Diagnostics in Programming Languages

Focus question: How do other programming languages manage diagnostics (errors, warnings, etc.)

Gleam

Gleam’s Diagnostic struct:

// TODO: split this into locationed diagnostics and locationless diagnostics
#[derive(Debug, Clone, PartialEq, Eq)]
pub struct Diagnostic {
    pub title: String,
    pub text: String,
    pub level: Level,
    pub location: Option<Location>,
    pub hint: Option<String>,
}

• title - used as the message
• text - can be used as a “help” message
• level - two levels: error and warning
• location - the location of the diagnostic
• hint - an optional hint for how to fix the diagnostic

Other random notes

• Gleam uses ecow::EcoString so that each diagnostic can store a reference to the source
• Gleam uses thiserror for its errors
• Gleam uses ANSI codes in its diagnostic displays (using colorterm)