[Rd] Is it possible to generate an error when a function is reassigned?

[thmsfuller066 at gmail.com]

Hello All,

length() is a function. If I accidentally assign something else to
length, it will give me some unexpected results.

Although the freedom to redefine any funcion maybe good in sometime,
it may be unwanted in many other cases. Is there a way to forbidden
such changes on functions?

-- 
Tom