On Friday, 19 January 2024 at 16:55:25 UTC, ryuukk_ wrote:
You do hash map lookup for every character in D, it's slow,
whereas in Rust you do it via pattern matching, java does the
same, pattern matching
Yet another reason to advocate for pattern matching in D and
switch as expression
There is another important difference, i quickly looked up D
associative array implementation and the search looks like
nlog(n) complexity with plain loop iteration of hashes, whereas
rust's implementation is using "swisstable" algorithm
implementation that has packed SIMD optimized lookups, this is
likely where the 3x speed difference comes from.
Tried to look up rust implementation and it is SOOO generic that
I was unable to decipher it to find the actual key search and
stores.
Anyway here is an interesting article about rust implementation
https://faultlore.com/blah/hashbrown-tldr/
