doc VS abseil-cpp

* list of list literals (1,2; 3,4) eqv ((1,2), (3,4));

to paraphrase Larry Walk “everyone wants the [semi] colon”

https://docs.raku.org/

amen to this … i recommend thinking about your problem in terms of effective data structures and then apply even a very simple DSL to handle access and transformations … fwiw the built in Grammars and Slang support in raku https://docs.raku.org are fantastic tools for this job.

When I was looking at the language, I didn't find the documentation "really poor". In fact I was impressed at how much of a one-stop-shop the official docs site was for both conceptual docs and API docs.

https://docs.raku.org/

The Raku Programming Language documentation already contains most (if not all) the documentation you need to deal with the issues you will confront in migrating Perl code to Raku. But, as documentation goes, the focus is on the factual differences. These blogs will try to go a little more in-depth about specific issues and provide a little more hands-on information based on my experience porting quite a lot of Perl code to Raku.

I will start working on the new version of Pod as a branch in https://github.com/raku/doc.

Well, performance has been improved by several orders of magnitude since the first release. So maybe it's time to look at https://raku.org again (or first have a look at its new documentation site https://docs.raku.org)

go to https://docs.raku.org/ and type "IO" into the search field. Behold the list that appears. Check out IO::Path or IO::Handle or whatever looks interesting. Maybe it's just me but I go "Ooh, look at all the things!".

Related: The Raku documentation does an excellent job explaining hashes/dictrionaries/associative arrays. If you've any issues, please submit a Github issue.

Raku has a lot of syntax. My first attempt at learning the language failed because I couldn't get past all the strange syntax I saw at https://docs.raku.org/. Sometimes I didn't know what the syntax was called, so I didn't know what to search for.

In the course of figuring this out, I realized that our docs also (slightly) misstate what \d means in a Regex, which led to this PR. So thanks for bringing all this up!

Yeah, it's nice! And Abseil does it, IFF you use LLVM libc++.

https://github.com/abseil/abseil-cpp/blob/master/absl/string...

The standard adopted it as resize_and_overwrite. Which I think is a little clunky.

This may be confusing to those familiar with Google's libraries. The baseline is the Go BTree, which I personally never heard of until just now, not the C++ absl::btree_set. The benchmarks aren't directly comparable, but the C++ version also comes with good microbenchmark coverage.

https://github.com/google/btree

https://github.com/abseil/abseil-cpp/blob/master/absl/contai...

An implementation of call_once that accommodates callbacks that throw: https://github.com/abseil/abseil-cpp/blob/master/absl/base/c...

I wouldn't say it's that cryptic. It's just a few bitwise rotations/shifts/xor operations.

You can see hashing optimizations as well https://www.deepmind.com/blog/alphadev-discovers-faster-sort..., https://github.com/abseil/abseil-cpp/commit/74eee2aff683cc7d...

I was one of the members who reviewed expertly what has been done both in sorting and hashing. Overall it's more about assembly, finding missed compiler optimizations and balancing between correctness and distribution (in hashing in particular).

It was not revolutionary in a sense it hasn't found completely new approaches but converged to something incomprehensible for humans but relatively good for performance which proves the point that optimal programs are very inhuman.

Note that for instructions in sorting, removing them does not always lead to better performance, for example, instructions can run in parallel and the effect can be less profound. Benchmarks can lie and compiler could do something differently when recompiling the sort3 function which was changed. There was some evidence that the effect can come from the other side.

For hashing it was even funnier, very small strings up to 64 bit already used 3 instructions like add some constant -> multiply 64x64 -> xor upper/lower. For bigger ones the question becomes more complicated, that's why 9-16 was a better spot and it simplified from 2 multiplications to just one and a rotation. Distribution on real workloads was good, it almost passed smhasher and we decided it was good enough to try out in prod. We did not rollback as you can see from abseil :)

But even given all that, it was fascinating to watch how this system was searching and was able to find particular programs can be further simplified. Kudos to everyone involved, it's a great incremental change that can bring more results in the future.

Check out https://abseil.io. It offers absl::optional, which is a backport of std::optional.