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1 point by stefano 5765 days ago | link | parent

To do the optimization when we see

  (general-function (your-type-creator 42))
we need a type inferencer to discover the return type of your-type-creator. The cache should also be able to change. For example I could write:

(general-function (your-type-creator 42))

(set your-type-creator another-type-creator)

(general-function (your-type-creator 42))

Now the optimization doesn't work if the cache doesn't change. This seems a rare case, though, and it's useless to optimize rare cases.

1 point by almkglor 5765 days ago | link

Actually we don't: general-function is actually defined this way:

  (with (PIC (table) ;init empty table
         num-calls 0
         (fn (n)
           (+ (method n) (other-meth n))))
    (def general-function (n)
         ; don't infer type: just look at the runtime type
         (PIC:type n)
         (is optimization-trigger-level** (++ num-calls))
            (do (= num-calls 0)
                (= (PIC:type n)
                   (optimize* orig-fn (type n))))
Basically s/type inference/just look at it directly/