title: Why does the YAML spec mandate a space after the colon?
body: <p>The <a href="http://yaml.org/spec/1.2/spec.html" rel="noreferrer">YAML spec</a> clearly states: </p>
  
  <blockquote>
    <p>Mappings use a colon and space (“: ”) to mark each key: value pair.</p>
  </blockquote>
  
  <p>So this is legal:</p>
  
  <pre><code>foo: bar
  </code></pre>
  
  <p>But this, Ain't:</p>
  
  <pre><code>foo:bar
  </code></pre>
  
  <p>I see many people online that are ranting about the space. I think they have a point. I got burned by it several times myself.</p>
  
  <p>Why is the space mandatory? What was the design consideration behind it?</p>