Yuan and Dmitry, thank you for review and suggestions.

> Can we do this instead: in python--treesit-fontify-string, we check if

string-interpolation feature is enabled, if it is, fontify string_start,

string_content and string_end only; if not, fontify the whole string.

Done.

Enable interpolation highlighting only if 'string-interpolation is presented on the third level of treesit-font-lock-feature-list.

Personally, If I saw a f-string with an interpolation fontified as string, I would assume that it is bug.

Clearly it is not a string, so it should be highlighted distinctly.

But if it is a convention across all languages, we should follow it.

> I think "for var in range(3)" should be part of the "definition" feature

because a variable is defined there. Alongside parameters.

I added it to definitions.

My thoughts about parameters. I started to extend rules for them since they are very limited now.

But I'm not sure what face to use for them.

I would like to not use the same face as for assignments, because I'd want to highlight them differently.

It seems that there is no appropriate face in font-lock.el, so I ended up creating my own face in my config.

Does it make sense to add new face for parameters in font-lock.el?

Or it is too small feature for its own face?

I also apply this face for keyword argument in function calls.

Summary for all changes in the patch.

definition feature:

`for var in range(3)` highlight var as font-lock-variable-name-face

assignment feature:

var := 3 (named_expression)

var *= 3 (augmented_assignment)

Highlight var as font-lock-variable-name-face.

Make list_splat_pattern query more precise.

list_splat_pattern may appear not only in assignments: var, *rest = call(),

but in the parameter list too: def f(*args).

Highlight args only for the first case in assignment feature.

type feature:

Fontify built-ins (dict,list,etc.) as types when they are used in type hints.

support nested union types, for example `Lvl1 | Lvl2[Lvl3[Lvl3], Lvl2]`.

This structure is represented via nesting binary_operator and subscript nodes in the grammar.

Function python--treesit-fontify-union-types iterates over all children and highlight identifier nodes.

Fontify base class names in the class definition: class Temp(Base1, pack0.Base2):

Fontify class patterns in case statement: case [TempC() | bytes(b)]:

Highlight the second argument as a type in isinstance/issubclass call:

isinstance(var2, (str, dict, Type1)); issubclass(var1, int|str)

For all dotted names of a type highlight only the last part of the name,

e.g. collections.abc.Iterator.

decorator feature:

Highlight dotted names: @pytest.mark.skip

Function python--treesit-fontify-dotted-decorator iterates over all nested attribute nodes and highlight identifier nodes.

When font-lock-level is set 4, `skip` had function-call face in: @pytest.mark.skip(reason='t')

Add `:override t` to decorator feature to override function-call face.

string feature:

Enable interpolation highlighting only if string-interpolation is presented on the third level of treesit-font-lock-feature-list.

Fix fontification of strings inside of f-strings interpolation,

e.g. for f"beg {'nested'}" - 'nested' was not fontified as string.

function feature:

Do not override the face of builtin functions (all, bytes etc.) with

the function call face

keyword feature:

Add "is not" to the `python--treesit-keywords` list.