Kanban Task Board
Tasks flow through: backlog -> todo -> in_progress -> done.
Example 067 of the basic Soma programs: a small, commented program that teaches one thing. Every output below was printed by soma 3.2.4 when this page was built.
How it is built
The cell TaskBoard keeps 2 memory slots: tasks (Map<String, String>, persistent and consistent) and status (Map<String, String>, persistent and consistent). Its state machine task_status starts in backlog and allows 7 transitions: backlog -> todo, todo -> in_progress, in_progress -> done, in_progress -> blocked, blocked -> in_progress, done -> todo and * -> cancelled. cancelled is terminal. Handlers: create (line 34) and demo (line 41).
The source
067_task_board.cell
// ============================================================================
// 067 — Kanban Task Board
// ============================================================================
// Tasks flow through: backlog -> todo -> in_progress -> done.
//
// Run: soma run 067_task_board.cell demo
// Expect:
// Task 'Implement login' created
// Task 'Write tests' created
// Task 1 -> todo
// Task 1 -> in_progress
// Task 2 -> todo
// Task 1 -> done!
cell TaskBoard {
memory {
tasks: Map<String, String> [persistent, consistent]
status: Map<String, String> [persistent, consistent]
}
state task_status {
initial: backlog
backlog -> todo
todo -> in_progress
in_progress -> done
in_progress -> blocked
blocked -> in_progress
done -> todo
* -> cancelled
}
on create(title: String) {
let id = to_string(next_id())
tasks.set(id, title)
status.set(id, "backlog")
return map("id", id, "title", title, "status", "backlog")
}
on demo() {
create("Implement login")
print("Task 'Implement login' created")
create("Write tests")
print("Task 'Write tests' created")
transition("1", "todo")
print("Task 1 -> todo")
transition("1", "in_progress")
print("Task 1 -> in_progress")
transition("2", "todo")
print("Task 2 -> todo")
transition("1", "done")
print("Task 1 -> done!")
return "done"
}
}What the toolchain says
$ soma check 067_task_board.cell
✓ All checks passed.$ soma run 067_task_board.cell demo
Task 'Implement login' created
Task 'Write tests' created
Task 1 -> todo
Task 1 -> in_progress
Task 2 -> todo
Task 1 -> done!
done