Struct Trigger 

pub struct Trigger { /* private fields */ }

A generic trigger handler for evaluating conditions. Trigger allows you to define a condition as a function, associate it with an optional argument, and check whether the condition is met.

Usage

Trigger is use for creating a Selector object.

Implementations

impl Trigger

pub fn new<T>( func: fn(&Option<Box<dyn Any>>) -> FtuiResult<bool>, arg: T, ) -> Self

where T: 'static,

Constructs a new Trigger with an associated argument.

Parameters

• func: A trigger function created using the trg_new_trigger_func! macro.
• arg: The argument value to associate with the Trigger (T: 'static).

Example

// Define a trigger function using the macro.
trg_new_trigger_func!(trigger_function, arg, {
    ...
});

// Create a `Trigger` with an associated `u32` value.
let _ = Trigger::new(trigger_function, 5u32);

pub fn no_arg(func: fn(&Option<Box<dyn Any>>) -> FtuiResult<bool>) -> Self

Constructs a new Trigger without an associated argument.

Parameters

• func: A trigger function created using the trg_new_trigger_func! macro.

Example

// Define a trigger function using the macro.
trg_new_trigger_func!(trigger_function, arg, {
    ...
});

// Create a `Trigger` without an associated argument.
let _ = Trigger::no_arg(trigger_function);

pub fn check(&self) -> FtuiResult<bool>

Check whether the Trigger evaluate to true or false. Typically used for testing purposes.

Returns

• Ok(bool): Whether the trigger condition was met.
• Err(FtuiError): Returns an error.

Example

// A trigger function that take in a u32 an evaluate whether it is five.
trg_new_trigger_func!(is_five, arg, {
    Ok(*trg::cast_arg::<u32>(arg)? == 5)
});

assert_eq!(Trigger::new(is_five, 5u32).check()?, true);  // Evaluates to true
assert_eq!(Trigger::new(is_five, 6u32).check()?, false); // Evaluates to false

pub fn update_arg<T>(&mut self, arg: T)

where T: 'static,

Updates the argument associated with the Trigger.

Parameters

• arg: The new argument value to associate with the Trigger (T' static).

Example

// Define a trigger function that checks if the argument is 5.
trg_new_trigger_func!(is_five, arg, {
    Ok(*trg::cast_arg::<u32>(arg)? == 5)
});

// Create a `Trigger` with an initial argument value of 5.
let mut trigger = Trigger::new(is_five, 5u32);

assert_eq!(trigger.check()?, true); // Evaluates to true.

// Update the argument to a different value.
trigger.update_arg(6u32);

assert_eq!(trigger.check()?, false); // Now evaluates to false.

pub fn remove_arg(&mut self)

Remove the argument associated with the Trigger.