What does this symbol mean in PHP <?=?
Example usage:
<h2>Manage Role: > (<?= $myACL->getRoleNameFromID($_GET['roleID']); ?>)</h2>
To add to Mark's answer: The short_tags option must be enabled for the <?= syntax to be valid. This presents a major portability problem when moving to a server that has this option disabled.
See the PHP Manual for more info on short tags
It's functionally the same as <?php echo $myACL->getRoleNameFromID($_GET['roleID']); ?>
It's the PHP Short Tag equivalent of printing.
From the PHP INI:
Using short tags is discouraged when developing code meant for redistribution
; since short tags may not be supported on the target server.
See "Are PHP Short Tags Acceptable to Use?" on StackOverflow.
The <?= ... > tag says to execute whatever is in ... and output the results.
Related
Even the official documentation used to tell us that PHP "short tags" (<? /*...*/ ?>) are "bad". However, since PHP 5.4, the echo variety <?= /*...*/ ?> is permanently enabled regardless of the short_open_tag setting.
What's changed?
Even if they were previously discouraged solely due to the unpredictable nature of whether short_open_tag is enabled on a shared hosting platform, surely that argument doesn't go away just because some subset of hosts will be running PHP 5.4?
Arguably this change to the language doesn't inherently signify a change in the recommendation that we should nonetheless avoid "short tags", but if they've gone to the trouble it would certainly seem like the PHP devs no longer "hate" them so much. Right?
The only logical conclusion I can draw at this time is that there must be some objective rationale for the introduction of this change in PHP 5.4.
What is it?
Short open tags are not always enabled since PHP 5.4. The documentation talks about the short echo tags. Which is a different thing. (short open tags are <? style tags, short echo tags are <?= style tags, for echo-ing).
Then why are they enabled by default now? Well, there are a lot of scripts out there, where it benefits to use <?= $somevar ?> instead of <?php echo $somevar ?>. And because the short echo tags aren't as bad as the short open tags, they chose to always enable the short echo tags. Because now developers (of frameworks and CMS-es) can count on them (or rather, when PHP 5.4 becomes mainstream).
However, the short open tags are still influenced by the short_open_tag setting in your php.ini.
Only short echo tag (<?=) is enabled permanently, not short open tags (<?).
It's because short echo tag is really handy when you're creating HTML templates (or any other view templates) and without that you have to write a lot more (like <?php echo $var; ?> instead of just <?= $var ?>).
Note: Starting with PHP 5.4, short echo tag <?= is always recognized and valid, regardless of the short_open_tag setting.
All that this is saying, is that <?= is always valid, and not <?
The reason is that < ? is used in XML documents and enabling short_open_tags will generate errors in XML codes.
But, < ?=, just like < ?php is not XML open tag and is safe to use.
By one hand, I know the use of the Short Open Tag <? in PHP is discouraged for several reasons: only available if enabled in php.ini, for clarity and avoiding confusions...
By the other hand, I see that from PHP 5.4.0 and above, <?= is always available regardless of the short_open_tag ini setting.
More about PHP tags here.
My question:
Is <?= considered Short Open Tag? Should I avoid using it in my PHP coding? Or should I do the opposite and use it since is very useful and not affected by the 'discourage recomendation'?
Edited for clarifying: <?= ... ?> is equivalent to <?php echo ... ?>
Since there is no formal answer, I put together some of the comments, which -in my opinion- actually answer the question:
<?= is no longer considered a short open tag. The reason why <? was discouraged was because it was ambiguous under some situations, i.e <?xml ... ?> or other markup languages.
This question already has answers here:
Are PHP short tags acceptable to use?
(28 answers)
Closed 9 years ago.
If
<?=$var?>
is used only if short tags are enabled, then does that mean the regular version of that is:
<?php=$var?>
The second one doesn't work tho.
<?php= is not valid syntax. Your choices are
Short tags <?=
Long version <?php echo (or print())
If the short tag is enabled you can use <?=$var?>
Which is the shorter version of <?php echo $var ?>
There is nothing called <?php=$var?> You have to replace the = with echo or print()
Because no one else has mentioned this, and after further searching using google... I wanted to post what I think is crucial info.
http://php.net/manual/en/function.echo.php
The following link states:
echo also has a shortcut syntax, where you can immediately follow the
opening tag with an equals sign. Prior to PHP 5.4.0, this short syntax
only works with the short_open_tag configuration setting enabled.
Which is very important, because there isn't a need for <?php= because <?= will work if short tags are disabled or enabled for all future versions of PHP!
This is very important as the use of all other short tags is considered futile. Anyway the use of the short echo tag is encouraged from now on. It does provide for a smoother and tidier code-base - esp. in view files. So for PHP >= 5.4.0 <?= ?> can be used without setting short_open_tag.
Always check Stack, Google, etc first, and check the PHP.net and read about it.
It's all in the manual clear as day! :)
http://php.net/manual/en/language.basic-syntax.phptags.php
When PHP parses a file, it looks for opening and closing tags, which are <?php and ?> which tell PHP to start and stop interpreting the code between them.
PHP also allows for short tags <? and ?> (which are discouraged because they are only available if enabled with short_open_tag php.ini configuration file directive, or if PHP was configured with the --enable-short-tags option.
http://www.php.net/manual/en/ini.core.php#ini.short-open-tag
This directive also affected the shorthand <?= before PHP 5.4.0, which is identical to <? echo. Use of this shortcut required short_open_tag to be on. Since PHP 5.4.0, <?= is always available.
Is it now totally and completely safe to use
<?=$var ?>
instead of
<?php echo $var; ?>
I wouldn't use the words "totally" and "completely", but with PHP5.4 the "short-open-and-echo"-syntax is part of the core and thus always available. Remind, that I only talk about <?= ?> and not the "regular" short-open-tags <? ?>.
Yes. As of PHP 5.4.0 from 01-Mar-2012 you can use short tag. From php 5.4 change log,
<?= is now always available regardless of the short_open_tag setting.
This was a General improvement.
So if you have PHP 5.4 you can use <?= syntax.
Yes. There is no real issue with using <?=$var?>, but if you want to be totally prepared for a host that doesn't have this enabled, then you may want to write it using full statement.
Typically, you can enable this feature even if it's disabled.
It's better to always use the regular <?php tag. That way you are sure that your scripts are always compatible with any PHP installation, regardless of the PHP version or php.ini settings.
Even more important if you are developing code that's meant to be shared, such as a library.
ref: http://php.net/ChangeLog.php#5.4.32
"short open tag is now always available regardless of the short_open_tagsetting"
Yes. As of PHP 5.4, echo tags are always enabled unless your host disables them.
This question already has answers here:
Closed 12 years ago.
Possible Duplicates:
Are PHP short tags acceptable to use?
What does “<?=” mean when seen in PHP
is there any difference in using <? ?> to signify a php block, or using <?php ?> ?
if there is not, why would anyone use <?php ?
figure the file extension of .php would give plenty of info about what type of code you are looking at.
The first is called short-open tags and second one is safe open and close tags.
You could enable/disable short open tags in php.ini using short_open_tag setting.
The short tags should be avoided, have a look at:
PHP Short Open Tag: Convenient Shortcut or Short Changing Security?
Servers must be configured to also use <?, so it is considered best practice to use <?php for portability reasons.
From the manual ( http://www.php.net/manual/en/language.basic-syntax.phpmode.php ):
There are four different pairs of
opening and closing tags which can be
used in PHP. Two of those,
and ,
are always available. The other two
are short tags and ASP style tags, and
can be turned on and off from the
php.ini configuration file. As such,
while some people find short tags and
ASP style tags convenient, they are
less portable, and generally not
recommended.
<?php can always be used. <? can only be used if the short_open_tag directive is turned on.
short_open_tag tells PHP whether the short form (<? ?>) of PHP's open tag should be allowed. If you want to use PHP in combination with XML, you can disable this option in order to use <?xml ?> inline. Otherwise, you can print it with PHP, for example: <?php echo '<?xml version="1.0"?>'; ?>. Also, if disabled, you must use the long form of the PHP open tag (<?php ?>).
Note: This directive also affects the shorthand <?=, which is identical to <? echo. Use of this shortcut requires short_open_tag to be on.
-- Description of core php.ini directives
As others have mentioned, this directive is often turned off so for portability reasons I prefer using <?php ?>. If this is not an issue, there shouldn't be much difference other than that if the directive is turned on you can also use the <?= shorthand thingy.
I have never personally run into this issue, but support for <? ?> is spotty when moving to different servers. I prefer to just stick to <?php ?> for clarity and consistency.
Using short tags <? ?> should be avoided when developing applications or libraries that are meant for redistribution, or deployment on PHP servers which are not under your control, because short tags may not be supported on the target server. For portable, redistributable code, be sure not to use short tags.
And also note that if you are embedding PHP within XML or XHTML you will need to use the <?php ?> tags to remain compliant with standards.
Always use <?php ?> because <? ?>:
will not work in coming PHP versions
could be mixed with XML definitions. (XML always starts with <?xml ...)
is not enabled on many shared hosting sites.
short tags <? ?> , only work in older php versions.
There is no difference language-wise, but many shop prefer the use of <?php because the simple <? opening tag can be found in XML files, which can lead to confusion for the interpreter.
Edit: I thought this was still an issue: http://terrychay.com/article/short_open_tag.shtml