仅在init语句中一次输入函数

Question

I am starting programming with Go and I am trying to create a program that makes queries to a DB and return the data. I have achieved this but I have encounter some problems and questions during this.

Firstly, I tried to create a for with a condition to tell the program when I want to stop making queries, but the Init Statement of the for looks that only is evaluated once -and I am never asked again to enter input via terminal- (I have read here that is because his value is hold and then it doesnt execute the function again: Golang switch statement only calls function once ):

Edited

func main() {
    var query string
    for query = ReadQuery(); query != "exit
"; {
        rows, err := db.Query(query)
        //Printing results and other operations
    }
    fmt.Println("Exiting")
}

func ReadQuery() string {
    reader := bufio.NewReader(os.Stdin)
    fmt.Print("Enter query in a single line, with no newline. 'exit' to terminate execution: 
")
    query, _ :=reader.ReadString('
')
    reader.Reset(os.Stdin)
    return query
}

...so I have done this fix that looks to me a bit dirty:

func main() {
    var query string
    for {
        query = ReadQuery()
        if query == "exit
" {
            fmt.Println("Exiting")
            break
        }
        //Printing results and other operations
    }
}

func ReadQuery() string {
   reader := bufio.NewReader(os.Stdin)
   fmt.Print("Enter query in a single line, with no newline. 'exit' to terminate execution: 
")
   query, _ :=reader.ReadString('
')
   reader.Reset(os.Stdin)
   return query
}

So the question is if there is another way to do this using for statements and avoid more lines to my code. Lot of thanks

Answer 1

You need to add a post statement to your loop that will be called on each iteration.

var query string
for query = ReadQuery(); query != "exit
"; query = ReadQuery() {
    // loop body
}

The Go Tour has a good explanation of this functionality.