feat: Selector autocompletate

[workgroupengineering]

Allow autocompletate for selector:

• Property
• Type
• Namespace
• Attached Property
• Name
• Property and Attached Property value (Nullable)

[workgroupengineering]

if anyone has time can try it and report any problems. In the tests I'm doing at the moment I haven't found any.

[workgroupengineering]

wait merge #302

[workgroupengineering]

@amwx
Thanks for the review, I'll fix it as soon as possible.

[workgroupengineering]

@amwx I finished. You can download the artifact from here.

[amwx]

Found a few issues:

• After :not(), :is(), etc, trying to add a name after will only suggest pseudoclasses (same thing if you type '/` to start /template/ without a space, which is allowed by the compiler). Normal pseudoclasses work fine, (e.g., Button:pointerover# will present names)

• Names aren't auto selected in the intellisense popup, requiring you to manually select them:
  

What I think is happening here, (line 374 in CompletionEngine), you're calculating the current start for the autocompletion as textToCursor.Length - delta where the delta includes the #, but all the completion sets are built without the # on the DisplayText member, which is what VS uses to match typed text. Adjusting the start position to start after the # should fix this

• Trying to add names or pseudoclasses after a property doesn't give autocomplete suggestions (hitting space will resume normally):
  Button[Tag=Value]: or Button[Tag=Value]#.

• I think pseudoclasses should be suggested in cases where its appropriate for types (the operators like :is(), :not() are the only things suggested after : if there's a space). Otherwise something like Button :pointerover won't suggest the pseudoclasses (there's no spec that says pseudoclasses, etc have to be right up against the type so spaces are allowed). This also fails in ControlTheme child styles:

Edit: Oh, also I got a random IndexOutOfRangeException inside SelectorParser. Of course I can't repro it now, but it occurred while backspacing trying to fix a typo

[workgroupengineering]

Hi @amwx here there is a new build.
Can you test?
There is lot of debug code, i will remove after.

[amwx]

From above:
1- typing something like Button:not(:disabled), closing the parenthesis for :not() will enter an infinite loop & freeze VS. I didn't have the debugger attached so I don't know where

2- Still not fixed (names aren't auto selected)

3- Still not fixed (no suggestions are offered after a property unless you hit space)

4- fixed

[workgroupengineering]

Thanks again for taking the time to test.

Here you can find the build with fixes.

I added parts name detection.
If you type # after templete it shows you the list of parts, or after the template enter the type and pressing # it displays only the parts of the corresponding type.

[amwx]

Latest changes look good to me. Adding support for TemplatePartAttribute is nice feature

Item 2 still isn't fixed, but I'll handle that in the future so don't worry about it. Its related to differences between what we send to our completion engine and what VS uses internally and I'm seeing that affect other places too, and in #302 I hinted I wanted to rework that aspect anyway, but that's a bigger project

[amwx]

Mostly just typos in "public" (or relating to public) members. I've only tagged their declaration, the usages will need to be updated too - but VS's renaming refactor should make that easy

[grokys]

Sorry for the delay in approving/merging these PRs, we've not had much time recently to review the VS extension PRs. Will try to resolve that shortly.