Parameters vs. Closures in Go: When to Use Which?

Passing Parameters to Function Closures

In Go, the choice between creating an anonymous function with a parameter or a closure can impact variable sharing and function behavior.

Parameters vs. Closures

• Parameters: Pass a copy of the value to the function.
• Closures: Reference the variable from the enclosing scope.

When to Use Parameters

• When the function needs a snapshot of the variable's value at the time of invocation.
• When preventing simultaneous modification of the variable by multiple goroutines is important.

When to Use Closures

• When the function needs to access and modify the variable within the enclosing scope.
• When sharing the variable across multiple invocations of the function is desired.

Example: Closures vs. Parameters

Consider the following code examples that illustrate the difference between closures and parameters:

Closure:

for i := 0; i < 3; i++ {
    go func() {
        fmt.Println(i)
    }()
}

Parameter:

for i := 0; i < 3; i++ {
    go func(v int) {
        fmt.Println(v)
    }(i)
}

Result:

• Closure: Prints the value of i at the time of goroutine creation, resulting in "3" for all invocations.
• Parameter: Prints the value of i when the goroutine executes, resulting in "0," "1," "2".

Conclusion

The choice between parameters and closures depends on the desired behavior and variable sharing requirements. When a function needs a snapshot of a value, parameters are preferred. Closures are useful when accessing and modifying variables within the enclosing scope or sharing them across multiple invocations.

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