re2c VS postgrest

(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.

hey hn, supabase ceo her

we just announced GA, after ~4 years of beta. for those who don't know: supabase is a postgres hosting company. we also host other open source "backend" tools that make it easy to get started with postgres (tools like PostgREST for auto-generate APIs [0])

we owe a lot to the HN community. you launched us 4 years ago [1], when we were just a few developers. since then HN has been a staple in our journey, one of the best sources of product feedback [2]

the GA badge is mostly to signify organizational readiness. we're at a stage where we can take any profile of customer. we have a support team that works 24/7, and a success team that will help customers improve their postgres usage. we released our Index Advisor [3] yesterday, and we'll be releasing a few more products this week that helps customer with performance and security.

on a personal note: i read HN most days, and love going through the ShowHN's to see what devs are building. thanks for being an awesome community and my favorite place to lurk on the internet. i'll stick around to answer any questions

[0] PostgREST: https://postgrest.org

[1] Launch: https://news.ycombinator.com/item?id=23319901

[2] HN journey: https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...

[3] Index Advisor: https://news.ycombinator.com/item?id=40028111

If you use PostgreSQL and are proficient with using its row-level security feature, you can choose from several tools/services built above RLS, including Supabase, PostgREST, and PostGraphile. They all provide a way to expose database CRUD as a web API, assuming you've configured the RLS rules to properly secure the access.

wget 'https://github.com/PostgREST/postgrest/releases/download/v11.2.0/postgrest-v11.2.0-linux-static-x64.tar.xz'

SupaBase is entirely based upon PostgREST. In fact, PostgREST is arguably 49% of their value proposition according to their own website. The other 49% is PostgreSQL. PostgreSQL of course is a super mature database, and some would argue the best RDBMS on the planet, so let's ignore that part for a moment, and consider it a mature thing and move on to PostgREST.

You don't need this PHP snippet:

To get the same functionality without the extra step, simply use PostgREST [1]

[1] https://postgrest.org/

PostgREST is a standalone web server that turns your PostgreSQL database into a RESTful API using the database's structural constraints and permissions to define the API's endpoints and operations. In this tutorial, you will create a simple note-taking app by leveraging PostgREST to construct a RESTful API for the app and using htmx to deliver HTML content.

You might find some info in the docs of PostgREST [1] or in the previous discussions on HN about it [2].

For the versioning, I just have a git repo where I keep every role, schema, table, view, function, trigger, etc. definitions. Every time I change something in the database I first change it in the git repo too to have an history.

[1] https://postgrest.org

[2] https://hn.algolia.com/?q=postgrest

Don't know if you would call this a "program" but PostgREST is written is Haskell too.

https://github.com/PostgREST/postgrest