Question

In Ruby, is it possible to pass by reference a parameter with value-type semantics (e.g. a Fixnum)? I’m looking for something similar to C#’s ‘ref‘ keyword.

Example:

def func(x)      x += 1 end  a = 5 func(a)  #this should be something like func(ref a) puts a   #should read '6' 

Btw. I know I could just use:

a = func(a) 

Answer 1

You can accomplish this by explicitly passing in the current binding:

def func(x, bdg)   eval '#{x} += 1', bdg end  a = 5 func(:a, binding) puts a # => 6