Super keyword behavior in Ruby - Step-by-Step Execution

Concept Flow - Super keyword behavior

Call method in subclass

↓

Use super keyword

↓

Call same method in superclass

↓

Execute superclass method

↓

Return to subclass method

↓

Continue subclass method execution

↓

Return final result

The super keyword calls the same method from the superclass, allowing the subclass to extend or modify behavior.

Execution Sample

Ruby

class Parent
  def greet
    "Hello from Parent"
  end
end

class Child < Parent
  def greet
    super + " and Child"
  end
end

puts Child.new.greet

This code shows how super calls the greet method from Parent inside Child's greet method.

Execution Table

Step	Action	Method Called	Return Value	Notes
1	Create Child instance	initialize (default)	Child instance	Object created
2	Call greet on Child instance	Child#greet	Calls super	Starts Child greet method
3	Inside Child#greet, call super	Parent#greet	"Hello from Parent"	Calls Parent greet method
4	Return from Parent#greet to Child#greet	Child#greet	"Hello from Parent and Child"	Concatenate strings
5	Print result	Main	"Hello from Parent and Child"	Output to console

💡 Method execution completes after returning combined string from Child#greet

Variable Tracker

Variable	Start	After Step 3	After Step 4	Final
result	nil	"Hello from Parent"	"Hello from Parent and Child"	"Hello from Parent and Child"

Key Moments - 3 Insights

Why does calling super inside Child#greet call Parent#greet?

Because super calls the method with the same name in the superclass, as shown in execution_table step 3.

What happens if super is called without parentheses?

It still calls the superclass method with the same arguments, as shown in step 3 where no arguments are passed.

Can super be called without a method of the same name in the superclass?

No, it will cause an error because super looks for the same method in the superclass, as implied by the flow in concept_flow.

Visual Quiz - 3 Questions

Look at the execution_table, what is the return value of Parent#greet at step 3?

A nil

B "Hello from Parent and Child"

C "Hello from Parent"

D An error

💡 Hint

Check the 'Return Value' column in execution_table row for step 3.

At which step does the Child#greet method concatenate the strings?

A Step 4

B Step 3

C Step 2

D Step 5

💡 Hint

Look at the 'Notes' column for the step where concatenation happens.

If super was not called in Child#greet, what would be the output?

A "Hello from Parent and Child"

B nil

C "Hello from Parent"

D An error

💡 Hint

Without super, Child#greet returns only what it explicitly returns; check variable_tracker for result changes.

Concept Snapshot

super keyword calls the same method in the superclass.
Used inside subclass methods to extend or reuse behavior.
Syntax: super or super(args).
Returns the result of the superclass method.
If no superclass method, calling super causes error.

Full Transcript

This visual execution shows how the super keyword works in Ruby. When a method in a subclass calls super, it runs the same method from its superclass. In the example, Child#greet calls super, which runs Parent#greet and returns "Hello from Parent". Then Child#greet adds " and Child" to that string and returns the combined result. The execution table traces each step: creating the object, calling Child#greet, calling Parent#greet via super, returning and concatenating strings, and finally printing the output. The variable tracker shows how the result variable changes after calling super and after concatenation. Key moments clarify why super calls the superclass method, what happens if called without parentheses, and that calling super without a matching method causes an error. The quiz tests understanding of return values, where concatenation happens, and what happens if super is omitted. The snapshot summarizes the main points about super keyword usage in Ruby.