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Re^4: Idiomatic optimizations

by tadman (Prior)
on May 01, 2002 at 08:37 UTC ( #163222=note: print w/ replies, xml ) Need Help??


in reply to Re: Re: Re: Idiomatic optimizations
in thread Idiomatic optimizations

Don't forget that ?: can get dangerous, not unlike juggling running chainsaws. It's a great show, but is liable to injure yourself something fierce:

$foo = $a? $b? $c : $d? $e : $f : $g : $h;
Sometimes an if is more verbose, but undeniably precise.

Instead of getting carried away with ?:, you can sometimes compact it using the regular logical operators || and &&. It really depends on what you're working with.


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Re: Re^4: Idiomatic optimizations
by demerphq (Chancellor) on May 02, 2002 at 13:13 UTC
    Hmm I sort of agree with your point, but Im troubled by your fierce but syntactically incorrect example (ternary ops should always have the same number of '?' as ':' )
    $a=1;$b=2;$c=3;$d=4;$f=5;$g=6;$h=7; $foo = $a? $b? $c : $d? $e : $f : $g : $h; print $foo; __END__ syntax error at C:\temp\ternary.pl line 2, near "$g :" Execution of C:\temp\ternary.pl aborted due to compilation errors.
    I believe that you meant to say
    $foo = $a ? $b ? $c : $d ? $e : $f : $g;
    My personal rule of thumb is that ternary ops should not be nested but may be chained. Thus I would say that your example could be rewritten
    $foo = !$a ? $g : $b ? $c : $d ? $e : $f;
    And its a little less troublesome. Even then I personally would add some whitespace so it would look like
    $foo = !$a ? $g : $b ? $c : $d ? $e : $f;
    This and a bit of paretheses would also help your nested example
    $foo = $a ? ($b ? $c : ($d ? $e : $f)) : $g;
    I find that formatting ternaries like this makes them only marginally more difficult to read than if statements, but I still tend to avoid nested ternaries.

    Yves / DeMerphq
    ---
    Writing a good benchmark isnt as easy as it might look.

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