a ruby solution to Dave Thomas' Kata Fourteen
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1. run the tests:

  $ rspec spec/

First, I started out with the TrigramAnalyzer. I knew this would take in a
String and would need to return a Hash to represent the trigram patterns. In
order to build the hash, I would need a list of strings that represented 3
word trigrams. Then I could build the hash using the first two words as the
key and the third word adding to the list of values for the given key.

I decided to extend the String class with a function `trigrams` which would
return a list of 3 word trigrams. In an effort to build code that is
reusable, I implemented the function `n_grams` to allow a caller to specify
the size of the N-gram.

`n_grams` was a bit more difficult than I had anticipated. Simply slicing a
string into n-sized parts wouldn't do.  Each chunk (or slice) needed to be
congruent to the previous i.e. sharing n-1 elements, moving along the list by
one, not the size of the slice.

Next was TrigramGenerator.  This would take the trigram patterns built from
TrigramAnalyzer and would cycle them to generate the new text.  No real magic
here, just simply followed the instructions from the kata description.

  1. Start with a random word pair (our hash keys in this case).
  2. Lookup a random word from it's value and append to our new text.
  3. Continue while the last two words exist as a key in our trigram patterns.

I implemented Array.random_element instead of using `sample` because it is
not in ruby 1.8.7 and I wanted my code to be compatible with both versions.

Both the TrigramAnalyzer and the TrigramGenerator can process single or
multiple sentences. Ideally, one could pass an entire book of text to
TrigramAnalyzer.analyze_text, it will then parse into sentences, then will
generate the trigrams from each individual sentence. This will eliminate
generating trigrams which cross sentence and paragraph boundries.

Then, pass these patterns to TrigramGenerator.generate_text passing it the
number of paragraphs to generate and the number of sentences each paragraph
will contain.

TODO: Next steps to be taken
1. Deal with inner-sentence punctuation like, commas, quotes, colons,
semicolons, parentheses, etc.
2. Finding keys case insensitive.
3. Generate random number of sentences up to given number, not all paragraphs
should have exactly n sentences.
4. Figure out how to kill an infinite loop. Have a MAX_WORDS which doesn't
allow a sentence to cycle indefinitely?