HXT/Practical/Ebay1

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Revision as of 17:54, 24 January 2011 by UweSchmidt (talk | contribs)

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{-# LANGUAGE Arrows, NoMonomorphismRestriction, ParallelListComp #-} module Main where import Text.XML.HXT.Core hiding (deep) import Data.List (nub,sort,isPrefixOf,transpose,groupBy) deep f = f `orElse` (getChildren >>> deep f) -- deep redefinition to allow a broader signature split "" = [] split xs = a : split (drop 1 b) where (a,b) = break (=='/') xs through = (getChildren >>>) . foldr1 (/>). map hasName . split -- contains = (getChildren >>>). foldr1 (</). (map hasName) mkReport = mkelem "p" [] . map constA {- The datas we are munging is unstructured - Every feedback is spanned on two contigous rows of a big table - We cannot catch the all data in a match, so we use listA to have the two single-row lists - and then zip them to rebuild the data. -} getFeedbackAndValue = hasName "table" >>> hasAttrValue "class" (=="fbOuter") /> hasName "tbody" >>> proc table -> do feedbacks <- listA (through "tr/td/img") -< table values <- listA (through "tr/td" /> hasText (isPrefixOf "EUR")) -< table catA (map mkReport $ transpose [values,feedbacks]) -<< () src = "feedback.example.html" dst = "feedback.report.html" main = runX ( readDocument [ withParseHTML yes , withInputEncoding unicodeString , withWarnings no ] src >>> root [] [deep getFeedbackAndValue] >>> writeDocument [ withIndent yes , withOutputEncoding unicodeString ] dst )

Note that the use of groupBy in defining 'split' abuses the implementation details of 'groupBy' which are not guaranteed by its definition in the Haskell 98 standard report.