Mastering Perlに含めるためにSafeモジュールで遊んでいます。v5.16 (サポートされている最も古いバージョン) より前のバージョンは、新しいキーワードを理解していないようです。何か不足していますか？
v5.16以降で動作すると言う
use v5.10;
use Safe;
say "Running $0 under $^V with Safe ", Safe->VERSION;
my $compartment = Safe->new;
$compartment->permit( ':base_io', ':load' );
my $code =<<"CODE";
use v5.10;
say "Hello Safe!";
CODE
$compartment->reval( $code ) or do {
my $error = $@;
warn "Safe compartment error! $@";
};
このコードは、v5.18 と v5.16 (公式にサポートされている Perl の 2 つのバージョン) で期待どおりに動作します。
% perl5.18.0 safe.pl
Running safe.pl under v5.18.0 with Safe 2.35
Hello Safe!
% perl5.16.3 safe.pl
Running safe.pl under v5.16.3 with Safe 2.35
Hello Safe!
sayキーワードが有効であるとは考えていないため、v5.16 より前では機能しません。
% perl5.14.4 safe.pl
Running safe.pl under v5.14.4 with Safe 2.35
String found where operator expected at (eval 5) line 2, near "say "Hello Safe!""
(Do you need to predeclare say?)
Safe compartment error! syntax error at (eval 5) line 2, near "say "Hello Safe!""
% perl5.12.3 safe.pl
Running safe.pl under v5.12.3 with Safe 2.35
String found where operator expected at (eval 5) line 2, near "say "Hello Safe!""
(Do you need to predeclare say?)
Safe compartment error! syntax error at (eval 5) line 2, near "say "Hello Safe!""
% perl5.10.1 safe.pl
Running safe.pl under v5.10.1 with Safe 2.35
String found where operator expected at (eval 5) line 2, near "say "Hello Safe!""
(Do you need to predeclare say?)
Safe compartment error! syntax error at (eval 5) line 2, near "say "Hello Safe!""
状態は機能しませんが、別の方法で壊れます
状態によって違います。
use v5.10;
use Safe;
say "Running $0 under $^V with Safe ", Safe->VERSION;
my $compartment = Safe->new;
$compartment->permit( ':base_io', ':load' );
my $code =<<'CODE';
use v5.10;
print "Hello Safe!\n";
foo();
sub foo {
state $n = 0;
print "n is $n\n";
}
CODE
$compartment->reval( $code ) or do {
my $error = $@;
warn "Safe compartment error! $@";
};
v5.18 と v5.16 は状態が構文エラーであると考えています:
% perl5.18.0 safe.pl
Running safe.pl under v5.18.0 with Safe 2.35
Hello Safe!
n is 0
% perl5.16.3 safe.pl
Running safe.pl under v5.16.3 with Safe 2.35
Hello Safe!
n is 0
stateそれらのバージョンの前は、間接的な方法として扱っていると思います:
% perl5.14.4 safe.pl
Running safe.pl under v5.14.4 with Safe 2.35
Hello Safe!
Safe compartment error! Can't call method "state" on an undefined value at (eval 5) line 5.
与えられた
given同じ問題があります：
use v5.10;
use Safe;
say "Running $0 under $^V with Safe ", Safe->VERSION;
my $compartment = Safe->new;
$compartment->permit( ':base_io', ':load' );
my $code =<<'CODE';
use v5.10;
print "Hello Safe!\n";
my $foo = 'Buster Bean';
given( $foo ) {
when( /Buster/ ) { print "Buster\n" }
}
CODE
$compartment->reval( $code ) or do {
my $error = $@;
warn "Safe compartment error! $@";
};
v5.16 と v5.18 では問題なく動作します。
% perl5.18.0 safe.pl
Running safe.pl under v5.18.0 with Safe 2.35
given is experimental at (eval 5) line 4.
when is experimental at (eval 5) line 5.
Hello Safe!
Buster
ただし、以前のバージョンでは壊れています。
% perl5.14.4 safe.pl
Running safe.pl under v5.14.4 with Safe 2.35
Safe compartment error! syntax error at (eval 5) line 4, near ") {"