def ListVarsCommand(): return Combine(['variables', 'vars', 'v'], Not(Identifier))
def my_rule(): return Combine(ZeroOrMore("a"), OneOrMore("b"))
def HelpCommand(): return Combine(['help', 'h', '?'], Not(Identifier))
def QuitCommand(): return Combine(['quit', 'exit', 'q'], Not(Identifier))
def DeleteCommand(): return ( Combine(['delete', 'del', 'd']), Whitespace, UnevaluatedVariable, )
def UnevaluatedVariable(): return Combine(Identifier)
def UnevaluatedExpression(): return Combine(Expression)
def RerollType(): return Combine(['r', 'R', ('!', Optional('!'), Optional('p'))])
def Number(): return Combine([Scientific, FloatingPoint, Integer])