Re^2: Is it safe to use external strings for regexes? (use Safe)

FWIW: there is the Safe module to disallow certain Op-codes inside a (r)eval.

use Safe;

$compartment = new Safe; 

$compartment->permit(qw(time sort :browse));

$result = $compartment->reval($unsafe_code);
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Unfortunately I couldn't find a way to disable compiletime blocks like BEGIN and there doesn't seem to be another way to disable or override BEGIN...

I'd love to be corrected.

UPDATE

oh Keyword::Simple could do the trick :)

Cheers Rolf
_{(addicted to the Perl Programming Language :)

Wikisyntax for the Monastery}

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Re^3: Is it safe to use external strings for regexes? (Keyword::Simple)
by LanX (Saint) on Oct 06, 2021 at 17:06 UTC

use strict;
use warnings;
use Keyword::Simple;

sub no_begin ($&){
    warn "no_begin(@_) called";
}

my @code;

BEGIN{
    my @compile_blocks = qw(BEGIN UNITCHECK CHECK INIT END);

    for my $block (@compile_blocks) {

        # bend parser
        Keyword::Simple::define $block, sub {
            my ($ref) = @_;
            substr($$ref, 0, 0) = "no_begin '$block', sub";
        };

        # test code
        push @code , <<__CODE__;
        $block { die "owened by $block" }
__CODE__

    }
}

BEGIN { die "owened by BEGIN" };
UNITCHECK { die "owened by UNITCHECK" };
CHECK { die "owened by CHECK" };
INIT { die "owened by INIT" };
END { die "owened by END" };

eval join "\n", @code;
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-*- mode: compilation; default-directory: "d:/tmp/pm/" -*- Compilation started at Wed Oct 6 19:04:01 C:/Strawberry/perl/bin\perl.exe -w d:/tmp/pm/KW_simple_regex_BEGIN.pl no_begin(BEGIN CODE(0x694268)) called at d:/tmp/pm/KW_simple_regex_BEG +IN.pl line 6. no_begin(UNITCHECK CODE(0x6556d0)) called at d:/tmp/pm/KW_simple_regex +_BEGIN.pl line 6. no_begin(CHECK CODE(0x6942b0)) called at d:/tmp/pm/KW_simple_regex_BEG +IN.pl line 6. no_begin(INIT CODE(0x6c8aa0)) called at d:/tmp/pm/KW_simple_regex_BEGI +N.pl line 6. no_begin(END CODE(0x6c8c38)) called at d:/tmp/pm/KW_simple_regex_BEGIN +.pl line 6. Bareword found where operator expected at (eval 5) line 5, near "} CHECK" (Missing operator before CHECK?)
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But unfortunately does evaling the code not catch parsing errors anymore... (reason here BEGIN{} blocks don't need a trailing semicolon)

so the answer is:

Yes BEGIN* blocks can be disabled.
But this is best done in an extra process

Cheers Rolf
_{(addicted to the Perl Programming Language :)

Wikisyntax for the Monastery}

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