Function un_expected_expression_error

crates/gitql-parser/src/parser.rs:3755–3834

(tokens: &[Token], position: &usize)

}

fn un_expected_expression_error(tokens: &[Token], position: &usize) -> Box<Diagnostic> {
    let location = calculate_safe_location(tokens, *position);

    if *position == 0 || *position >= tokens.len() {
        return Diagnostic::error("Can't complete parsing this expression")
            .with_location(location)
            .as_boxed();
    }

    let current = &tokens[*position];
    let previous = &tokens[*position - 1];

    // Make sure `ASC` and `DESC` are used in ORDER BY statement
    if current.kind == TokenKind::Ascending || current.kind == TokenKind::Descending {
        return Diagnostic::error("`ASC` and `DESC` must be used in `ORDER BY` statement")
            .with_location(location)
            .as_boxed();
    }

    // Similar to SQL just `=` is used for equality comparisons
    if previous.kind == TokenKind::Equal && current.kind == TokenKind::Equal {
        return Diagnostic::error("Unexpected `==`, Just use `=` to check equality")
            .add_help("Try to remove the extra `=`")
            .with_location(location)
            .as_boxed();
    }

    // `> =` the user may want to write `>=`
    if previous.kind == TokenKind::Greater && current.kind == TokenKind::Equal {
        return Diagnostic::error("Unexpected `> =`, do you mean `>=`?")
            .add_help("Try to remove space between `> =`")
            .with_location(location)
            .as_boxed();
    }

    // `< =` the user may want to write `<=`
    if previous.kind == TokenKind::Less && current.kind == TokenKind::Equal {
        return Diagnostic::error("Unexpected `< =`, do you mean `<=`?")
            .add_help("Try to remove space between `< =`")
            .with_location(location)
            .as_boxed();
    }

    // `> >` the user may want to write '>>'
    if previous.kind == TokenKind::Greater && current.kind == TokenKind::Greater {
        return Diagnostic::error("Unexpected `> >`, do you mean `>>`?")
            .add_help("Try to remove space between `> >`")
            .with_location(location)
            .as_boxed();
    }

    // `< <` the user may want to write `<<`
    if previous.kind == TokenKind::Less && current.kind == TokenKind::Less {
        return Diagnostic::error("Unexpected `< <`, do you mean `<<`?")
            .add_help("Try to remove space between `< <`")
            .with_location(location)
            .as_boxed();
    }