On Aug 14, 2020, Nathan Sidwell <nat...@acm.org> wrote: > This seems a useful feature. I don;t think it needs language > lawyering -- it's an extension, right?
Well, yeah, but I think it's usually good for even extensions to be sound language-wise. > By 'same-linkage', do you mean same linkage as the *symbol* of the > thing it is aliasing, or same linkage as the language entity it is > aliasing? > I suspect you mean the former. Yeah, ultimately the symbol declared as exalias gets the same object-level linkage and visibility properties as those of the primary symbol emitted for the language entity. Conceptually, the entity introduced by the attribute is not even visible or accessible in the standard language; it can only be referenced by alias attributes and by Ada import declarations, but conceptually, in as much as you conceive of it as a separate entity, I suppose it makes some sense to say it gets the same linkage as the entity it refers to. > I'm sure we can bikeshed the name 'exalias' doesn't seem very mnemonic > to me. 'symbol_alias' or something? I don't like symbol_alias; that this feature names a symbol is not a distinguishing feature from the preexisting alias attribute. 'ex' can be read as both extra, exported, external, and all of these sort of make sense, at least for entities that have linkage. Even for exclusively internal uses, say to introduce a mnemonic symbol for another alias-attributed declaration to refer to, the "ex" prefix, that means the opposite of "in", fitting in well with the functionality of "ex"posing the symbol through a name that other alias declarations can take *in*, *im*port. Another possible spelling for this proposed attribute that might be more mnemonic is "aka"; unfortunately, that's pretty much a synonym to alias, so it might be mistaken as such, rather than as a complementary feature, akin to the other end of a power extension cable: whereas alias does the job of a plug, *ex*alias provides a socket/*out*let. -- Alexandre Oliva, happy hacker https://FSFLA.org/blogs/lxo/ Free Software Activist GNU Toolchain Engineer
