Function builtin_as_date 

fn builtin_as_date(
    args: &[RValue],
    named: &[(String, RValue)],
) -> Result<RValue, RError>

Convert a character string or numeric value to a Date object.

@param x character string, numeric (days since origin), or Date to convert @param format strptime-style format string for parsing (optional) @param origin Date or string giving the origin for numeric conversion @return a Date object