[Haskell-cafe] Abstraction leak

Miles Sabin miles at milessabin.com
Fri Jun 29 14:49:16 EDT 2007

Andrew Coppin wrote,
> If this was Java, you would write all these compression and
> decompression stages as stream wrappers. So you wrap the raw input
> stream with an RLE decoder, have the function read the Huffman table,
> and then take off the RLE decoder and process the rest of the stream.

Except that if the RLE decoding stream wrapper contains any internal 
buffering, then stripping it off would very likely result in data loss. 
What you actually have to do is have the RLE decoding stream wrapper 
build and return you a stream wrapper which delivers the remainder of 
the stream.

Which I think shows that the abstraction isn't leaky ... where "the 
remainder" starts is very much dependent on the precise encoding of the 
prefix of the stream.



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