C++ Syntax Sucks and Carbon Fixes It

Isn’t C++ syntax perfectly fine? Why did the Carbon guys need to change it?

Judging by the many twitter comments I have read about Carbon, there is a significant number of C++ developers who are very displeased with the syntax of the Carbon programming language. A question I have seen repeatedly asked is:

If they are making a new language for C++ developers, then why did they make it look completely different? C++ syntax is perfectly fine and well known.

Actually, no, C++ syntax is not fine at all, but it is easy to internalize that fact and become blind to it once you spend enough years in the C++ trenches. When Chandler Carruth presented Carbon, he may not have done a good enough job of really explaining why C++ syntax is so problematic. I cannot promise that I will succeed either, but I will make an attempt at digging into the details of why C++ syntax is problematic and why we would want an upgrade. Let us start with a simple comparison:

What you will notice with Carbon is that most statements in Carbon have an introducer keyword such as fn, var, let and class. These keywords allow you to determine what kind of statement you are dealing with by just looking at one keyword. That is a deliberate design by Carbon. Let me quote from the first presentation of Carbon:

I don’t know if anyone has worked on a C++ parser, which doesn’t get to be a full compiler. It is incredibly difficult. We can make that better.

— Chandler Carruth

As a developer who has often made various tools to aid my C++ development, I can absolutely sign off on this observation. Writing code to parse C++ is very hard. Since I began writing C++ code back in 1998 that is something I have seen first hand. While the Java and C# communities got spoiled by amazing IDEs and tools, us C++ developers have for many years had very poorly working tools. Command completion would very regularly break, especially on larger projects…