[Haskell-cafe] Is lazyness make big difference?

Donald Bruce Stewart dons at cse.unsw.edu.au
Thu Feb 15 06:38:49 EST 2007

>    Hi all,
>    (Another topic stolen from a Russian forum discussion).
>    As everyone know, there are lot of strict languages, that
>    have possibilities to "switch on" lazy evaluation when
>    needed.
>    But the examples that I saw on Haskell, there was not much
>    use of lazy evaluation, often there were just several lazy
>    points, and the rest could be done strictly without loss of
>    generality. For example, in finding primes:

Some good examples are on the shootout:

   The lazily generated trees in particular,

    (note the much smaller memory footprint)

    And here, a lazy infinite DNA sequence generator:


    (the cycle alu part generates an infinite dna stream, which we then
    print only as much of as we need. Greatly simplifies the code).

-- Don

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