PHP's 'or' operator

[Xx r3negade]

I've seen before in scripts something like this:

doSomething() or doSomethingElse()
 

So in other words, if doSomething() fails, doSomethingElse() will execute.
I've tried to do the same thing:

<?php
function doSomething($x)
{
  if ( $x != 0 )
  {
    throw new Exception('error!');
  }
}
function doSomethingElse()
{
  print 'something else';
}
doSomething(0) or doSomethingElse();
?>
 

The problem is, it *always* executes doSomethingElse(), regardless of whether an exception was thrown or not. Any help?

And yes, I know about "try...catch"; I just like to have a one-liner alternative.

[MarkSponge]

If you make the first function return a bool then it will only call the second function after the 'or' if it returns false.

If show is passed a 1 - "number is 1" is echoed.
If show is passed <> 1 - "number not 1" is echoed.

<?php
  function show($x){
    if($x==1){
      echo "number is 1";
      return true;
    }else{
      return false;
    }
  }
 
  function show2(){
    echo "number not 1";
  }
 
  show(1) or show2();
?>
 

[TheServant]

I've seen before in scripts something like this:

doSomething() or doSomethingElse()
 

So in other words, if doSomething() fails, doSomethingElse() will execute.
I've tried to do the same thing:

<?php
function doSomething($x)
{
  if ( $x != 0 )
  {
    throw new Exception('error!');
  }
}
function doSomethingElse()
{
  print 'something else';
}
doSomething(0) or doSomethingElse();
?>
 

The problem is, it *always* executes doSomethingElse(), regardless of whether an exception was thrown or not. Any help?

And yes, I know about "try...catch"; I just like to have a one-liner alternative.

What about just doing:
[PHP]if ($x != 0)
{
throw new Exception('error!');
} else {
print 'something else';
}
[/PHP]

When you wirte doSomething(0) or doSomethingElse(); it makes no sense to the computer. It doesn't know which to choose because you have not given it any conditions. You need to say IF (this) {dothis} ELSEIF (that) {dothat}. You use OR like so: if (x ==1 OR x==0) {dothis} That's the logic anyway.

[Motoma]

Hi Xx r3negade,
MarkSponge is right on the money: The return value of your function is what makes the different. PHP utilizes a programming concept called "Short Circuit Evaluation." The return values from your functions are used to determine if the program continues to call functions or quit.

My apologies, I feel that I am inarticulate tonight, so I will show some code!

<?php
 
function returnTrue()
{
  echo 'returnTrue called!<br />';
  return true;
}
 
function returnFalse()
{
  echo 'returnFalse called!<br />';
  return false;
}
 
echo 'returnTrue() or returnFalse();<hr />'
returnTrue() or returnFalse();
echo '<hr />';
 
echo 'returnFalse() or returnTrue();<hr />'
returnFalse() or returnTrue();
echo '<hr />';
 
 
echo 'returnTrue() and returnFalse();<hr />'
returnTrue() and returnFalse();
echo '<hr />';
 
echo 'returnFalse() and returnTrue();<hr />'
returnFalse() and returnTrue();
echo '<hr />';
 
?>
 

I hope that helps you out,
Motoma

I've seen before in scripts something like this:

doSomething() or doSomethingElse()
 

So in other words, if doSomething() fails, doSomethingElse() will execute.
I've tried to do the same thing:

<?php
function doSomething($x)
{
  if ( $x != 0 )
  {
    throw new Exception('error!');
  }
}
function doSomethingElse()
{
  print 'something else';
}
doSomething(0) or doSomethingElse();
?>
 

The problem is, it *always* executes doSomethingElse(), regardless of whether an exception was thrown or not. Any help?

And yes, I know about "try...catch"; I just like to have a one-liner alternative.