Substring Diffing Ruby Challenge

Ruby
1

first = ‘Joe went to the store and bought 2 loaves of bread’
second = ‘Joe and I went to the market and bought 3 loaves of bread
and butter’

assert_equal [4…9, 21…29, 57…68], diff(first, second) # diff()
returns a list of Ranges spanning the position of edits or insertions

Anyone know an algorithm (or code) that can make that work?

2

S. Robert J. wrote:

first = ‘Joe went to the store and bought 2 loaves of bread’
second = ‘Joe and I went to the market and bought 3 loaves of bread
and butter’

assert_equal [4…9, 21…29, 57…68], diff(first, second) # diff()
returns a list of Ranges spanning the position of edits or insertions

Anyone know an algorithm (or code) that can make that work?

I extended Austin Z.'s LCS/Diff library to do just this for my
project

LCS/Diff:
http://raa.ruby-lang.org/project/diff-lcs/

Weft QDA code that does it:
http://viewvc.rubyforge.mmmultiworks.com/cgi/viewvc.cgi/trunk/weft-qda/lib/weft/diff.rb?root=weft-qda&view=co

The ‘transform’ method accepts two strings and returns an array of
‘Transformation’ objects, each representing a single
insert/delete/change

hth
alex