Add textmate scope for declarations and definitions

Type: Feature Request

I tried to create a color theme that all name introduction (like declarations and definitions) are bold. However, it's not possible to unambiguously select all of those.

For example, here's a struct definition and usage:

struct MyStruct {}; // 1

MyStruct myInstance; // 2

auto function() -> decltype(myInstance) { // 3
    MyStruct myVar; // 4
    return myVar;
}

I tried to make MyStruct in 1, myInstance in 2, function in 3, myVar in 4 all bold. However, any attempt to make them bold also resulted in MyStruct being bold in 2, but it's a usage of MyStruct, not it's definition. Then any attempt to make myInstance bold in 2 also resulted in myInstance being bold in 3, but it is also a usage of it, not it's declaration like in 2. Then, same thing at 4. Local variable are indistinguishable in declaration and uses.

A solution would be to introduce a new meta scope around all name introduction.

Today myVar at line 4 have those scopes:

• meta.body.function.definition.cpp
• meta.function.definition.cpp
• source.cpp

And semantic token type variable with modifier local.

With my proposition, it would look like this:

• meta.name-introduction.cpp
• meta.body.function.definition.cpp
• meta.function.definition.cpp
• source.cpp

That meta scope would surround the name MyStruct in 1, the name myInstance in 2, the name function in 3 and the name myVar in 4.

That way, a color theme could highlight declaration and definition differently from uses of a name.

A name can be introduced multiple times. For example:

struct MyStruct;

struct MyStruct {
    auto fn() -> void;
};

auto MyStruct::fn() -> void {
   // ...
}

Here, both name have a declaration and a definition and no uses.

Start by tracing how C++ declarations, definitions, and semantic token type variable with modifier local become TextMate scopes. Use the examples in the issue as cases, including struct names, variables, functions, and repeated declarations. Done means meta.name-introduction.cpp surrounds introductions without also matching ordinary uses.