generate.py

#!/usr/bin/env python
from pymarkov import markov
from random import choice
import doctest
import argparse


class Generate:
    """ A song generator. Generate takes input (musician, album) and returns
        a version of that musician's songs.

        It expects songs in a text file, in a directory structure such as:
        ./music
            /artist_name
                album_title <-- that's the text-file, no extension   

        It requires pymarkov, via https://pypi.python.org/pypi/PyMarkov/0.1.0
        This version of pymarkov prints all input out, removing that print
        statement increases sanity.

        TODOs:
            * Build out a whole song
            * Build in song variance (self.attributes)
            * How build a rhyme?
        >>> generate = Generate('elliott_smith')
        >>> song = generate.build_song('either_or')
        >>> print song['title']
        Elliott Smith, Either Or
        """

    def __init__(self, artist, phrase_length=2):
        self.artist = artist
        self.phrase_length = phrase_length
        self.attributes = {
            'song': ['no-rhyme', 'no-chorus'],
            'stanza': [],
            'chorus': ['one-line'],
            'verse': []
        }

    def build_line(self, markov_dict, length):
        return markov.generate(markov_dict, length, self.phrase_length)

    def build_stanza(self, markov_dict, lines):
        i = 0
        line = []
        pattern_types = {
            2: ['aa', 'ab'],
            3: ['aaa', 'aba', 'aab', 'abb'],
            4: ['aaaa', 'aaab', 'aabb', 'abbb', 'abba', 'aaba', 'abaa']
        }
        #seed_lengths = [3, 4, 5, 6, 7, 8]
        
        length_patterns = {
            2: [[6, 6], [4,6], [4,8]],
            3: [[6, 4, 6], [8, 4, 8]],
            4: [[6, 4, 4, 6], [4, 4, 4, 4], [7, 2, 2, 7], [5, 5, 7, 7], [3, 3, 3, 3]]
        }
        length_pattern = choice(length_patterns[lines])

        while i < lines:
            line += [self.build_line(markov_dict, length_pattern[i])]
            i += 1
        return line

    def build_song(self, album):
        fp = 'music/%s/%s' % (self.artist, album)
        try:
            with open(fp, 'rb') as f:
                text = f.read()
            f.closed
        except:
            print 'Could not open album'
            return False
        markov_dict = markov.train([text], self.phrase_length)
        
        return self.build_stanza(markov_dict, 4)


def main(args):
    pass

def build_parser():
    """ This method handles command-line arguments.
        """
    parser = argparse.ArgumentParser(usage='$ python generate.py',
                                     description='',
                                     epilog='')
    parser.add_argument("-v", "--verbose", dest="verbose", default=False, action="store_true")
    parser.add_argument("-a", "--artist", dest="artist", default="lana-del-rey")
    parser.add_argument("-s", "--song", dest="song", default="all")
    return parser

if __name__ == '__main__':
    parser = build_parser()
    args = parser.parse_args()
    generate = Generate(args.artist, 3)
    song = { 'body': generate.build_song(args.song) }
    print '\n'.join(song['body'])

requirements.txt

PyMarkov==0.1.0
wsgiref==0.1.2

Current example output:
separate from the victim of
images stuck in love with
nobody broke your heart you
throwing out now like it