Method Definitions

Method definitions define functions within a structure or class that can be accessed directly within either other methods of the object or its derived classes, or indirectly from instances of it with the member access operator.

Methods marked as virtual may have their functionality overridden by derived classes, and in those overrides one can use the Super keyword to call the parent function.

If const is placed after the function signature and before the function body, the method will not be allowed to modify any members in the object instance it's being called on.

The keyword void can be used in place of the return type (or type list) to have a method which does not have any return value. Similarly, one can place void where the argument list might be, although this is redundant as having no argument list at all is allowed.

Arguments of methods may only be of certain types due to technical limitations. See the type table for a list of which are usable and which are not.

All methods which are not static have an implicit self parameter which refers to this object, although if you wish to refer to a member of self, you do not need to reference it directly, as it is already implicitly in scope.

MethodDefinition

MethodDeclarationFlag* Type (, Type)* Identifier ( MethodArgumentListOrVoid? ) const? { Statement* }

Method Argument Lists

Method arguments must all have a name and type, and optionally the last arguments in the list may have a default value, 3.3.0+ unless the function is marked override.

MethodArgumentList

• Type VariableName (, MethodArgumentList)*
• Type VariableName = ConstantExpression (, MethodArgumentList)*

MethodArgumentListOrVoid

• MethodArgumentList
• void

Method Declaration Flags

MethodDeclarationFlag

• action (( ActionScope (, ActionScope)* ))?
• clearScope
• deprecated ( StringLiteral (, StringLiteral)? )
• final
• native
• override
• play
• private
• protected
• static
• ui
• varArg
• version ( StringLiteral )
• virtual
• virtualScope

Action Scopes

ZScript includes an extra method type for descendents of Actor called actions, which are intended to be run from actor states and give extra information to the function. Action functions change the meaning of the self parameter and may pass in invoker and stateinfo parameters as well. stateinfo refers to the State which this action was called from.

Action functions may have any amount of scopes. Actor scope and un-scoped action functions do not have invoker or stateinfo parameters and as such are not often useful.

Here are charts for the meanings of the self and invoker parameters under each scope. Scopes lower down on the chart override the meanings of scopes above them:

ActionScope

• actor
• item
• overlay
• weapon

Examples

Method argument lists

// With the function:
void DoSomething(int one, int two, int a = 0, int b = 0) {}

// One could do the following:
DoSomething(4, 5);
DoSomething(5, 6, 7);
DoSomething(6, 7, 8, 9);

// Or using named default arguments,
DoSomething(5, 6, a: 7);

// Equivalent to:
DoSomething(5, 6, 7);

// And more examples:
DoSomething(6, 7, b: 8);
DoSomething(7, 8, a: 9, b: 10);
DoSomething(7, 8, 9, 10);