PHP: Run Functions Only After Checking Variable After Each - php

Question

I have a series of functions that I'd like to run. At the end of each function, it either sets a variable TRUE or FALSE. What I'd like to do is break the series if the variable sets to TRUE.
For example. I have the following:
$done = false;
step1(); // Sets $done to false
step2(); // Sets $done to false
step3(); // Sets $done to true
step4(); // Because step3() set $done to true, I wan't step4() to NOT run.
Of course if step3() returns false, I'd like to keep going and run step4().
I know I'll need to use a while, switch, and/or a break. I'm just unclear on how to set this up.
Much appreciated.

Answer 1

It's not much clear to me, but if your functions return booleans, you can try:
step1() || step2() || step3() || step4();
The operator || only evaluate the second operand if the first is false.

Answer 2

it can be done by using a simple if statement if you want.
$done = false;
$done = step1(); // each function returns true or false
if (!$done)
{
$done = step2();
}
if (!$done)
{
$done = step3();
}
if (!$done)
{
$done = step4();
}
correct me if there is any mistakes.

Answer 3

$done = false;
function step1($done){
if($done===false){
//proceed step 2
}
else{
return;
}
}
function step2($done){
if($done===false){
//proceed step 3
}
else{
return;
}
}
function step3($done){
if($done===false){
//proceed step 4
}
else{
return;
}
}
function step4($done){
if($done===false){
//finish
}
else{
return;
}
}

Answer 4

Your question is not very straight forward, probably similar to the form you have so far.
You could create an array with callbacks of your functions and consume them while $done is false and there are still functions to consume:
$doFunctions = ['step1', 'step2', ... , 'stepN'];
$done = false;
while (!$done && $doFunctions)
{
$function = array_shift($doFunctions);
call_user_func($function);
}
As this shows, no switch and no break needed, because you have a simple condition here.
Another alternative would be to "make" the functions return something by wrapping it inside a closure and keep the $done as a reference (context), then return it:
$done = false;
$call = function ($function) use (&$done) {
$function();
return $done;
}
$call('step1')
|| $call('step2')
|| $call('step3')
|| $call('step4')
;
It depends a bit of what you actually need to achieve.

Answer 5

So perhaps my question was misunderstood, but after a while I realized that a try/catch block with exceptions was exactly what I was after. Here is roughly what I ended up doing.
First I set up my functions to throw exceptions on errors.
function step1() {
// do awesome stuff
if ($errorInStep1) {
throw new Exception('There was an error in step 1.');
}
}
function step2() {
// do awesome stuff
if ($errorInStep2) {
throw new Exception('There was an error in step 2.');
}
}
function step3() {
// do awesome stuff
if ($errorInStep3) {
throw new Exception('There was an error in step 3.');
}
}
function step4() {
// do awesome stuff
if ($errorInStep4) {
throw new Exception('There was an error in step 4.');
}
}
So now if there is an error in each of the functions, the script will throw an exception.
Then I wrap those functions in a try/catch block. The script will try to go through each statement, and if something throws and exception...it will stop right there. Perfect.
try {
step1();
step2();
step3();
step4();
} catch (Exception $e) {
echo 'Caught exception: ', $e->getMessage(), "\n";
}