Uri Guttman wrote: Thanks to all for the fantastic feedback, and for the very detailed examples. After reading and practising them a few times, I don't think I'll ever be able to forget how to use this op anymore :)
> it is actually very simple to understand. the key point to knowing it > and how to use it is that the 2 value expressions SHOULD NOT have side > effects. that means changing something by assignment or other > modification. your example below is one exception to that. Since I use functions/methods to perform side effects frequently, I believe what you mean is that in *most* cases, the conditional op shouldn't ever have anything that must be evaluated in one of the either/or fields. For example, this: my $num = 1; my $add_to = 2; my $ret = ( $foo == 1 ) ? ( $num + $add_to ) : 2; ...SHOULD _always_ ( where possible ) be written as: my $expr_result = ( $num + $add_to ); my $ret = ( $foo == 1 ) ? $expr_result : 2; > whenever you see an if/else where the code just assigns one or another > value to the same variable that should be coded as a ternary op as this > is what is it designed to do: > > $gst = ( $gst eq 'Yes' ) ? $self->tax_rate( 'gst' ) : 0 ; > > now, using the same variable $gst for the input and then a value is > slightly dodgy IMO. I agree completely with the "dodgy" comment. In fact, at the same time I'm writing new code, I'm noticing "red flags" in adjacent code, and changing it as I go. The more I learn, the more I'm changing. Recently, I was bit by a self-induced 'bug' by doing something very similar, and it took hours to track down. ( may as well vent about my 12 hour, a full day and a half to track problem, simply by having a forgotten-about global variable. Code goes > 600 lines, and results were far from what I expected. I noticed the global var in a diff in passing, removed it, and voila... ). > this is common dumbass code as it breaks what > the conditional op is for and also breaks the code because of > precedence: > > ( $foo == 0 ) ? $bar = 1 : $bar = 2 ; > > i won't go deeper into the precedence bug but instead focus on the > dumbass part. why is that coded assigning to the same var inside the ?: > ? the whole point of ?: is to get a value from one of two choices to > USE. so that should be written as: > > $bar = ( $foo == 0 ) ? 1 : 2 ; I definitely get it now :) Thanks for the straight-up explanation. ...and thanks John for all of the different examples. Cheers! Steve
smime.p7s
Description: S/MIME Cryptographic Signature
