Source Error

source_error.rs

/// Information pertaining to an error from a source file.
#[derive(Clone, Debug, PartialEq, Eq)]
pub struct SourceError<'path, 'source> {
    /// Path to the file that contains the source.
    pub path: &'path Path,
    /// The expression that this error is for.
    pub expr: Expr<'source>,
    /// The suggestion or hint to provide to the user.
    pub suggestion: Option<Suggestion<'source>>,
    /// Whether this is a denied error or warning.
    pub severity: Severity,
}

/// Line number and full line containing an expression.
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub struct ExprContext {
    /// Start (inclusive) and end (exclusive) positions of the line in the source file.
    pub span_source: Span,
    /// Line number of the line within the source.
    pub line_number: usize,
    /// Full line containing the expression.
    pub line: &'file str,
}

/// A token or value in the source file.
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub struct Expr<'source> {
    /// Line number and full line containing the expression.
    pub context: ExprContext<'source>,
    /// Start (inclusive) and end (exclusive) positions of the value in the source file.
    pub span_source: Span,
    /// Value of the expression.
    pub value: &'source str,
}

/// Start (inclusive) and end (exclusive) positions of a `&str`.
///
/// This type is used instead of [`std::ops::Range`] because `Range` is `!Copy`.
///
/// See:
///
/// * <https://github.com/rust-lang/rust/issues/48649>
/// * <https://github.com/rust-lang/rust/pull/27186#issuecomment-123390413>
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub struct Span {
    /// Exclusive start position of the `&str`.
    pub start: usize,
    /// Exclusive end position of the `&str`.
    pub end: usize,
}

#[derive(Clone, Debug, PartialEq, Eq)]
pub enum Suggestion<'source> {
    /// Suggestions to provide as valid exprs.
    ValidExprs(Vec<&'source str>),
    /// Simple message to give to the user.
    Hint(&'source str),
}

/// Whether this is a denied error or warning.
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum Severity {
    /// Error should prevent the operation from progressing.
    ///
    /// Recommended when the user needs to address an issue before retrying the operation.
    Deny,
    /// Error should not prevent the operation from continuing.
    ///
    /// Recommended for informatives such as deprecation notices and convention changes.
    Warn,
}