inpla' target='_blank'>Inpla</a>'s notation for rules in which the principal ports are taken out of the brackets and their equivalent connection written as <kbd>&gt;&lt;</kbd>. When an agent has an arity of 0, the brackets are removed altogether. Thus, we can write the entire addition program as:</p>

<pre>
<b>Rules:</b>
	add(y, z) >< Z => y~z;
	add(y, z) >< S(x) => add(y, S(z))~x;
<b>Exec:</b>
	add(res,S(Z))~S(S(Z)); <span style='color:#777'>1 + 2</span>
	res; 
<b>Result:</b>
	<span style='color:#777'>S(S(