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Posted on Sep 1

Structured purpose flow method(SPF)

Structured Purpose Flow (SPF): A New Way to Embed Intent in Code

Preface: Why This Article

This article grew out of a collaborative journey between a developer (working through practical coding challenges) and ChatGPT as a co-pilot. Along the way, we kept circling the same problem:

“How do I clearly show where my code starts, what it achieves, and why it exists?”

From that question, the Structured Purpose Flow (SPF) Method was born. SPF is not presented as a rigid framework but as a lightweight, evolving tool designed to help developers — from beginners to professionals — make code more purpose-driven, traceable, and usable.

We’re publishing this here on Dev.to because of its strong, engaged developer community. The goal is not just to explain SPF, but to open a conversation:

Try it in your projects.
Tell us what works and what doesn’t.
Share refinements and new use cases.

Your input can shape the next iteration of SPF. This is as much your method as it is ours.

Introduction

Code should do more than “run.” It should communicate intent and purpose. Traditional methodologies like KISS, DRY, SOLID, TDD, and Agile practices help with maintainability and clarity — but they often don’t explicitly tie code to its purpose flow. That’s where the Structured Purpose Flow (SPF) method steps in.

SPF adds a Schneiderman-like structured chart alongside your code that:

Breaks down steps (start → purpose → outcome).
Tracks where in the code each purpose is fulfilled.
Bridges the gap between human reasoning and machine execution.

Part 1: Beginner-Level Example

Scenario: A simple bank account logic — charging if overdrawn, rewarding if balance maintained.

SPF Table (Beginner)

Step	Action	Purpose
1	Set bank charge	Define penalty for overdraft
2	Set bank bonus	Define reward for good standing
3	Set account balance	Initialize current balance
4	Check if overdrawn	Decision point
5	Apply charge if overdrawn	Enforce penalty
6	Apply bonus if not overdrawn	Reward good balance
7	Display account balance	Show final outcome

Code Example

# Step 1: set the bank charge
charge = 50

# Step 2: set the bank bonus
bonus = 20

# Step 3: set account balance
balance = 100

# Step 4: check condition if account is overdrawn
if balance < 0:
    # Step 5: apply charge if overdrawn
    balance -= charge
else:
    # Step 6: credit the bonus if not overdrawn
    balance += bonus

# Step 7: display account balance
print(f"Final balance: {balance}")

Beginner-Level Flow Diagram

(Image: Bank Account SPF Flow)

Part 2: Intermediate to Professional-Level Example

Scenario: Eligibility checker with input validation — more complex, more maintainable.

SPF Table (Pro)

Step	Action	Purpose
1	Accept input	Gather data
2	Validate input	Ensure correctness
3	Convert input to integer	Prepare for evaluation
4	Check eligibility	Decision-making
5	Return outcome	Provide result

Code Example (with TDD mindset)

def check_eligibility(age_input):
    # Step 1: Accept input
    # Step 2: Validate input
    if not age_input.isdigit():
        return "Invalid input"

    # Step 3: Convert input to integer
    age = int(age_input)

    # Step 4: Check eligibility
    if age >= 18:
        return "Eligible"
    else:
        return "Not Eligible"

# Step 5: Return outcome
print(check_eligibility("20"))   # Eligible
print(check_eligibility("abc"))  # Invalid input
print(check_eligibility("15"))   # Not Eligible

Pro-Level Flow Diagram

(Image: Eligibility SPF Flow)

Harmony with Maintainability Practices

SPF doesn’t replace existing methodologies; it complements them.

KISS: SPF keeps steps explicit and simple.
DRY: By mapping purposes, it prevents duplication of intent.
SOLID: Supports Single Responsibility Principle by showing each purpose clearly.
TDD: SPF tables can be converted directly into test cases.
Agile & Refactoring: Easier iteration since every flow step is documented.

SPF as a Hub (Diagram 3)

(Image: SPF hub with arrows to KISS, DRY, SOLID, TDD, Agile)

Why This Matters for Professionals

In a large codebase, purpose often gets lost in abstractions. SPF creates a narrative layer:

Junior devs see what happens.
Senior devs see why it happens.
Teams see how the flow ties to business rules.

This reduces onboarding time, makes refactoring safer, and aligns code directly with stakeholder intent.

Conclusion

SPF is not a “silver bullet” but a missing link — a lightweight, structured way to map code to intent. By combining it with trusted practices like KISS, DRY, SOLID, and TDD, it bridges the gap between purpose clarity and code maintainability.

We invite you to:

Try SPF in your project.
Share results and refinements.
Join us in shaping this into a community-driven tool.

Call to Action

Would you use SPF in your daily workflow? Drop your thoughts below — your feedback may shape the next version of this method.

DEV Community