Hello Bulat, Monday, November 13, 2006, 2:28:09 AM, you wrote:
in the last poll for Haskell', it was widely noted that some form of attribute (annotation) system for Haskell will be great, although there is no any design yet. i think that i've found rather good one:
i was sleepy and forgot to add some more information: this design is obviously grown from HadDoc ideas. HadDoc adds documentation comments to the same entities - values, types and classes, so one of things we can do is to treat haddoc comments as one sort of attributes, say Documentation :: String this implies that haddoc front-end should be changed to generate xml files that will include this Documentation attributes and haddoc backend should parse these xml files to generate html/tex/... documentation files another haddoc detail that we should reuse is using comments to hold all annotations, in order to make annotated program compilable by old compilers and the third detail is to simplify annotations syntax by allowing to omit "" for String annotations, [] for annotation having type [a] and so on. So, annotation value should be read by some smart variation of "read" function. then, the whole example may look like: -- |Great function f = 1 -- *Documentation: Great function g = 1 -- Two above annotations are equivalent, "-- |" is a legacy shortcut for the full syntax of "-- *Documentation: " -- *Author: Bulat data NewAnnotationType = TextAnnotation String | IntAnnotation Int | PrioritiesList [Int] | Deriving [String] deriving Annotation -- *TextAnnotation: It works! -- *IntAnnotation: 31415 -- *PrioritiesList: 1,2,3,4,5 data T = X | Y -- *^Deriving: DeepSeq, Binary, XMLizable -- Best regards, Bulat mailto:Bulat.Ziganshin@gmail.com