How to break if loop in Perl?

Barca · 07-28-2005, 03:15 PM

How to break "if" checking in Perl? Let's see:

if ($cap)
{
Net::Pcap::close ($cap);
>>> HERE <<<
print "\nExit\n";
}

I'd like to add another "if" block in this. I'd like to exit from "if" checking in marked place if variable $test would be equal to 1. So, if $test =1, $cap will be closed but text "Exit" won't be displayed.
How to do that? "last" doesn't seem to work, because it's designed to use in "while" loops etc., not in "If" statement. Thanks for your help

Matir · 07-28-2005, 03:21 PM

Yeah, if is not a loop, but a language construct. That aside, the only solution I'm aware of is the ultra-ugly "goto".

Barca · 07-28-2005, 03:42 PM

Thx it helped

I doesn't think that using goto is bad. I'd say that using it too many times isn't good, but it's not "ugly" as many people says. It's a command like any other, created to be used when necessary - like in this example

Matir · 07-28-2005, 03:48 PM

Yeah, well, there essays out there on using goto (and when to or not to).

Which makes me wonder how an optimizing compiler would handle this: (granted, this is C code)

Code:

void foo(){
    goto subarea;
    if( 0 ) /* False constant condition */
    {
        subarea:
        printf("Hit subarea.\n");
    }
}

luxitan · 07-28-2005, 04:00 PM

Maybe I don't understand the problem but why don't you use another if:

Code:

 

if ($cap)
{
   Net::Pcap::close ($cap);
   if (!$test)
  {
     print "\nExit\n";
  }
}

Matir · 07-28-2005, 04:18 PM

No, he seems to be desiring to break out of multiple areas, as in this code:

Code:

if($cap)
{
    Net::Pcap::close($cap);
    if(!$test){
        goto outside;
    }
    # more code
}
outside:
#even more code

f76 · 07-29-2005, 08:48 AM

how about else?

nkthrasher · 08-01-2005, 03:28 PM

Too easy.

Code:

for(;;){
  if ($cap){
    Net::Pcap::close ($cap);
    if(wewanttobreakhere){
      last;
    }
    #insert other code here
    if(wewanttobreakhere){
      last;
    }
    print "\nExit\n";
  }
  last;
}

Cant break from the if since its not a loop, but you can put the if into a useless loop, and break from the useless loop.

Matir · 08-01-2005, 03:35 PM

How about placing that within [ code] brackets?

jaylink1971 · 08-03-2011, 01:15 PM

We're all so stupid. Just do this, as suggested by "John" in another forum:

just put a loop inside the if block:

Code:

if ( $expression ) { {
 last if $oops;
 } }