C++ vs. Rust Build Times

Re:C++ vs. Rust Build Times by petesergeant on Friday January 06, 2023 @06:55AM (#34273738)

> the only addition that a beginner needs to know is that there is a new option that those two languages don't have which is pass by reference or pass by value

I think anyone who's done anything beyond beginner JavaScript is going to understand the difference between pass by value and pass by reference, even if they don't call them that?

    function foo1( val : string ) { val = "hi" }
    function foo2( val : [string] ) { val[0] = "hi" }

    const bar : [string] = ["yo"];
    foo1( bar[0] );
    console.log( bar );
    foo2( bar );
    console.log( bar );

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Re:C++ vs. Rust Build Times by iterateoften on Friday January 06, 2023 @07:30AM (#34273945)

The big difference when I use Rust is that in Rust every variable you accept in a function requires you to make that choice. Whereas JS it’s kind of chosen for you. In your example you had to go out of your way to do it. So just a bit more mental overhead for implementing libraries. But not a huge deal.

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Re:C++ vs. Rust Build Times by ptero on Friday January 06, 2023 @07:55AM (#34274123)

It is not just the abstract knowledge of the difference, but the fact that "let b = a" makes a undefined and, especially, some comfort with a Rust-ic way of dealing with this. My 2c.

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Re:C++ vs. Rust Build Times by gavinray on Friday January 06, 2023 @03:40PM (#34280731)

  > I think anyone who's done anything beyond beginner JavaScript is going to understand the difference between pass by value and pass by reference, even if they don't call them that?

Pass-by-reference is a concept that is unfamiliar to many (most?) modern JS/TS developers, as the common idiom is that you "return" a new object or value at the end of your function.

If you want to update a value in an existing object, you pass it by value and return a clone of it with the updated values

Performance doesn't matter, you can do the most pants-on-head-stupid thing you can imagine, or have your frontend page/component be re-rendering 20 times on every state change, and it makes no perceptible difference. (This has been my experience)

It wasn't until I learned C that I realized you might even program in this fashion (somewhat to my horror) where passing variables to functions could mutate them

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Re:C++ vs. Rust Build Times by petesergeant on Sunday January 08, 2023 @12:05AM (#34296215)

> It wasn't until I learned C that I realized you might even program in this fashion (somewhat to my horror) where passing variables to functions could mutate them

If you pass an array to a function in JavaScript, then any changes you make to it will mutate the version the caller has.

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