[Haskell-cafe] Seeking advice on a style question

Steve Schafer steve at fenestra.com
Thu Dec 28 21:41:38 EST 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/


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