Set a flag on x. Check it at the same time you check whether the usecount
is 1 to perform an in-place operation. If the operation is one of a few
interesting ones (catenate, amend), look up the corresponding hash table
and update it too. Otherwise discard the hash table.
(As for where to put the flag, perhaps steal a bit from the usecount?
I'm sure no one will mind, seeing as there's not enough address space to
saturate a full word's worth of usecount.)
-E
On Wed, 2 Feb 2022, Henry Rich wrote:
That's a possibility, but how would you know when x changes, or is
assigned to a different name?
Henry Rich
On 2/1/2022 8:27 PM, Elijah Stone wrote:
On Mon, 31 Jan 2022, Henry Rich wrote:
The deficiency in J is that m&i. gives you a hashtable for searching
m, but if you modify m you have to recalculate the hash from
scratch. This makes m&i. a good read-mostly Dictionary but slow for
frequent updates.
Why not cache the hash table for x when computing x i. y, and update
it in-place when x is updated in-place? That should provide ideal
performance without requiring any changes to language semantics.
-E
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