Comment by josephg

I really like this analogy. In a sense, C restricts what you can do compared to programming directly in assembly. Like, there's a lot of programs you can write in assembly that you can't write in the same way in C. But those restrictions also constrain all the other code in your program. And that's a wonderful thing, because it makes it much easier to make large, complex programs.

The restrictions seem a bit silly to list out because we take them for granted so much. But its things like:

- When a function is called, execution starts at the top of the function's body.

- Outside of unions, variables can't change their type halfway through a program.

- Whenever a function is called, the parameters are always passed using the system calling convention.

- Functions return to the line right after their call site.

Rust takes this a little bit further, adding more restrictions. Things like "if you have a mutable reference to to a variable, there are no immutable references to that variable."