[mdspan.sub.map.left]

Returns:

(1.1)
submdspan_mapping_result{*this, 0}, if Extents::rank() == 0 is true;
(1.2)
otherwise, submdspan_mapping_result{layout_left::mapping(sub_ext), offset}, if SubExtents::rank() == 0 is true;
(1.3)
otherwise, submdspan_mapping_result{layout_left::mapping(sub_ext), offset}, if
- (1.3.1)
  for each k in the range [0, SubExtents::rank() - 1)), is_convertible_v< $S_{k}$ , full_extent_t> is true; and
- (1.3.2)
  for k equal to SubExtents::rank() - 1, $S_{k}$ models index-pair-like<index_type> or is_convertible_v< $S_{k}$ , full_extent_t> is true;
[Note 1:
If the above conditions are true, all $S_{k}$ with k larger than SubExtents::rank() - 1 are convertible to index_type.
— end note]
(1.4)
otherwise, submdspan_mapping_result{layout_left_padded<S_static>::mapping(sub_ext, stride(u + 1)), offset} if for a value u for which $u + 1$ is the smallest value p larger than zero for which $S_{p}$ models index-pair-like<index_type> or is_convertible_v< $S_{p}$ , full_extent_t> is true, the following conditions are met:
- (1.4.1)
  $S_{0}$ models index-pair-like<index_type> or is_convertible_v< $S_{0}$ , full_extent_t> is true; and
- (1.4.2)
  for each k in the range [u + 1, u + SubExtents::rank() - 1), is_convertible_v< $S_{k}$ , full_extent_t> is true; and
- (1.4.3)
  for k equal to u + SubExtents::rank() - 1, $S_{k}$ models index-pair-like<index_type> or is_convertible_v< $S_{k}$ , full_extent_t> is true;
and where S_static is:
- (1.4.4)
  dynamic_extent, if static_extent(k) is dynamic_extent for any k in the range [0, u + 1),
- (1.4.5)
  otherwise, the product of all values static_extent(k) for k in the range [0, u + 1);
(1.5)
otherwise, submdspan_mapping_result{layout_stride::mapping(sub_ext, sub_strides), offset}

23 Containers library [containers]

23.7 Views [views]

23.7.3 Multidimensional access [views.multidim]

23.7.3.7 submdspan [mdspan.sub]

23.7.3.7.6 Specializations of submdspan_mapping [mdspan.sub.map]

23.7.3.7.6.2 layout_left specialization of submdspan_mapping [mdspan.sub.map.left]