&gt;<i>only a subset of s-expressions are valid Lisp programs.</i><p>Sure, but the thing we&#x27;re debating is whether &quot;all s-expressions are valid Lisp programs&quot; (that would be a miracle actually), but whether Lisp syntax is all lists.<p>And all those examples are still lists -- that the lists can also contain other items inside them, or that underneath they are implemented as cons etc, doesn&#x27;t really change that.<p>&gt;<i>Comments are not expressed as lists.</i><p>They are not retained anyway when the strings are parsed to the &quot;live&quot; AST (AFAIK), so they are an exception to the other syntax in that too.