On Thu, 14 May 2009 17:21:02 -0400, Derek Parnell <[email protected]> wrote:
On Thu, 14 May 2009 16:59:32 -0400, Steven Schveighoffer wrote:
I guess I understand the mentality of picking -1 or uint.max as a
reasonable "failure" return, but what I don't understand is why you
would
do so when you could use the length of the string, which is useful for
many other purposes. -1 or uint.max just is a failure, and needs to be
checked, it can't be used to do any slicing operations.
A problem with .length is that it requires the knowledge of the string
for
it to be meaningful. If find() can return any integer, we can only know
if
that integer represents WasFound or WasNotFound if we have the string in
context.
Currently we can do this ...
funcA( find(needle, haystack), xyzzy);
and 'funcA' doesn't need to know anything more about the 'haystack' to
work. If find/indexOf() can return any integer we would have to code ...
funcA( indexOf(needle, haystack) != haystack.length ? uint.max : 0,
xyzzy);
(assuming that funcA is expecting uint.max to mean WasNotFound).
So there are really arguments for employing both methods. It just depends
on why you are trying to 'find' stuff.
Not really. What could funcA possibly do with the index without the
string itself? If it's just a flag (uint.max or not), then funcA should
be:
funcA(bool found, ...)
and you call it with
funcA(find(needle, haystack) < haystack.length, xyzzy)
This doesn't cause any problems with people who use Tango, which returns
the length if not found. In other words, if you find yourself writing
code to "morph" the length into uint.max or -1, you are thinking about the
problem incorrectly.
-Steve
