seuss

A Python system for generating rhyming poetry with Markov chains.

Overview

The Rhyming Robot (seuss) uses Markov chains to generate random text. The chains are generated from analysis of selected source texts placed in the sources/ directory -- preferably source texts of 50,000 words or greater. Each line in a poem can be generated using different source texts, allowing surprising and amusing combinations (the Bible and legal disclaimers, for instance).

Markov chains are generated in advance and cached in the cache/ directory by makeChains.py. There are three Markov chains used:

• A forward-looking 2nd-order chain; that is, the next word depends on the previous two.
• A reverse-looking 2nd-order chain
• A reverse-looking 1st-order chain

The basic process looks like this:

1. The first line of the poem is generated using the forward-looking chain.
2. If the second line does not need to rhyme, it uses the forward chain. Otherwise, it uses the rhyming dictionary to find words that rhyme, then attempts to find those words in the reverse 1st-order chain. This chain is used to find the next-to-last word, and the line is filled in in reverse usng the 2nd-order chain after this.
3. Subsequent lines follow the same process, according to the supplied rhyme scheme.

Setup

The rhyming dictionary is contained in data/words.sql.gz. You'll need to import this into an SQLite database named data/sql-words. To do this, open a shell in the data/ directory and type:

$ gunzip words.sql.gz
$ sqlite3 sql-words
SQLite version 3.7.13 2012-06-11 02:05:22
Enter ".help" for instructions
Enter SQL statements terminated with a ";"

sqlite> .read words.sql
sqlite> .quit

This creates the database and reads the data into it. You're now ready to use the Rhyming Robot.

Usage

First, supply the robot with a source text. Ideal source texts are very long (50,000 words or more) and amusing. Choose a source with a normal English vocabulary -- the rhyming dictionary does not understand specialized terminology or foreign languages. You may supply as many source texts as you like and switch between them.

In this example, we will use the World English Bible from ebible.org; use the plain-text version and put it all in one text file. Cut out any parts you do not want and save it in sources/ as bible-raw.txt.

Next, run format.pl to split the file into sentences:

$ format.pl bible

format.pl will take name-raw.txt and transform it into name.txt, which contains the same source with one sentence per line. This can be loaded by the Markov chain generator.

Heading back up to the directory containing makeChains.py, run:

$ python makeChains.py bible

This may take a long time. Ensure the script has access to the cache/ directory and can create files there. Once done, there should be three new files in cache/ containing the Markov chains.

Now you'll need to edit the people dictionary in rhyme.py to know about your new source. The dictionary maps single characters to source names; you'll use these characters when choosing what sources will be written in your poem.

You can now write poetry. If you added the Bible with code b in the people dictionary, you can specify a rhymescheme aabba and personality bbbbb to have the generator use the Bible for every line. The personality specification must be the same length as the rhymescheme.

Run python rhyme.py to see the detailed usage instructions.

IRC Bot

seuss.py contains a very simple IRC bot based on twisted.words. It contains a number of hard-coded configuration parameters; you will have to adjust it to your needs.

By default, it loads the "brains" (source texts, which must have premade Markov chains in cache/) specified in self.brains. self.chatFraction gives the fraction of messages which are responded to by the robot automatically; the bot will respond to random messages along with any message that mentions its name.

The server can be specified in the block at the bottom of the file, and the channel name must be given when the bot is started; e.g.,

$ python seuss.py channelName

The bot will join any channel it is /invited to, so be wary. It will also respond to any /msg directed to it; be careful of infinite loops that may occur when a bot msgs the rhyming bot. (For example, in testing the bot received a msg from NickServ on connecting, responded, received an "unknown command" error, responded, etc.) You can use self.nickExcludeList to avoid this issue.

Web Interface

The web interface is not recommended, as poetry generation can use a substantial amount of processing power. Nevertheless, for your amusement, poetry.php is included. Simply place the rhyming robot in a web-accessible directory and point people to poetry.php. Make sure they can't invoke the Python files from the web, of course. poetry.php must be adjusted with a list of all the valid source texts you have provided.

Recommended References

It turns out that random generation of amusing content has been around for a while. Here's some suggestions:

• Wisdom of Chopra, a random Deepak Chopra quote generator.
• Mathgen, a random academic mathematics paper generator
• A poem generator in Haskell