dan-the-shell.pl

use strict;
use warnings;
use URI::Escape 'uri_escape';
use LWP::UserAgent;
use JSON 'decode_json';
use Term::ReadLine;

my $ua = LWP::UserAgent->new(agent => "Dan the shell");
&main;exit;

sub main {
    if (@ARGV) {
        my $src = do { local $/; <> };
        die "invalid dan" unless $src;
        do_dan($src);
        exit;
    }

    my $term = Term::ReadLine->new("Dan the shell");
    while (defined($_ = $term->readline("dan> "))) {
        do_dan($_);
        $term->addhistory($_) if /\S/;
    }
}

sub do_dan {
    my $src = shift;
    $_ =~ s/\n//;
    $_ =~ s/^\s+//;
    $_ =~ s/\s+$//;

    if ($src =~ /^ls\s+(.+)$/) {
        $src = sprintf q{use File::Spec; opendir my $d, '%s' or die $!;print join "\n", map { File::Spec->catfile('%s', $_) } readdir($d);}, $1, $1;
    } elsif ($src =~ /^cat\s+(.+)$/) {
        $src = sprintf q{open my $f, '%s' or die "$! '%s'";print do { local $/; <$f>;}}, $1, $1;
    } elsif ($src eq 'ENV') {
        $src = 'while (my($k, $v) = each %ENV) { print "$k => $v\n" }';
    } elsif ($src eq 'INC') {
        $src = 'print join "\n", @INC;';
    } elsif ($src eq 'SEGV') {
        $src = 'unpack "p", 0xdeadbeef';
    } elsif ($src eq 'RUN') {
        use Path::Class;
        my $src = file('run.pl')->slurp;
        $src = $src;
    }

    print "Your code is ", length($src), " bytes\n";

    my $url = "http://api.dan.co.jp/lleval.cgi?l=pl&c=c&s=" . uri_escape($src);
    print "access to $url\n";
    my $res = $ua->get($url);
    if ($res->is_success) {
        my $json = $res->content;
        $json =~ s/c\((.+)\);\n/$1/;
        my $dat = eval{ decode_json $json };
        if ($dat->{error}) {
            print $dat->{error}, "\n";
        } elsif (defined $dat->{result}) {
            print $dat->{result}, "\n";
        } else {
            print "invalid json: $json\n";
        }
    } else {
        print $res->status_line, "\n";
    }
}