Struct YarnEngine 

pub struct YarnEngine { /* private fields */ }

The engine that stores all conversation-related state.

Implementations

impl YarnEngine

pub fn new(handler: Box<dyn YarnHandler>) -> YarnEngine

Create a new YarnEngine instance associated with the given handler.

pub fn load_from_string(&mut self, s: &str) -> Result<(), ()>

Parse the provided string as a series of Yarn nodes, appending the results to the internal node storage. Returns Ok if parsing succeeded, Err otherwise.

pub fn register_function( &mut self, name: String, num_args: usize, callback: Box<FunctionCallback>, )

Register a native function for use in Yarn expressions.

pub fn set_variable(&mut self, name: VariableName, value: Value)

Set a given variable to the provided value. Any Yarn expressions evaluated after this call will observe the new value when using the variable.

pub fn activate(&mut self, node: NodeName)

Begin evaluating the provided Yarn node.

pub fn choose(&mut self, choice: usize)

Make a choice between a series of options for the current Yarn node’s active step. Execution will resume immediately based on the choice provided.

pub fn proceed(&mut self)

Resume execution of the current Yarn node.