Function parse_case

src/expr-parser/src/parser.rs:992–1010

Parses `case when {cond} then {then} else {els} end`.

(input: ParseStream)

    /// Parses `case when {cond} then {then} else {els} end`.
    fn parse_case(input: ParseStream) -> Result {
        input.parse::<kw::case>()?;
        if input.peek(kw::when) {
            input.parse::<kw::when>()?;
            let cond = parse_expr(input)?;
            input.parse::<kw::then>()?;
            let then = parse_expr(input)?;
            input.parse::<syn::Token![else]>()?;
            let els = parse_expr(input)?;
            input.parse::<kw::end>()?;
            Ok(MirScalarExpr::If {
                cond: Box::new(cond),
                then: Box::new(then),
                els: Box::new(els),
            })
        } else {
            Err(Error::new(input.span(), "expected 'when' after 'case'"))
        }
    }

    pub fn parse_column(input: ParseStream) -> Result {
        Ok(MirScalarExpr::column(parse_column_index(input)?))