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Posted by Jerry Stuckle on 01/08/08 13:57
A Bit Narked wrote:
> On Tue, 08 Jan 2008 08:00:23 -0500,
> Jerry Stuckle <jstucklex@attglobal.net> wrote:
>
>> A Bit Narked wrote:
>>> On Sun, 6 Jan 2008 23:19:45 +0000,
>>> Toby A Inkster <usenet200712@tobyinkster.co.uk> wrote:
>>>
>>>> A Bit Narked wrote:
>>>>
>>>>> And yet you can echo true. The output is '1'.
>>>> No -- you can't echo a boolean in PHP. Why you try, the boolean is
>>>> implicitly cast to a string.
>>>>
>>>> This:
>>>>
>>>> echo $bool;
>>>>
>>>> is actually executed as if you coded this:
>>>>
>>>> echo (string)$bool;
>>>>
>>>> If you look up the manual on type casting, you'll find that FALSE is cast
>>>> to an empty string, and TRUE is cast to a non-empty string.
>>>>
>>>> If you cast to an integer instead of a string, then you'll find that FALSE
>>>> is cast to 0, which seems to be what you want.
>>>>
>>>> echo (int)FALSE;
>>> Apologies for imprecise expression :-) PHP provides free
>>> casting (e.g. to string in echo) so I ignore it.
>>>
>>> My real point is that there is no logical relationship between a
>>> boolean value of TRUE and a string value '1' _except_ where the
>>> same relationship yields a string value '0' for boolean FALSE.
>>> I.e., the C precedent.
>>>
>>> I'm not fashed by the idea that there's a special boolean type
>>> whose values are TRUE and FALSE. But logically, the string
>>> representations of such sui generis values should be 'true' and
>>> 'false'. There is no logic whatever in string representions of
>>> '1' and ''. No one has articulated a relationship such that
>>> '1' and '' makes any sort of sense.
>>>
>>> One of the basic principles of good design is predictability.
>>> 'From one thing know ten thousand things' as the Chinese stated
>>> it ages ago. So if there's a well-known precedent, we should
>>> follow it unless we have a powerful reason for not doing ('Ensure
>>> that everyone after us makes the same mistake we did', as Maurice
>>> Wilkes put it, to appreciative laughter). And whatever we do
>>> should be internally consistent. So the calling sequence for
>>> some new function should be guessable by anyone who knows the
>>> sequences of similar functions, one value should tell us about
>>> neighboring values, and so forth.
>>>
>>> The PHP developers' choice for the string reps of true and false
>>> violate this principle all to buggery, which is what got up my
>>> nostril.
>>>
>>> I thought everyone here would immediately see how daft it is, but
>>> I expect we're circling the drain as a species precisely because
>>> so many people -even very smart ones- go through life accepting
>>> without examination that 'whatever is, is right'.
>>>
>> Sorry, but it makes perfect sense.
>>
>> C does not have real boolean values "true" or "false". Rather, it
>> gimmicks them up by saying anything with a non-zero value is true, and
>> anything with a zero value is false. One of the problems is that both 1
>> and 2 are considered true - but in this case true != true (1 != 2).
>>
>> PHP does have a real boolean "type" with the values "true" and "false".
>> So true == true all the time.
>>
>> PHP can also do conversions. Like with C, anything with a non-zero
>> value is true, and anything with a zero value is false. This includes
>> an empty string.
>>
>> And if we kept doing things the same old way, we'd still be rubbing
>> sticks together to keep the cave warm. Progress always means change.
>
> Progress is a type of change, but change is not a type of
> progess.
>
> This seems to be a very easy error to make. You've made it 3
> times in your reply!
>
Not at all. I explained exactly how it works.
If you don't like it, no one is forcing you to use PHP.
--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex@attglobal.net
==================
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