On 6/22/07, Duncan Coutts
You might find that lazy IO is helpful in this case. The primitive that implements lazy IO is unsafeInterleaveIO :: IO a -> IO a
Personally, unsafeInterleaveIO is so horribly evil, that even just having typed the name, I'll have to put the keyboard through the dishwasher (see http://www.coudal.com/keywasher.php). Also, I need to support concurrent querying and updates, and trying to manage the locking is quite hard enough as it is, without trying to keep track of which postings vectors have closures pointing to them!
Note that using a Map will probably not help since it needs to read all the keys to be able to construct it so that'd pull in all the data from disk.
Well, in the case I'm dealing with, the map can contain the current key from each postings vector, and the closure for reading the remainder of the vector. E.g. Map Key ([IO (Maybe Key)]). T. -- Dr Thomas Conway drtomc@gmail.com Silence is the perfectest herald of joy: I were but little happy, if I could say how much.