view release on metacpan or  search on metacpan

lib/Acme/AsciiArtinator.pm  view on Meta::CPAN

         \ \ \/____|____\/ / /
          \ \/_____|_____\/ /
           \/______|______\/
           /       |       \

=head1 UNDER THE HOOD

To fill in the shape of the spider, we inserted whitespace,
semi-colons, sharps, and maybe the occasional C<{> C<}> pair
into the original code. Certain blocks of text, like
C<print>, C<while>, and C<y#_ # _#> are kept intact since
splitting them would cause the program to either fail to
compile or to behave differently. 

The ASCII Artinator tokenizes the code and
does its best to identify 

=over 4

=item 1. Character strings that must not be divided

These include alphanumeric literals, quoted strings,
and most regular expressions.

=item 2. Places in the code where it is OK to insert padding.

=item 3. Places in the ASCII artwork where there are multiple
consecutive darkspace characters

=back

The next step is to try to align the tokens from the code
with enough contiguous blocks of darkspace in the art. When
a token is misaligned, we attempt to align it by inserting
some padding at some point in the code before that token.

There are currently two ways that we pad the code. Each
time there is a need to pad the code, we randomly choose
a padding method and randomly choose an eligible position
for padding.

=over 4

=item 1. Inserting semi-colons at the beginning or end of a statement

In general, we can put as many semi-colons as we like at the beginning
or end of statements. The following lines of code should all do the
same thing:

    $a=$b+$c;$d=4
    $a=$b+$c;;;;;;$d=4;;;;;;
    ;;;;;;;;;$a=$b+$c;;;;;;;;$d=4;

=item 2. Putting braces around a variable name.

In general, we can replace C<$name> with C<${name}> and the code
will run the same.

=back

There are several other interesting ways to pad code (putting parentheses
around expressions, adding and or-ing zeros to expressions, using quoted
strings in a void context) that may be put to use in future versions
of this module.

When all tokens from the code are successfully aligned with the
blocks of darkspace from the artwork, we can paste the code on top
of the art and write the output file. 

Sometimes we insert too many characters without successfully
aligning the tokens and darkspace blocks (and actually in the
spider example, this happens about 90% of the time). If this
happens, we will start over and retry up to 100 times.

=head1 BEST PRACTICES

Certain coding practices will increase the chance that
C<Acme::AsciiArtinator> will be able to embed your code
in the artwork of your choice. In no particular order,
here are some suggestions:

=over 4

=item * Make sure the original code works

Make sure the code compiles and test it to see if it
works like you expect it to
before running the ASCII Artinator. It would be frustrating to
try to debug an artinated script only to later realize that
there was some bug in the original input.

=item * Get rid of comments

This module won't handle comments very well. There's no way
to stop the ASCII Artinator from splitting your comment across
two lines and breaking the code.

=item * Reduce whitespace

In addition to making the code longer and thus more difficult
to align, any whitespace in your code will be printed out as
space over a darkspace in the art and put a "hole" in your
picture. It would be nice if there was a way to align the
whitespace in the code with the whitespace in the art, but that
is probably something for a far future version.

=item * Avoid significant newlines

Newlines are stripped from the code before the code is tokenized.
If there are any significant newlines (I mean the literal 0x0a char.
It should still be OK to say  C<print"\n">), then the artinated
code will run differently.

=item * Consider workarounds for quoted strings

Quoted strings are parsed as a single token. Consider ways to break
them up so that can be split into multiple tokens. For example, instead
of saying C<$h="Hello, world!";>, we could actually say something like:

    &I;($c,$e)=qw(, !);$h=H.e.l.l.o.$c.$".W.o.r.l.d.$e;