What is the Ruby equivalent of PHP's compact?

Question

Given some local variables, what would be the easiest way to compact them in Ruby?

def foo
  name = 'David'
  age = 25
  role = :director
  ...
  # How would you build this:
  # { :name => 'David', :age => 25, :role => :director }
  # or
  # { 'name' => 'David', 'age' => 25, 'role' => :director }
end

In PHP, I can simply do this:

$foo = compact('name', 'age', 'role');

Answer 1

I came up with a significant improvement on my original answer. It is cleaner if you inherit from Binding itself. The to_sym is there because older versions of ruby have local_variables as strings.

instance method

class Binding
  def compact( *args )
    compacted = {}
    locals = eval( "local_variables" ).map( &:to_sym )
    args.each do |arg|
      if locals.include? arg.to_sym
        compacted[arg.to_sym] = eval( arg.to_s ) 
      end 
    end 
    return compacted
  end
end

usage

foo = "bar"
bar = "foo"
binding.compact( "foo" ) # => {:foo=>"bar"}
binding.compact( :bar ) # => {:bar=>"foo"}

---

Original answer

This is the nearest I could get to a method that behaves like Php's compact -

method

def compact( *args, &prok )
  compacted = {}
  args.each do |arg|
    if prok.binding.send( :eval, "local_variables" ).include? arg
      compacted[arg.to_sym] = prok.binding.send( :eval, arg ) 
    end
  end 
  return compacted
end

example usage

foo = "bar"
compact( "foo" ){}
# or
compact( "foo", &proc{} )

Its not perfect though, because you have to pass a proc in. I am open to suggestions about how to improve this.