* Update cabal synopsis, description, and homepage

* Add missing let statements for some example code
* Add a couple more examples

Diff.cabal

@@ -1,8 +1,12 @@
 name:                Diff
 version:             0.5
-synopsis:            O(ND) diff algorithm in haskell.
-description:         Implementation of the standard diff algorithm, and utilities for pretty printing.
+synopsis:            Diff algorithm in pure Haskell
+description:         Implementation of the standard diff algorithm in Haskell.
+ .
+ Time complexity is O(ND) (input length * number of differences).
+ Space complexity is O(D^2).  Includes utilities for pretty printing.
 category:            Algorithms
+homepage:            https://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.4.6927
 license:             BSD3
 license-file:        LICENSE
 author:              Sterling Clover

src/Data/Algorithm/Diff.hs

@@ -8,7 +8,7 @@
 -- Portability :  portable
 --
 -- This is an implementation of the diff algorithm as described in
--- \"An \( O(ND) \) Difference Algorithm and Its Variations (1986)\"
+-- /An \( O(ND) \) Difference Algorithm and Its Variations (1986)/
 -- <http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.4.6927>.
 -- For inputs of size \( O(N) \) with the number of differences \( D \)
 -- it has \( O(ND) \) time and \( O(D^2) \) space complexity.
@@ -92,11 +92,19 @@ lcs eq as bs = path . head . dropWhile (\dl -> poi dl /= lena || poj dl /= lenb)
 
 -- | Takes two lists and returns a list of differences between them. This is
 -- 'getDiffBy' with '==' used as predicate.
+--
+-- > > getDiff ["a","b","c","d","e"] ["a","c","d","f"]
+-- > [Both "a" "a",First "b",Both "c" "c",Both "d" "d",First "e",Second "f"]
+-- > > getDiff "abcde" "acdf"
+-- > [Both 'a' 'a',First 'b',Both 'c' 'c',Both 'd' 'd',First 'e',Second 'f']
 getDiff :: (Eq a) => [a] -> [a] -> [Diff a]
 getDiff = getDiffBy (==)
 
 -- | Takes two lists and returns a list of differences between them, grouped
 -- into chunks. This is 'getGroupedDiffBy' with '==' used as predicate.
+--
+-- > > getGroupedDiff "abcde" "acdf"
+-- > [Both "a" "a",First "b",Both "cd" "cd",First "e",Second "f"]
 getGroupedDiff :: (Eq a) => [a] -> [a] -> [Diff [a]]
 getGroupedDiff = getGroupedDiffBy (==)
 

src/Data/Algorithm/DiffContext.hs

@@ -38,34 +38,36 @@ groupBy' eq (x : xs) = go [x] xs
 -- This new one corrects the issue.  Here is the example from the test
 -- suite:
 --
---     > prettyContextDiff (text "file1") (text "file2") text (getContextDiffOld 2 (lines textA) (lines textB))
---     --- file1
---     +++ file2
---     @@
---      a
---      b
---     -c
---     @@
---      d
---      e
---     @@
---      i
---      j
---     -k
---
---     > prettyContextDiff (text "file1") (text "file2") text (getContextDiff 2 (lines textA) (lines textB))
---     --- file1
---     +++ file2
---     @@
---      a
---      b
---     -c
---      d
---      e
---     @@
---      i
---      j
---     -k
+-- > > let textA = unlines ["a","b","c","d","e","f","g","h","i","j","k"]
+-- > > let textB = unlines ["a","b","d","e","f","g","h","i","j"]
+-- > > prettyContextDiff (text "file1") (text "file2") text (getContextDiffOld 2 (lines textA) (lines textB))
+-- > --- file1
+-- > +++ file2
+-- > @@
+-- >  a
+-- >  b
+-- > -c
+-- > @@
+-- >  d
+-- >  e
+-- > @@
+-- >  i
+-- >  j
+-- > -k
+-- >
+-- > > prettyContextDiff (text "file1") (text "file2") text (getContextDiff 2 (lines textA) (lines textB))
+-- > --- file1
+-- > +++ file2
+-- > @@
+-- >  a
+-- >  b
+-- > -c
+-- >  d
+-- >  e
+-- > @@
+-- >  i
+-- >  j
+-- > -k
 getContextDiffNew ::
   Eq a
   => Maybe Int -- ^ Number of context elements, Nothing means infinite

src/Data/Algorithm/DiffOutput.hs

@@ -45,6 +45,14 @@ diffToLineRanges = toLineRange 1 1
                         : toLineRange (leftLine+linesF) (rightLine+linesS) rs
 
 -- | pretty print the differences. The output is similar to the output of the diff utility
+--
+-- > > putStr (ppDiff (getGroupedDiff ["a","b","c","d","e"] ["a","c","d","f"]))
+-- > 2d1
+-- > < b
+-- > 5c4
+-- > < e
+-- > ---
+-- > > f
 ppDiff :: [Diff [String]] -> String
 ppDiff gdiff =
    let  diffLineRanges = diffToLineRanges gdiff