Value semantics #51
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Value semantics #51
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Python
argparse.ArgumentParseris stateless, so adding parents is only inheriting argument configurations. This is equivalent to having value semantics.argparse::ArgumentParseris stateful. Instead of returning parsed states,parse_argschanges the parser's own states. And I think we should also deliver value semantics, that is,parse_argsin child parser does not change parents' parsing states, andparse_argsin a parser copy does not change the parsing states parser that was copied from.Updated the docs to use the term "common" rather than "shared" to clarify the intention.
Strictly speaking this is a runtime breaking change. But the current behavior is undocumented, untested, and I doubt anybody is relying on that in real code.
The proposed change also eliminates the uses of
shared_ptr. It maintains two linked lists (not worse than two vectors of shared_ptrs :) ofArguments, and index them by pointing the keys into Argument's own storage for names, and the values into list iterators.fixes: #50