I face the task to create condition/filter editor every time I need to develop a data/request/event processing system. As usual, there is no universal one and only solution.

Google shows a lot of various examples:

enter image description here

Some solutions are designed to handle only short logical operations and will explode with longer functions (example 1). Other solutions are ugly because of the layout and information noise. Frankly speaking any approach with some custom layout and default controls seems to be a little big ugly and artificial.

So can universal editor be created?

My answer was: yes, sure. Simple TextArea with syntax highlighting can be used as a universal and flexible editor. It does provide natural support for all operations including copy/paste, free editing, infix notation, simplified navigation, etc. Templates and error highlighting will make such approach user-friendly and simple to start with.

This approach was not fully approved, because free text editing sounds complex almost for everyone.

By the way, I've also spend some time searching for similar questions. My results are:

First suggests to use a form with tree-like layout and default components. Second invents Lisp. Don't get me wrong, I like Lisp quite a lot, but parenthesized Polish prefix notation will drive crazy any ordinary user in 5 minutes max. So I decided to keep strict hierarchy, infix notation, provide some tweaks and make free text editing available in parallel.

Early implementation I can show looks like the following:

enter image description here

So the questions are:

  • Do you think this is good approach?
  • What will you suggest for condition editing?


Wireshark filters can be used as an example of the task being solved:

(ip.src >= && ip.src <= || (ip.dst >= && ip.dst <=

Please note, expressions can be complex (4,8 .. 16 lines in C-like form) and some specific functions (COMPARE_ALL for example) sometimes can be used instead of simple AND/OR.

Target audience

The idea is to satisfy experienced users and also let newbies to find their way.

  • Could you give some more info: what kind of conditions are you building (the area of use), who are your target audience, how complicated the expressions might be?
    – Pasha
    Commented Mar 28, 2013 at 2:02
  • It's not a solution but a tip... The naming of AND / OR is for newbies (not only for newbies) not intuitive. In my company we discuss regulary about the meaning. Better solution is to use natural speaking e.g. "Contains all". See the post from Michael Zuschlag ux.stackexchange.com/q/1737/21423
    – sysscore
    Commented Mar 28, 2013 at 10:06
  • @RenatGilmanov did you put this question as an answer for the intuitive interface for boolean logic question? I think I would have awarded a bounty for this answer.
    – Michael Lai
    Commented May 30, 2016 at 22:38
  • @MichaelLai, thanks. I'd better provide a completely new solution. The approach above is completely outdated and way too complex. Commented Jun 1, 2016 at 0:21
  • @RenatGilmanov I think there are certainly elements that have been touched on in the answers posted, but if you have an even better idea then at least I would be interested.
    – Michael Lai
    Commented Jun 1, 2016 at 2:22

2 Answers 2


I find none of the suggested solutions from your question very intuitive. The main problem, IMHO, is the very unnatural ordering of the operators and the components. Everywhere, the 'AND' is the first thing you see. That doesn't fit a users' model how how the components belong together.

As a solution, I'd suggest something like this:


download bmml source – Wireframes created with Balsamiq Mockups

Clicking on a split icon, would allow selecting the split type: and, or, or either...or (exclusive or).

In this solution, you can read the whole structure like you would natural language.

  • Although I agree with your remark that the "and" and "or" in the question seem out of place, I personally think they are a bit in yours as well. I would expect that "and"'s and "or"'s at the beginning of a line (so not on the first line, but at the beginning from the second onwards). Would be interesting to test this on users at various levels of familiarity with conditions and boolean expressions, whether in SQL or in any programming language. Commented Mar 28, 2013 at 18:14
  • I think the point of these editors is to make them readable for people who are not too familiar with such expression languages. Putting the and before the lines would work, but would also make the editor look more technical, I think. Note that I, as a programmer in my day job, usually put the operators at the end of the line if I break conditions over multiple lines, not the beginning.
    – André
    Commented Mar 29, 2013 at 8:02
  • The are not exclusively for inexperienced users. These builders come in handy for experienced expression language users as well, if only to expedite the selection of attribute and criteria names. And these builders should also address the intricacies of AND, OR, and NOT combinations there of because even experienced expression language users get these wrong on a daily basis. Yes putting the And/Or at the beginning makes it look more technical, but will enable more consistency when dealing with compound conditions. Commented Mar 29, 2013 at 11:44

Remove the chrome. People don't like living in houses with scaffolding. Similarly, it's hard to read an expression where everything is surrounded by a box and has several buttons attached.

Generally you want to start by asking "What is the most understandable format that I can write this expression in?" Use a whiteboard, and imagine you're trying to explain your condition to a 10-year old, or to your boss.

Instead of making trees, I would probably use the time-tested standard mathematical notation: { joins conditions with AND, and [ means OR:

mathematical-boolean formula

Obviously this representation is optimized for reading, not for editing. But this is the intention: when a complicated condition is easy to read, you're less likely to make mistakes. Note also that whenever possible you want to allow chaining of inequalities, because this reflects the way people think about them. For example, you must allow A ≤ B < C ≤ D, and A > B > C ≥ D, and A = B ≠ C = D. However the expression A ≠ B ≠ C is already ambiguous (from a user's perspective A ≠ C is also implied).

Editing can be performed in an environment very similar to a text editor, only with braces / brackets automatically expanding as you add more conditions. It could be similar to how MathType UI works. You can also allow users to "resize" braces with a mouse, adding placeholders for new conditions. Also assist newbies with tooltips for each bracket stating which logical condition is implied.

One last boolean condition that you didn't mention is XOR. For a series of operators it means "one and only one of conditions must be true". There is no standard math notation for that, so just invent your own. Angle bracket 〈 maybe? Just make sure to provide a tooltip, because this will confuse your users the first time they see it.

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