Tom Worster wrote:
On 10/3/09 12:25 PM, "Ashley Sheridan" <ash@xxxxxxxxxxxxxxxxxxxx> wrote:
On Sat, 2009-10-03 at 11:57 -0400, Tom Worster wrote:
On 10/3/09 7:21 AM, "clancy_1@xxxxxxxxxxxx" <clancy_1@xxxxxxxxxxxx> wrote:
However there is one feature of PHP which, to my mind, is really bad design.
How many of
you can see anything wrong with the following procedure to search a list of
names for a
particular name?
$i = 0; $j = count ($names); while ($i < $j)
{ if ($names[$i] == $target) { break; }
++$i;
}
As long as the names are conventional names, this procedure is probably safe
to use.
However if you allow the names to be general alphanumeric strings, it is not
reliable. One
of my programs recently broke down in one particular case, and when I
eventually isolated
the bug I discovered that it was matching '2260' to '226E1'. (The logic of
this is: 226E1
= 226*10^1 = 2260).
I agree that I was well aware of this trap, and that I should not have used
a
simple
comparison, but it seems to me to be a bizarre design decision to assume
that
anything
which can be converted to an integer, using any of the available notations,
is
in fact an
integer, rather than making the default to simply treat it as a string.
this is odd.
i might think it ok for (2260 == '226E1') to be true since php would be
doing type juggling in a logical left-to-right manner: we start with an
integer 2260, next is the juggling comparison operator, then a string, so it
might reasonably try to convert the string to an integer and then compare.
but with ('2260' == '226E1'), where both lhs and rhs are already of the same
time, it seems elliptical, to say the least, that php should search the
types to which it can convert the strings looking for one in which they are
equal.
I don't know what you mean by elliptical, but I'd expect and certainly
hope that PHP wouldn't try to convert both strings to something which
would mean they had the same value. Also, afaik, if the variables types
are exactly the same, PHP won't try to convert either of them for a
comparison
i once had such hope too.
$ php -r "var_dump('2260' == '226E1');"
bool(true)
Numeric strings are special :)
Cheers,
Rob.
--
http://www.interjinn.com
Application and Templating Framework for PHP
--
PHP General Mailing List (http://www.php.net/)
To unsubscribe, visit: http://www.php.net/unsub.php
