Trait Emitter 

pub trait Emitter<T>
where
    T: Clone + PartialEq + Eq + Style + Debug,
{
    // Required methods
    fn format_diagnostic(
        &mut self,
        diag: &Diagnostic<T>,
    ) -> Result<StyledBuffer<T>, ComponentError>;
    fn emit_diagnostic(&mut self, diag: &Diagnostic<T>) -> Result<()>;

    // Provided method
    fn supports_color(&self) -> bool { ... }
}

trait Emitter for emitting diagnostic.

T: Clone + PartialEq + Eq + Style is responsible for the theme style when diaplaying diagnostic. Builtin DiagnosticStyle provided in ‘compiler_base/error/diagnostic/style.rs’.

To customize your own Emitter, you could do the following steps:

Examples

1. Define your Emitter:

// create a new `Emitter`
struct DummyEmitter {
    support_color: bool
}

// `Dummy_Emitter` can use `DiagnosticStyle` or other style user-defined.
impl Emitter<DiagnosticStyle> for DummyEmitter {
    fn supports_color(&self) -> bool {
        // Does `Dummy_Emitter` support color ?
        self.support_color
    }

    fn emit_diagnostic(&mut self, diag: &Diagnostic<DiagnosticStyle>) {
        // Format `Diagnostic` into `String`.
        let styled_string = self.format_diagnostic(diag);
        todo!("displaying the 'styled_string'");
    }

    fn format_diagnostic(&mut self, diag: &Diagnostic<DiagnosticStyle>) -> StyledBuffer<DiagnosticStyle> {
        // Format `Diagnostic` into `String`.
        // This part can format `Diagnostic` into a `String`, but it does not automatically diaplay,
        // and the `String` can be sent to an external port such as RPC.
        let mut sb = StyledBuffer::<DiagnosticStyle>::new();
        diag.format(&mut sb);
        sb
    }
}

2. Use your Emitter with diagnostic:

// Create a diagnostic for emitting.
let mut diagnostic = Diagnostic::<DiagnosticStyle>::new();

// Create a string component wrapped by `Box<>`.
let msg = Box::new(": this is an error!".to_string());

// Add it to `Diagnostic`.
diagnostic.append_component(msg);

// Create the emitter and emit it.
let mut emitter = DummyEmitter {};
emitter.emit_diagnostic(&diagnostic);

Required Methods

fn format_diagnostic( &mut self, diag: &Diagnostic<T>, ) -> Result<StyledBuffer<T>, ComponentError>

Format struct Diagnostic into String and render String into StyledString, and save StyledString in StyledBuffer.

fn emit_diagnostic(&mut self, diag: &Diagnostic<T>) -> Result<()>

Emit a structured diagnostic.

Provided Methods

fn supports_color(&self) -> bool

Checks if we can use colors in the current output stream. false by default.

Dyn Compatibility

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors

impl<'a, T> Emitter<T> for EmitterWriter<'a>

where T: Clone + PartialEq + Eq + Style + Debug,