Witcher Script

Witcher Script (.ws) is the primary scripting language for The Witcher 3: Wild Hunt. A very large chunk of the game's logic is written in Witcher Script. Mods can override scripts and thus can drastically change game behavior. Witcher Script is either based on or identical to ActionScript 3 (and very similar to UnrealScript).

The specification for ActionScript 3, which is also used in the Shockwave Flash file format and can be described as a dialect of ECMAScript, can be found in its official language reference (unofficially also here, here and here).

Technically, Witcher Script is a strongly-typed, class-based object-oriented programming language, though it supports functions declared outside of the scope of classes. It uses C-like control flow with a single global namespace. Functions use pass-by-value by default for native datatypes and structs, with the keyword  indicating pass-by-reference. Pass-by-reference is used for objects. Like C, Witcher Script is free form, with semi-colons serving as statement terminators and curly brackets pairs defining groups of statements as well as scope. It is pre-compiled prior to runtime though it supports line-by-line debugging.

Witcher Script doesn't appear to have function references, though it is possible to pass function names for callbacks, though this seems limited to the engine (see implementation of Initialize in W3Class CPlayerInput for example of this).

Novel Features
Some of the following information is speculation based on information in the scripts as well as information from other game engines. CDPR has been fairly mum about the inner workings of REDengine. If you know something, please edit the wiki so that the correct information is available!

Timer Functions
Timer functions are functions that are periodically called on a timer while that timer is active. They are started with the functions  and stopped with the function , both member functions of W3Class CEntity. It is likely that these start and stop timer functions only work if the script is "hooked" on to a native W3Class CEntity. Timer functions always take the parameters:



is probably the time since the last activation of the timer, while  is likely the id of the timer.

Latent Functions
Latent functions are functions that execute over more than one game tick. They use either the global functions  or , or call other latent functions (including native ones!) that do. These functions can only be called from inside another latent function or from a state's  functions.

exec/storyscene/quest Functions
Global functions declared with one of these modifiers will be available to different portions of the game to execute. Generally speaking, only exec functions are interesting to modders, as it allows modders to add console commands to the game.


 * exec functions are available to the debug console
 * storyscene functions are likely accessible to cutscenes
 * quest functions are likely accessible to quests

default
This declares a default value for a class field.

editable
Likely, this means that this class field is available for editing in the REDkit 2 editor.

Statemachine Classes
Classes defined with the  keyword are able to take on states, which are special kinds of classes that override behavior (i.e. functions/events) in their parent while the   class in in the child. A  class transitions between states and keeps a running stack. All  classes must eventually inherit from W3Class IScriptable and that class contains applicable functions.

Entry Functions
Functions within a  can be declared as   functions. functions are also, though it isn't clear what else this denotes.

virtual_parent
In states, there is some distinction between  and.

Keywords
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Access Limitations

 * private
 * protected
 * public

Control Flow

 * if
 * else
 * for
 * switch
 * case
 * while
 * return
 * break
 * continue

Inheritance

 * extends
 * parent
 * virtual_parent
 * this
 * super

Boolean

 * true
 * false

Nullability

 * NULL

Declarations

 * var
 * enum
 * struct
 * function
 * event
 * class

Declaration Modifiers

 * abstract
 * statemachine
 * default
 * editable
 * const
 * import
 * final
 * timer
 * exec
 * quest
 * storyscene
 * saved
 * out
 * entry

Memory Management
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 * new
 * delete
 * in