Re2c Alternatives

re2c reviews and mentions

• Ask HN: What are some unpopular technologies you wish people knew more about?
  56 projects | news.ycombinator.com | 2 Dec 2023

  (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

• Irregular Expressions
  1 project | news.ycombinator.com | 9 Apr 2023

  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.

• My experience crafting an interpreter with Rust (2021)
  3 projects | news.ycombinator.com | 25 Mar 2023

  > 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.

• How to compile DPDK-22.11.1
  3 projects | dev.to | 6 Dec 2022

  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

• Best approach for writing a lexer
  1 project | /r/Compilers | 28 Nov 2022

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

• re2c is a free and open-source lexer generator for C/C++, Go and Rust
  1 project | news.ycombinator.com | 21 Sep 2022
• File parsing with PHP, Bison and re2c
  2 projects | dev.to | 25 Aug 2022

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

• Best option for Rust Parser and Lexer Generators?
  3 projects | /r/rust | 25 Feb 2022

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

• How Does One Develop the Grammar for their New Language
  2 projects | /r/ProgrammingLanguages | 15 Oct 2021
• Javascript Date String Parsing
  8 projects | dev.to | 29 Apr 2021

  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.

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