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