fluidattacks-blends-domain 0.6.1

//! Failure modes of the syntax graph build.

#[derive(Clone, Copy, PartialEq, Eq, Debug)]
pub enum SyntaxGraphError {
    EmptyAstGraph,
    MissingRootNode,
    MissingAstNode,
    UnexpectedAstShape,
    UnsupportedLanguage,
}

impl core::fmt::Display for SyntaxGraphError {
    fn fmt(&self, formatter: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
        formatter.write_str(match *self {
            Self::EmptyAstGraph => "ast graph has no nodes",
            Self::MissingRootNode => "ast graph has no root node at id 1",
            Self::MissingAstNode => "a reader reached an id absent from the ast graph",
            Self::UnexpectedAstShape => "a reader found an ast shape its grammar cannot produce",
            Self::UnsupportedLanguage => "no syntax dispatcher is implemented for this language",
        })
    }
}

#[cfg(test)]
mod tests {
    use super::SyntaxGraphError;
    use alloc::string::ToString;

    #[test]
    fn every_error_renders_its_failure_mode() {
        assert_eq!(
            SyntaxGraphError::EmptyAstGraph.to_string(),
            "ast graph has no nodes"
        );
        assert_eq!(
            SyntaxGraphError::MissingRootNode.to_string(),
            "ast graph has no root node at id 1"
        );
        assert_eq!(
            SyntaxGraphError::MissingAstNode.to_string(),
            "a reader reached an id absent from the ast graph"
        );
        assert_eq!(
            SyntaxGraphError::UnexpectedAstShape.to_string(),
            "a reader found an ast shape its grammar cannot produce"
        );
        assert_eq!(
            SyntaxGraphError::UnsupportedLanguage.to_string(),
            "no syntax dispatcher is implemented for this language"
        );
    }
}