test[S8Struct] samples

| point |
point := S8Struct
	type:    #x -> #float ,(#y -> #float)
	values: #x -> 1	 ,(#y -> 2).
point @ #x = 1 ifFalse: [ self error: 'Wrong contents at x' ].
point @ #y = 2 ifFalse: [ self error: 'Wrong contents at y' ].