Function parse_csv

prqlc/prqlc/src/semantic/resolver/transforms.rs:1070–1092

TODO: Can we dynamically get the types, like in pandas? We need to put quotes around strings and not around numbers. https://stackoverflow.com/questions/64369887/how-do-i-read-csv-data-without-knowing-the-structure-at-compile-time

(text: &str)

    // quotes around strings and not around numbers.
    // https://stackoverflow.com/questions/64369887/how-do-i-read-csv-data-without-knowing-the-structure-at-compile-time
    pub fn parse_csv(text: &str) -> Result<RelationLiteral, String> {
        let text = text.trim();
        let mut rdr = csv::Reader::from_reader(text.as_bytes());

        fn parse_header(row: &csv::StringRecord) -> Vec<String> {
            row.into_iter().map(|x| x.to_string()).collect()
        }

        fn parse_row(row: csv::StringRecord) -> Vec<Literal> {
            row.into_iter()
                .map(|x| Literal::String(x.to_string()))
                .collect()
        }

        Ok(RelationLiteral {
            columns: parse_header(rdr.headers().map_err(|e| e.to_string())?),
            rows: rdr
                .records()
                .map(|row_result| row_result.map(parse_row))
                .try_collect()
                .map_err(|e| e.to_string())?,
        })
    }

    type JsonFormat1Row = HashMap<String, serde_json::Value>;