-----
title: "Concatenative 0.2.0 released"
content-type: article
timestamp: 1240126920
tags: "ruby|concatenative"
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<p>Version 0.2.0. of the <a href="/concatenative">Concatenative</a> <span class="caps">DSL</span> has been <a
		href="http://rubyforge.org/frs/?group_id=8068&amp;release_id=33575">released</a>.</p>
<p>Here are some highlights from the changelog:</p>
<ul>
	<li>Implemented new combinators:
		<ul>
			<li>binrec</li>
			<li>split</li>
			<li>twodip</li>
			<li>threedip</li>
		</ul>
	</li>
	<li>Performance improvements:
		<ul>
			<li>Stack is never copied.</li>
			<li>No symbol/string conversion when processing words.</li>
		</ul>
	</li>
	<li>Pseudo-namespace support (e.g. :kernel/:while and :math/:factorial)</li>
	<li>~ and &lt;= operators to unquote and define words, respectively.</li>
	<li>No more uppercase words!</li>
</ul>
<p>Oddly enough, I realized that it is possible to defined methods named after reserved words like &#8220;while&#8221;
	or &#8220;if&#8221;, so now all the concatenative words (combinators) in <code>kernel.rb</code> are now defined
	<em>without</em> a leading undersore. Similarly, there's no real need to use <span class="caps">UPPERCASE</span>
	symbols, so as a result, method lookup is significantly faster and will use less resources.</p>
<p>Here's how the lookup works. Say you have the following program:</p>
<div class='ruby'>
	<pre><code>[[1,2,3], [4.5.6], :concat]</code></pre>
</div>
<p>If <code>:concat</code> has been defined by the user (<code>:concat &lt;= [...]</code>), that definition will be
	used, otherwise the <code>Concatenative::Kernel</code> combinator <code>concat</code> will be called. If you want to
	use the corresponding Ruby method, all you have to do is specifying the arity explicitly using the <code>|</code>
	operator.</p>
<p>To remove any ambiguity, it is now possible to specify the <em>namespace</em> of a word explicitly, e.g.
	:kernel/:concat or :ruby/concat. The <code>/</code> operator simply concatenates the two symbols together
	(<code>:"kernel/concat"</code>) and sets the namespace (<code>:kernel</code>) and name (<code>:concat</code>) of the
	new symbol. <code>:kernel</code> and <code>:ruby</code> are not meant to be used when defining new words, but you
	can use anything else you like, for example :math/:factorial or :local/:a, etc.</p>
<p>As I pointed out in the <a href="/articles/concatenative-programming-in-ruby">first article</a> about concatenative,
	even with the new performance improvement a concatenative program still runs slower than a standard Ruby program,
	but at least now you won't run out of stack space (the <em>Ruby</em> stack, in this case) too soon.</p>
<p>If you have any issues to report, feature requests, etc., feel free to use <a
		href="http://github.com/h3rald/concatenative/issues">GitHub</a> to do so.</p>