Hi folks,
I'm writing a Gnu DBM module as an exercise for learning Haskell and
its FFI. I'm wondering how I might write a function that returns the
database keys as a lazy list. I've wrapped the two relevant foreign
functions:
firstKey :: Ptr Db -> IO (Maybe String)
nextKey :: Ptr Db -> String -> IO (Maybe String)
NextKey takes a key, and returns the next one. Either function could
return Nothing, since the db may have 0 or 1 keys.
Given these, is it possible to write a (simple) function
allKeys :: Ptr Db -> IO [String]
that lazily fetches the keys? (Or, an idiomatic way of achieving the
same end?)
Thanks,
Graham
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