> That same logic can be used to argue that functions should only support one input argument, too.
Some languages do (more if you consider things that support what looks like multiple arguments but which the complete set of arguments that can be passed to a function corresponds directly to a single data structure in the language.)
> There's a big difference between simply and efficiently returning multiple values on the stack without generating intermediate garbage and memory references, and packing multiple values up into a single tuple
Fundamentally, there's not, since you have to represent both the number of items and each item either way. It's true that there are more and less efficient means of performing the task, but the information required is identical, so it is quite possible for any method capable of doing what looks like one to a user of the language to implement what looks like the other from the same perspective.
The obvious implementation when conceptualized each way given other elements of a language or it's implementation design may be different, but that's not an inherent difference, and implementing efficiencies in the implementation has no necessary reflection in language-level features (and supporting any particular language-level feature isn't a guarantee of efficient implementation.)
Some languages do (more if you consider things that support what looks like multiple arguments but which the complete set of arguments that can be passed to a function corresponds directly to a single data structure in the language.)
> There's a big difference between simply and efficiently returning multiple values on the stack without generating intermediate garbage and memory references, and packing multiple values up into a single tuple
Fundamentally, there's not, since you have to represent both the number of items and each item either way. It's true that there are more and less efficient means of performing the task, but the information required is identical, so it is quite possible for any method capable of doing what looks like one to a user of the language to implement what looks like the other from the same perspective.
The obvious implementation when conceptualized each way given other elements of a language or it's implementation design may be different, but that's not an inherent difference, and implementing efficiencies in the implementation has no necessary reflection in language-level features (and supporting any particular language-level feature isn't a guarantee of efficient implementation.)