Re^2: Reading binary files - program structure

I think would prefer to use subs rather than string eval here. Eg.

my %varlengths = (
    'that' => sub(){ 2 }, 
    'theother' = sub{ $v{this}*2 },
}
...
  $readlength = $varlengths{$var}->(); # compute it
[download]

Slightly more work, but worth it I think.

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority".

In the absence of evidence, opinion is indistinguishable from prejudice.

RIP an inspiration; A true Folk's Guy

Comment on Re^2: Reading binary files - program structure Download Code

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Re^3: Reading binary files - program structure by Anonymous Monk on May 25, 2010 at 16:47 UTC
Interesting, I didn't even know you could do that! Presumably the advantage is speed? Being a compile-time thing rather than a run-time eval? If/when I finally make progress on this I'll compare the approaches.	[reply]
Re^4: Reading binary files - program structure by BrowserUk (Patriarch) on May 25, 2010 at 20:50 UTC
Presumably the advantage is speed? Being a compile-time thing rather than a run-time eval? That's a beneficial side-effect of avoiding string eval. But mostly just a healthy aversion to using it, if it is easier to avoid it. I don't subscribe to the evil-eval notion--if I need to evaluate a runtime mathematical expression, I will. Far easier to use Perl's expression parser than write my own, or discover the limitations of someone else's--but for the usage outlined, everything is known at compile-time, so no need to invoke the compiler again (multiple times) at runtime. Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error. "Science is about questioning the status quo. Questioning authority". In the absence of evidence, opinion is indistinguishable from prejudice. RIP an inspiration; A true Folk's Guy	[reply]