Expressions allows to play with regular expressions*. Just type your pattern and some text to test it. All the changes are updated while you're typing text or pattern. App highlights the syntax, so the pattern is easy-to-read and modify. If you use subexpressions (groups), you can highlight them by pressing cmd+shift+] (or [ – for decreasing the highlighted group number).
If you don't remember the regex syntax, just press cmd+r or click button in the top-right. You will get the reference sheet, so you don't have to remember everything.
The user interface is very minimalistic and non-distractive. By default the color is the same as your menubar, but you can always switch to dark or light mode (see: Preferences). You can also open app in beautiful full screen mode which is perfect when you want to focus or to demonstrate regular expressions to other people.
* Expressions uses ICU regular expression standard. More information you will find here: https://developer.apple.com/reference/foundation/nsregularexpression
- fixed bug that appeared on macOS 10.11
Ratings and Reviews
Did not live up to expectations
I expected that the application will show different groups.
But it shows everything monolithically.
Text for example: "...1...2...3..."
Expression for example: "(?<char1>1).*(?<char2>2)"
Application result: hightlighted symbols "1...2"
Expected result: hightlighted symbols "1", "2"
PHP preg_match result: ["0" => "...1...2...3...", "char"' => "1", "char2" => "2"]
p.s. See the RegExRX for view the "ideal" visualization of result.
By default Expressions highlights the 0th group which is the whole regex.
To highlight a group, press cmd+shift+} (Menu View -> Highlight next group).
Best tool for quickly developing and testing regular expressions
The primary feature that was previously lacking was the inclusion of a quick little reference sheet, but that has been added in this release. Expressions is functionally equivalent to the other regex apps in most regards, but has a much cleaner design. For that reason, it has become my goto app for quickly developing and testing regular expressions.
Lastly, I just want to note that the developer is also very friendly and quick to respond to feedback/suggestions. 👍🏼
Very helpful learning tool
I’m just starting to learn about regular expressions, and I’m very happy to have such a well-made native app to work with.
With Family Sharing set up, up to six family members can use this app.