[C/C++] Add attributes

[12Thanjo]

I added support for syntax highlighting of C/C++ attributes based on the cppreference documentation for C and C++.

In addition, this fixes a bug where the syntax highlighting breaks when an attribute is in the same line as a function (it no longer considered it to be a function).

[michaelblyons]

• It looks like the .c and .c++ got mixed up in some of the test assertions.
• Most syntax files avoid deeply nested push or set
• If you're interested in the C/C++ family, perhaps consider taking [C Family] Full rewrite of C family syntaxes #4147 across the finish line! (No pressure. This is not a trivial quest.)

[12Thanjo]

If you're interested in the C/C++ family, perhaps consider taking [C Family] Full rewrite of C family syntaxes #4147 across the finish line! (No pressure. This is not a trivial quest.)

I'll definitely consider it, but not soon. I don't understand how it all works well enough yet to do what I'd consider a good enough job yet. However, I am working on a programming language, so I'll have practice writing the syntax highlighting for that - it's (in part) designed to be much easier to parse than C++, so it should be easier to do and good practice before I try full production-grade C++ syntax.

In addition, I have never touched Objective-C or Objective-C++, so I wouldn't be able to complete those rewrites.

[michaelblyons]

However, I am working on a programming language, so I'll have practice writing the syntax highlighting for that

Cool! If you have questions, feel free to visit the ST forum or Discord.

Edit: I should also mention that if you're the one designing the language, and you're using formal syntax to do so, there are projects to convert them to Sublime Syntax: SBNF original in Rust, SBNF re-implementation in Python, and Langspec.

But if you're writing a syntax the by-hand way, people are happy to help. (Maybe help with the formal things, too, just not me.)

[rwols]

From what I understand, “Objective-X is a strict superset of X”, so all you have to do is understand the Objective syntax extensions to bolt it on top. (Contrast with the fact that C++ is not a strict superset of C)