la::m_rec!

macro_rules! m_rec(
  ( [ $($row:tt),* ] [$($i:expr),*]) => ({
     let _rows = 0 $(+ m_one!($row) )*;
     let _cols = (0 $(+ m_one!($i))*) / _rows;
     Matrix::new(
       _rows,
       _cols,
       vec![$($i),*]
     )
  })
);

Helper macro for m!