How Can Child Functions Affect Parent Function Execution?

Returning Control in Child Functions

When calling a child function from a parent function, the execution normally continues in the parent function after the child function returns. However, in some situations, we may want to end execution in the parent function based on the result of the child function call.

Consider the following example:

func apiEndpoint() {
    if false {
        apiResponse("error") // Call child function
        // Expect to end execution after apiResponse() call
    }

    apiResponse("all good")
}

func apiResponse(message string) {
    // Returns message to user via JSON
}

In this example, we want the apiEndpoint function to end its execution if the apiResponse function is called with an "error" message. However, the code as is does not achieve this goal.

The Limitation of Child Functions

The key limitation here is that a child function cannot control the execution of its parent function. The parent function determines its own execution flow.

Alternative Solutions

There are alternative ways to accomplish the desired behavior:

• Use if-else Blocks: Replace the if condition with an if-else block:

func apiEndpoint() {
    if false {
        apiResponse("error")
    } else {
        apiResponse("all good")
    }
}

• Use Return Values: If the child function returns a value, we can use it as the return value of the parent function:

func apiEndpoint() string {
    if false {
        return apiResponse("error")
    }

    return apiResponse("all good")
}

func apiResponse(message string) string {
    return message
}

• Note: Panic-recover is not a reliable solution in this scenario.

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