my $match = "\Q" . join ("\E|\Q", keys %translate) . "\E";

##</code><code>##

>perl -wMstrict -le
"my %translate = (
   'tr??u++e' => 1,
   'fa+l?se'  => 0,
   );
 ;;
 my $match = qq{\Q} . join(qq{\E|\Q}, keys %translate) . qq{\E};
 print qq{'$match'};
 $match = qr{$match};
 print $match;
 ;;
 my $mooch = '\Q' . join('\E|\Q', keys %translate) . '\E';
 print qq{'$mooch'};
 $mooch = qr{$mooch};
 print $mooch;
"
'tr??u++e|fa+l?se'
(?-xism:tr??u++e|fa+l?se)
'\Qtr??u++e\E|\Qfa+l?se\E'
Unrecognized escape \Q passed through in regex...
Unrecognized escape \E passed through in regex...
Unrecognized escape \Q passed through in regex...
Unrecognized escape \E passed through in regex...
(?-xism:\Qtr??u++e\E|\Qfa+l?se\E)

##</code><code>##

>perl -wMstrict -le
"my %xlate = (
   A    => '1',
   AA   => '2',
   AAA  => '3',
   AAAA => '4',
   );
 my $mooch = join '|', keys %xlate;
    $mooch = qr{ (?i) $mooch }xms;
 my $match = join '|', reverse sort keys %xlate;
    $match = qr{ (?i) $match }xms;
 print $mooch;
 print $match;
 ;;
 my $s = 'xAxAAxAAAxAAAAx';
 print qq{'$s'};
 $s =~ s{ ($mooch) }{$xlate{ uc $1 }}xmsg;
 print qq{'$s'};
 ;;
 $s = 'xAxaaxAaAxaAaAx';
 print qq{'$s'};
 $s =~ s{ ($match) }{$xlate{ uc $1 }}xmsg;
 print qq{'$s'};
"
(?msx-i: (?i) A|AA|AAAA|AAA )
(?msx-i: (?i) AAAA|AAA|AA|A )
'xAxAAxAAAxAAAAx'
'x1x11x111x1111x'
'xAxaaxAaAxaAaAx'
'x1x2x3x4x'

##</code><code>##

>perl -wMstrict -le
"my %xlate = (
   'string a' => '3',
   'string b' => '2',
   true       => '1',
   false      => '0',
   tt         => '22',
   ttt        => '33',
   );
 my $xl = join '|', map { quotemeta } reverse sort keys %xlate;
    $xl = qr{ (?i) \b (?: $xl) \b }xms;
 ;;
 my $s =
   'vv TTT ww TT String A xx sTrInG b xtruex True yy FALSE zz';
 print qq{'$s'};
 ;;
 $s =~ s{ ($xl) }{$xlate{ lc $1 }}xmsg;
 print qq{'$s'};
"
'vv TTT ww TT String A xx sTrInG b xtruex True yy FALSE zz'
'vv 33 ww 22 3 xx 2 xtruex 1 yy 0 zz'