Dev tools · September 29, 2025
Resrap – A Parser but in Reverse
I built Resrap, a Go package that takes a grammar in ABNF format and generates infinitely long sequences of syntactically correct code...either completely randomly or with seeds for a deterministic generation. ABNF is a modified version of EBNF(https://en.wikipedia.org/wiki/Extended_Backus%E2%80%93Naur_f...) I made for this project, basically means you can specify when generating code 20% of lines will be if{} blocks and 50% will be while{} blocks which allows for more natural code generation, plus support for infinite generation of code. It’s very fast...it generated ~40…
What it does
In the maker’s words, at launch
I built Resrap, a Go package that takes a grammar in ABNF format and generates infinitely long sequences of syntactically correct code...either completely randomly or with seeds for a deterministic generation. ABNF is a modified version of EBNF(https://en.wikipedia.org/wiki/Extended_Backus%E2%80%93Naur_f...) I made for this project, basically means you can specify when generating code 20% of lines will be if{} blocks and 50% will be while{} blocks which allows for more natural code generation, plus support for infinite generation of code. It’s very fast...it generated ~40 million tokens of C syntax in about 26 seconds on my laptop and supports multithreading which actually saw boosts in performance since its very easy to parallelize. I originally made this for a typing-test project (I didn’t want to store code snippets manually), but it turned out to be useful in other contexts too, like: - Stress-testing parsers and linters - Creating non-copyrighted “lorem ipsum” code for tech demos - Generating those endless “hacker” code scenes you see in movies Curious what other cool things people might do with it! Github: https://github.com/osdc/Resrap Website: https://resrap.osdc.dev/
Does the same job
all alternatives →- UPUsing Parsing Expression Grammars to rewrite source code2016 · github.com · ▲63
- HTHow to write a recursive descent parser2017 · craftinginterpreters.com · ▲347
- SASparser – A Multilanguage Parser2019 · ▲65
* https://sparser.io * https://github.com/Unibeautify/sparser This is my attempt at creating a universal language parser. It attempts to solve a couple of problems: * Support multiple languages * Recursively extend support to languages embedded within other languages * Output a uniform format for all supported languages This is a personal project so any feedback would be helpful. Something interesting I found after I built it is that this parser is not as fast to write output as many other JavaScript parsers, but its output is much faster to read from due to the…
- IWI wrote a book on Python regular expressions2019 · ▲193
My book titled "Python re(gex)?" is free to download through this weekend [1][2] The book covers both 're' and 'regex' modules, has plenty of examples and chapters also have cheatsheets and exercises. Code snippets, exercises, sample chapters, etc are available on GitHub repo [3] I used pandoc+xelatex [4] to generate the pdf. [1] https://gumroad.com/l/py_regex [2] https://leanpub.com/py_regex [3] https://github.com/learnbyexample/py_regular_expressions [4]…


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