Here is something I had in my library, written by someone else, called entry_auto_complete.pl. I adapted it to your problem, you may like it. 
#!/usr/bin/perl -w
#entry_auto_complete.pl
use Tk;
use strict;

my $mw = MainWindow->new;

#list of recognized words/phrases
#perhaps read in from a file of recognized words/phrases
my (@list) = (
    "apo\'strophe",
    "Upper",
    "this one",
    "that one",
    "the other one",
    "the something",
    "go west",
    "go east",
    "go north",
    "go south",
);
@list = sort(@list);

#show the list
print "Upper, lower, space, apostrophe and all case insensitive\n";
print "\n";
foreach (@list) {
    print "$_\n";
}
print "\n";

my $text  = '';
my $entry = $mw->Entry( -textvariable => \$text, -width => 60 )->pack(
+);

$entry->bind(
    '<Key>' => sub {
        my ($w) = @_;    #widget referenced
        my $ev = $w->XEvent;    #get the event object
        my $A  = $ev->A;        #get ascii char from the event

        print "---------------------$A---------------\n";

        #if the character entered is [lowercase] OR
        #[uppercase] OR [a space] OR [an apostrophe] ...
        if ( $A =~ m/[a-z]|[A-Z]| |'/ ) {
            foreach (@list) {

                #compare the entered text to the items in the list
                if ( $text ne '' and $_ =~ m/^$text/i ) {
                    print "$text -- $_\n";
                    my $input_length = length($text);
                    my $match_length = length($_);
                    $text = $_;

                    #highlight/select the tail end of the entry field 
+text
                    $entry->selectionFrom($input_length);
                    $entry->selectionTo($match_length);
                }    #if
            }    #foreach
        }    #end if
      }    #sub
);         #end bind

$mw->Button( -text => 'Quit', -command => sub { exit } )->pack( -fill 
+=> 'x' );

$entry->focus();
MainLoop;

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I'm not really a human, but I play one on earth. Cogito ergo sum a bum

In reply to Re: how to use validatecommand for string checking by zentara
in thread how to use validatecommand for string checking by dannytrannox

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