Le 02/03/2012 02:10, Jonathan M Davis a écrit :
On Thursday, March 01, 2012 18:57:15 bearophile wrote:
Jonathan M Davis:
They also often do poorly when you
need to use the functional programming,
As you know functional languages use tuples all the time.
Yes, but chaining functions is the issue. It doesn't work well with tuples
unless the function you're passing the result to wants the tuple. If all it
wants is one piece of the tuple, then that doesn't work well at all. You're
forced to assign the tuple to something else and then call then function
rather than chain calls. That's one of the reasons that you constantly end up
using stuff like let expressions and pattern matching in functional languages.
You don't _want_ a tuple. Dealing with a tuple is annoying. It's just that
it's often the best tool that you have to pass disparate stuff around, so
that's what you use.
And if you're not looking to assign the parts of a tuple to
existing variables, then they're not quite as bad as when you are, since
you don't necessarily have to then assign the pieces to other variables.
There are parts of your post that I don't fully understand.
It is often really annoying to have to deal with tuple return values, because
you have to worry about unpacking the result. I don't want to use a tuple in
the caller. Tuples are generally for grouping unrelated data that you don't
necessarily want to keep togother (since if you did, you'd generally use a
struct). I want the result to actually be assigned to variables. That is
definitely cleaner with out than with tuples.
int exp;
auto result = frexp(value, exp);
vs
auto tup = frexp(value);
result = tup[0];
exp = tup[1];
Getting tuple return values is annoying. Yes, it can be useful, but most stuff
doesn't operate on tuples. It operates on the pieces of tuples. So, you have
to constantly break them up. So, using out results in much nicer code.
It always feels like I'm fighting the code when I have to deal with tuple
return values.
- Jonathan M Davis
Do you rally think that shorter is always better ? I don't think so. I
think better is what the piece of code do pretty much what you expect it
to do. And most of the time, I want to pass argument to a function not
return value throw arguments. At the callee place, version look just
like any other function call, but exp isn't a parameter, it is actually
a returned value. You cannot know that reading the code, you need to
know about frexp declaration - thus you scroll more source
code/documentation or rely on your memory that will sometime fail. To
emphasis that, just imagine the same scenario with a function that isn't
from the standard lib.
This practice will confuse a newcomer that don't know the stdlib well,
and, used in thrid party code, will confuse anyone expect the one that
write that piece of code.
