By_Word not sensitive enough.

[sergio-rivas]

I tested the following two strings:

@original = "The second aspect is that graphic design is a very inclusive subject, and enables me to explore various art fields. For instance, if I am going to create a poster, I could create it solely with a computer, or I can create a sculpture and then take a photo of it, or I can learn photography and create a photograph for it, or I can use traditional ways like drawing or painting, and so forth. The numerous possibilities and great potential of graphic design attract me as well."

@current = "The first aspect is that graphic design is a very inclusive subject. It enables me to explore various art fields, and incorporate a mixture of media in my works. For instance, if I am going to create a poster, I could create it solely by computer, or I can create a sculpture and then take a photo of it, then cut it and edit it digitally. I can learn photography and create a photograph for it. I can even use traditional methods like drawing or painting, and mix it with digital work. The numerous possibilities and great potential of graphic design attract me to this exciting art field."

Your Gem handled the first few phrases well, but then chunked together the remaining part. I've tried many different plugins and gems so far for this, and so far, the best algorithm for comparison is the JS plugin jsdiff. Perhaps you can incorporate some stuff from their algorithm for this gem? I would love it if a ruby gem can take care of this all.

jsdiff: github url
live demo

jsdiff was able to handle very well the complexity of large text revision (by_word).