Imply span_FEATURE_MAKE_SPAN from span_FEATURE_NON_MEMBER_FIRST_LAST_SUB - Githubissues

martinmoene / span-lite

span lite - A C++20-like span for C++98, C++11 and later in a single-file header-only library

Boost Software License 1.0

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Imply span_FEATURE_MAKE_SPAN from span_FEATURE_NON_MEMBER_FIRST_LAST_SUB #35

Closed martinmoene closed 5 years ago

martinmoene commented 5 years ago

Imply span_FEATURE_MAKE_SPAN when span_FEATURE_NON_MEMBER_FIRST_LAST_SUB is on, as the non-member functions first(), last() and subspan() require make_span().

Currently enabling first() etc. without enabling make_span() leads to #error.

Plan:

[x] In code, imply span_FEATURE_MAKE_SPAN from span_FEATURE_NON_MEMBER_FIRST_LAST_SUB
[x] Document span_FEATURE_MAKE_SPAN, mentioning it is implied by span_FEATURE_NON_MEMBER_FIRST_LAST_SUB
[x] In document of span_FEATURE_NON_MEMBER_FIRST_LAST_SUB, mention it implies span_FEATURE_MAKE_SPAN

Originates from issue #32 .