Just to make it clear, do not use EVAL() ever on untrusted user input. In the example I wrote, if the string contained a '>', anything after that point would be executed. While it works, it's a bad idea to use it.
On Mon, Jul 17, 2017 at 2:17 AM, ToddAndMargo <toddandma...@zoho.com> wrote: > On Sun, Jul 16, 2017 at 11:34 PM, ToddAndMargo <toddandma...@zoho.com >>> <mailto:toddandma...@zoho.com>> wrote: >>> >>> On 07/16/2017 07:48 PM, Brent Laabs wrote: >>> >>> $ perl6 >>> > my $x='ls -al "Program Files" "Moe Curly Larry"'; >>> ls -al "Program Files" "Moe Curly Larry" >>> > &EVAL( "qww<$x>" ).perl >>> ("ls", "-al", "Program Files", "Moe Curly Larry") >>> >>> How about this? Obligatory: Much EVAL, very danger wow. >>> >>> >>> I don't understand. Would you put this into a full executable >>> example? >>> >>> >>> > On 07/17/2017 02:08 AM, Brent Laabs wrote: > >> I would put it in an executable example, and I already did. But here's >> another one, if you like. >> >> $ perl6 -e 'my $x = q<ls -al "Program Files" "Moe Curly Larry">; my @y = >> &EVAL( "qww<$x>"); for @y.kv -> $i, $j { say " \@y[$i] = \c39$j\c39" }' >> @y[0] = 'ls' >> @y[1] = '-al' >> @y[2] = 'Program Files' >> @y[3] = 'Moe Curly Larry' >> >> The last loop is just so it's printed in the way you demonstrated in the >> first post. >> >> The main point of me writing that example in the first place is because I >> know that the Perl 6 language itself is very good at parsing quotes. If >> you knew what the string was at compile time, you could just write this: >> my @y = qww<ls -al "Program Files" "Moe Curly Larry">; >> And it would know exactly how to deal with the quotes. But I don't know >> how to access this functionality of the quote language from within the Perl >> 6 language. You can't use qqww directly, because the quote protection is >> handled before interpolation, and we want it to happen after. So I can >> eval a qww string instead, and that does work, though it does recognize >> kinds of quoting that you wouldn't expect, like dumb quotes or halfwidth >> katakana quotes. >> >> All of this is to say that I wish the Str.words method had a way of >> applying Perl 6 quoting rules as if it were the qww operator. >> >> > Thank you! > > > -- > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > Computers are like air conditioners. > They malfunction when you open windows > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >
