poemy - A poetry generator

Poemy is a program that creates computer-generated poetry in any meter or rhyming scheme. It was written by Justine Tunney using C++11 and lots of Googley libraries. Poemy works by using markov chains and the isledict speech pronunciation dictionary.

To learn more about how poemy works, see the developers section at the bottom.

Getting Started

First you need to install some dependencies:

• Google gflags: http://code.google.com/p/gflags/
• Google glog: http://code.google.com/p/google-glog/
• Google SparseHash: http://code.google.com/p/sparsehash/
• Optional: libunwind: http://www.nongnu.org/libunwind/
• Optional: Google gperftools: http://code.google.com/p/gperftools/
• Optional: Ragel State Machine Compiler: http://www.complang.org/ragel/

The following commands have been provided for your convenience if they're not available in your package manager:

sudo apt-get install pkg-config autoconf automake ragel
sudo ./install-gflags.sh
sudo ./install-glog.sh
sudo ./install-sparsehash.sh

Then build / install poemy as follows:

./autogen.sh
./configure
make
make check

Support for C++11 is still really goofy, especially since clang and GNU libstdc++ like to fight each other. If the commands above didn't work, you can also try installing clang and running CXX=clang++ ./configure. On other systems you might want to try running home to g++ with CXX=g++ ./configure.

Here's some example invocations of poemy:

./poemy
./poemy --help
./poemy --alsologtostderr --minloglevel=0
./poemy --alsologtostderr --tries=500 --lines=40 --corpora=goth --dict=isle

By default, poemy uses iambic pentameter. Here's how you can customize the meter to be the same as Edgar Allen Poe's The Raven:

./poemy --foot=trochaic --length=octameter

The generated poetry is very much influenced by the corpus text with which poemy is changed. By default, poemy uses goth music lyrics and sad poetry, but you can change this to use the literature corpus which currently contains the book "War and Peace" by Leo Tolstoy:

./poemy --corpora=literature
./poemy --corpora=goth,literature,shakespeare-sonnets

Example Poems

Even though poemy is in the experimental proof of concept stage, it still writes poetry better than most humans. Take for instance this poem which was generated from the goth corpus (included with poemy) in iambic pentameter using a couplet rhyming scheme. What you see below was generated verbatim; the only thing I changed was I added punctuation and removed two lines that ripped off Edgar Allan Poe too heavily.

We're lost in this cruel place your voice above
Young soul from out my heart be still in love
Worth this cruel place your voice from the deep snow
That this is the night of the world so slow
Will leave me as my hopes have flown before
Which answered not with a love that was more
I'm sitting in this kingdom by the grave
Your clothes by your voice at the stillness gave
She's gone to the floor floating on our side
She speaks in the earth and the truth inside
Have naught but the pain you feel the bright eyes
Beyond the waves wipe out my heart denies
Your voice from the laugh of the desolate
You're looking for the moon is full of hate
Forgive if I could change the time has come
We're lost in this world is not like a drum
Earth and the stillness broken by reply
Through the night tide I lie down in the sky
Beyond the waves wipe out the joyous light
And dancing in the power of the night
Want things to go before it is too late
Night tide I lie here in this world of hate
Away like the mist of the desolate
I'll show you all the world is full of hate
Pretend that I forgot who I was blind
Fall just to see the light in my own mind
Leave leave me as my hopes have flown before
Your clothes by your voice from the nightly shore
The london bridge is falling down my heart
Die! Please hang up now; I take it apart!
That's happened to my thoughts which help to note
Forever live on the earth and the boat
Whose name is on the ground and kiss those black
Melts into the deep of the faces back
Might have seen the end, you will understand
That's why I feel what I want my own land
Dear tokens of the saintly days abhor
Break all the night for me behind the door

This poem uses the same scheme but it was trained by the Shakespeare sonnet corpus. This time I generated two poems, one with a preference towards large words, the other for short words, and then I just sort of merged the lines together haphazardly.

O if I should despair I should despair
Lov'd I view in thee it is my love's fair
It no form of thee that the thought of hearts
But let your love and love that in thy parts
Assistance in my love's sweet face survey
Breathes even in the bay where all the day
Though absence seem'd my flame to qualify
Came tripping by but in the world must die
Translated and for that which flies before
Believe though in thy heart in love to score
Perfect'st love being made from thee I speed
Came tripping by but in my heart doth plead
On whom frown'st thou that which doth in it live
Phrase by all the world that I do forgive
Applying fears to hopes and hopes to fears
Believe though in thy glass and there appears
Mouthed graves will give thee so thine own bright eyes
Deliver'd from thy heart in love with sighs
Thee when I shall live your self but love hate
O no thy love though much is not so great
Time's leisure with my love's sweet face survey
Deliver'd from thy heart which I new pay
Friend's heart let my heart think that we before
Consum'd with that which is not love thee more
Remember'd not to love things nothing worth
Conceal'd wherein I am that I in earth
This to thee which thou hast passed by the height
As I think on thee when I in my sight
Thou shouldst print more not let that copy die
Still farther off from thee I both defy
Mine appetite I never more will grind
Believe though in my love that doth my mind
Contented when that mine eye may be straight
Return rebuk'd to my thoughts and my great
Where wasteful time debateth with decay
What conscience is born of love if I say
Those children nursed deliver'd from thy friend
Perfect'st love being made from thee I send
Eternal summer shall not be thy chief
Believe though in my love and all my grief
Breathes even in the world's due by the height
Believe though in my heart thy picture's sight
Love put in my thought whose love to hear why
Make my love thou my love that keeps mine eye
Thou shouldst print more not let that copy die
Deliver'd from thy walks and in the eye
And strangely but by all the better part
Thou stick'st not to love that thou shouldst depart
Increasing store with loss and loss with store
Return rebuk'd to my dear love to score
This separation I may change my state
Supposing thou art and that thou dost hate
At my abuses reckon up their own
What's in the world that I will not be shown
Soul that I cannot blame thee for her sake
Yet love knows it is but as the waves make
Deaf heaven with my love's sweet face survey
To play the tyrants to the world away
Bears it out even to the ending doom
Wait on thee in the world will be the tomb
Not on thy heart torment me with disdain
You live your epitaph to make one twain
Than theirs less false in this change is my heart's
Reigns love and all my soul which in thy parts
Might I from my love's picture then my friend's
That thou hast her it is my love depends
To show false art what beauty was of yore
Save where thou dost seek to have thy love more
The lack of many lives upon his gains
Him I lose thee my loss is my love's veins
This fair gift in me that you should prepare
Cheeks need blood in thee it is my love's fair
Most I wink then do mine eyes out of sight
If thou wilt thou art all the day or night
Thief whence didst thou steal thee all my grief lies
As you to love that in my heart and eyes
Dead there's no more be griev'd at that which flies
Home of love to thee but what they despise

Developers, Developers, Developers!

The algorithm that generates poetry is in src/main.cc and src/pronounce.cc contains the algorithm that determines if two words rhyme.

Rather than using pre-fabricated "mad libs", sentences are generated by randomly selecting words from a markov chain trained with corpus text. Here's what that data structure looks like with arbitrary sentinel values:

make_markov_chain("once upon a midnight dreary upon a moon") ->
  { (SENTINEL, SENTINEL): ["once"],
    (SENTINEL, "once"): ["upon"],
    ("once", "upon"): ["a"],
    ("upon", "a"): ["midnight", "moon"],
    ("a", "midnight"): ["dreary"],
    ("midnight", "dreary"): ["upon"],
    ("dreary", "upon"): ["a"],
    ("a", "moon"): [SENTINEL] }

So to generate a line, we choose a random key which gives us the first two words, then we pick a random word from that key's value list, and repeat. To learn more, see src/markov.cc and src/markov_test.cc.

The Markov class reads data from the Corpus class (src/corpus.cc) which is nothing more than a simple routine that tokenizes words from raw corpus text.

But we also need to know how words are pronounced. data/isledict/isledict0.2.txt will tell us how a word is pronounced in each accent, which sounds (phonemes) are contained in the word, where the syllables are broken apart, and which syllables are stressed. data/cmudict.txt is also supported, although it's less informative than isledict. To get a better understanding of how this data structure works, see src/cmudict_test.cc.

The code inside .rl files that parses the dictionary files is written using a tool called [[http://www.complang.org/ragel/][ragel]] which is a state machine compiler. Even though the syntax is a bit daunting, I like to use Ragel because I'm not smart enough to write high-performance parsers by hand that are free of bugs / security holes without expending a tremendous amount of effort.

Using the data from these dictionaries, we are able to determine if words rhyme and match the desired rhythm.

The Dict class also serves the important purpose of assigning an int ID to each word in the english language. This makes the poetry generating algorithms significantly faster.

This code is written in conformance to the Google style guide with the exception of using STL streams and some unapproved C++11 features.