Push: Improving Heap Residency for Lazy Stream Processing by Concurrency

Prototype implementation of a language Push, accompanying our recently submitted paper. The prototype is implemented and prepared by Ta-Chung Tsai.

While studying XML stream processing, we noticed that programmers need concurrency to save space, especially in a lazy language. We propose the idea of pushing datatypes — when a pushing closure is demanded, all expressions referring to it are evaluated concurrently to weak head normal forms. The closure is no more alive and may thus be garbage collected.

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Maximum Segment Sum and Density with Bounded Lengths

It may be surprising that variations of the maximum segment sum (MSS) problem, a textbook example for the squiggolists, are still active topics for algorithm designers. These literate Haskell scripts presents a program solving two recently studied variations: computing the maximum sum of segments not longer than an upper-bound, and the maximum density (average) of segments not shorter than a lower-bound. 2007/06/26 Update: fixed binary search.
2007/11/04 Update: linear time algorithm for MSDL.