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32 lines
1.1 KiB
Plaintext
32 lines
1.1 KiB
Plaintext
10 years ago
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#lang scribble/manual
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@(require scribble/eval (for-label racket sugar))
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@(define my-eval (make-base-eval))
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@(my-eval `(require sugar))
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@title{Cache}
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@defmodule[sugar/cache]
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If, like Ricky Bobby and me, you want to go fast, then try using more caches. They're wicked fast.
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@defproc[
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(make-caching-proc
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[proc procedure?])
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procedure?]
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Make a caching version of @racket[_proc]. This means a hash table will be attached to @racket[_proc], and result values will automatically be saved & retrieved. The arguments to the procedure are used as the hash key.
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In the example below, notice that both invocations of @racketfont{slow-op} take approximately the same time, whereas the second invocation of @racketfont{fast-op} uses the cache instead and thus is nearly instantaneous.
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@examples[#:eval my-eval
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(define (slow-op x) (for/sum ([i (in-range 100000000)]) i))
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(time (slow-op 42))
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(time (slow-op 42))
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(define fast-op (make-caching-proc slow-op))
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(time (fast-op 42))
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(time (fast-op 42))
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]
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@defform[(define/caching (name arg ... . rest-arg) body ...)]
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Like @racket[define], but automatically uses @racket[make-caching-proc] to define a caching version of the function.
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