This looks pretty cool, but as a non-Rubyist, I remain confused about the purpose of all these "DSL" libraries that lispy aims to simplify.

In the examples, at least, the language was only used to declaratively build hierarchical list/dictionary structures. The only constructs I can see used are blocks and method invocations; there aren't any loops or conditionals or anything else imperative. Can someone more experienced with Ruby DSLs explain what lispy accomplishes that something like YAML or a simple custom parser doesn't? (Other than a bunch of extra "do"s and ":"s.)