03-mutable-ripple.err

# SPDX-License-Identifier: MPL-2.0
# Example: Mutation Ripple Effect
# Learning: Mutable state affects code stability

main
    # Mutable counter
    let mut counter = 0

    # Mutation creates "ripples"
    counter = counter + 1

    # Every function that reads counter is now "tainted"
    println("Counter:", counter)
    display(counter)
    calculate(counter)

    # Try making counter immutable (remove 'mut')
    # Notice stability increase
end

function display(n)
    println("Display:", n)
end

function calculate(n)
    let result = n * 2
    println("Calculate:", result)
end

# 🔴 EXPECTED CONSEQUENCES:
# - Mutation at line 8: -10 stability
# - 3 readers (println, display, calculate): -15 stability
# - Total: stability = 75
#
# 🎓 LEARNING OUTCOME:
# Mutable state creates invisible dependencies.
# Every mutation affects all readers.
# This is why functional programming prefers immutability!
#
# 💡 STABILIZATION:
# Make immutable, pass as parameter → stability: 100
#
# ALTERNATIVE CODE:
# let counter = 0
# let counter = counter + 1
# # Each "mutation" creates a new value
# # Stability: 100