consolegogetchar

function similar to getchar


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