PROMPT: Calculator (MVPL Platform) prompt for a custom extension

✅ CUSTOM EXTENSION GENERATION PROMPT

MVPL Extension Generator — CustomExtension

SYSTEM ROLE

You are Codex.

You are generating a fully compliant MVPL calculator extension that integrates with an already existing MVPL Modular Calculator Core (index.html is already implemented and loaded in the environment).

GLOBAL OBJECTIVE

Generate a new MVPL extension script named:

custom.js

This extension must fully comply with the MVPL extension architecture, lifecycle system, and safety model already implemented in the core platform.

OUTPUT REQUIREMENTS

Generate EXACTLY ONE FILE:

custom.js

Do NOT include explanations outside code comments.

Return ONLY the JavaScript source code.

GLOBAL TECHNICAL CONSTRAINTS

• Must be standalone JavaScript
• Must run offline
• Must not require external libraries
• Must not modify core globals
• Must interact ONLY through extensionAPI
• Must follow MVPL lifecycle model
• Must preserve backward compatibility
• Must be safe if lifecycle hooks are missing in other extensions
• Must prevent duplicate UI insertion
• Must preserve profile state isolation

MVPL EXTENSION CONTRACT

The extension MUST use the manifest structure:

{

  name: string,

  version: string,

  description: string,

  dependencies?: string[],

  priority?: number,

  stateSchema?: object,

  onInit(api, state),

  onProfileSwitch(api, state),

  onLayoutChange(api, state),

  onDestroy(api, state)

}

Extension must be registered using:

registerExtension(manifest)

EXTENSION NAME

CustomExtension

FUNCTIONAL BEHAVIOR

The extension must:

• Add a button labeled K
• When pressed, compute a custom function of the current display value
• Initially, the function MUST return the value unchanged
• The function logic must be clearly isolated and documented so developers can easily edit it later inside custom.js

PROFILE RESTRICTION

The K button MUST:

• Only appear in the education profile
• Be removed automatically when switching to any other profile
• Only execute its function when the education profile is active
• Remain inactive or hidden otherwise

UI INSERTION RULES

• Must insert using extension slot system
• Must use slot-extension-2
• Must NOT replace or reposition core calculator buttons
• Must prevent duplicate button insertion

ERROR HANDLING REQUIREMENTS

The extension MUST:

• Display "Error" if display value is invalid numeric input
• Display "Error" if division by zero occurs within future custom functions
• Fail safely without crashing the calculator core

STATE SCHEMA REQUIREMENTS

The extension must implement a namespaced state model using:

stateSchema: {

  lastUsed: null

}

State must be stored and retrieved through:

api.state("CustomExtension")

State must persist per profile and MUST NOT leak across profiles.

LIFECYCLE REQUIREMENTS

CustomExtension MUST implement:

onInit
onProfileSwitch
onLayoutChange
onDestroy

Lifecycle behavior must follow MVPL rules:

onInit:
• Create button
• Insert button only if education profile is active

onProfileSwitch:
• Insert or remove button based on profile

onLayoutChange:
• Must remain safe and not duplicate UI

onDestroy:
• Must remove UI components
• Must preserve stored state

SAFETY REQUIREMENTS

The extension MUST:

• Never modify calculator core variables
• Never assume slot exists without checking
• Safely remove UI elements when destroyed
• Avoid duplicate event bindings
• Fail gracefully if extensionAPI functions are unavailable

DOCUMENTATION REQUIREMENTS (INSIDE CODE COMMENTS)

Include clear teaching comments explaining:

• MVPL extension lifecycle
• Profile restriction logic
• Slot keypad insertion rules
• Namespaced state handling
• How developers can later customize the function logic

ACCEPTANCE CRITERIA

The extension is considered complete ONLY if:

✔ K button appears only in education profile
✔ Button disappears when profile changes
✔ Button inserts using slot-extension-2
✔ Extension uses lifecycle hooks correctly
✔ State persists per profile
✔ Calculator core remains stable
✔ Button executes identity function initially
✔ Error handling works
✔ No duplicate UI insertion occurs

TESTING INSTRUCTIONS (INSIDE CODE COMMENTS)

In index.html:

• Edit the profile for ‘education’, adding CustomExtension to enabledExtensions, and just before the </body> end tag add <script src="custom.js"></script>

Include instructions describing how to:

• Load custom.js alongside index.html
• Switch to education profile
• Verify K button visibility
• Verify button removal when switching profiles
• Confirm state persistence
• Confirm error handling
• Confirm calculator arithmetic remains correct

FINAL AUTHORITATIVE RULE

If any instruction conflicts:

Preserve calculator core stability
Preserve backward compatibility
Preserve profile state isolation
Preserve lifecycle correctness

OUTPUT FORMAT (STRICT)

Return EXACTLY:

----- custom.js -----

<full code>

No summaries
No explanations
Only code output