# Type Configuration

The types used by [HFSM2](https://hfsm.dev/) can be configured using parameterized `hfsm2::MachineT<hfsm2::Config>` structure in place of default-configured `hfsm2::Machine`, e.g.:

`using M = hfsm2::MachineT<`\
&#x20;             `hfsm2::Config`\
&#x20;                 `::ContextT<Empty>`\
&#x20;                 `::RandomT<hfsm2::XoShiRo128Plus>`\
&#x20;         `>;`

(from [test\_debug.cpp](https://github.com/andrew-gresyk/HFSM2/blob/master/test/test_debug.cpp)).

Once `hfsm2::Config` is fully declared, it needs to be passed as a template argument into `hfsm2::MachineT<>` to define configured [HFSM2](https://hfsm.dev/) parent struct containing all derivative types used in client code.

### `hfsm2::Config` customization points:

| Feature Define                | Type                    | Used In                                                                                                                                                                              | Default                                          |
| ----------------------------- | ----------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------ |
|                               | `ContextT<T>`           | <p><code>Context& Control::context()</code></p><p>(see <a href="https://doc.hfsm.dev/user-guide/configuration/context">Context</a>)</p>                                              | `EmptyContext`                                   |
| `HFSM2_ENABLE_UTILITY_THEORY` | `RankT<T>`              | `Rank State::rank()`                                                                                                                                                                 | `int8_t`                                         |
| `HFSM2_ENABLE_UTILITY_THEORY` | `UtilityT<T>`           | `Utility State::utility()`                                                                                                                                                           | `float`                                          |
| `HFSM2_ENABLE_UTILITY_THEORY` | `RandomT<T>`            | Used internally by `randomize()` transition and `Random` region                                                                                                                      | `RandomT<float>`                                 |
|                               | `SubstitutionLimitN<N>` | Maximum number of times `State::entryGuard()`methods are allowed to substitute the transition into their class for a transition into another one during the single `*Root::update()` | `4`                                              |
| `HFSM2_ENABLE_PLANS`          | `TaskCapacityN<N>`      | Total number of tasks across all plans in an FSM                                                                                                                                     | 2x Number of Sub-States of All Composite Regions |


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