I like the first one (it would've been better to post them separately, anyway). Reminds me of the old trick of checking balanced parentheses: 
#!/usr/bin/perl
use warnings;
use strict;
use feature qw{ say };

my $size = shift;
my @strings;

sub recurse {
    my ($string) = @_;
    if (2 * $size > length $string) {
        recurse($_ . $string) for qw/ ( ) /;
    } else {
        push @strings, $string if eval "qw($string) and 1";
    }
}

recurse($_) for qw/ ( ) /;
say for sort @strings;

[download]

($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,

[download]

In reply to Re: Two small programs for comment by choroba
in thread Two small programs for comment by Jambo Hamon

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