Undefine variable in Ruby

ruby metaprogramming local-variables
Peter picture Peter · Jan 6, 2010 · Viewed 21.9k times · Source

Let's say I'm using irb, and type a = 5. How do I remove the definition of a so that typing a returns a NameError?

Some context: later I want to do this:

context = Proc.new{}.binding
context.eval 'a = 5'
context.eval 'undef a'  # though this doesn't work.

Answer

mikej picture mikej · Jan 6, 2010

There are remove_class_variable, remove_instance_variable and remove_const methods but there is currently no equivalent for local variables.

Related questions

Dynamically set local variables in Ruby

I'm interested in dynamically setting local variables in Ruby. Not creating methods, constants, or instance variables. So something like: args[:a] = 1 args.each_pair do |k,v| Object.make_instance_var k,v end puts a > 1 I want locally …

Read More
How to list local-variables in Ruby?

def method a = 3 b = 4 some_method_that_gives # [a, b] end

Read More
Calling a Method From a String With the Method's Name in Ruby

How can I do what they are talking about here, but in Ruby? How would you do the function on an object? and how would you do a global function (see jetxee's answer on the post mentioned)? EXAMPLE CODE: event_…

Read More