function similar to getchar

Question

Is there a Go function similar to C's getchar able to handle tab press in console? I want to make some sort of completion in my console app.

Answer 1

C's getchar() example:

#include <stdio.h> void main() {     char ch;     ch = getchar();     printf("Input Char Is :%c",ch); } 

Go equivalent:

package main  import (     "bufio"     "fmt"     "os" )  func main() {      reader := bufio.NewReader(os.Stdin)     input, _ := reader.ReadString('\n')      fmt.Printf("Input Char Is : %v", string([]byte(input)[0]))      // fmt.Printf("You entered: %v", []byte(input)) } 

The last commented line just shows that when you press tab the first element is U+0009 ('CHARACTER TABULATION').

However for your needs (detecting tab) C's getchar() is not suitable as it requires the user to hit enter. What you need is something like ncurses' getch()/ readline/ jLine as mentioned by @miku. With these, you actually wait for a single keystroke.

So you have multiple options:

1. Use ncurses / readline binding, for example https://code.google.com/p/goncurses/ or equivalent like https://github.com/nsf/termbox

2. Roll your own see http://play.golang.org/p/plwBIIYiqG for starting point

3. use os.Exec to run stty or jLine.

refs:

https://groups.google.com/forum/?fromgroups=#!topic/golang-nuts/zhBE5MH4n-Q

https://groups.google.com/forum/?fromgroups=#!topic/golang-nuts/S9AO_kHktiY

https://groups.google.com/forum/?fromgroups=#!topic/golang-nuts/icMfYF8wJCk

Answer 2

Assuming that you want unbuffered input (without having to hit enter), this does the job on UNIX systems:

package main  import (     "fmt"     "os"     "os/exec" )  func main() {     // disable input buffering     exec.Command("stty", "-F", "/dev/tty", "cbreak", "min", "1").Run()     // do not display entered characters on the screen     exec.Command("stty", "-F", "/dev/tty", "-echo").Run()     // restore the echoing state when exiting     defer exec.Command("stty", "-F", "/dev/tty", "echo").Run()      var b []byte = make([]byte, 1)     for {         os.Stdin.Read(b)         fmt.Println("I got the byte", b, "("+string(b)+")")     } }