Le 30/04/2012 11:17, SomeDude a écrit :
On Monday, 30 April 2012 at 02:33:35 UTC, H. S. Teoh wrote:
On Sun, Apr 29, 2012 at 11:18:12PM +0200, deadalnix wrote:
[...]
C don't have out parameters as D have. C have pointer to do kind of
out parameters, and D have pointers too, this is a non issue.
I argue that using 'out' vs. a pointer is a good thing, because it
clarifies intent. When you see a pointer, it's far from clear whether
it's an input parameter, an output parameter, or both.
More and more, I'm leaning towards the opinion that all code should
reveal intent, preferably in a language-supported way. Unclear intent is
what leads to subtle bugs caused by people calling functions with wrong
assumptions. (You'd think this should be a non-problem with programmers,
who are presumably smart enough to figure things out without being told
in the face, but I've seen too much "enterprise" code by now to not be
cynical about it.)
T
Of course, a better way would be to change the meaning of the comma
operator to allow a Python-style syntax for return values, i.e something
like
int, Error foo(char[] input, ref Bar){...}
auto res, err = foo(input, bar);
Exactly.
We would then only allow in and inout parameters. This would be much
closer to functional style. There would be no longer any need for the
"in" and "out" keywords.
If we push a little further, you can also get rid of inout by doing this:
int, ref Bar foo(char[] input, ref Bar){...}
auto out, bar = foo(input, bar);
Every time the compiler sees the same symbol as an input and output
parameter, it can assume it's an inout parameter. This, of course, would
break a lot of code.
It isn't a good idea.
