Hello henzcoop,

You’re nearly there. But (1) eval returns the value of the last expression evaluated; but you don’t want the number of transliterations, you want the transliterated string, which is $message. (2) Within an eval, a variable such as $message will itself be interpolated. But you want to evaluate the expression $message =~ ..., so you need to escape the $ sigil to prevent interpolation of the $message variable into the string to be evaluated.

#! perl
use strict;
use warnings;

print "Please enter your message to be encrypted.\n";

my $message = <STDIN>;
chomp($message);

# generate randomized alphabet
my @chars = ("A".."Z", "a".."z");
my $string;
$string .= $chars[rand @chars] for 1..26;

# I want to drop the random alphabet in $string into the replace-with 
+slot of tr//
eval "\$message =~ tr/a-z/$string/;";

print "Here is your encrypted message: $message\n";
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Alternatively, you can add an /r modifier to the transliteration to get it to return the transliterated value:

my $code = eval "\$message =~ tr/a-z/$string/r;";

print "Here is your encrypted message: $code\n";
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See the entry for tr/SEARCHLIST/REPLACEMENTLIST/cdsr under perlop#Quote-Like-Operators.

Hope that helps,

Hey, look at that--it works! Thanks for walking me through this, Athanasius. You're a natural teacher.

tr/// modifies the string you apply it to rather than returns the modified value. And, you need string eval not block eval:

eval "\$message =~ tr/abcdefghijklmnopqrstuvwxyz/$string/);
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Note that you must escape $message, but not $string. After the above code, $message will contain the "secret code".

(One thing: How are you going to decrypt it, given that the encryption key will be lost when the program ends?)

Good question, Browser. The de-encryption step will take some thought. For now, though, I can at least make my very own cryptograms. Thanks for the feedback!

For now, though, I can at least make my very own cryptograms.

Not so useful if you can't decrypt them; but ...

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This will cause problems when decoding, because multiple letters will be mapped to those repeated letters.

Here is (an inefficient, but functioning) way to avoid that when creating $string:

my $string = join '',map {splice(@chars,rand @chars,1)} 1..26;
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You need to change the context:

my $code;
eval "(\$code = \$message) =~ tr/abcdefghijklmnopqrstuvwxyz/$string/";
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# in
steve

#out
fnbrb
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Thanks, Steve, that also worked. I guess that's how perl got its "TMTOWTDI" reputation.