Syntax improvements for defs and symbols

[tonsky]

Description of the Change

In top-level definitions like

(defn f [] (+ 1 2))

we shouldn’t mark the whole expression as "meta.definition.global.clojure". Instead, we should mark only f (function name) as "entity.name.global.clojure meta.definition.global.clojure". This is similar to how other syntaxes do it, e.g. JavaScript and Python.

In addition to that, this PR contains a couple of fixes to existing regexps:

• Recognize single-char symbols
• Symbols can’t start with [0-9#']
• Symbols can contain [#$%&'|]
• When defining dynamic var (def *var* ...), capture *var* as "entity.name.global" as well

Alternate Designs

Not applicable

Benefits

• Better syntax highlighting
• Syntax highlighting working closer to other languages

Possible Drawbacks

Existing themes that were designed specifically with Clojure syntax in mind might break (I doubt ones exist, though)

Applicable Issues

Not applicable

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This change is 

[winstliu]

I think this meta should be kept and the actual function changed to just entity.name.global.clojure.

[winstliu]

Scopes != CSS classes and while this may look correct in the DOM it will appear as one scope internally.

[winstliu]

Like so.

[tonsky]

Agree. Looks like in other languages meta.definition tends to capture the whole expression, while entity.name is usually just class/function name. I made the appropriate changes. I also think entity.name.definition.clojure is a better name than entity.name.global.clojure because meta is called meta.defintion.global.clojure, with definition being the main semantic part and global just a modifier

[winstliu]

And why was this removed?

[tonsky]

This was placing the same entity.name.function to all function calls inside defn. Because the token is the same, there was no way to distinguish between function declaration and function call. I checked with other syntaxes and they seem to put entity.name.* on definitions only as well

[winstliu]

Hmm, I think this is worth keeping. I checked language-javascript, language-java, and language-php and all use entity.name.function for function declarations and function calls but have an additional meta scope to differentiate between whether it's a declaration or call (usually meta.function vs meta.{function|method}-call).

[tonsky]

maybe you’re right. I was looking at Ruby. Returned it back

[winstliu]

I don't think that patterns: include $self block should actually be there. Since before it was at the wrong indentation and not doing anything and similar grammars don't have it.

[tonsky]

Actually, I think I messed up the indentation when I copied it back. 'patterns' was on the same level as 'captures' and I accidentally made it deeper. Would it make more sense if I return it the way it was before?

[winstliu]

@tonsky the previous indentation, with the patterns at the same level as captures, also doesn't make sense. That syntax is only for begin/end patterns and not regular matches.