Re: "or die" versus "|| die"

I think in a lot of cases it doesn't matter (especially if die'ing), but there is a difference in precedence. perldoc perlop shows that || is higher than = and some other operators, and or has the lowest pecedence.

I've had cases where || return needed to be changed to or return so that Devel::Cover wouldn't complain about never getting a true value for the other half of the construct.

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Re^2: "or die" versus "\|\| die" by davido (Cardinal) on Jun 24, 2005 at 15:44 UTC
Just because you're invoking die after an \|\| or a `or` doesn't mean you don't have to think about precedence. Consider the following: `somesub $this, $that \|\| die;` [download] If you use 'or' here, you'll die upon failure of somesub (assuming it returns false to indicate failure). If you use \|\|, you'll die if $that is false. Big difference. Dave	[reply] [d/l] [select]
Re^3: "or die" versus "\|\| die" by Anonymous Monk on Jun 24, 2005 at 20:30 UTC
Just because you're invoking die after an \|\| or a or doesn't mean you don't have to think about precedence. Consider the following: somesub $this, $that \|\| die; If you use 'or' here, you'll die upon failure of somesub (assuming it returns false to indicate failure). If you use \|\|, you'll die if $that is false. Big difference. If you call somesub with parens, the argument list is clearer to novice coders, the notation matches what they learned in grade 6 math class, and in this case, the precedence issue disappears. In my experience, thinking too hard about precedence is usually a clue that you're being too tricky with your code.	[reply]

Replies are listed 'Best First'.
Re^2: "or die" versus "\|\| die" by davido (Cardinal) on Jun 24, 2005 at 15:44 UTC
Just because you're invoking die after an \|\| or a `or` doesn't mean you don't have to think about precedence. Consider the following: `somesub $this, $that \|\| die;` [download] If you use 'or' here, you'll die upon failure of somesub (assuming it returns false to indicate failure). If you use \|\|, you'll die if $that is false. Big difference. Dave	[reply] [d/l] [select]
Re^3: "or die" versus "\|\| die" by Anonymous Monk on Jun 24, 2005 at 20:30 UTC
Just because you're invoking die after an \|\| or a or doesn't mean you don't have to think about precedence. Consider the following: somesub $this, $that \|\| die; If you use 'or' here, you'll die upon failure of somesub (assuming it returns false to indicate failure). If you use \|\|, you'll die if $that is false. Big difference. If you call somesub with parens, the argument list is clearer to novice coders, the notation matches what they learned in grade 6 math class, and in this case, the precedence issue disappears. In my experience, thinking too hard about precedence is usually a clue that you're being too tricky with your code.	[reply]