mustache.pl

use v5.10;
use strict;
use warnings;
use Data::Dumper;

sub _quote_var {
    my $s = $_[0];
    my $d = Data::Dumper->new([$s]);
    $d->Terse(1);
    my $qs = $d->Dump;
    substr($qs, -1, 1, '') if substr($qs, -1, 1) eq "\n";
    return $qs;
}

my $tmpl = 'The {{ PLANET }} is shining and {{ WHO }} glad to kill them all\'s at once, "yeah"';

sub translate_tmpl {
    my $tmpl    = $_[0];
    my $bodysub = '';
    my $lastidx;
    while ($tmpl =~ m|(.*?)\{\{\s*(\w+)\s*\}\}|g) {
        $lastidx = $+[0];
        my $var = lc $2;
        $bodysub .= "." if $bodysub;
        $bodysub .= _quote_var($1) . qq|.(\$_[0]->{'$var'}//'')|;
    }
    my $left = substr($tmpl, $lastidx);
    if ($left) {
        $bodysub .= "." if $bodysub;
        $bodysub .= _quote_var($left);
    }
    return "sub { $bodysub }";
}

say translate_tmpl($tmpl);
my $cfunc = eval translate_tmpl($tmpl);
say $cfunc->({
        planet => 'sun',
        who    => 'children',
    }
);