3 ms·

It means not using explicit functions, just writing the same code as little inline blocks inside the main function because it allows you to see all the things t

It means not using explicit functions, just writing the same code as little inline blocks inside the main function because it allows you to see all the things that would be hidden if all the code wasn't immediately visible. To the other point though, the quality of compiler inlining heuristics is a bit of a white lie. The compiler doesn't make optimal choices, but very few people care enough to notice the difference. V8 used a strategy of considering the entire source code function length (including comments) in inlining decisions for many years, despite the obvious drawbacks.

shortrounddev2 2y ago
Well there's also compiler directives other than `inline`, like msvc's `__inline` and `__forceinline` (which probably also have an equivalent in gcc or clang), so personally I don't think you need to make the tradeoff between readability and reusability while avoiding function calls. Not to mention C++ constevals and C-style macros, though consteval didn't exist in 2007
- AlotOfReading 2y ago
  __forceinline is purely a suggestion to the compiler, not a requirement. Carmack's point isn't about optimizing the costs of function calls though. It's about the benefits to code quality by having everything locally visible to the developer.
  - shortrounddev2 2y ago
    It's an interesting view because I find neatly compartmentalized functions easier to read and less error prone, though he does point out that copying chunks of code such as vector operations can lead to bugs when you forget to change some variable. I guess it depends on the function. Something like Vector c = dotProduct(a, b); is readable enough and doesn't warrant inlining, I think. There's nothing about `dotProduct` that I would expect to have any side effects, especially if its prototype looks like: Vector dotProduct(Vector const& a, Vector const& b) const;
    - AlotOfReading 2y ago
      That's a pure function, which he says should be the goal. It's impure functions that he's talking about.

shortrounddev2 2y ago

Well there's also compiler directives other than `inline`, like msvc's `__inline` and `__forceinline` (which probably also have an equivalent in gcc or clang), so personally I don't think you need to make the tradeoff between readability and reusability while avoiding function calls. Not to mention C++ constevals and C-style macros, though consteval didn't exist in 2007

AlotOfReading 2y ago
__forceinline is purely a suggestion to the compiler, not a requirement. Carmack's point isn't about optimizing the costs of function calls though. It's about the benefits to code quality by having everything locally visible to the developer.
- shortrounddev2 2y ago
  It's an interesting view because I find neatly compartmentalized functions easier to read and less error prone, though he does point out that copying chunks of code such as vector operations can lead to bugs when you forget to change some variable. I guess it depends on the function. Something like Vector c = dotProduct(a, b); is readable enough and doesn't warrant inlining, I think. There's nothing about `dotProduct` that I would expect to have any side effects, especially if its prototype looks like: Vector dotProduct(Vector const& a, Vector const& b) const;
  - AlotOfReading 2y ago
    That's a pure function, which he says should be the goal. It's impure functions that he's talking about.