Now I spent an hour trying to get that to work in my UDL, but it would not colour no matter what I did.

But just now, on a whim, after reading that it worked for you, I went and stuck &# in the exact same place I had tried it before (I like it in Styler 3 just below the @) and it just worked.

I have no explanation why except that I deserve every bit of my frustration for whatever I have done in my life so far.

Now it’s working for some reason! haaaaaaaaaahhhhhaaaaa

not in my squiffy UDL

Works for me. Well, the UDL you linked didn’t define &# as a prefix-keyword. So I added it to keyword4, and it highlighted just fine:

I added some of your other keywords, to prove the other squiffy keywords were also highlighting for me. But the critical thing is that &#39 is highlighted red, matching the definition of keyword4

Or, if you’d prefer it to count as a number:

Either work for me, starting with your UDL xml that I downloaded from the link you shared.

Maybe you need to delete your SquiffyUDL.xml, exit Notepad++, download a fresh copy into your UDL folder, and reload Notepad++ (maybe it got “stuck” somehow). Or maybe there’s an example set of data that doesn’t work, whereas the data I show does work – maybe there’s some contextual problem with your exact sequence of data that makes it not work, even though it works with my example data.

You know, it works easily as a keyword in a fresh UDL, but not in my squiffy UDL. I can’t figure it out. There’s not even much in the UDL.

Here’s my UDL file.

For numbers, it can work, either as prefix2:

or as prefix1:

I also took it out of both numeric prefixes, and moved it to keyword1 in prefix mode, and it worked correctly for me:

(Side experiment: to get both &# and & to work as number-prefixes in the same category, you have to order it as &# &. In keyword, it didn’t matter, probably because &# matches &-prefix anyway. In numbers, it matters, because # wasn’t an “extra” numeric character)

Can you show us a minimal example? (Create a brand new UDL – or just use the default “user defined” – assign the active document to User Defined, and show the screenshot of both your text and the relevant UDL-dialog entry, like I did (if UDL is floating, like mine was, you can use Snipping Tool / Win+Shift+S to grab both text and UDL at once; if UDL docked, a simple Alt+PrintScreen will grab everything you need)

here is the example text I was using.

0x59
&39
&#39
prefix1 2# 8# 10#
prefix1 2#111 8#777 10#999
prefix2 16# 0x 0X
prefix2 16#999 0xFFF 0X9FF
extras 1: A B C D E F a b c d e f _ :

I set the keyword1 to burgandy/red, and the numeric to bold green