Debugger State

Sometimes it is useful to keep a persistent state within the debugger.

The Engine::register_debugger API accepts a function that returns the initial value of the debugger’s state, which is a Dynamic and can hold any value.

This state value is the stored into the debugger’s custom state.

Access the Debugger State

Use EvalContext::global_runtime_state_mut().debugger to gain access to the current debugger::Debugger instance.

The following debugger::Debugger methods allow access to the custom debugger state.

MethodParameter typeReturn typeDescription
statenone&Dynamicreturns the custom state
state_mutnone&mut Dynamicreturns a mutable reference to the custom state
set_stateimpl Into<Dynamic>nonesets the value of the custom state

Example

engine.register_debugger(
    |engine| {
        // Say, use an object map for the debugger state
        let mut state = Map::new();
        // Initialize properties
        state.insert("hello".into(), 42_64.into());
        state.insert("foo".into(), false.into());
        Dynamic::from_map(state)
    },
    |context, node, source, pos| {
        // Print debugger state - which is an object map
        let state = context.global_runtime_state_mut().debugger.state();
        println!("Current state = {}", state);

        // Get the state as an object map
        let mut state = context.global_runtime_state_mut()
                               .debugger.state_mut()
                               .write_lock::<Map>().unwrap();

        // Read state
        let hello = state.get("hello").unwrap().as_int().unwrap();

        // Modify state
        state.insert("hello".into(), (hello + 1).into());
        state.insert("foo".into(), true.into());
        state.insert("something_new".into(), "hello, world!".into());

        // Continue with debugging
        Ok(DebuggerCommand::StepInto)
    }
);