How to recursively capture user input - go

Question

I'm trying to capture the input of a bunch of numbers in Go. I am not allowed to do for loops. User input is multi-lined. However the function below is not returning the expected results of an []int, it instead returns with an empty array. Why is this? Or is there another way to capture multi-lined user input without for loops?
func input_to_list() []int {
fmt.Print("continuously enter text: ")
reader := bufio.NewReader(os.Stdin)
user_input, _ := reader.ReadString('\n')
print(user_input)
var result []int
if user_input == "\n" {
return result
}
return append(result, input_to_list()...)
}

Answer 1

How to recursively capture user input?
I am not allowed to do for loops.
For example,
package main
import (
"bufio"
"fmt"
"io"
"os"
"strconv"
"strings"
)
func readInt(rdr *bufio.Reader, n []int) []int {
line, err := rdr.ReadString('\n')
line = strings.TrimSpace(line)
if i, err := strconv.Atoi(line); err == nil {
n = append(n, i)
}
if err == io.EOF || strings.ToLower(line) == "end" {
return n
}
return readInt(rdr, n)
}
func ReadInts() []int {
fmt.Print("enter integers:\n")
var n []int
rdr := bufio.NewReader(os.Stdin)
return readInt(rdr, n)
}
func main() {
n := ReadInts()
fmt.Println(n)
}
Output:
enter integers:
42
7
end
[42 7]

Answer 2

Your function never assigns any value to result.
func input_to_list() []int {
/* ... */
var result []int // Create empty `result` slice
if user_input == "\n" {
return result // Return empty result slice
}
return append(result, input_to_list()...) // Combine two empty slices, and return the (still) empty slice
}
Let's step through:
You create an empty slice called result
If user_input is empty, you return the result immediately.
If user_input is not empty, you call input_to_list() recursively, and add its (empty) result to your empty result, then return that (still) empty result.
To get your desired behavior, you should be doing something (other than just checking for empty) with user_input. Probably something related to strconv.Atoi or similar, then adding that to result.