PHP conditionals, brackets needed?

Question

I was just browsing a forum and someone asked about a php file they had found on the web. It has several spots like this in the code:

if ($REMOTE_ADDR == "") $ip = "no ip"; else $ip = getHostByAddr($REMOTE_ADDR);

I have always thought brackets are needed to enclose what you want to do if the condition is true. Is there some other alternative, such as if it is on the same line you don't?

There is also another line like this: IF ($action != ""): mail("$adminaddress","Visitor Comment from YOUR SITE",

My instinct is to say this wouldn't work, but I also don't know if it is an outdated php file and it used to work?

Any input would be great.

Thanks, Levi

Answer 1

you can do if else statements like this:

<?php
if ($something) {
   echo 'one conditional line of code';
   echo 'another conditional line of code';
}


if ($something) echo 'one conditional line of code';

if ($something)
echo 'one conditional line of code';
echo 'a NON-conditional line of code'; // this line gets executed regardless of the value of $something
?>

and then you can also write if - else in an alternate syntax:

<?php
if ($something):
   echo 'one conditional line of code';
   echo 'another conditional line of code';
elseif:
   echo 'one conditional line of code';
   echo 'another conditional line of code';
else:
   echo 'one conditional line of code';
   echo 'another conditional line of code';
endif;
?>

with the alternate syntax you can also fall out of parsing mode like this:

<?php
if ($something):
?>
one conditional line of code<br />
another conditional line of code
<?php
else:
   echo "it's value was: $value<br />\n";
?>
another conditional line of code
<?php
endif;
?>

But this gets really messy really fast and I won't recommend it's use (except maybe for template-logic).

and to make it complete:

<?php
$result = $something ? 'something was true' : 'something was false';
echo $result;
?>

equals

<?php
if ($something) {
   $result = 'something was true';
} else {
   $result = 'something was false';
}
echo $result;
?>

Answer 2

Braces (not brackets) are optional in PHP, as in most C-like syntax. Maybe you're thinking of Perl; they're required there, for that form of if syntax.

The colon thing is an alternate control structure form that PHP supports. I hate it, but some people (particularly template system designers, apparently) love it.

Answer 3

To go into a little more detail, the reason that the braces are optional is that the syntax looks like:

if(CONDITION) BLOCK
[elseif(CONDITION) BLOCK]
[else BLOCK]

BLOCK can be a single statement:

foo();

or it can be a brace-enclosed group of statements:

{
    foo();
    bar();
}

Answer 4

In my opinion

if ($REMOTE_ADDR == "") $ip = "no ip"; else $ip = getHostByAddr($REMOTE_ADDR);

is valid, but much harder to read than:

if ($REMOTE_ADDR == "") {
    $ip = "no ip"; 
} else {
    $ip = getHostByAddr($REMOTE_ADDR);
}

Answer 5

brackets are needed to enclose what you want to do if the condition is true

I can't think of any language that requires this

Answer 6

Yes, excluding the braces is allowed, although many times I have heard 2 reasons for not using that syntax:

1. It's harder to read. Less obvious to another programmer.
2. If you ever wany to add something inside the if, then you need to add the braces which is harder after then when you're first coding since most editors will add the closing brace for you.

Also, yes, the colon syntax is valid. The alternatives can be found here: http://php.net/manual/en/control-structures.alternative-syntax.php