\ontology#a{
	\struct#b{
		\primitive#f1[subtree=true,type=string]{
			\syntax{
				\open{=}
				\close{\newline}
				\whitespace{preserve}
			}
		}
		\field#f2{
			\syntax{
				\open{++}
				\close{--}
				\whitespace{collapse}
			}
			\childRef[ref=b]
		}
		\syntax{
			\short{~}
		}
	}
}