P0009 LWG Review Notes 2022-02-18

[crtrott]

Terms:

• ~para 2: connect the "rank" to a particular multidimensional index space.~ (was already done in R15)
• ~paragraph 3: "multidimensional" index space make r in math font, drop (or representation thereof)~ (done in f9d2e0aef989 )
• ~paragraph 3: space in [0,rank)~ (done in f9d2e0aef989)

mdspan.extents.overview:

• ~delete copy constructor and assignment operator~ (done in ea8252187f37)
• ~add: using rank_type = size_t;~ (done in ea8252187f37)
  • ~convert fold expression to rank_type static_cast(Extents==dynamic_extent)~ (done in ea8252187f37)
• ~paragraph 3: Extents in code font~ (done in f9d2e0aef989 )
• ~paragraph 6: The rth interval of a multidimensiona index space represented by an extents object is [..)~ (done in f9d2e0aef989 )
• ~move static stuff up front in synopsis so we can use them in constructor explicit clauses~ (done in f9d2e0aef989)
  • Note also moved non-static extent(i) up in order to keep it next to static_extent
  • did not move the full description of the functions before constructors - should we?
• ~paragraph 2: is a trivially copyable type that models regular~ (done in f9d2e0aef989).

later stuff

• ~remove move ctors/assign for mapping~ (was already done in R15)
• ~remove unnecessary std:: prefix~ (done in 39d9e5f459f77)
• ~layout_stride::mapping remove unnecessary typename~ (done in fd9ddb95a3684d)

[crtrott]

See #201

[crtrott]

• ~[mdspan.submdspan] p5: "otherwise, if is_convertible_v<Sr,full_extent_t> is true, then first[r] equals 0, and last[r] equals src.extent(r)." - the if is not necessary as we are limited to 3 options
~ (DONE in be945ca873)
• ~[mdspan.submdspan] p11.1:  that is_convertible_v<Sk,tuple<size_t,size_t>> || is_convertible_v<Sk,full_extent_t> is true and is_convertible_v<Sk,size_t> is false. - only last condition is needed after we added Mandates
~ (DONE in be945ca873)
• [mdspan.submdspan] p11.2: "if LayoutPolicy is not one of layout_left, layout_right, layout_stride, then SubLayout is implementation defined, otherwise":  is not one of -> is none of (this is English so please check
  • not done, think is better before
• ~[mdspan.submdspan] p11.3: remove "where" at the end
~ (DONE in be945ca873)
• ~[mdspan.submdspan] p4: Let map-rank be an array<size_t,Extents::rank()> such that for all j in the range [0, Extents::rank()) map-rank[j] equals: -> for each rank index j of Extends?
~ (DONE in be945ca873)
• ~[mdspan.mdspan.overview] p8,p9  Make "If LayoutPolicy does not meet the layout mapping policy requirements, then behavior is undefined." and "AccessorPolicy shall meet the accessor policy requirements".
 I prefer shall version, so LayoutPolicy shall mmet layout mapping policy requirements. But you can use unedefined version.
~ (DONE in 1cfc248f9)
• ~[mdspan.accessor.reqs] 15.2 "a_sub.access(p_sub,j) provides acces to the same element as a.access(p,i+j)", needs some precondition, like if j < n - i
~ (DONE in 1cfc248f9)
• ~[mdspan.layout.stride] p9.2 fwd-prod-of-extents(extents(), extents_type::rank()-1)==0,m I believe this should be up to rank() - last dimension being zero is ok~ (DONE in 1cfc248f9)
• [mdspan.layout.stride] p2.1 we are missing is_nothrow_constructible_v here, for strides

  • isn't this implied by the constraints?
• ~[mdspan.layout] p1.7 we need to san rank index into E (or of E)
~ (DONE in 1cfc248f9)
• ~[mdspan.extents.cons] p10  N + rank_dynamic() ->  N != rank_dynamic()~ (DONE in 1cfc248f9)