Re^2: Logic expression evaluation not working. What am I doing wrong?

in reply to Re: Logic expression evaluation not working. What am I doing wrong?
in thread Logic expression evaluation not working. What am I doing wrong?

#from Anonymous Monk code
> my %allowed = qw{ ( ( ) ) ! !! & &&  };
> my $finalExpr = map { $allowed{$_} || die "not allowed '$_'" } split
+ '', $expr;
[download]

The %allowed hash doesn't look right and it isn't, among other things because it forgets digits [0-9]. A solution along these lines might do something like using taint mode for the script and then:

 print "EXPR = ",$newExpr,"\n";

 # don't know how to execute shell commands without [A-Za-z] letters
 $newExpr =~ /^([\d\s()&|!]+)$/;
 printf "%b\n", eval $1;
}
[download]

Ron

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Re^3: Logic expression evaluation not working. What am I doing wrong? by AnomalousMonk (Archbishop) on Jan 04, 2016 at 20:02 UTC
The %allowed hash doesn't look right ... I would be more concerned about the map statement: `c:\@Work\Perl>perl -wMstrict -le "my $expr = '(!(C)&T)&!Q'; my %allowed = qw{ ( ( ) ) ! !! & && C 1 T 1 Q 1 }; my $finalExpr = map { $allowed{$_} \|\| die qq{not allowed '$_'} } spli +t '', $expr; print qq{'$finalExpr'}; " '11'` [download] Give a man a fish: `<%-{-{-{-<`	[reply] [d/l] [select]
Re^4: Logic expression evaluation not working. What am I doing wrong? by Anonymous Monk on Jan 04, 2016 at 20:42 UTC
I would be more concerned about the map statement: :D I was hoping the OP would be concerned when trying, so he can get a link to Basic debugging checklist Then add the missing `join '',`	[reply] [d/l]
Re^5: Logic expression evaluation not working. What am I doing wrong? by AnomalousMonk (Archbishop) on Jan 04, 2016 at 20:50 UTC
The map also fails if any of `C T Q` is 0. This is easily fixed, but as you say, it's always nice to try stuff. Give a man a fish: `<%-{-{-{-<`	[reply] [d/l] [select]
Re^3: Logic expression evaluation not working. What am I doing wrong? by Anonymous Monk on Jan 04, 2016 at 18:41 UTC
Why would boolean logic need more than 1 and 0? If using %allowed all the values are already untainted	[reply]

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