Could you please describe your question more specifically?
-- Benjamin L. Russell
On Sat, 28 Mar 2009 16:48:47 +0000, RAJESH DALSANIYA
* *
*Both sections relate to the case study: Index for a document of text.*
* *
*SECTION A: *
* *
*Given the attached Haskell code which produces an index of words, make the following alterations by modifying existing functions and including new functions where necessary ? parts 1) to 5):*
* *
*1) **Where a word occurs N times on the same line, ensure that the line number occurs n times in the index entry for that word. *
* *
*2) **Allow words to be hyphenated and treat a hyphenated word as a single word. However, for those words which are split over two lines, treat a split word as a single word without the hyphen. *
* *
*3) **Treat a capitalised word (one or more capitals) as being different from the word in all lower case (but they should still be sorted alphabetically) ? unless it is at the start of a sentence with only the initial letter capitalised. A sentence is terminated by a ‘.’, ‘?’ or ‘!’. *
* *
*4) **Make the output more readable in the form of an index table in columns with appropriate spacing and without brackets. *
* *
*5) **Include a user-friendly menu, so that the user can choose input/output file names or default files, and choose to rerun or exit. *
* *
*Parts 1) to 5) may be developed in any order. *
* *
* *
*SECTION B:*
* *
*6) **For your version of function, makeIndex (only), show how an alternative ordering of the composed functions would provide a more efficient execution of makeIndex. Justify your answer. *
* *
*7) **For the parts 1) to 5) above that you have attempted, discuss the use you have made of a) higher-order functions, b) list comprehension, c) monadic input/output, d) functional composition, and/or e) partial parameterisation (or Curried functions). Include an evaluation of how useful your use of these concepts has been. *
* *
* * * *
*import Prelude*
* *
*type Doc = String*
*type Line = String*
*type Word = String *
* *
*makeIndex :: Doc -> [ ([Int], Word) ]*
* *
*makeIndex*
* = shorten . -- [([Int], Word)] -> [([Int], Word)]*
* amalgamate .-- [([Int], Word)] -> [([Int], Word)]*
* makeLists . -- [(Int, Word)] -> [([Int], Word)]*
* sortLs . -- [(Int, Word)] -> [(Int, Word)]*
* allNumWords .-- [(Int, Line)] -> [(Int, Word)]*
* numLines . -- [Line] -> [(Int, Line)]*
* splitUp -- Doc -> [Line]*
* *
*splitUp :: Doc -> [Line]*
* *
*splitUp [] = []*
*splitUp text*
* = takeWhile (/='\n') text : -- first line*
* (splitUp . -- splitup other lines*
* dropWhile (==’\n’) . -- delete 1st newline(s)*
* dropWhile (/='\n')) text -- other lines*
* *
*numLines :: [Line] -> [(Int, Line)]*
* *
*numLines lines -- list of pairs of *
* = zip [1 .. length lines] lines -- line no. & line*
* *
*-- for each line*
*-- a) split into words*
*-- b) attach line no. to each word*
* *
*splitWords :: Line -> [Word] -- a)*
* *
*splitWords [] = []*
*splitWords line *
* = takeWhile isLetter line : -- first word in line*
* (splitWords . -- split other words*
* dropWhile (not.isLetter) . -- delete separators*
* dropWhile isLetter) line -- other words*
* where*
* isLetter ch*
* = (‘a’<=ch) && (ch<=’z’)*
* || (‘A’<=ch) && (ch<=’Z’)*
* *
*numWords :: (Int, Line) -> [(Int, Word)] -- b)*
* *
*numWords (number, line)*
* = map addLineNum ( splitWords line) -- all line pairs*
* where*
* addLineNum word = (number, word) -- a pair*
* *
*allNumWords :: [(Int, Line)] -> [(Int, Word)]*
* *
*allNumWords = concat . map numWords -- doc pairs *
* *
*sortLs :: [(Int, Word)] -> [(Int, Word)]*
* *
*sortLs [ ] = [ ]*
*sortLs (a:x)*
* = sortLs [b | b <- x, compare b a] -- sort 1st half*
* ++ [a] ++ -- 1st in middle*
* sortLs [b | b <- x, compare a b] -- sort 2nd half*
* where*
* compare (n1, w1) (n2, w2)*
* = (w1 < w2) -- 1st word less*
* || (w1 == w2 && n1 < n2) -- check no. *
* *
*makeLists :: [(Int, Word)] -> [([Int], Word)]*
* *
*makeLists *
* = map mk -- all pairs*
* where mk (num, word) = ([num], word)*
* -- list of single no.*
* *
*amalgamate :: [([Int], Word)] -> [([Int], Word)]*
* *
*amalgamate [ ] = [ ]*
*amalgamate [a] = [a]*
*amalgamate ((n1, w1) : (n2, w2) : rest)-- pairs of pairs*
* | w1 /= w2 = (n1, w1) : amalgamate ((n2, w2) : rest)*
* | otherwise = amalgamate ((n1 ++ n2, w1) : rest)*
* -- if words are same grow list of numbers*
* *
*shorten :: [([Int], Word)] -> [([Int], Word)]*
* *
*shorten*
* = filter long -- keep pairs >4*
* where*
* long (num, word) = length word > 4 -- check word >4*
* * -- Benjamin L. Russell / DekuDekuplex at Yahoo dot com http://dekudekuplex.wordpress.com/ Translator/Interpreter / Mobile: +011 81 80-3603-6725 "Furuike ya, kawazu tobikomu mizu no oto." -- Matsuo Basho^