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[range.view] Add complexity requirement normatively #2592

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[range.view] Add complexity requirement normatively #2592

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[range.view] Move description above the definitions
JohelEGP Dec 11, 2018
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[range.view] Add complexity requirement normatively
JohelEGP Dec 11, 2018
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9 changes: 7 additions & 2 deletions source/ranges.tex
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Expand Up @@ -850,6 +850,10 @@
which cannot be done in constant time.
\end{example}

\pnum
Since the difference between \libconcept{Range} and \libconcept{View} is largely
semantic, the two are differentiated with the help of \tcode{enable_view}.

\indexlibrary{\idxcode{enable_view}}%
\indexlibrary{\idxcode{View}}%
\begin{itemdecl}
Expand All @@ -863,8 +867,9 @@

\begin{itemdescr}
\pnum
Since the difference between \libconcept{Range} and \libconcept{View} is largely
semantic, the two are differentiated with the help of \tcode{enable_view}.
\tcode{T} models \libconcept{View} only if the complexity
for each initialization and assignment required by \libconcept{Copyable<T>}
is constant time.
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@zygoloid zygoloid Jan 19, 2019

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This may well be intended, but I don't see how it's editorial. Is this somehow justified by the existing text?

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@CaseyCarter CaseyCarter Jan 19, 2019

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Paragraph 1 above: "The View concept specifies the requirements of a Range type that has constant time copy, move, and assignment operators...".

Although I wouldn't mind sending this to LWG: we need to add the missing requirement that destruction is O(1) as well which is certainly not editorial.

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@zygoloid zygoloid Jan 21, 2019

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Let's send the whole thing to LWG then. If they want us to apply the non-normative change editorially we can, but I think it's generally better for holistic changes with a normative component to be applied together.


\pnum
For a type \tcode{T}, the default value of \tcode{enable_view<T>} is:
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