re2c VS moment

(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.

Moment.js lets you do amazing things with dates and times in JavaScript. You can easily compare, change, and format them in different ways. For example, you can say things like "today is Monday" or "3 hours ago" or "12/31/2020". To start with Moment.js, you need to install it and import it into your JavaScript project. For example:

To learn more about Moment.js, please visit their official website.

Ah, Moment.js, the guardian angel of date and time manipulation. Ever needed to format a date, calculate durations, or display something like "2 days ago"? Moment.js has got your back. It's a lifesaver for anything date and time-related, making it a must-have in your project, especially if you're into making your users feel like you really get them.

After hours of trying to figure out why Jekyll was still showing "Today" for a post I modified last week, I remembered that I am using the timeago filter from jekyll-timeago plugin. I was rendering the dates using {{ doc.last_modified_at | timeago }}. As you know, Jekyll is a static site generator, and it renders this as HTML at the time of build, and only then. This means any date rendered with timeago is hardcoded as is in the HTML and won't change until the next build. I switched all the dates to the "%-d %b %y" format for now. Might use moment.js in the future to get the timeago dates back.

moment: Handles date and time manipulations with ease. Learn more

For the longest time working with dates in JavaScript was a huge pain. That’s why libraries such as moment.js or date-fns are so popular. A lot of times I’d reach for these libraries when working with relative time formatting, but since late last year we’ve had pretty great browser support for the RelativeTimeFormat() method. In my mind, relative dates are just more visually appealing, especially for working with dates internationally. Dates like "5 days ago" or "in 2 months" are far more intuitive for users than 12/12/2023, or 03/11/2027. Folks in the US will see that as March 11, 2027, whereas the rest of the world will see that as November 03, 2027. What a nightmare.

İ am using moment js for a long time. You can check it also. https://momentjs.com/

We could control the DST flip by setting the test's input time to the appropriate time of year (summer/winter). However we couldn't control the timezone. We had to adjust the expected data in the test 🤢 using the same library which the production code used (momentjs).

8. Moment.js