Perl 一个简单的 GUI 程序，有退出按钮

#!/usr/bin/perl -w 
use Tk; 

$Tk::strictMotif = 1; 
 
$main = MainWindow->new(); 
 
$button1 = $main->Button(-text => "Exit", 
                       -command => \&exit_button, 
                       -foreground => "orangered" ); 
 
$button1->pack(); 
$button1->configure(-background => "white" ); 
$button2 = $main->Button(-text => "Push Me", 
                   -command => \&change_color, 
                         -foreground => "black",  
                         -background => "steelblue"); 
  
$button2->pack(); 
  
MainLoop(); 
  
sub exit_button { 
   print "You pushed the button!\n"; 
   exit; 
} 
  
sub change_color { 
    $button1->configure(-background => "red", 
                       -foreground => "white"); 
    $button2->configure(-background => "maroon", 
                   -foreground => "white", 
    -font       => "-*-times-bold-r-normal-20-140-*"); 
}