Hi Bryan!
On Saturday 20 Feb 2010 04:53:18 Bryan R Harris wrote:
> This is unintuitive:
>
> perl -e 'print "> "; while(<>) {print(( eval $_ )[-1], "\n> ")}'
>
> ... then enter 2*012. It prints "20". 2*12 is obviously 24, but perl's
> interpreting that "012" as octal. We sometimes have our numbers zero
> padded to make the columns line up, they're not octal.
>
> Is there any way to keep perl's eval from interpreting numbers starting
> with "0" as octal?
No, there isn't. But why are you writing a custom calculator using eval? A
user may enter something like << system('rm -fr $HOME'); >> and get his home
directory deleted. And other stuff like that.
If you're interested in writing a calculator or a different interpreter the
look at parser-generator modules:
http://www.nntp.perl.org/group/perl.module-authors/2009/09/msg7844.html
(Also see the replies).
Regards,
Shlomi Fish
>
> I tried to regex them out but that regex is tricky since I'm writing a
> custom calculator, and I have no idea what the user might enter.
>
> TIA.
>
> Bryan
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