On Sun, Sep 29, 2024 at 07:46:58PM -0500, Jeremy Rifkin via Std-Proposals wrote:
> Hi,
> I'm drafting a proposal to add std::arguments which would provide an
> encoding-friendly and modern interface for accessing program arguments.
> This is a follow-up for half of Izzy Muerte's paper P1275 Desert
> Sessions: Improving hostile environment interactions. A follow-up to the
> other half, std::environment, is being separately worked on.
>
> Draft: https://jeremy-rifkin.github.io/proposals/drafts/cpp/arguments-draft-1.html
> Very rough sketch to get a feel for the interface: https://godbolt.org/z/d7zvKc4xj
>
> The two main places I'm still weighing pros and cons on the design are
> whether the iterators for std::arguments_view should meet the
> requirements of Cpp17RandomAccessIterator, which would require backing
> storage for the `std::argument`s being iterated over, and what the
> behavior should be if the user modifies argv from main. While I think it
> would be desirable to not have changes to argv reflected in
> std::arguments, it would require copying arguments on startup which may
> be seen as undesirable even if opt-in. The rough implementation sketch I
> provided is a zero-overhead view over argv, with no allocation or
> caching of things like strlen computations on arguments.
>
> I'd very much appreciate comments, thoughts, and guidance.

How does a third party library that uses this facility discern various
cases?

Presume that the program sees an argument spelled "/bin" - is this an
argument to a previous flag or a flag in it's own right using windows
style arguments?

Presume that the program sees an argument spelled -x - is this a sub
argument dependant on position or a global argument and how should the
third party library know what was meant?
A prime example of a program where this style is used is sox.

Presume that the program sees an argument spelled -- - is this a posix
end of arguments marker or not (sure, having it not beeing that is bad
style but it is still permissible today)

Presume that the program sees an argument spelled +x - is this an
independent argument that negates a -x or is it something else?

Presume that the program sees an argument spelled -log - is this a
short form of -l -o -g or is it intended as a log flag?
A prime example of this is ls which have covered almost the whole alphabet
with argument flags.


What I am trying to say here is that just beeing able to see the arguments
doesn't allow a library to correctly parse them so the whole idea is starting
from the wrong direction and that argument parsing can get arbitrarily
complex.

/MF