examples: add vmatrix.v showing a Matrix like terminal screen effect

[mike-ward]

A fun example of the, "Matrix" screen effect in V.

[Delta456]

The program tears apart when scrolling.

[spytheman]

The program tears apart when scrolling.

A patch like this seems to work:

import term.termios
...
fn init_terminal() ! {
    mut old_state := termios.Termios{}
    termios.tcgetattr(0, mut old_state)
    // restore cursor, exit alternate buffer mode on Ctrl+C
    os.signal_opt(os.Signal.int, fn [mut old_state] (sig os.Signal) {
        println('\e[?1049l\e[?25h')
        termios.set_state(0, old_state)
        exit(0)
    })!
    // turn off cursor, enter alternate buffer mode
    print('\e[?1049h\e[?25l')
    mut new_state := old_state
    new_state.disable_echo()
    termios.set_state(0, new_state)
}

[spytheman]

https://github.com/abishekvashok/cmatrix/blob/master/cmatrix.c#L468C5-L468C11
also calls noecho()

[mike-ward]

@spytheman Thanks for the patch. I'll add it.

[spytheman]

@mike-ward happy to help.

Good work on the effect, the code is very readable.

[medvednikov]

https://x.com/v_language/status/1810380646348632508