``La belle dame sans merci'' is one of John Keats's most beautiful and most memorable poems. It is a ballad, describing a romantic encounter between a knight and a beautiful but supernaturally captivating woman. Because it expresses, in twelve short stanzas, intense feelings of love, joy, loss, terror, and melancholy, and because of the beauty of its language, it is a favorite poem of many readers.
Enthusiasts for ``La belle dame sans merci'' have, naturally, made it available through the Internet. For this exercise, I have identified twenty different Internet documents, mostly on the World Wide Web, containing the poem. Unfortunately, no two of these documents agree on its exact wording! Some of the variations are perhaps not very important (for instance, the first word of the poem is variously given as ``O,'' ``Oh,'' and ``Ah''). Other differences, however, have significant effects on the reader's interpretation of the poem:
Is the gentleman a ``knight-at-arms,'' as most of the versions describe him, or is he a ``wretched wight''?
Does the lady weep (in line 30), as fifteen of the versions assert, or does she merely gaze at him, as the other five say?
Does she ``lull him to sleep'' in line 33 (which suggests that she remains awake as he dreams on), or do they both ``slumber on the moss''?
The exercise is to write a Scheme program that will compare all twenty versions of the poem and report any significant differences among them -- in other words, any differences that could affect the reader's understanding of the content and meaning of the poem. You can design the format of the report however you like, provided that the output from your program clearly explains the nature of each reported difference and identifies which of the versions contains which of the differing elements.
I have downloaded each of the twenty versions of the poem into a separate file, from which your Scheme program should read the text directly. The names of the files are:
In case you're curious, the file /home/stone/courses/scheme/Keats/sources gives the source of each of the versions, as a URL that you can type into the Location: field of Netscape Navigator if you want to inspect the original document.
This document is available on the World Wide Web as
http://www.math.grin.edu/courses/Scheme/spring-1998/exercise-6.html
created March 12, 1998
last revised June 21, 1998