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Section: 22.10.6.5 [refwrap.invoke] Status: C++17 Submitter: Stephan T. Lavavej Opened: 2014-10-01 Last modified: 2017-07-30
Priority: 4
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Discussion:
22.10.6.5 [refwrap.invoke]/2 is no longer useful. (It was originally TR1 2.1.2.4 [tr.util.refwrp.invoke]/2.) First, we already have the As If Rule (6.9.1 [intro.execution]/1) and the STL Implementers Can Be Sneaky Rule (16.4.6.5 [member.functions]). Second, with variadic templates and other C++11/14 tech, this can be implemented exactly as depicted.
[2015-05, Lenexa]
DK: I don't see a defect here
STL: the issue is that the standard is overly verbose, we don't need this sentence. It's redundant.
MC: does anyone think this paragraph has value?
JW: it has negative value. reading it makes me wonder if there's some reason I would want to provide a set of overloaded
functions, maybe there's some problem with doing it the obvious way that I'm not clever enough to see.
Move to Ready status: 8 in favor, none against.
Proposed resolution:
This wording is relative to N3936.
Change 22.10.6.5 [refwrap.invoke] p2 as depicted:
template <class... ArgTypes> result_of_t<T&(ArgTypes&&...)> operator()(ArgTypes&&... args) const;-1- Returns: INVOKE(get(), std::forward<ArgTypes>(args)...). (20.9.2)
-2- Remark: operator() is described for exposition only. Implementations are not required to provide an actual reference_wrapper::operator(). Implementations are permitted to support reference_wrapper function invocation through multiple overloaded operators or through other means.