use strict;
use warnings;
use Text::Template;

my $template = Text::Template->new(
    TYPE   => 'STRING',
    SOURCE => 'fred has {$color} eyes'
);

our $color = 'blue';
print $template->fill_in;

##</code><code>##

use strict;
use warnings;
use HTML::Template;

my $data = 'fred has <tmpl_var color> eyes';

my $template = HTML::Template->new(
    scalarref => \$data,
);

$template->param(
    color => 'brown',
);

print $template->output;

##</code><code>##

use strict;
use warnings;
use Template;

my $data = 'fred has [% color %] eyes';
my $vars = {
    color => 'blue',
};

my $tt = Template->new;
$tt->process(\$data, $vars) || die $tt->error;