[Solved] Given this class, what will obj.foo.bar(1) output?class CatchAll def method_missing(name, *args) if name == :bar "Handled bar with #{args[0]}" else self end end end obj = CatchAll.new puts obj.foo.... | Ruby

Ruby - Metaprogramming Fundamentals

Given this class, what will obj.foo.bar(1) output?

class CatchAll
  def method_missing(name, *args)
    if name == :bar
      "Handled bar with #{args[0]}"
    else
      self
    end
  end
end

obj = CatchAll.new
puts obj.foo.bar(1)

ANoMethodError for foo

BHandled bar with nil

Cself

DHandled bar with 1

Step-by-Step Solution

Solution:

Step 1: Trace obj.foo call
Calling obj.foo triggers method_missing with name=:foo, which returns self (the object itself).
Step 2: Trace .bar(1) call on returned self
Calling .bar(1) triggers method_missing with name=:bar and args [1], which returns "Handled bar with 1".
Final Answer:
Handled bar with 1 -> Option D
Quick Check:
Chained method_missing returns handled string [OK]

Quick Trick: method_missing can return self to chain calls [OK]

Common Mistakes:

Expecting NoMethodError on first call
Not realizing method_missing returns self for chaining
Assuming args are missing for bar method

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More Ruby Quizzes

Given this class, what will obj.foo.bar(1) output?

Step 1: Trace obj.foo call

Step 2: Trace .bar(1) call on returned self

Final Answer:

Quick Check:

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