Deriving PathInfo class in web routes?
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drozzy
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Published on 2012-06-24T15:11:54Z
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I am reading the web-routes tutorial in Happstack, and I have no idea what this is doing:
$(derivePathInfo ''Sitemap)
class PathInfo a where
toPathSegments :: a -> [String]
fromPathSegments :: URLParser a
The doc simply says:
we use template-haskell to derive an instance of PathInfo for the Sitemap type.
but where does it "store" it? I thought haskell had no state, and is PathInfo
our own thing, or is it part of happstack?
If someone could explain this, for dummies? Thanks.
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