Async Classes¶

AsyncCombinator¶

class AsyncCombinator(Generic[T], ABC)

Base class for async combinators. Integrates with use_tracing().

Methods:

async run(ctx: T) -> tuple[bool, T] -- Execute the combinator
if_else(then, else_) -> AsyncCombinator[T] -- Conditional branching
__and__, __or__, __invert__, __rshift__ -- Operator overloading

AsyncPredicate¶

class AsyncPredicate(AsyncCombinator[T])

Async predicate that checks a condition without modifying context.

Constructor:

AsyncPredicate(fn: Callable[[T], Awaitable[bool]], name: str = "")

Example:

@async_rule
async def has_permission(user):
    return await db.check_permission(user.id)

AsyncPredicateFactory¶

class AsyncPredicateFactory(Generic[T])

Factory for parameterized async predicates. Created by @async_rule_args.

Example:

@async_rule_args
async def has_role(user, role):
    return await db.check_role(user.id, role)

check = has_role("admin")  # AsyncPredicate[User]

AsyncTransform¶

class AsyncTransform(AsyncCombinator[T])

Async transform that modifies context.

Attributes:

last_error: Exception | None -- The last exception (not concurrency-safe)

Methods:

async run(ctx: T) -> tuple[bool, T] -- Execute the transform
async run_with_error(ctx: T) -> tuple[bool, T, Exception | None] -- Concurrency-safe error access

Example:

@async_pipe
async def load_profile(user):
    user.profile = await api.get_profile(user.id)
    return user

ok, result, error = await load_profile.run_with_error(user)

AsyncTransformFactory¶

class AsyncTransformFactory(Generic[T])

Factory for parameterized async transforms. Created by @async_pipe_args.

Example:

@async_pipe_args
async def add_metadata(ctx, key, value):
    ctx.metadata[key] = value
    return ctx

transform = add_metadata("source", "api")  # AsyncTransform