G'day abualiga,

As ++NetWallah points out, eval can be unsafe.

If your eval code started off like this: 

$ perl -Mstrict -Mwarnings -E 'say eval for map { "12 $_ 3" } qw{+ - *
+ / % **}'
15
9
36
4
0
1728

[download]

Using a despatch table like this is a safer option. 

$ perl -Mstrict -Mwarnings -E '
    my %op_hash = (
        q{+}    => sub { $_[0] + $_[1] },
        q{-}    => sub { $_[0] - $_[1] },
        q{*}    => sub { $_[0] * $_[1] },
        q{/}    => sub { $_[0] / $_[1] },
        q{%}    => sub { $_[0] % $_[1] },
        q{**}   => sub { $_[0] ** $_[1] },
    );
    say for map { $op_hash{$_}->(12, 3) } qw{+ - * / % **};
'
15
9
36
4
0
1728

[download]

And you can add your own sanity checks: 

$ perl -Mstrict -Mwarnings -E '
    my %op_hash = (
        q{+}    => sub { $_[0] + $_[1] },
        q{-}    => sub { $_[0] - $_[1] },
        q{*}    => sub { $_[0] * $_[1] },
        q{/}    => sub { die "Divide by zero!" if $_[1] == 0; $_[0] / 
+$_[1] },
        q{%}    => sub { $_[0] % $_[1] },
        q{**}   => sub { $_[0] ** $_[1] },
    );
    say for map { $op_hash{$_}->(12, 0) } qw{+ - * / % **};
'
Divide by zero! at -e line 6.

[download]

I don't know what context you're intending to use this in: the overload pragma may be of some use.

Update: s/unsafe:/unsafe./ and added "If your eval code started off like this: "

-- Ken

In reply to Re: interpolating operators within strings by kcott
in thread interpolating operators within strings by abualiga

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