Question

For a project I am working on in ruby I am overriding the method_missing method so that I can set variables using a method call like this, similar to setting variables in an ActiveRecord object:

Object.variable_name= 'new value'

However, after implementing this I found out that many of the variable names have periods (.) in them. I have found this workaround:

Object.send('variable.name=', 'new value')

However, I am wondering is there a way to escape the period so that I can use

Object.variable.name= 'new value'

Answer 1

Don’t do it!

Trying to create identifiers that are not valid in your language is not a good idea. If you really want to set variables like that, use attribute macros:

attr_writer :bar attr_reader :baz attr_accessor :foo 

Okay, now that you have been warned, here’s how to do it. Just return another instance of the same class every time you get a regular accessor, and collect the needed information as you go.

class SillySetter   def initialize path=nil     @path = path   end    def method_missing name,value=nil     new_path = @path ? '#{@path}.#{name}' : name     if name.to_s[-1] == ?=       puts 'setting #{new_path} #{value}'     else       return self.class.new(path=new_path)     end   end end  s = SillySetter.new s.foo = 5              # -> setting foo= 5 s.foo.bar.baz = 4      # -> setting foo.bar.baz= 4 

I didn’t want to encourage ruby sillyness, but I just couldn’t help myself!