Re: Re: Re: Re: Re: system & shell metacharacters

Using || die is fine as long as parens are used.

open(FOO, $file) || die "Couldn't open $file - $!\n";
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When no parens are present, you should use or die instead.

Personally, I always use parens everywhere so my code is littered with || dies.

-- vek --

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\|\| die or or die :) by snax (Hermit) on Jul 23, 2003 at 20:00 UTC
I'm just surprised that I've never seen a problem using it exactly as I've written it above, which I do with great regularity. The docs say that the calling signatures are `open FILEHANDLE, EXPR` [download] and `open FILEHANDLE` [download] My syntax falls into the first case, but what constitutes an "EXPR"? I've got a string, the \|\| operator, then the die -- does that qualify as an EXPR? I'll have to poke around the docs some more..... Oh. Playing around with the right and wrong way shows me that my "\|\| die" syntax fails without `die`-ing.	[reply] [d/l] [select]
Re: \|\| die or or die :) by ChemBoy (Priest) on Jul 23, 2003 at 20:41 UTC
I've got a string, the \|\| operator, then the die -- does that qualify as an EXPR? Yes, it does (as you seem to have discovered): since `\|\|` is higher precedence than the comma, it's parsed roughly as `open ( FILEHANDLE, ("filename" \|\| die( ...) ) );` Since your string is always true, the die is never reached. If God had meant us to fly, he would never have given us the railroads. --Michael Flanders	[reply] [d/l]

Replies are listed 'Best First'.
\|\| die or or die :) by snax (Hermit) on Jul 23, 2003 at 20:00 UTC
I'm just surprised that I've never seen a problem using it exactly as I've written it above, which I do with great regularity. The docs say that the calling signatures are `open FILEHANDLE, EXPR` [download] and `open FILEHANDLE` [download] My syntax falls into the first case, but what constitutes an "EXPR"? I've got a string, the \|\| operator, then the die -- does that qualify as an EXPR? I'll have to poke around the docs some more..... Oh. Playing around with the right and wrong way shows me that my "\|\| die" syntax fails without `die`-ing.	[reply] [d/l] [select]
Re: \|\| die or or die :) by ChemBoy (Priest) on Jul 23, 2003 at 20:41 UTC
I've got a string, the \|\| operator, then the die -- does that qualify as an EXPR? Yes, it does (as you seem to have discovered): since `\|\|` is higher precedence than the comma, it's parsed roughly as `open ( FILEHANDLE, ("filename" \|\| die( ...) ) );` Since your string is always true, the die is never reached. If God had meant us to fly, he would never have given us the railroads. --Michael Flanders	[reply] [d/l]