Re: [Haskell-cafe] Seeking advice on a style question

28 Dec 2006

      On Tue, 26 Dec 2006 20:21:45 -0800, you wrote:
...
How would this example look if you named only multiply-used expressions?
I'd like to see it in a more conventional pointful style with nested
expressions.  I'm still wondering whether the awkwardness results from your
writing style or is more inherent.  Showing the real variable names may also
help also.
This is what it looks like "for real":
...
process :: Item -> MediaKind -> MediaSize -> Language -> SFO
process item mediaKind mediaSize language =
  let pagemaster = loadPagemaster item mediaKind mediaSize;
      questions = stripUndisplayedQuestions mediaKind $
                  appendEndQuestions item pagemaster $
                  coalesceParentedQuestions $
                  validateQuestionContent $
                  loadQuestions item;
     (numberedQuestions,questionCategories) = numberQuestions pagemaster questions;
     numberedQuestions' = coalesceNAQuestions numberedQuestions;
     (bands,sequenceLayouts) = buildLayout mediaKind language numberedQuestions';
     bands' = resolveCrossReferences bands;
     groupedBands = groupBands bands';
     pages = paginate item mediaKind mediaSize pagemaster groupedBands;
     pages' = combineRows pages;
     sfo = pages' sequenceLayouts;
     in sfo
These are the function signatures:
...
loadPagemaster :: Item -> MediaKind -> MediaSize -> Pagemaster
loadQuestions :: Item -> [Question]
validateQuestionContent :: [Question] -> [Question]
coalesceParentedQuestions :: [Question] -> [Question]
appendEndQuestions :: Item -> Pagemaster -> [Question] -> [Question]
stripUndisplayedQuestions :: MediaKind -> [Question] -> [Question]
numberQuestions :: Pagemaster -> [Question] -> ([NumberedQuestion],[QuestionCategory])
coalesceNAQuestions :: [NumberedQuestion] -> [NumberedQuestion]
buildLayout :: MediaKind -> Language -> [NumberedQuestion] -> ([Band],[SequenceLayout])
resolveCrossReferences :: [Band] -> [Band]
groupBands :: [Band] -> [[Band]]
paginate :: Item -> MediaKind -> MediaSize -> Pagemaster -> [[Band]] -> [Page]
combineRows :: [Page] -> [Page]
createSFO :: [Page] -> [SequenceLayout] -> SFO
MediaKind, MediaSize and Language are simple enumerations; everything
else is a complex structure.

Steve Schafer
Fenestra Technologies Corp.
http://www.fenestra.com/