goto

(PHP 5 >= 5.3.0, PHP 7, PHP 8)

What's the worse thing that could happen if you use goto?

Image courtesy of » xkcd

The goto operator can be used to jump to another section in the program. The target point is specified by a case-sensitive label followed by a colon, and the instruction is given as goto followed by the desired target label. This is not a full unrestricted goto. The target label must be within the same file and context, meaning that you cannot jump out of a function or method, nor can you jump into one. You also cannot jump into any sort of loop or switch structure. You may jump out of these, and a common use is to use a goto in place of a multi-level break.

Example #1 goto example

<?php

goto a;
echo
'Foo';

a:
echo
'Bar';

?>

The above example will output:

Bar

Example #2 goto loop example

<?php

for ($i = 0, $j = 50; $i < 100; $i++) {
while (
$j--) {
if (
$j == 17) {
goto
end;
}
}
}
echo
"i = $i";
end:
echo
'j hit 17';

?>

The above example will output:

j hit 17

Example #3 This will not work

<?php

goto loop;
for (
$i = 0, $j = 50; $i < 100; $i++) {
while (
$j--) {
loop:
}
}
echo
"$i = $i";

?>

The above example will output:

Fatal error: 'goto' into loop or switch statement is disallowed in
script on line 2

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User Contributed Notes 4 notes

up
56
Lollo
4 years ago
You should mention the label can't be a variable
up
34
devbyjesus at example dot com
3 years ago
the problem of goto is that it is a good feature but in a large codebase it reduces the readability of the code . that's all . i try to not use it to think about the person who is going to read after me .
up
10
georgy dot moshkin at techsponsor dot io
1 year ago
You can use goto to hide large HTML blocks without using echo():<html><body><?php if ($hide_form_and_script) { goto label_1;} ?><form action="" method="post"><!-- some HTML here --></form><script>let a='test'; // no need to escape nested quotes as with echo()// some JavaScript here</script><?php label_1: ?></body></html>
up
8
BPI
2 years ago
You can jump inside the same switch. This can be usefull to jump to default<?php$x=3;switch($x){    case 0:    case 3:        print($x);            if($x)            goto def;    case 5:        $x=6;    default:        def:        print($x);}?>
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