local_variable($this)operator(?)local_variable($is)operator(+)constant(NO)operator(:)local_variable($label)operator(;)

comment(// Two labels:)
label(foo)operator(:) reserved(switch) operator(()constant(TYPE)operator(()ident(v)operator(\))operator(\)) operator({)
  reserved(case) constant(T_CLASS)operator(:) reserved(case) constant(T_MODULE)operator(:)
    ident(rb_str_append)operator(()ident(s)operator(,) ident(rb_inspect)operator(()ident(v)operator(\))operator(\))operator(;)
    reserved(break)operator(;)
  reserved(default)operator(:)
    label(bar)operator(:)
    ident(rb_str_append)operator(()ident(s)operator(,) ident(rb_any_to_s)operator(()ident(v)operator(\))operator(\))operator(;)
    reserved(break)operator(;)
operator(})
comment(// These are two more labels:)
reserved(function)operator(()ident(call)operator(\))operator(;)
label(label2)operator(:) ident(label3)operator(:) ident(a) operator(=) ident(b) operator(+) ident(c)operator(;)

comment(// Another label:)
reserved(if) operator(()integer(1)operator(\)) operator({)
  label(label4)operator(:) ident(a) operator(=) ident(b) operator(+) ident(c)operator(;)
operator(})

comment(// Not a label.)
ident(test)operator(()
  ident(a)operator(?)
  ident(b)operator(:)
  ident(c)
operator(\))