Function builtin_scan 

fn builtin_scan(
    args: &[RValue],
    named: &[(String, RValue)],
    context: &BuiltinContext<'_>,
) -> Result<RValue, RError>

Read data from a file, splitting into tokens.

@param file character scalar: path to the file to read @param what example value determining the return type (default: character) @param sep character scalar: token separator (default: whitespace) @return vector of tokens coerced to the type of what