Mentioned above already, but thought I'd give an example of Template Toolkit to illustrate how similiar it is to your request:

use Template;
my $template = Template->new();

my $my_template_string = 'bar [% var1 %] foo foo [% var2 %] bar bar BA
+AAR!';
my $vars = {var1=>"Guybrush", var2=>"Purcell"};

my $string;
$template->process(\$my_template_string, $vars, \$string);
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Note that TT it is very powerful and supports all kinds (IF, FOREACH, BLOCK, etc) of logic. http://www.template-toolkit.org