initial commit [141.14.129.234,mike]

input.go

@@ -0,0 +1,46 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"os/exec"
+	"strings"
+)
+
+// yesno asks a y/n question with a default. Reads a single keypress.
+func yesno(prompt string, def bool) bool {
+	suffix := " y/N ? "
+	if def {
+		suffix = " Y/n ? "
+	}
+	ans := strings.ToLower(strings.TrimSpace(getkey(prompt + suffix)))
+	if ans == "" {
+		return def
+	}
+	return ans == "y" || ans == "yes"
+}
+
+// getkey reads a single keypress from the terminal without echo. It reads a
+// single byte directly from stdin; readline is not reading at this point (we
+// are inside command execution), so there is no reader to desync with.
+func getkey(prompt string) string {
+	fmt.Print(prompt)
+	stty("-icanon", "-echo")
+	var buf [1]byte
+	n, err := os.Stdin.Read(buf[:])
+	stty("icanon", "echo")
+	key := ""
+	if err == nil && n > 0 {
+		key = strings.Trim(string(buf[:n]), "\r\n\t")
+	}
+	fmt.Println(key)
+	return key
+}
+
+func stty(args ...string) {
+	c := exec.Command("stty", args...)
+	c.Stdin = os.Stdin
+	c.Stdout = os.Stdout
+	c.Stderr = os.Stderr
+	c.Run()
+}