a[low:high:max] in Golang – A Rare Slice Trick

Re:a[low:high:max] in Golang – A Rare Slice Trick by tedunangst on Saturday March 18, 2023 @01:43PM (#35211325)

There are no immutable arrays. If you have a slice of capacity ten with four elements, you can write a fifth element to it. If you reduce the capacity to four, then a new slice must be allocated to store five elements.

The backing store for a slice is just a pointer. The rule is you don't give people pointers that you don't want them to write to.

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Re:a[low:high:max] in Golang – A Rare Slice Trick by andrewstuart2 on Saturday March 18, 2023 @01:47PM (#35211385)

That's just not true. There are immutable arrays in length. [4]int cannot be appended to. The backing of all slices are array types and array doubling is used for appends that go beyond the capacity.

https://go.dev/ref/spec#Array_types

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Re:a[low:high:max] in Golang – A Rare Slice Trick by tedunangst on Saturday March 18, 2023 @02:29PM (#35211770)

Yeah, that was a mistake.

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Re:a[low:high:max] in Golang – A Rare Slice Trick by yencabulator on Sunday March 19, 2023 @10:06PM (#35226378)

No array can change its length, the length is part of the type. There really are no "immutable array"s.

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