That Kotlin page calls them "Groovy-style", perhaps because many of those working on Kotlin (e.g. James Strachan, Alex Tkachman) used to develop the Groovy Language.

But doesn't Ruby also have those builders? Wouldn't it be easy enough for Scala to implement them in a library if they haven't already? Wouldn't Python also provide this type of syntax? E.g. a possible translation into Python from the Kotlin code on the linked page...

    html:
      head:
        title {"XML encoding with Python"}
      body:
        h1 {"XML encoding with Python"}
        p {"this format can be used as an alternative markup to XML"}
 
        // an element with attributes and text content 
        a(href = "http://python.org") {"Python"}

        // mixed content 
        p:
          "This is some" 
          b {"mixed"} 
          "text. For more see the" 
          a(href = "http://python.org") {"Python"} 
          "project" 
        p{"some text"} 
 
        // content generated by 
        p: 
          for (arg in args) arg 

So what are they called "Groovy-style" builders for?