move span to boost::core:: #196

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1. glenfe commented on May 26, 2025

   

   glenfe

   on May 26, 2025

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   I can understand doing this for new components in Core, but why would we want to do this for existing components?
2. Lastique commented on May 26, 2025

   

   Lastique

   on May 26, 2025

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   One big reason to place components into more compartmentalized namespaces is avoiding unintended conflicts caused by ADL. When a type is likely to be passed as function or template parameters, or used as a base class, you don't want it to pull lots of unrelated stuff from wide namespaces, such as boost.
3. vinniefalco commented on May 26, 2025

   

   vinniefalco

   on May 26, 2025

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   why would we want to do this for existing components?

   I want to reiterate that this proposal does not break anything. The reason we want to do this for existing components is for teaching/documentation. It is better to see core::span in header files and documentation rather than span or boost::span as this makes the origin of the symbol clear and unambiguous.

   Existing code deeply nested in the boost namespace can still utter span if it wants to, with the ambiguities it brings. Or authors can opt-in to less ambiguity by writing core::span (my preference) or the more wordy boost::core::span.

   Lately I have been writing system::error_code and core::string_view instead of using aliases to those types in my own namespace for clarity, as when you have N libraries each providing aliases for error codes, string views, and other things, the result is unergonomic.
4. glenfe commented on May 26, 2025

   

   glenfe

   on May 26, 2025

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   That sounds fine; I have no objection to it.
5. glenfe

   self-assigned this

   on May 26, 2025