How to pass a variable to a Ruby proc that updates dynamically?

Question

p = Proc.new{ |v| puts v }
p(5) #=> 5

This works fine, but what if I want to "bind" v so it updates dymanically. For example:

p = Proc.new{ ... puts v }
v = 5
p #=> 5
v = 7
p #=> 7

Answer 1

You already did it right. Just use call to execute your proc:

irb(main):001:0> v= 42
=> 42
irb(main):002:0> p= Proc.new{ puts v }
=> #<Proc:0x422007a8@(irb):2>
irb(main):003:0> p.call
42
=> nil
irb(main):004:0> v= 43
=> 43
irb(main):005:0> p.call
43
=> nil
irb(main):006:0>