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/*******************************************************************************
*
* Copyright 2017 Stefan Majewsky <majewsky@gmx.net>
*
* This program is free software: you can redistribute it and/or modify it under
* the terms of the GNU General Public License as published by the Free Software
* Foundation, either version 3 of the License, or (at your option) any later
* version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
* A PARTICULAR PURPOSE. See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along with
* this program. If not, see <http://www.gnu.org/licenses/>.
*
*******************************************************************************/
package main
import (
"bufio"
"fmt"
"os"
"strings"
)
//ShowError prints the given error on stderr if it is non-nil, or returns false otherwise.
func ShowError(err error) bool {
if err == nil {
return false
}
fmt.Fprintf(os.Stderr, "ERROR: %s\n", err.Error())
return true
}
//FatalIfError prints the given error on stderr and exits with an error code.
func FatalIfError(err error) {
if err != nil {
fmt.Fprintf(os.Stderr, "FATAL: %s\n", err.Error())
os.Exit(255)
}
}
var stdin = bufio.NewReader(os.Stdin)
//Prompt prints the question, then waits for the user to press one of the
//possible answer keys. Answer keys will automatically be converted to lower
//case and returned as such.
//
// choice := Prompt("(y)es or (n)o", []string{"y","n"})
// //choice is either "y" or "n"
func Prompt(question string, answers []string) string {
for idx, answer := range answers {
answers[idx] = strings.ToLower(answer)
}
os.Stdout.Write([]byte(">> " + strings.TrimSpace(question) + " "))
for {
input, err := stdin.ReadString('\n')
FatalIfError(err)
input = strings.TrimSpace(input)
for _, answer := range answers {
if strings.ToLower(input) == answer {
return answer
}
}
//user typed gibberish - ask again
os.Stdout.Write([]byte("Please type "))
for idx, answer := range answers {
if idx > 0 {
if idx == len(answers)-1 {
os.Stdout.Write([]byte(" or "))
} else {
os.Stdout.Write([]byte(", "))
}
}
os.Stdout.Write([]byte("'" + answer + "'"))
}
os.Stdout.Write([]byte(": "))
}
}
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