function similar to getchar

Issue

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.

Solution

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

Answered By – rputikar

Answer Checked By – David Marino (GoLangFix Volunteer)

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