Operation Discovery Tool

What can happen to it? Write the operations you think exist, then see them sorted into CREATE / READ / UPDATE / DELETE and the domain actions that are none of those — each analysed as inputs, state read, state changed, output, side effects, errors.

I need X→What is X?→What must it remember?→What can happen to it?→What must always hold?→Examples→Represent the state→Which structure?→Each operation→Pseudocode→Implement one→Test with examples→Edge cases→Integrate

An operation is anything that can happen to the concept. CRUD is the checklist that finds the obvious ones; the operations that make the concept this concept — calculate the total, reserve stock, merge two carts — are verbs of the domain, and a design that only has CRUD has usually missed them.

Which concept?

beginner

intermediate

advanced

Shopping Cart — what can happen to it?

One operation per line. Write before you look.

write at least one to reveal

Sorted by kind

Click an operation for its analysis.

The columns appear after you reveal.

SIMPLIFIED

The analysis is the catalog's V1. Side effects in particular grow with the version — `add item` has none in V0 and an inventory reservation in V5 — so an operation's row is a snapshot of one stage, not a property of the operation.

Take it further

State Discovery Tool →

The stage before: which fields does each operation read?

crud-and-beyond →

Why the domain actions are the ones worth finding.

Cart Lab →

Run the cart's operations for real and watch each one's trace.