Re: not_null function

On Thu, Jul 3, 2014 at 3:24 AM, Tjerk Meesters <tjerk.meesters@gmail.com> wrote: > Hi Bart, > > > On Thu, Jul 3, 2014 at 5:40 PM, Xen <xen@dds.nl> wrote: > > > Heya, > > > > I was just wondering about something. > > > > It seems way more natural and flowing to have and use a "not_null" > > function in addition to some "is_null" that currently exists. > > > > The reason is that most of the time you are not checking null condition, > > you are really checking the non-null condition. > > > > But a line like "if (!is_null($a))" feels like there are two verbs in it. > > > > For this particular case I would use this: if (isset($a)) > > For undefined variables it will return false and for defined > variables > it's equivalent to the expression $a !== null. > > > > It is like you are saying "if $a is not is null". > > > > It is different for the "empty" function because there is no "is_" > > prefix > > in it. So "if (!empty($a)) feels completely sane. > > > > So generally I will *want* to test a null condition but I just hope my > > variable won't contain anything that evaluates to false and just test "if > > ($a)". > > > > If there was a not_null() I would use that instead, because "if > > (not_null($a))" only contains one "verb" instead of two. > > > > And I would define that helper function myself, but I don't want to write > > code that another person would not be able to run just because not_null > is > > not defined in his library. > > > > -------- > > In general I believe this is rather a problematic feature of most > > languages. > > > > The "if" statement implies a verb, but many functions and methods also > > contain a verb in their name. > > > > This seems to be only the case for the "is" verb. I know in my language > > (Dutch) the "to be" verb (zijn) is treated differently from all other > verbs > > when it comes to the adverb/adjective difference. > > > > When you state "I am good" the adjective is used, but "I work good" > should > > be "I work well". The adjective applies to the subject "I" but the > > adverb > > applies to the verb "work". I guess there are all sorts of mixtures, "I > am > > well" is also used. But I think it is improper. > > > > Thus, "if (has_members())" feels natural because it uses a different verb > > replacing the default "is". > > > > But "if (is_null())" feels odd because "if (null())" would say the > > same > > thing only more concise and more natural as far as if statements go, or > at > > least it seems that way to me. > > > > Personally I try to avoid those "is_something" functions whenever I can. > > It is not so much an issue if it is some rarely used library call. > > > > Like WordPress has functions like "is_single()" which returns a boolean > > indicating whether the currently loaded page is a single post display. > > > > But notice that "if (single())" would give very little information as to > > what you were actually testing. There is no parameter, and just "single" > > would be so general that it would completely obfuscate the fact that it > had > > to do with WordPress. It would have to become "page_is_single()" although > > "page" is (improperly) dedicated to a special type of post that sits > > outside of the regular post structure. They ought to rename it to > > "staticpage" or "static". "page_is_single" and > > "page_is_home" and > > "page_is_category" would be more descriptive. > > > > But in any case, this language incongruency is most annoying with core > > functions you have to use all the time, or would be using all the time if > > they were okay. > > > > So my suggestion would be to consider introducing at least "not_null". > > "isset" seems to be a different category, if only because the verb is not > > visually separated from the condition. > > > > So "if (isnull($a))" would again be more natural. But because the verb is > > visually separated using the underscore, you get two verbs in your mind. > > Perhaps creating an "isnull" alias and then deprecating the "is_null" > > function would be best. > > > > There's also is_array(), > is_bool(), etc. so changing only > is_null() > would be a big wtf ;-) > > You could propose to change isset() into > is_set() though =D > > > > Regards, > > > > Bart Schouten > > > > ps. please "reply all" for I am not subscribed as of yet. > > > > -- > > PHP Internals - PHP Runtime Development Mailing List > > To unsubscribe, visit: http://www.php.net/unsub.php > > > > > > I've found over the years that a lot of developers, particularly those who specialize in languages other than PHP, use is_null() when what they really want is empty(). The problem with is_null() and the === operator is that PHP will throw a notice if the variable is not set. If you're just looking for whether a variable is blank or not, empty() will handle that whether the variable is set or not. Personally, I don't understand why we need is_null() at all in its current form, since it's exactly the same as === NULL, except that it doesn't perform as well. Rather than removing it, I think is_null() should be changed into a language construct like isset() and empty(). That way, people could pass undefined variables to is_null() without triggering notices. It'd basically be the same as empty, except that it would only return true of the value is exactly NULL. I.e. it'd go like this: empty( $var ) is functionally equivalent to isset( $var ) && $var != NULL is_null( $var ) is functionally equivalent to isset( $var ) && $var !== NULL I think that would make a hell of a lot more sense than the way is_null() works now. Thoughts? --Kris