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anagrapheus.beliefs.index

anagrapheus.beliefs.index

The belief index's query surface.

The one question the rest of the stack cannot answer: which beliefs mention this entity? doxastica's BeliefFilter is closed over four fields and can filter by a belief id, but nothing in its seam looks inside one; the identity layer knows entities and has never heard of a belief. So the join between them lives here, and without it identity's re-key seam has no other side.

This is a projection over what was minted, not over what is believed. A belief id in the index says an id was minted, never that anything currently holds a belief under it — that is doxastica's question, asked with the id this index hands back.

BeliefIndex 

BeliefIndex(store: BeliefIndexStore)

Reads the belief index the fold maintains.

Source code in src/anagrapheus/beliefs/index.py 
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def __init__(self, store: BeliefIndexStore) -> None:
    self._store = store

beliefs_for 

beliefs_for(entity_id: UUID) -> Sequence[BeliefRow]

Every belief id naming entity_id, oldest first.

The re-key seam's input. A belief naming the entity twice — sibling(a, a), say — appears once.

Source code in src/anagrapheus/beliefs/index.py 
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def beliefs_for(self, entity_id: UUID) -> Sequence[BeliefRow]:
    """
    Every belief id naming ``entity_id``, oldest first.

    The re-key seam's input. A belief naming the entity twice — ``sibling(a, a)``,
    say — appears once.
    """
    return self._store.beliefs_for(entity_id)

beliefs_of 

beliefs_of(predicate: str) -> Sequence[BeliefRow]

Every belief id minted for predicate, oldest first.

Source code in src/anagrapheus/beliefs/index.py 
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def beliefs_of(self, predicate: str) -> Sequence[BeliefRow]:
    """Every belief id minted for ``predicate``, oldest first."""
    return self._store.beliefs_of(predicate)

entities_of 

entities_of(belief_id: str) -> tuple[UUID, ...]

The entities belief_id names, in argument order, or () if unknown.

Empty rather than raising: the index is a fold over a range of the log, so an id it has not seen is an ordinary answer — the mint may be above the position, or in another application's namespace entirely.

Source code in src/anagrapheus/beliefs/index.py 
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def entities_of(self, belief_id: str) -> tuple[UUID, ...]:
    """
    The entities ``belief_id`` names, in argument order, or ``()`` if unknown.

    Empty rather than raising: the index is a fold over a range of the log, so an
    id it has not seen is an ordinary answer — the mint may be above the position,
    or in another application's namespace entirely.
    """
    row = self._store.belief(belief_id)
    return () if row is None else row.entity_ids