# Attempt

A call that can fail must say so where it is called. `attempt` passes the
call's failures on to the caller, whose `fails` list must include them. A
`match` on the call handles them instead.

`attempt` starts a statement: a variable, a `return`, or a statement on
its own.

```jadpo
var todo: Todo = attempt Todo.get(todo_id)
return attempt todo_by_id(todo_id)
attempt Todo.get(todo_id)
```

It can't stand inside an expression, so this is refused:

```jadpo
var total: Stock = Stock(attempt stock_of(a) + attempt stock_of(b))
```

So every point where a callable can stop early is at the start of a line.
`attempt` on a call that can't fail is an error.

`reject` and `propagate` follow the same rule: each starts a statement or
is the result of a `match` arm, never part of a value
(`failure.reject_placement`, `failure.propagate_placement`). More is in
[Passing a failure on: `attempt`](passing-a-failure-on-attempt.md).