[Haskell-cafe] Do I have this right? "Remembering" Memoization!

Mark Wotton mwotton at gmail.com
Sun Sep 13 19:45:28 EDT 2009


On 14/09/2009, at 9:28 AM, Casey Hawthorne wrote:

> Do I have this right?  "Remembering"  Memoization!
>
> For some applications, a lot of state does not to be saved, since
> "initialization" functions can be called early, and these functions
> will "remember" - (memoize) their results when called again, because
> of lazy evaluation?

You don't get memoisation for free.
If you define a variable once in a where block, it's true that you'll  
evaluate it at most once, but if you repeatedly call a function "foo"  
that then calls "bar 12" each time, "bar 12" will be evaluated once  
per "foo" call.

Cheers
Mark


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