re2c VS PHPT

(1) Zulip Chat - https://zulip.com/ - seems to be reasonably popular, but more people should know about it

I’ve been using it for over 5 years now [1], and it’s as good as ever. It’s way faster than any other chat app I’ve used. It has a good UI and conversation model. It has a simple and functional API that lets me curl threads and write blog posts based on them.

(only problem is that I Ctrl-+ in my browser to make the font bigger – I think it’s too dense for most people)

(2) re2c regex to state machine compiler - https://re2c.org

A gem from the 90’s, which people have done a great job maintaining and improving (getting Go and Rust target support in the last few years). I started using it in 2016, and used for a new program a few months ago. I came to the conclusion that it should have been built into C, because C has shitty string processing – and Ken Thompson both invented C AND brought regular languages to computing !!

In comparison, treesitter lexers are very low level, fiddly, and error prone. I recently saw dozens of ad hoc fixes to the tree-sitter-bash lexer, which is unsurprising if you look at the structure of the code (manually crawling through backslashes and braces in C).

https://github.com/tree-sitter/tree-sitter-bash/blob/master/...

These fixes are definitely appreciated, but I think it indicates a problem with the model itself.

(based on https://lobste.rs/s/endspx/software_you_are_thankful_for#c_y...)

[1] https://www.oilshell.org/blog/2018/04/26.html

The "Papers" section on re2c's web site continues Laurikari's work: http://re2c.org/

... but I haven't found them particularly accessible. And it's not clear it's a viable strategy in a general purpose regex engine. Namely, I'm not sure how much bigger it makes the DFA.

Also, AFAIK, these are DFAs. They are different theoretical structures with explicitly more power.

> and then an NDFA is used to match a third time, to extract the capture groups.

That's the PikeVM. It's an NFA simulation. Although it uses additional storage and is otherwise more computationally powerful than just a plain NFA.

> What do you gain by using it?

Performance, although this possibly depends on your compiler, whether you use PGO, and similar finicky issues.

Example: https://eli.thegreenplace.net/2012/07/12/computed-goto-for-e...

Some prior HN discussion: https://news.ycombinator.com/item?id=18678920

Another example where goto is relevant is implementing finite automata. A (very short) paper from 1988 that discusses three different ways of implementing a finite state machine is "How (Not) to Code a Finite State Machine". The documentation of RE2C may be even more interesting: https://re2c.org

RE2C is a program that compiles finite automata into C, Go, or Rust code. It provides many implementation strategies: it can make use of computed or labelled gotos when the language provides them.

Implementing pushdown automata comes with similar issues.

wget https://github.com/skvadrik/re2c/releases/download/1.0.3/re2c-1.0.3.tar.gz tar -zxvf re2c-1.0.3.tar.gz cd re2c-1.0.3/ ./configure make make install

In Rust I use https://docs.rs/logos/latest/logos/. I think another similar is http://re2c.org

re2c is an open-source lexer generator. It uses regular expressions to recognize tokens.

Those suggested crates are still more or less the popular options. There was also recently added support for Rust in re2c.

First, the implementation of strtotime is a textbook study in why other people's C code is not where you want to spend time. You can see the guts of the implementation logic here. This isn't stock C code -- it's code for a system called re2c. This system allows you to write regular expressions in a custom DSL (domain specific language), and then transform/compile those regular expressions down to C programs (also C++ and Go) that will execute those regular expressions. Something in PHP's make file uses this parse_date.re file to generate parse_date.c. If you don't realize parse_date.c is a generated file, this can be extremely rough going. If you've not familiar with re2c is can be regular rough going. We leave further exploration as an exercise for the reader -- an exercise we haven't taken ourself.

In our latest story we show a couple of smart ways to get around some import conflicts in PHP.

The values [0, 15] represent 16 possible values, which is a power of 2.

The correct way to get an unbiased distribution from a sample of 2^x to a modulo that is not an even power of 2 is to use rejection sampling.

This is what RFC 6979 says to do https://datatracker.ietf.org/doc/html/rfc6979#section-3.2

But you can also see this technique in CSPRNG code; i.e. https://github.com/php/php-src/blob/d40726670fd2915dcd807673...

I am running this code on MacOS on Apple Silicon hardware which is crashing when using the JIT in a ZTS build of PHP, so the 1m 35s result is without JIT, it might be even faster if I could use it

49. PHP - $58,899

A little about me; I'm a web developer and have been for around 5 years, though I'd dabbled for years. I have experience with Perl and PHP but my day to day is JavaScript/TypeScript be it through NodeJS or ReactJS. I want to learn Rust for no specific reason other than it's fun to learn new things.

Consider a web application where requests are handled through NGINX as the web server and PHP as the dynamic backend language. Let’s say something in the application logic results in a fatal error or process termination. This doesn’t affect NGINX’s ability to serve a response to the client, which would most likely be an HTTP 503 - Service Unavailable message.

In the beginning, I used a technology called CGI to develop server applications written in Perl. This technology was later replaced by Microsoft’s ASP (Active Server Pages) and then PHP. PHP, which you may already know, is still powering over 77% of all the websites as of the time of writing (ever heard of WordPress?).

PHP

As Shopware is mostly based on the Symfony framework, which is in turn based on the PHP language, we should also consider learning about the basics, which will also be useful for other frameworks apart from Shopware, like Symfonycasts, symfony.com, php.net.