# `syntax.try_catch`

Failure handled with `try`, `catch` or `?`.

Area 3, [Logic](../topics/logic.md); not declinable; the next step is usually the agent's.

A call that can fail is marked where it is made: `attempt` passes its failures on, and a `match` on the call handles them. `try {` and `catch` have no edit, since what to do with each failure is the author's to say.

```jadpo
type Count = Int {
    min: 0
}

type CountMissing = Failure {
    kind: FailureKind.not_found
}

function counted_or_missing(count: Count) fails CountMissing -> Count {
    if (count == 0) {
        reject CountMissing
    }
    return count
}

function first(count: Count) fails CountMissing -> Count {
    var result: Count = try counted_or_missing(count)
    return result
}
```

```text
error: Jadpo writes `attempt`, not `try`
 --> main.jadpo:17:25
   |
17 |     var result: Count = try counted_or_missing(count)
   |                         ^^^ write `attempt`
  reason: `try` marks a call that can fail in Swift; Jadpo writes `attempt`, which passes the call's failures on to the caller.
  next: Use `attempt` instead of `try` (agent)
  rule: syntax.try_catch
  help: https://jadpo.dev/docs/errors/syntax.try_catch

check failed: 1 error, 1 file
```