accruals:

Config file section

Valid in machine config files YES
Valid in mode config files YES

The structure of accrual logic blocks are like this:

accruals:
   the_name_of_this_logic_block:
      <settings>
   some_other_logic_block:
      <settings>
   a_third_logic_block:
      <settings>

Note that the actual name of the logic block doesn’t really matter. Mainly they’re used in the logs.

Required settings

The following sections are required in the accruals: section of your config:

events:

List of one (or more) events. The device will add handlers for those events. Defaults to empty.

The events section of an accrual logic block is where you define the events this logic block will watch for in order to make progress towards completion.

The real power of logic blocks is that you can enter more than one event for each step, and only one of the of the events of that step has to happen for that step to be complete.

Another way to look at it is that there’s an AND between all the steps. For the Accrual to complete, you need Step 1 AND Step 2 AND Step 3. But since you can enter more than one event for each step, you could think of those like OR*s. So you have Step 1 (event1 *OR event2) AND Step 2 (event3) AND Step 3 (event4 OR event5), like this:

accruals:
  my_accrual:
    events:
      - event1, event2
      - event3
      - event4, event5
This example is tested to be valid MPF config. However, it is not integration tested.
accruals:
  my_accrual:
    events:
      - event1, event2
      - event3
      - event4, event5

It might seem kind of confusing at first, but you can build this up bit-by-bit and figure them out as you go along.

You can enter anything you want for your events, whether it’s one of MPF’s built-in events or a made-up event that another logic block posts when it completes. (This is how you chain multiple logic blocks together to form complex logic.)

For example:

accruals:
  logic_block_1:
    events:
      - event1
      - event2
      - event3
      - event4
      - event5
    events_when_complete: logic_block_1_done
  logic_block_2:
    events:
      - event1, event2, event3
      - event4
      - event5
    events_when_complete: logic_block_2_done
This example is tested to be valid MPF config. However, it is not integration tested.
accruals:
  logic_block_1:
    events:
      - event1
      - event2
      - event3
      - event4
      - event5
    events_when_complete: logic_block_1_done
  logic_block_2:
    events:
      - event1, event2, event3
      - event4
      - event5
    events_when_complete: logic_block_2_done

In the example above, there are two logic blocks. The first one just has five steps that need to complete (in any order since we’re dealing with accrual logic blocks), and each step only has one event that will mark is as complete. So basically any of those five events 1-5 can be posted in any order, and then logic_block_1_done will be posted.

In the second example, if event 1, 2, or 3 is posted, that will count for step 1, and then both events 4 and 5 need to be posted for steps 2 and 3. (Again, in any order.)

So in the second one, you could get event4, event2, then event5 posted, for example, and that will lead to logic_block_2_done being posted.

Note that you can have two logic blocks with the same events at the same time, and MPF will track the state of each logic block separately. So in the above config with those two logic blocks, if the events were posted in the order event2, event3, event4, then event5, that would complete logic block 2. Then later if event1 was posted, that would complete logic block 1.

Optional settings

The following sections are optional in the accruals: section of your config. (If you don’t include them, the default will be used).

advance_random_events:

List of one (or more) device control events (Instructions for entering device control events). Defaults to empty.

The advance_random_events section of an accrual logic block is where you define the event or events that this logic block will watch for in order to randomly complete one of the steps in the logic block. As stated above, while there can be multiple steps that could complete this step of the logic block, this will act as one of the events as well that will complete the given step.

This will not update any lights that are associated with the events that are required to complete this step. For example, if you have a shot that could complete this step, and the step is completed by this event, the light will still remain on even though it will not progress this logic block any further. To update the lights you will want to add a hit_event to the underlying shot. This should be the event from the log logicblock_YOUR_ACCRUAL_hit {step == X} where YOUR_ACCRUAL is the name of your accrual, and X is the value of the step to which this shot is tied, which begins with 0.

console_log:

Single value, type: one of the following options: none, basic, full. Default: basic

Log level for the console log for this device.

debug:

Single value, type: boolean (true/false). Default: false

Set this to true to see additional debug output. This might impact the performance of MPF.

file_log:

Single value, type: one of the following options: none, basic, full. Default: basic

Log level for the file log for this device.

label:

Single value, type: string. Default: %

Name of this device in service mode.

tags:

List of one (or more) values, each is a type: string. Defaults to empty.

Currently unused.

Optional settings

The following sections are optional in the logic_blocks_common: section of your config. (If you don’t include them, the default will be used).

disable_events:

List of one (or more) device control events (Instructions for entering device control events).

Event(s) that will disable this logic block.

A logic block must be enabled to track hits, progress, and to post events.

disable_on_complete:

Single value, type: boolean (true/false). Default: true

True/False (or Yes/No) which controls whether this logic block disables itself once it completes. This does not reset the current value.

enable_events:

List of one (or more) device control events (Instructions for entering device control events).

Event(s) that will enable this logic block.

A logic block must be enabled to track hits, progress, and to post events.

If you don’t have any enable_events listed, then the logic block will automatically be enabled when the player’s ball starts.

events_when_complete:

List of one (or more) events.

Events that will be posted when this device is completed.

events_when_hit:

List of one (or more) events.

Events that will be posted when this device is hit or advanced.

persist_state:

Single value, type: boolean (true/false). Default: false

Boolean setting (yes/no or true/false) which controls whether this logic block remembers where it was from ball-to-ball. If False, then this logic block will reset itself whenever a new ball starts. If True, then this logic block will be saved to the player variable <logic_block_name>_state.

Note that logic block state is reset on mode end when this is False and, as normal modes stop at the end of a ball, the state is always maintained on a per-player basis, regardless of what this setting is configured for.

reset_events:

List of one (or more) device control events (Instructions for entering device control events).

Event(s) that will reset this logic block back to its original value. This has no effect on the enabled/disabled state of the block.

Note that there are also reset_on_complete: and persist_state: settings which also affect how and when the logic block is reset.

You can reset a logic block regardless of whether it’s enabled.

reset_on_complete:

Single value, type: boolean (true/false). Default: true

True/False (or Yes/No) which controls whether this logic block resets itself once it completes. This just resets the current value or progress. It does not change the enabled or disabled state.

restart_events:

List of one (or more) device control events (Instructions for entering device control events).

List of one (or more) events which, when posted, will restart this logic block. A restart is a reset, then an enable, combined into a single action.

start_enabled:

Single value, type: boolean (true/false).

If true this device will start enabled. If false this device will start disabled. If you omit this the device will start enabled unless you specify enable_events in which case the device will start disabled.