GHC 10.0.0.20260917 · lts/ghc-10.0.x · 2b27632 · 2026-10-31
Modulevortex-combinators-0.1.1.0GHC2024
What an interpreter combinator needs to know about a theory, each as its own small class, and the handler shape every combinator transforms.
Every class here extends FirstOrder. A combinator ships an operation
to another process, runs it twice, stores it in a log or a cache, or
sends it to one of several owners; each of those treats the operation as
a value. A higher-order (scoped) operation such as Local f m or
Catch m h holds a computation in the interpreter's own monad, which
can be neither serialised nor run twice without running its effects
twice, so it cannot be treated as a value and no combinator here accepts
it.
A theory whose operations hold no computation, so an operation can be
moved to any monad index. Write the instance as reindex = coerce: it
typechecks exactly when the monad parameter is phantom, which is what
first-order means, and polysemy's own interpret checks the same
coercion.
reindex :: e m a -> e n aFirstOrder (KVStore k v)Defined in vortex-combinators-0.1.1.0 · Vortex.Combinators.TheoryThe monad index of an operation held as a value. It has no values, so
an e Inert a cannot hold a computation to run.
An operation as a value, ready to log, cache or ship.
An operation whose result type is forgotten, as decoded from the wire or drawn from a generator.
The wire form of a theory, in vortex's convention: an operation is a Call of its verb with its arguments show-rendered, and a result is the show of the value, recovered with read.
wireVerbs :: Proxy e -> [Verb]Every verb the theory has, for a served table and :commands.
encodeArgs :: e m a -> [String]decodeOp :: Call -> Maybe (SomeOp e)encodeResult :: e m a -> a -> StringdecodeResult :: e m a -> String -> Maybe aTwo outcomes of one operation agree: equal results, or equal failures.
What an operation does to the state, by the keys it touches. A read depends on its keys; a write changes them and so invalidates every read that depends on any of them. An uncached read changes nothing but is never served from a cache: its answer depends on more than the state its keys could name, such as the caller, the clock or a token it checks.
The read/write split of a theory, for the cache. A read, cached or not, must not change the state; a write must declare every key whose reads it can change. The cache coherence law checks the declaration.
type family InvalidationKey (e :: Effect)access :: e m a -> Access (InvalidationKey e)The key that names which owner an operation belongs to: a namespace, an owner or a shard key. Every operation has exactly one.
Why an operation has no result. Refused is the theory's own refusal, the rest are the combinators': no reply came, a reply did not decode, or no owner holds the key.
Eq FailureDefined in vortex-combinators-0.1.1.0 · Vortex.Combinators.TheoryOrd FailureDefined in vortex-combinators-0.1.1.0 · Vortex.Combinators.TheoryRead FailureDefined in vortex-combinators-0.1.1.0 · Vortex.Combinators.TheoryShow FailureDefined in vortex-combinators-0.1.1.0 · Vortex.Combinators.TheoryRun an operation and keep its failure as a value.
An operation and what it came to: one entry of a recording.
One operation that two interpreters, or a recording and an interpreter, answered differently: the first answer, then the second.
An outcome with its result in wire form.
One recorded outcome as a line: the show of its call and its wire-form outcome.
A first-order interpreter: each operation, at any monad index, to a
computation in r. polysemy's interpreters for a first-order effect
have this shape; interpretWith and fromInterpreter convert.
Run a program's e with a handler.
The handler of an ordinary polysemy interpreter, such as
polysemy-kvstore's runKVStoreAsState: each operation is sent as a
one-operation program and run.
Run a handler over one part of a larger state. A failing operation leaves the part as it was.