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Go: 'new' (vs. 'make')

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David Eisinger
2023-08-07 10:15:27 -04:00
parent fc0bb6ace0
commit 7cfeac6139
1 changed files with 11 additions and 8 deletions
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content/notes/golang/index.md
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@@ -133,6 +133,8 @@ I find [Go][1] really compelling, even though it's not super applicable to my jo
> The iteration order over maps is not specified and is not guaranteed to be the same from one iteration to the next. > The iteration order over maps is not specified and is not guaranteed to be the same from one iteration to the next.
* [`new` allocates zeroed storage for a new item or type whatever and then returns a pointer to it.][22]
* First-class functions * First-class functions
* Go supports first-class functions (functions as arguments and return values of other functions) * Go supports first-class functions (functions as arguments and return values of other functions)
* Go has closures (so variables defined inside a function that returns a function get closed over) * Go has closures (so variables defined inside a function that returns a function get closed over)
@@ -147,7 +149,7 @@ I find [Go][1] really compelling, even though it's not super applicable to my jo
* Define a `String() string` method for types so that `fmt` knows how to stringify them * Define a `String() string` method for types so that `fmt` knows how to stringify them
* E.g. `fmt.Sprintf("%s", yourThing)` will call `yourThing`'s `String()` function * E.g. `fmt.Sprintf("%s", yourThing)` will call `yourThing`'s `String()` function
* Structs * Structs
* [What Are Golang's Anonymous Structs?][22] * [What Are Golang's Anonymous Structs?][23]
> An anonymous struct is just like a normal struct, but it is defined without a name and therefore cannot be referenced elsewhere in the code. > An anonymous struct is just like a normal struct, but it is defined without a name and therefore cannot be referenced elsewhere in the code.
> >
@@ -155,7 +157,7 @@ I find [Go][1] really compelling, even though it's not super applicable to my jo
> >
> To create an anonymous struct, just instantiate the instance immediately using a second pair of brackets after declaring the type. > To create an anonymous struct, just instantiate the instance immediately using a second pair of brackets after declaring the type.
* [Time][23] * [Time][24]
* `time.Duration` -- `time.Second * 1e9` is a duration of one billion seconds * `time.Duration` -- `time.Second * 1e9` is a duration of one billion seconds
* `1e9` is the same as `1.0*math.Pow(10, 9)` * `1e9` is the same as `1.0*math.Pow(10, 9)`
* Runes * Runes
@@ -167,11 +169,11 @@ I find [Go][1] really compelling, even though it's not super applicable to my jo
* Generics * Generics
* Use `[]` to define types * Use `[]` to define types
* `func keep[T int | []int | string](in []T, filter func(T) bool) (out []T) {` * `func keep[T int | []int | string](in []T, filter func(T) bool) (out []T) {`
* [Use `~` to allow "inheriting" (?) types][24] * [Use `~` to allow "inheriting" (?) types][25]
> In Go generics, the ~ tilde token is used in the form ~T to denote the set of types whose underlying type is T. > In Go generics, the ~ tilde token is used in the form ~T to denote the set of types whose underlying type is T.
* [Type Aliases][25] * [Type Aliases][26]
> An alias declaration doesn’t create a new distinct type different from the type it’s created from. It just introduces an alias name T1, an alternate spelling, for the type denoted by T2. > An alias declaration doesn’t create a new distinct type different from the type it’s created from. It just introduces an alias name T1, an alternate spelling, for the type denoted by T2.
@@ -180,7 +182,8 @@ I find [Go][1] really compelling, even though it's not super applicable to my jo
[19]: https://exercism.org/tracks/go/concepts/errors [19]: https://exercism.org/tracks/go/concepts/errors
[20]: https://go.dev/blog/maps [20]: https://go.dev/blog/maps
[21]: https://go.dev/ref/spec#RangeClause [21]: https://go.dev/ref/spec#RangeClause
[22]: https://blog.boot.dev/golang/anonymous-structs-golang/ [22]: https://stackoverflow.com/a/34543716
[23]: https://pkg.go.dev/time [23]: https://blog.boot.dev/golang/anonymous-structs-golang/
[24]: https://stackoverflow.com/a/70890514 [24]: https://pkg.go.dev/time
[25]: https://yourbasic.org/golang/type-alias/ [25]: https://stackoverflow.com/a/70890514
[26]: https://yourbasic.org/golang/type-alias/