title: Concatenate left-to-right (LTR) and right-to-left (RTL) text
body: <p>It seems that combining left-to-right (LTR) and right-to-left (RTL) text using <code>paste</code> can produce unexpected results for the resulting order:</p>
  <pre><code>(x = paste(c('green', 'أحمر', 'أزرق'), collapse=' ')) # arabic for blue and red
  #&gt; [1] &quot;green أحمر أزرق&quot;
  paste(x, 'yellow')
  #&gt; [1] &quot;green أحمر أزرق yellow&quot;
  paste(x, 123)
  #&gt; [1] &quot;green أحمر أزرق 123&quot;
  </code></pre>
  <p>Is there any known solution to this - i.e. a way to ensure concatenation in the same sequence as the arguments are given?  Perhaps the answer is <em>don't concatenate different alphabets</em>!</p>