of content in the game.

Respawn modified large parts of the language to fit their needs, for example adding a static type compiler to the language.

Squirrel still allows you to write dynamically typed code but this is discouraged if possible.

The syntax of squirrel is very similar to C++ or Javascript and very easy to learn.

The programmer doesn’t need to think about memory management in scripts since all objects are refcounted and the garbage collector can be invoked manually.

int function fibonacci( int n )
{
 if ( n < 2 )
   return n

 return fibonacci( n - 1 ) + fibonacci( n - 2 )
}

The language provides easy interfaces for coroutines and asynchronous code.

void main()
{
 thread timer( 1.0, timercallback )
}

void function timercallback( int iteration )
{
 print( iteration )
}

// call the callback function every n seconds
void function timer( float n, void functionref( int ) callback )
{
 int iterations
 while ( true )
 {
   wait n
   iterations += 1
   callback( iterations )
 }
}

Signals and Flags allow you to control code execution based on events that happen elsewhere in the code or in the ingame world.

void main()
{
 AddCallback_OnPlayerRespawned( OnPlayerRespawned )
}

void function OnPlayerRespawned( entity player )
{
 thread CountPlayerTimeAlive( Time() ) // execute this function as threaded so we can use Signals in there
}

void function CountPlayerTimeAlive( entity player, float time )
{
 player.WaitSignal( "OnDestroy" ) // wait until the player dies or disconnects
 print( Time() - time ) // print how long the player was alive
}