Howard Hinnant wrote:
On Oct 10, 2005, at 10:36 AM, Fernando Cacciola wrote:
Dubious of use of references.
Does this mean they don't see that as useful or that is not well supported?
I believe there was specific concern about reference rebinding under optional<T&>. There were also several comments that went like: I use optional all the time (gives use case), but I've never needed to use it with reference types.
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You might explore a interface here on boost which did not have the pointer interface, and which dropped reference support. Then perhaps submit a follow on paper reflecting that experience. Said paper may either modify your current proposal, or more fully support it.
I use optional reference but I do not like the way rebinding works. I still insist that it follow the way boost::tuple does it. IMO, the same way with tie, when you need it, you'll really need it. I think it was I who requested for optional references, so let me present my use case: In Spirit, a parser may return an attribute. This attribute should only be constructed on a successful match. Thus, optional<T>. A symbol table is a parser in Spirit. Each symbol has a corresponding data slot. On a successful match, the attribute returned is a reference to the data slot. Thus optional<T&>. Ah, yes, and I will forever be against the pointer interface. Zen of Python: ... There should be one-- and preferably only one --obvious way to do it. ... Regards, -- Joel de Guzman http://www.boost-consulting.com http://spirit.sf.net