How Can I Efficiently Set a Bool Pointer to True within a Go Struct Literal?

Setting Bool Pointer in a Struct Literal

In Go, when passing a pointer to a bool into a function, it's possible to set the value of the bool field in the struct literal directly. However, the standard syntax requires defining a new identifier, as seen below:

func check(is handler){}

type handler struct{
    is *bool
}

func main() {
    var x bool = true
    check(handler{is: &x})
}

To circumvent this requirement and set the bool pointer to true directly in the struct literal, there are several approaches:

Option 1: Using a Slice

This method creates a slice with a single bool of value true, indexes its first element, and takes its address:

h := handler{is: &[]bool{true}[0]}

While this technique avoids defining a new variable, it introduces unnecessary boilerplate and leaves a backing array in memory.

Option 2: Using a Helper Function

A more optimal solution is to create a helper function that generates a bool pointer with a true value:

func newTrue() *bool {
    b := true
    return &b
}

With this function, setting the bool pointer in the struct literal becomes:

h := handler{is: newTrue()}

Option 3: Using One-Liner Anonymous Functions

Another method involves using anonymous functions to accomplish the same task in a single line:

h := handler{is: func() *bool { b := true; return &b }()}

Option 4: Variant with Anonymous Function

A slight variation of the previous approach:

h := handler{is: func(b bool) *bool { return &b }(true)}

These techniques provide alternatives for setting a bool pointer to true in a struct literal without the need for additional identifiers or unnecessary overhead. Developers can choose the approach that best suits their needs and style preferences.

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