Software for visually building regular expressions?

Question

I frequently need to create regular expressions for use in scripts (mostly when used in sed), however, I find, sometimes the regular expressions get very complicated and difficult for me to understand and edit. Is there any software which allows one to visually creates the code for regular expressions, which I can then copy and paste into a script?

Answer 1

How about Visual Regexp?

Answer 2

How about kregexpeditor

Answer 3

Try txt2regex and see if that helps. I've never used it seriously, but it seemed cool when I tried it out.

Answer 4

Yes, text2re.com should be close to what you're looking for. Given source text, you can choose to generate a regex that matches any of the given text. The tool generates code for a smattering of languages, as well.

The regex builder UI (step 2 on the page) is slightly difficult to learn; note that hovering over any of the options explains the object against which you're matching:

Answer 5

I'm not quite sure what you mean by "visually create the code" (do you mean a GUI tool?). If you are like me, I find it impossible to work with complex regular expressions, unless I lay them out in a structured manner, so I can get a better visual representation of the logic.

Really, sed is just a scripting language, and it can be laid out like other languages, ie. with one command per line. Here is a typical example of what I mean: A sed regex showing structured layout.

A very handy feature of sed is its debugging command l, which is a simple line dump showing the pattern space with embedded newlines shown as \n, etc..

The issue with sed is not just the regular expressions. It has a funky cryptic set of commands for looping and condition testing; this takes time to get used to... The best tool I've ever found to assist me with dealing with sed is quite simply: I read the manual in detail.. From that, it is just a process of starting small and getting the simple things working; then build up to bigger things to gain experience..

Perl regex has some useful features to assist in laying out complex patterns; eg. the ability to ignore whitespace in your expression.. (As a challenge, and for the expereince factor, I wrote a sed parser to parse my sed code to allow such whitespace... PS. I don't need it now; because of the experience :) Actually just laying out commands, one per line, is almost as good as the perl feature.

The best tool to help you is: experience. eg. Tackling the regex questions on this site is a great way to get that experience... I feel that GUI tools don't really help much, because they inhibit the experience...

In summary, the best helper tools are experience and structured layout, and read the manual (in detail)..

I've used the word "expereince" a lot.. by it I mean that the act of preparing regular-expressions (and in the case of sed, any looping logic etc.) is the key factor.. "Regex-Builder" type tools; don't write the regex for you; they only test it, and they certainly won't handle sed's program logic, because that isn't a regex..(and you have specifically singled out sed)... The syntax-highlighting they may offer doesn't do much for me. An editor with good bracket matching is pretty handy though (I use emacs)..