This will be the last RegExr related post for awhile, I promise! I’m just having a lot of fun playing around with this.
I just uploaded version 0.2.1b of RegExr. This version includes support for using replace with regular expressions, including replacement codes (ex. $& is replaced with the RegExp match substring). Even better, I wrote a full RegEx lexer / tokenizer, so that RegExr understands the expressions you write at the token level. This allows it to provide accurate capturing group reports, nested token highlighting including display of errors, and contextual information on tokens as you roll over parts of your regular expression.
These new features make it way easier to learn regular expressions if you’re just starting out.
Here’s what the code sense looks like, notice the nested grey highlights:
And here’s the same view, but with a missing end bracket: