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When I previously asked about memoization, I got the impression that
memoization is not something that just happens magically in Haskell.
Yet, on a Haskell wiki page about <a
href="http://www.haskell.org/haskellwiki/Memoization#Memoization_with_recursion">Memoization</a>,
an example given is<br>
<br>
<blockquote>
<pre>memoized_fib :: Int -> Integer
memoized_fib = (map fib [0 ..] !!)
where fib 0 = 0
fib 1 = 1
fib n = memoized_fib (n-2) + memoized_fib (n-1)</pre>
</blockquote>
<br>
I guess this works because, for example, I tried "memoized_fib
10000" and the interpreter took three or four seconds to calculate.
But every subsequent call to "memoized_fib 10000" returns
instantaneously (as does "memoized_fib 10001").<br>
<br>
Could someone explain the technical details of why this works? Why
is "map fib [0 ..]" not recalculated every time I call memoized_fib?<br>
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