Function interp_apply 

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

Apply a function over rows or columns of a matrix.

@param X matrix or array @param MARGIN 1 for rows, 2 for columns @param FUN function to apply @param … additional arguments passed to FUN @return vector, matrix, or list of results