Comment by bsaul

1 year ago

my feeling with slices is that go wanted to really make programmers mindful of the cost of allocating new space on array operations.

By having this weird API on slices, they force you to be explicit on allocating new memory.

5 comments

bsaul

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masklinn  1 year ago

None of that makes any sense. Slices don't force you to be explicit on allocating new memory in any way. you can literally do this:

    s := []int{}
    for i := range 29754 {
        s = append(s, i)
    }

do you see explicit allocation of new memory? As far as I'm concerned that's not in any way more explicit than e.g.

    var s = new List();
    foreach(var i in Enumerable.Range(0, 29754)) {
        s.Add(i);
    }

  • bsaul  1 year ago

    s = append(s,i) makes you realize something happened to the memory behind s. Otherwise you would simply call s.append(i)

    • masklinn  1 year ago

      The something that happens is that slices are not heap collections (unlike hashmap which say even less about allocations, but I'm sure you'll find an other excuse), so you can't even increment their length without returning a new copy.

      I also fail to see how this would translate to

      > make programmers mindful of the cost of allocating new space on array operations.

      anyway. `append` is not taking in an allocator, reporting allocation failures, or reporting reallocations here. Like proper vectors, it's silently reallocating (and over-allocating) as needed.

shakow  1 year ago

> they force you to be explicit on allocating new memory.

Not at all. With e.g. `append` being a “maybe I'll allocate, maybe not, take a guess” kind of method, it's basically just like Java's `List.add` with extra steps and much worse egonomics.