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Why regex still exists? It is unintuitive, requires mastering an obscure syntax, it is very hard to debug, and very difficult to explain to others how it works.

Why regex still exists? It is unintuitive, requires mastering an obscure syntax, it is very hard to debug, and very difficult to explain to others how it works. It feels like we are trying to write intermediate code by ourselves, while we should have a human readable language that generates regex.

frabert 7y ago
Do it! You will find that it's very easy, but the result will either be extermely verbose or just like regex. Since most regexes (at least for me) are meant as one-time-use, the extra verboseness has no added benefit. If you have complex needs, you should probably be using something other that regex, anyways.
- thanatos_dem 7y ago
  Extremely verbose is right. Here's one such approach in java that I found last year - https://github.com/sgreben/regex-builder https://github.com/sgreben/regex-builder. Yeah, regex can be a bit clunky at times and has a steeper learning curve, but they're pretty industry standard at this point, and portable across languages with a few caveats.
GrantZvolsky 7y ago
The investment into learning regexes is worth it if you write or read enough of them. They become the human readable language you speak of, eventually. The question is where the threshold lies.
tyingq 7y ago
"Why regex still exists?" Is there an alternative that is clearly superior?
- samatman 7y ago
  Your mileage may vary, but to my taste, the lpeg flavor of Parsing Expression Grammars is clearly superior. It uses operator overloading to build patterns from component parts. I don't think anything can replace the terseness of regex for command line use, or vim searching, cases like that. But for a program, give me lpeg every time.
roryokane 7y ago
You might be interested in “Eggex”, which aims to be a human-readable language that generates regexes. It’s currently written as a feature of the Oil shell, but in theory any tool could support them. Eggex docs: https://www.oilshell.org/release/latest/doc/eggex.html https://www.oilshell.org/release/latest/doc/eggex.html. Recent blog post about their development: https://www.oilshell.org/blog/2019/12/22.html https://www.oilshell.org/blog/2019/12/22.html. However, Eggexes are a thin, mostly-syntactic layer over regexes. You still have to understand the regex engine to use them. If this sounds useless to you because you don’t currently understand any flavor of regex or parsing, I encourage you not to give up on learning regexes. (https://www.regular-expressions.info/ https://www.regular-expressions.info/ was how I learned; it’s a great tutorial.) Text-parsing engines, including regex engines, are a powerful concept that can be used in many situations, and I think it’s worth spending the effort learning them until, to paraphrase another commenter, regexes become the human-readable language you were searching for. Or Eggexes, at least.
deleted 7y ago
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GordonS 7y ago
Because it's really powerful, and some people actually like it (I'm one of them). I can understand that a complex pattern might look scary if you're unfamiliar, but if you work with it long enough, you can put patterns together with relative ease.

frabert 7y ago

Do it! You will find that it's very easy, but the result will either be extermely verbose or just like regex. Since most regexes (at least for me) are meant as one-time-use, the extra verboseness has no added benefit. If you have complex needs, you should probably be using something other that regex, anyways.

thanatos_dem 7y ago
Extremely verbose is right. Here's one such approach in java that I found last year - https://github.com/sgreben/regex-builder https://github.com/sgreben/regex-builder. Yeah, regex can be a bit clunky at times and has a steeper learning curve, but they're pretty industry standard at this point, and portable across languages with a few caveats.

GrantZvolsky 7y ago

The investment into learning regexes is worth it if you write or read enough of them. They become the human readable language you speak of, eventually. The question is where the threshold lies.

tyingq 7y ago

"Why regex still exists?" Is there an alternative that is clearly superior?

samatman 7y ago
Your mileage may vary, but to my taste, the lpeg flavor of Parsing Expression Grammars is clearly superior. It uses operator overloading to build patterns from component parts. I don't think anything can replace the terseness of regex for command line use, or vim searching, cases like that. But for a program, give me lpeg every time.

roryokane 7y ago

You might be interested in “Eggex”, which aims to be a human-readable language that generates regexes. It’s currently written as a feature of the Oil shell, but in theory any tool could support them. Eggex docs: https://www.oilshell.org/release/latest/doc/eggex.html https://www.oilshell.org/release/latest/doc/eggex.html. Recent blog post about their development: https://www.oilshell.org/blog/2019/12/22.html https://www.oilshell.org/blog/2019/12/22.html. However, Eggexes are a thin, mostly-syntactic layer over regexes. You still have to understand the regex engine to use them. If this sounds useless to you because you don’t currently understand any flavor of regex or parsing, I encourage you not to give up on learning regexes. (https://www.regular-expressions.info/ https://www.regular-expressions.info/ was how I learned; it’s a great tutorial.) Text-parsing engines, including regex engines, are a powerful concept that can be used in many situations, and I think it’s worth spending the effort learning them until, to paraphrase another commenter, regexes become the human-readable language you were searching for. Or Eggexes, at least.

deleted 7y ago

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GordonS 7y ago

Because it's really powerful, and some people actually like it (I'm one of them). I can understand that a complex pattern might look scary if you're unfamiliar, but if you work with it long enough, you can put patterns together with relative ease.