Hello,
in the codemirror 6 plugin I need to use a regex to match the completion-source for autocompletion.
It is done like:
var word = context.matchBefore(/\w*/)
context.matchBefore() matches everything before the cursor using the regex
Now, what I want to achieve is, that also strings like tv-config-toolbar-text get matched.
Basically, a regex that matches any single string
Do you have an idea?
Thank you,
Simon
@TiddlyTitch has skills in this area, perhaps also @Mohammad
ChatGPT may be able to help /^tv-config-toolbar-text$/
Here’s how it works:
^ and $ are start and end anchors. They ensure that the match occurs at the start and end of the string, respectively.Here’s a JavaScript example showing how this regex can be used:
javascriptCopy code
const regex = /^tv-config-toolbar-text$/;
console.log(regex.test("tv-config-toolbar-text")); // true
console.log(regex.test("not-tv-config-toolbar-text")); // false
This will only return true for the string “tv-config-toolbar-text”.
\w+(?:-\w+)+ to match hyphenated words or tv(?:-\w+)+ to match hyphenated words that begin with tv.
Is that what you are looking for?
Thank you @john.edw_gmail.com
That’s already a good start!
I need more than hyphenated words, there can also be underscores, dollar signs, slashes, backslashes, brackets… I’m not totally sure yet what should be included
On the CodeMirror 6 plugin site you can test your regex how it works with autocomplete, see the last entry in the “Some things to try out” tiddler
in addition to the above i recommend using a site like regex101 if you aren’t already, makes it way easier (still not easy) to test / debug regex.
Thank you @Scribs, very helpful!
I was using regexr.com
\w+(?:[^a-zA-Z0-9\s]\w+)+ match word characters separated by non alphanumeric and non space characters.
matches: Now-is\the/time$for]all[good_men^to&come*to(the)aide+of@their~country
Probably matches on more than you really want, but not knowing which characters are in play…
Perfect @john.edw_gmail.com!
I cannot know which characters are in play, that’s the problem
I’ll try your regex as soon as I’m at home
\S+ - one or more non-whitespace chars
That makes it hard to work with. 
Well that’s trivial: /.*/, or /.+/ if you want it to contain at least one character. There’s more we can do for multi-line stuff if necessary.
But I’m guessing the requirements are a little more stringent than this.
Thanks @Scott_Sauyet ,
yes, the requirements are a bit more stringent 
It cannot match ALL the text - it must detect a bit before the cursor but not the whole - and somehow understand what the user wants to complete
Thanks @grantwparks ,
that regex does a good job!
Maybe a regex that matches two strings with one or more spaces in between would do it even better.
Would that look like:
\S+\s*\S* ?
Maybe others are making sense of this, but it’s really not clear to me. How would you expect to tell a regex, which only takes a string, to know anything about a cursor?
Can you give a handful of examples, both input strings and what’s expected to match? That might make it a bit more clear.
Sorry @Scott_Sauyet - I wasn’t clear
The regex must set something like a boundary
Like \w
I’m not so sure how the codemirror 6 function matches the text but it seems like it does it so that it matches from the end of the string to the beginning. I don’t know - I will look into the native functions, then I can tell you more.
What I know is that the example where I got my initial regex (\w*) is from the codemirror programmer himself and he must know what he’s doing ^^
I believe the regex must set such a word-boundary so that this works well but I want to figure all possibilities out
the \s would have to use + also instead of * I think
Just to be clear, \w* matches any number of “word” characters, and is entirely equivalent to [a-zA-Z0-9_], which means it matches any digits, any upper- or lower-case characters between a and z, and any underscores (_)… We can write one that adds other characters you want to include by expanding on what’s in the brackets. Often we will have to escape punctuation characters with a single backslash (\).
For example, if we want to include all the characters above as well as these ones: + - * / ? !, we might write /[a-zA-Z0-9_\+\-\*\/\?\!]*/. The trouble with this (or with /\w*/ for that matter), is that they will match all strings, since we allow for zero characters in our matches.
Thanks for the explanation @Scott_Sauyet !
I’m indecisive what I should use at the moment. I feel like a more complicated regex matching all special characters is better but I haven’t tested it
I will test it though and with your help I got an insight how this stuff works. Thank you!
As I understand it, you want to “grab” the last entered auto-completable text snippet when the user presses a keyboard shortcut for autocomplete?
If the last thing the user wrote was “tv-config-toolbar-text”, the regex pattern /\w*/ will only match “text”. To get the whole thing, you need /[-\w]*/.
If you really want to match “all” characters, you could use a negative pattern such as /[^\s]*/, which will capture everything until the first/last whitespace. But do you want to include parentheses, periods and so on?
“If I had only one hour to solve a problem, I would spend up to two-thirds of that hour in attempting to define what the problem is.”
Thank you @cdaven
Well, your last regex does it perfectly!