Strange PHP syntax

Question

I've been working on PHP for some time but today when I saw this it came as new to me:

if(preg_match('/foo.*bar/','foo is a bar')):
        echo 'success ';
        echo 'foo comes before bar';

endif;

To my surprise it also runs without error. Can anyone enlighten me?

Thanks to all :)

Serpens

as the answers below have said, this is an alternative syntax. It's also awfully painful to read IMO, please avoid this in your own code. – Pourpoint

this kind of syntax is used in templates when you often open and close <?php?> and you use html in between. It is horrible and unreadable even in those cases, and should be avoided altogether. – Imparity

@Lo'oris, I disagree with you. Using it in your templates can improve readability if you ask me: see https://mcmap.net/q/1036794/-strange-php-syntax/… for an example. – Passade

I agree with those who recommend against it. Even in templates, as Lo'oris mentioned, it does almost nothing for readability. But the main problem I have with it is that I haven't found an IDE which highlights matching if/endif or foreach/endforeach or any other alternate syntax tags. For that reason alone it should be avoided. Netbeans will highlight matching braces even if they span <?php ?> blocks, but it hasn't a clue how to do so with the alternates. I think the fact that this question is being asked is further evidence that it should be avoided, to prevent confusion. – Basildon

Answer 1

That style of syntax is more commonly used when embedding in HTML, especially for template/display logic. When embedded this way, it's a little easier to read than the curly braces syntax.

<div>
<? if ($condition): ?>
  <ul>
    <? foreach($foo as $bar): ?>
        <li><?= $bar ?></li>
    <? endforeach ?>
  </ul>
<? endif ?>
</div>

Versus:

<div>
<? if ($condition) { ?>
  <ul>
    <? foreach($foo as $bar) { ?>
      <li><?= $bar ?></li>
    <? } ?>
  </ul>
<? } ?>

The verbose end tags make it a little easier to keep track of nested code blocks, although it's still mostly personal preference.

Quaker

Answer 2

This is PHP's Alternative syntax for control structures.

Your snippet is equivalent to:

if(preg_match('/foo.*bar/','foo is a bar')) {
        echo 'success ';
        echo 'foo comes before bar';
}

In general:

if(cond):
...
...
endif;

is same as

if(cond) {
...
...
}

Heliochrome

I believe you... but why in Satan's good name would you want to do that? – Reputation

@CodeSlave: I suppose it looks nicer if you're embedding html code. – Heteronomy

Answer 3

http://php.net/manual/en/control-structures.alternative-syntax.php

Works for if, for, while, foreach, and switch. Can be quite handy for mixing PHP and HTML.

Heaver

Answer 4

You can read about it in Alternative syntax for control structures in the PHP manual. Reformatted, the code you posted looks like this:

if (preg_match('/foo.*bar/','foo is a bar')):
    echo 'success ';
    echo 'foo comes before bar';
endif;

This code is equivalent to:

if (preg_match('/foo.*bar/','foo is a bar')) {
    echo 'success ';
    echo 'foo comes before bar';
}

This syntax is available for several other control structures as well.

if ( condition ):
  // your if code
elseif ( other_condition ):
  // optional elseif code
else:
  // optional else code
endif;

while ( condition ):
  // your while code
endwhile;

for ( condition ):
  // your for code
endfor;

foreach ( condition ):
  // your foreach code
endforeach;

switch ( condition ):
  // your switch code
endswitch;

Singletree

Answer 5

It's the equivalent of:

if(preg_match('/foo.*bar/','foo is a bar')):
 echo 'success ';
 echo 'foo comes before bar';
endif;

which is equivalent to:

if(preg_match('/foo.*bar/','foo is a bar')){
    echo 'success ';
    echo 'foo comes before bar';
}

The wisdom of supporting non-standard conditional syntax is obviously questionable.

Notum

This syntax can be very useful in templates, hence ihmo not questionable. Or at least not obviously;) – Passade