Function parse_flat_map

src/expr-parser/src/parser.rs:349–401

(ctx: CtxRef, input: ParseStream)

    }

    fn parse_flat_map(ctx: CtxRef, input: ParseStream) -> Result {
        use mz_expr::TableFunc::*;

        let flat_map = input.parse::<kw::FlatMap>()?;

        let ident = input.parse::<syn::Ident>()?;
        let func = match ident.to_string().to_lowercase().as_str() {
            "unnest_list" => UnnestList {
                el_typ: SqlScalarType::Int64, // FIXME
            },
            "unnest_array" => UnnestArray {
                el_typ: SqlScalarType::Int64, // FIXME
            },
            "wrap1" => Wrap {
                types: vec![
                    SqlScalarType::Int64.nullable(true), // FIXME
                ],
                width: 1,
            },
            "wrap2" => Wrap {
                types: vec![
                    SqlScalarType::Int64.nullable(true), // FIXME
                    SqlScalarType::Int64.nullable(true), // FIXME
                ],
                width: 2,
            },
            "wrap3" => Wrap {
                types: vec![
                    SqlScalarType::Int64.nullable(true), // FIXME
                    SqlScalarType::Int64.nullable(true), // FIXME
                    SqlScalarType::Int64.nullable(true), // FIXME
                ],
                width: 3,
            },
            "generate_series" => GenerateSeriesInt64,
            // Both int widths display as `generate_series`; this spelling lets a
            // test pin the 32-bit variant (e.g. its widening casts) on input.
            "generate_series_i32" => GenerateSeriesInt32,
            "jsonb_object_keys" => JsonbObjectKeys,
            _ => Err(Error::new(ident.span(), "unsupported function name"))?,
        };

        let exprs = {
            let inner;
            syn::parenthesized!(inner in input);
            scalar::parse_exprs(&inner)?
        };

        let parse_input = ParseChildren::new(input, flat_map.span().start());
        let input = Box::new(parse_input.parse_one(ctx, parse_expr)?);

        Ok(MirRelationExpr::FlatMap { input, func, exprs })
    }

    fn parse_filter(ctx: CtxRef, input: ParseStream) -> Result {
        use mz_expr::MirScalarExpr::CallVariadic;