You’ll recognize literal parentheses too. You probably know about capturing parentheses. The 3 types of parentheses are Literal, Capturing, and Non-Capturing. Even so, I was still surprised when I learned that there are 3 different kinds of parentheses in regular expressions, not just 2.Īnd no, the 2 aren’t left and right, wise guy.

Tl dr just like with any other code, use good practices.Įdit: 'does support recursion' => 'does not support recursion'.If you’ve spent any time writing code you’ve no doubt abused regular expressions until they were an inscrutable character jumble that could give a real parser a run for its money. If you just split it up though, write out example tests, and run them as you build the regex, and keep that stuff around, then it's really not so bad.

The problem is that developers sit down to write regular expressions, and write them out like how I have posted it above. Obviously you can have things optionally turned on or off with a parser approach, but it tends to come more naturally with regex based solutions. SyntaxHighlight( errorRegex, 'syntax-error' ) error'ing syntax gets a 'syntax-error' class applied to them Plus because it's just a regex, I can easily slot them in or out. The regex above, also points out syntax errors, so you can do some clever stuff. I ripped it out, and had it replaced with a regex version built on top of Ace, within a single afternoon! Ok, it does not support full recursion, but for syntax highlighting, I don't need a full parser. After about 2 or 3 months of work, what I had was slow, error prone, and hard to extend. Version 1, was done 'properly', with no regular expression, on top of Code Mirror. The regex was built for a language parser in an editor. That is because the parts of it are split up, and cruft/boiler plate regex is generated or tacked on appropriately.Ībove the regex is a list of rules of what it matches, written in english, with example code of what it does and does not match, and links to tests. In my code, it is about 3 or 4 pages long. That is how the regex looks, after it is generated!. The regular expression I posted actually doesn't represent the reality. I actually disagree, pretty heavily, if you do it right!

Regular expression not multiple of 3