You should find this of interest because this is how USE is written in Rebol:<p><pre><code>  &gt;&gt; source use
  
  use: make function! [[
      &quot;Defines words local to a block.&quot;
      vars [block! word!] &quot;Local word(s) to the block&quot;
      body [block!] &quot;Block to evaluate&quot;
  ][
      apply make closure! reduce [to block! vars copy&#x2F;deep body] []
  ]]</code></pre>