Method try_cast

prqlc/prqlc/src/semantic/mod.rs:136–148

(self, f: F, who: Option<&str>, expected: S2)

impl pl::Expr {
    fn try_cast<T, F, S2: ToString>(self, f: F, who: Option<&str>, expected: S2) -> Result<T, Error>
    where
        F: FnOnce(pl::ExprKind) -> Result<T, pl::ExprKind>,
    {
        f(self.kind).map_err(|i| {
            Error::new(Reason::Expected {
                who: who.map(|s| s.to_string()),
                expected: expected.to_string(),
                found: format!("`{}`", write_pl(pl::Expr::new(i))),
            })
            .with_span(self.span)
        })
    }
}

/// Write a PL IR to string.