int ofthen(int n)
  if_plus(0)
    isit = 42
  else
    maybenot = 667
  end
end
-- -- --
s(:statements,
  s(:function, :Integer,
    s(:name, :ofthen),
    s(:parameters,
      s(:parameter, :Integer, :n)),
    s(:statements,
      s(:if_statement, :plus,
        s(:condition,
          s(:int, 0)),
        s(:true_statements,
          s(:assignment,
            s(:name, :isit),
            s(:int, 42))),
        s(:false_statements,
          s(:assignment,
            s(:name, :maybenot),
            s(:int, 667)))))))