[Haskell-cafe] ANN: Data.Stream 0.4

Wouter Swierstra wss at cs.nott.ac.uk
Wed Oct 21 15:44:15 EDT 2009

I'm happy to announce a new release of the Data.Stream library.


The only change with the previous version has been to add irrefutable  
patterns to several function definitions. This is rather delicate  
design decision: too many irrefutable patterns could result in thunks  
not being evaluated; too few irrefutable patterns could cause your  
functions diverge. As a rule of thumb I've chosen only to use  
irrefutable patterns in functions that produce streams from streams.  
The operations that observe finite information (a prefix, the element  
at index i, etc.) do not have have irrefutable patterns and force  
evaluation to weak head normal form.

I've uploaded a new version to Hackage. I'd be interested to hear if  
any existing code takes a performance hit as a result of these changes.


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