/// Returns entry at `$matrix[$coords[1], $coords[2]]`
/// @group getters
/// @param {Matrix} $matrix - matrix
/// @param $coords - (x y) coordinates
/// @return {*}
/// @require {function} _valid-coords
@function get-entry($matrix, $coords) {
  @if length($coords) == 1 {
    $coords: ($coords $coords);
  }

  @if _valid-coords($coords, $matrix) {
    @return nth(nth($matrix, nth($coords, 1)), nth($coords, 2));
  }

  @return false;
}