Module holochain::core

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Expand description

Defines the core Holochain workflows

Modules

  • builder
  • conversions
  • data
  • encode
    Include nice string encoding methods and From impls
  • encrypted_data
  • fixt
  • genesis
    Types related to the genesis process whereby a user commits their initial records and validates them to the best of their ability. Full validation may not be possible if network access is required, so they perform a “self-check” (as in “check yourself before you wreck yourself”) before joining to ensure that they can catch any problems they can before being subject to the scrutiny of their peers and facing possible rejection.
  • hash_type
    Defines the prefixes for the various HashTypes, as well as the traits which unify them
  • inline_zome
    A variant of Zome which is defined entirely by native, inline Rust code
  • key_ref
  • nonce
  • op
    Dht Operations
  • queue_consumer
    Manages the spawning of tasks which process the various work queues in the system, as well as notifying subsequent queue processors to pick up the work that was left off.
  • ribosome
    A Ribosome is a structure which knows how to execute hApp code.
  • workflow
    Workflows are the core building block of Holochain functionality.
  • x25519

Macros

  • assert_length
    Helper for ensuring the the proper number of bytes is used in various situations
  • holochain_serial
    unidiomatic way to derive default trait implementations of TryFrom in/out of SerializedBytes
  • impl_hashable_content
    A default HashableContent implementation, suitable for content which is already TryInto<SerializedBytes>, and uses a PrimitiveHashType

Structs

  • ActionBuilderCommon
  • AgentActivity
    An agents chain records returned from a agent_activity_query
  • AgentInfo
    The struct containing all information about the executing agent’s identity.
  • AgentValidationPkg
    Action for an agent validation package, used to determine whether an agent is allowed to participate in this DNA
  • AppEntryBytes
    Newtype for the bytes comprising an App entry
  • AppEntryDef
    Information about a class of Entries provided by the DNA
  • AppEntryDefLocation
    The location of an app entry definition.
  • AppEntryName
    Identifier for an entry definition. This may be removed.
  • AppSignal
    A signal emitted by an app via emit_signal
  • Block
    Represents a block. Also can represent an unblock. NOT serializable and NOT pub fields by design. try_new MUST be the only entrypoint to build a Block as this enforces that the start/end times are valid according to invariants the SQL queries rely on to avoid corrupting the database.
  • BlockAgentInput
  • Call
  • CallInfo
  • CapClaim
    System entry to hold a capability token claim for use as a caller. Stored by a claimant so they can remember what’s necessary to exercise this capability by sending the secret to the grantor.
  • CapSecret
    A CapSecret is used by a caller to prove to a callee access to a committed CapGrant.
  • CellId
    The unique identifier for a Cell. Cells are uniquely determined by this pair - this pair is necessary and sufficient to refer to a cell in a conductor
  • ChainFilter
    Filter source chain items. Starting from some chain position given as an ActionHash the chain is walked backwards to genesis. The filter can stop early by specifying the number of chain items to take and / or an ActionHash to consume until.
  • ChainFork
    The chain has been forked by these two actions
  • ChainHead
    The action at the head of the complete chain. This is as far as this authority can see a chain with no gaps.
  • ChainQueryFilter
    Specifies arguments to a query of the source chain, including ordering and filtering.
  • CloneId
    Identifier of a clone cell, composed of the DNA’s role name and the index of the clone, starting at 0.
  • CloseChain
    When migrating to a new version of a DNA, this action is committed to the old chain to declare the migration path taken. Currently unused
  • CompositeHashConversionError
    Error converting a composite hash into a subset composite hash, due to type mismatch
  • CoordinatorZomeDef
  • CoordinatorZomeMarker
    A type marker for a coordinator InlineZome.
  • CounterSigningAgentState
    Every countersigning agent must sign against their chain state. The chain must be frozen until each agent decides to sign or exit the session.
  • CounterSigningSessionData
    All the data required for a countersigning session.
  • CounterSigningSessionTimes
    Every countersigning session must complete a full set of actions between the start and end times to be valid.
  • CrdtType
  • Create
    A action which “speaks” Entry content into being. The same content can be referenced by multiple such actions.
  • CreateBase
    Base data for Create actions.
  • CreateInput
    Zome input to create an entry.
  • CreateLink
    Declares that a metadata Link should be made between two EntryHashes
  • CreateLinkInput
    Zome IO inner type for link creation.
  • CurryPayloads
    @todo Ability to forcibly curry payloads into functions that are called with a claim.
  • Delete
    Declare that a previously published Action should be nullified and considered deleted.
  • DeleteAction
    Placeholder for future when we want to have deletes on actions Not currently in use.
  • DeleteInput
    Zome input for all delete operations.
  • DeleteLink
    Declares that a previously made Link should be nullified and considered removed.
  • DeleteLinkInput
  • DeterministicGetAgentActivityFilter
    Query arguments for the deterministic version of GetAgentActivity
  • DeterministicGetAgentActivityResponse
  • Dna
    The Dna Action is always the first action in a source chain
  • DnaDef
    The definition of a DNA: the hash of this data is what produces the DnaHash.
  • DnaDefBuilder
    Builder for DnaDef.
  • DnaInfoV1
    Information about the current DNA.
  • DnaInfoV2
    Information about the current DNA.
  • DnaModifiers
    Modifiers of this DNA - the network seed, properties and origin time - as opposed to the actual DNA code. These modifiers are included in the DNA hash computation.
  • DnaModifiersBuilder
    Builder for DnaModifiers.
  • DnaModifiersOpt
    DnaModifiers options of which all are optional.
  • DynInlineZome
    An inline zome clonable type object.
  • EntryDef
  • EntryDefIndex
  • EntryDefs
    All definitions for all entry types in an integrity zome.
  • EntryDetails
    An Entry with all its metadata.
  • EntryHashes
    A newtype for a collection of EntryHashes, needed for some wasm return types.
  • EntryRateWeight
    Combination of the three main rate limiting data types, for convenience
  • EphemeralSignatures
    The output of ephemeral signing. The private key for this public key has been discarded by this point. The signatures match the public key provided but cannot be reproduced or forged because the private key no longer exists. The signatures match the input items positionally in the vector, it is up to the caller to reconstruct/align/zip them back together.
  • ExternIO
  • FunctionName
    A single function name.
  • GenesisSelfCheckDataV1
    Data passed into the genesis_self_check callback for verifying the initial chain entries
  • GenesisSelfCheckDataV2
    Data passed into the genesis_self_check callback for verifying the initial chain entries. DnaInfo can be read with a call to dna_info within the self check callback, it is elided here to minimise/stabilise the callback function signature.
  • GetAgentActivityInput
  • GetInput
    Zome input for get and get_details calls.
  • GetLinksInput
  • GetOptions
    Options for controlling how get works
  • GrantZomeCallCapabilityPayload
    Parameters for granting a zome call capability.
  • Hash256Bits
    256 Bit generic hash.
  • Hash512Bits
    512 Bit generic hash.
  • HashConversionError
    Error converting a composite hash into a primitive one, due to type mismatch
  • HighestObserved
    The highest action sequence observed by this authority. This also includes the actions at this sequence. If there is more then one then there is a fork.
  • HoloHash
    A HoloHash contains a vector of 36 bytes representing a 32-byte blake2b hash plus 4 bytes representing a DHT location. It also contains a zero-sized type which specifies what it is a hash of.
  • HoloHashB64
    A wrapper around HoloHash that Serializes into a base64 string rather than a raw byte array.
  • HoloHashed
    Represents some piece of content along with its hash representation, so that hashes need not be calculated multiple times. Provides an easy constructor which consumes the content.
  • InclusiveTimestampInterval
    It’s an interval bounded by timestamps that are not infinite.
  • IncomingDhtOpSender
    Allows you to send an op to the incoming_dht_ops_workflow if you found it on the network and were supposed to be holding it.
  • InitZomesComplete
    A action which declares that all zome init functions have successfully completed, and the chain is ready for commits. Contains no explicit data.
  • InlineZome
    An “inline” zome definition in pure Rust, as opposed to a zome defined in Wasm.
  • IntegrityZomeDef
  • IntegrityZomeMarker
    A type marker for an integrity InlineZome.
  • Judged
    Data with an optional validation status.
  • Link
  • LinkDetails
    CreateLinks with and DeleteLinks on them [CreateLink, [DeleteLink]]
  • LinkQuery
    A query for links to be used with host functions that support filtering links
  • LinkTag
    Opaque tag for the link applied at the app layer, used to differentiate between different semantics and validation rules for different links
  • LinkType
  • MetadataRequest
    Metadata that can be requested on a basis
  • MustGetActionInput
    Zome input for must_get_action.
  • MustGetAgentActivityInput
    Input to the must_get_agent_activity call.
  • MustGetEntryInput
    Zome input for must_get_entry.
  • MustGetValidRecordInput
    Zome input for must_get_valid_record.
  • OpenChain
    When migrating to a new version of a DNA, this action is committed to the new chain to declare the migration path taken. Currently unused
  • PreflightBytes
    Every preflight request can have optional arbitrary bytes that can be agreed to.
  • PreflightRequest
    The same PreflightRequest is sent to every agent. Each agent signs this data as part of their PreflightResponse. Every preflight must be identical and signed by every agent for a session to be valid.
  • PreflightResponse
    Every agent must send back a preflight response. All the preflight response data is signed by each agent and included in the session data.
  • PrevActionError
    Context information for an invalid action to make it easier to trace in errors.
  • QueryFilter
    Specifies arguments to a query of the source chain, including ordering and filtering.
  • RateWeight
    Combination of two rate limiting data types, for convenience
  • Record
    a chain record containing the signed action along with the entry if the action type has one.
  • RecordDetails
    A specific Record with any updates and deletes. This is all the metadata available for a record.
  • RegisterAgentActivity
    Registers a new Action on an agent source chain. This is the act of creating any Action and publishing it to the DHT.
  • RegisterCreateLink
    Registers a link between two Entrys. This is the act of creating a Action::CreateLink and publishing it to the DHT. The authority is the entry authority for the base Entry.
  • RegisterDelete
    Registers a deletion of an instance of an Entry in the DHT. This is the act of creating a Action::Delete and publishing it to the DHT.
  • RegisterDeleteLink
    Deletes a link between two Entrys. This is the act of creating a Action::DeleteLink and publishing it to the DHT. The delete always references a specific Action::CreateLink.
  • RegisterUpdate
    Registers an update from an instance of an Entry in the DHT. This is the act of creating a Action::Update and publishing it to the DHT. Note that the Action::Update stores an new instance of an Entry and registers it as an update to the original Entry. This operation is only concerned with registering the update.
  • RemoteSignal
    Remote signal many agents without waiting for responses.
  • RequiredValidations
    The number of validations required for an entry to be considered published.
  • Role
    Agents can have a role specific to each countersigning session. The role is app defined and opaque to the subconscious.
  • ScheduledFn
    A fully qualified scheduled function.
  • ScopedZomeType
    A type with the zome that it is defined in.
  • ScopedZomeTypes
    zome types that are in scope for the calling zome.
  • ScopedZomeTypesSet
    The set of EntryDefIndex and LinkTypes in scope for the calling zome.
  • SerializedBytes
    A Canonical Serialized Bytes representation for data If you have a data structure that needs a canonical byte representation use this Always round-trip through SerializedBytes via. a single TryFrom implementation. This ensures that the internal bytes of SerializedBytes are indeed canonical. The corrolary is that if bytes are NOT wrapped in SerializedBytes we can assume they are NOT canonical. Typically we need a canonical serialization when data is to be handled at the byte level by independently implemented and maintained systems.
  • Sign
    Input structure for creating a signature.
  • SignEphemeral
    Ephemerally sign a vector of bytes (i.e. a Vec<Vec<u8>>) Each of the items of the outer vector represents something to sign and will have a corresponding Signature in the output. The public key for the ephemeral operation will be returned in the output. Structurally mirrors/complements the Signature struct as a new type. There we know the key on the input side, here we receive the key on the output.
  • Signature
    The raw bytes of a signature.
  • SignedAction
    A combination of an action and its signature.
  • SignedHashed
    Any content that has been hashed and signed.
  • StoreEntry
    Stores a new Entry in the DHT. This is the act of creating a either a Action::Create or a Action::Update and publishing it to the DHT. These actions create a new instance of an Entry.
  • StoreRecord
    Stores a new Record in the DHT. This is the act of creating a new Action and publishing it to the DHT. Note that not all Actions contain an Entry.
  • Timestamp
    A microsecond-precision UTC timestamp for use in Holochain’s actions.
  • TraceMsg
    Representation of message to be logged via the debug host function
  • UnsafeBytes
    UnsafeBytes the only way to implement a custom round trip through bytes for SerializedBytes It is intended to be an internal implementation in TryFrom implementations The assumption is that any code using UnsafeBytes is NOT valid messagepack data This allows us to enforce that all data round-tripping through SerializedBytes is via TryFrom and also allow for custom non-messagepack canonical representations of data types.
  • Update
    A action which specifies that some new Entry content is intended to be an update to some old Entry.
  • UpdateAction
    Placeholder for future when we want to have updates on actions Not currently in use.
  • UpdateBase
    Base data for Update actions.
  • UpdateInput
    Zome input type for all update operations.
  • VerifySignature
    Mirror struct for Sign that includes a signature to verify against a key and data.
  • Warrant
    Placeholder for warrant type
  • WasmZome
    A zome defined by Wasm bytecode
  • WrongActionError
  • X25519PubKey
  • X25519XSalsa20Poly1305Decrypt
  • X25519XSalsa20Poly1305Encrypt
  • XSalsa20Poly1305Data
    Data that can be encrypted with secretbox.
  • XSalsa20Poly1305Decrypt
  • XSalsa20Poly1305Encrypt
  • XSalsa20Poly1305EncryptedData
  • XSalsa20Poly1305KeyRef
    Key refs represent shared secrets stored in the keystore. They can either be user-specified, or auto-generated at time of secret creation, or ingestion.
  • XSalsa20Poly1305SharedSecretExport
  • XSalsa20Poly1305SharedSecretIngest
  • YamlProperties
    A type to allow json values to be used as SerializedBytes
  • Zome
    A Holochain Zome. Includes the ZomeDef as well as the name of the Zome.
  • ZomeCallCapGrant
    The entry for the ZomeCall capability grant. This data is committed to the callee’s source chain as a private entry. The remote calling agent must provide a secret and we source their pubkey from the active network connection. This must match the strictness of the CapAccess.
  • ZomeCallUnsigned
    Zome calls need to be signed regardless of how they are called. This defines exactly what needs to be signed.
  • ZomeDependencyIndex
    The index into the ZomeIndex vec.
  • ZomeIndex
    this id is an internal reference, which also serves as a canonical ordering for zome initialization. The value should be auto-generated from the Zome Bundle def
  • ZomeInfo
    The properties of the current dna/zome being called.
  • ZomeName
    ZomeName as a String.
  • ZomeTypesKey
    A key to the ScopedZomeTypes container.

Enums

  • Action
    Action contains variants for each type of action.
  • ActionBase
    Enum to mirror Action for all the shared data required to build session actions. Does NOT hold any agent specific information.
  • ActionError
  • ActionType
    A unit enum which just maps onto the different Action variants, without containing any extra data
  • ActivityRequest
    Get either the full activity or just the status of the chain
  • AnyDhtHashPrimitive
    The primitive hash types represented by this composite hash
  • AnyLinkableHashPrimitive
    The primitive hash types represented by this composite hash
  • BlockTarget
    Target of a block. Each target type has an ID and associated reason.
  • BlockTargetId
  • BlockTargetReason
  • CallTarget
  • CallTargetCell
  • CapAccess
    Represents access requirements for capability grants.
  • CapGrant
    Represents a potentially valid access grant to a zome call. Zome call response will be Unauthorized without a valid grant.
  • CellBlockReason
    Reason why we might want to block a cell.
  • ChainFilters
    Specify which Actions to allow through this filter.
  • ChainQueryFilterRange
    Defines several ways that queries can be restricted to a range. Notably hash bounded ranges disambiguate forks whereas sequence indexes do not as the same position can be found in many forks. The reason that this does NOT use native rust range traits is that the hash bounded queries MUST be inclusive otherwise the integrity and fork disambiguation logic is impossible. An exclusive range bound that does not include the final action tells us nothing about which fork to select between N forks of equal length that proceed it. With an inclusive hash bounded range the final action always points unambiguously at the “correct” fork that the range is over. Start hashes are not needed to provide this property so ranges can be hash terminated with a length of preceeding records to return only. Technically the seq bounded ranges do not imply any fork disambiguation and so could be a range but for simplicity we left the API symmetrical in boundedness across all enum variants. @TODO It may be possible to provide/implement RangeBounds in the case that a full sequence of records/actions is provided but it would need to be handled as inclusive first, to enforce the integrity of the query, then the exclusiveness achieved by simply removing the final record after the fact.
  • ChainStatus
    Status of the agent activity chain
  • ChainTopOrdering
  • CloneIdError
    Errors during conversion from RoleName to CloneId.
  • CounterSigningError
    Errors related to the secure primitive macro.
  • Details
    Return type for get_details calls. ActionHash returns a Record. EntryHash returns an Entry.
  • Entry
    Structure holding the entry portion of a chain record.
  • EntryCreationAction
    Either a Action::Create or a Action::Update. These actions both create a new instance of an Entry.
  • EntryDefId
  • EntryDefLocation
    Either an EntryDefIndex or one of:
  • EntryDefsCallbackResult
  • EntryDhtStatus
    The status of an Entry in the Dht
  • EntryError
    Errors involving app entry creation
  • EntryType
    Allows Actions which reference Entries to know what type of Entry it is referencing. Useful for examining Actions without needing to fetch the corresponding Entries.
  • EntryVisibility
  • GetStrategy
    Describes the get call and what information the caller is concerned about. This helps the subconscious avoid unnecessary network calls.
  • GrantedFunctions
    A collection of zome/function pairs
  • HashInput
    Input to holochain hash function.
  • HashOutput
    Output from the holochain hashing host function.
  • HashableContentBytes
    HashableContent can be expressed as “content”, or “prehashed”, which affects how a HoloHashed type will be constructed from it.
  • HostFnApiError
    Anything that can go wrong while calling a HostFnApi method
  • HumanTimestamp
    A human-readable timestamp which is represented/serialized as an RFC3339 when possible, and a microsecond integer count otherwise. Both representations can be deserialized to this type.
  • InitCallbackResult
    The result of the DNA initialization callback.
  • InlineZomeError
  • IpBlockReason
    Reason why we might want to block an IP.
  • Level
    Maps directly to the tracing Levels but here to define the interface. See https://docs.rs/tracing-core/0.1.17/tracing_core/struct.Level.html
  • LinkTypeFilter
    Filter on a set of LinkTypes.
  • MigrateAgent
  • MigrateAgentCallbackResult
  • NodeBlockReason
    Reason why we might want to block a node.
  • Op
    These are the operations that can be applied to Holochain data. Every Action produces a set of operations. These operations are each sent to an authority for validation.
  • PreflightRequestAcceptance
    A preflight request can be accepted, or invalid, or valid but the local agent cannot accept it.
  • PrevActionErrorKind
  • RecordEntry
    Represents the different ways the entry_address reference within an action can be intepreted
  • RequiredValidationType
    The level of validation package required by an entry.
  • Schedule
    Defines either a persisted or ephemeral schedule for a schedule function. Persisted schedules survive a conductor reboot, ephemeral will not. Persisted schedules continue beyond irrecoverable errors, ephemeral do not.
  • ScheduleError
    Scheduling errors.
  • SerializedBytesError
  • SourceChainError
  • SysValidationError
    Validation can result in either
  • TimestampError
  • UnitEnumEither
    A full UnitEnum, or just the unit type of that UnitEnum
  • UnresolvedDependencies
    Unresolved dependencies that are either a set of hashes or an agent activity query.
  • ValidateCallbackResult
  • ValidationOutcome
    All the outcomes that can come from validation This is not an error type it is the outcome of failed validation.
  • ValidationStatus
    The validation status for an op or record much of this happens in the subconscious an entry missing validation dependencies may cycle through Pending many times before finally reaching a final validation state or being abandoned
  • WeighInput
    Input to the weigh callback. Includes an “unweighed” action, and Entry if applicable.
  • ZomeCallAuthorization
  • ZomeCallResponse
    Response to a zome call.
  • ZomeDef
    Just the definition of a Zome, without the name included. This exists mainly for use in HashMaps where ZomeDefs are keyed by ZomeName.
  • ZomeError
    Anything that can go wrong while calling a HostFnApi method

Constants

  • CAP_SECRET_BITS
    The number of bits we want for a comfy secret.
  • CAP_SECRET_BYTES
    The number of bytes we want for a comfy secret.
  • CLONE_ID_DELIMITER
    Delimiter in a clone id that separates the base cell’s role name from the clone index.
  • ENTRY_SIZE_LIMIT
    Entries larger than this number of bytes cannot be created
  • HOLO_HASH_CORE_LEN
    Length of the core bytes (32)
  • HOLO_HASH_FULL_LEN
    Length of the full HoloHash bytes (39 = 3 + 32 + 4)
  • HOLO_HASH_LOC_LEN
    Length of the location bytes (4)
  • HOLO_HASH_PREFIX_LEN
    Length of the prefix bytes (3)
  • HOLO_HASH_UNTYPED_LEN
    Length of the core bytes + the loc bytes (36 = 32 + 4), i.e. everything except the type prefix
  • MAX_COUNTERSIGNING_AGENTS
    8 seems like a reasonable limit of agents to countersign.
  • MAX_ENTRY_SIZE
    16mb limit on Entries due to websocket limits. 4mb limit to constrain bandwidth usage on uploading. (Assuming a baseline 5mbps upload for now… update this as consumer internet connections trend toward more upload) Consider splitting large entries up.
  • MAX_HASHABLE_CONTENT_LEN
    The maximum size to hash synchronously. Anything larger than this will take too long to hash within a single tokio context
  • MAX_TAG_SIZE
    1kb limit on LinkTags. Tags are used as keys to the database to allow fast lookup so they should be small.
  • MIN_COUNTERSIGNING_AGENTS
    Need at least two to countersign.
  • MM
    One million
  • PERSISTED_TIMEOUT
    Expire persisted schedules after this long.
  • POST_GENESIS_SEQ_THRESHOLD
    Any action with a action_seq less than this value is part of a record created during genesis. Anything with this seq or higher was created after genesis.
  • SCHEDULER_INTERVAL
    Tick the scheduler every this many millis.
  • SESSION_ACTION_TIME_OFFSET
    The timestamps on actions for a session use this offset relative to the session start time. This makes it easier for agents to accept a preflight request with actions that are after their current chain top, after network latency.
  • SESSION_TIME_FUTURE_MAX
    Maximum time in the future the session start can be in the opinion of the participating agent. As the action will be SESSION_ACTION_TIME_OFFSET after the session start we include that here.
  • SIGNATURE_BYTES
    Ed25519 signatures are always the same length, 64 bytes.
  • X25519_PUB_KEY_BYTES

Traits

  • ActionBuilder
    Builder for non-genesis Actions
  • ActionExt
  • ActionUnweighed
    A trait to unify the “inner” parts of an Action, i.e. the structs inside the Action enum’s variants. This trait is used for the “unweighed” version of each struct, i.e. the version with weight information erased.
  • ActionWeighed
    A trait to unify the “inner” parts of an Action, i.e. the structs inside the Action enum’s variants. This trait is used for the “weighed” version of each struct, i.e. the version without weight information erased.
  • CallbackResult
  • Deserialize
    A data structure that can be deserialized from any data format supported by Serde.
  • EntryDefRegistration
    Trait for binding static EntryDef property access for a type. This trait maps a type to its corresponding EntryDef property at compile time.
  • EntryTypesHelper
    Helper trait for deserializing Entrys to the correct type.
  • HasHash
    Anything which has an owned HoloHashOf.
  • HasValidationStatus
    Data that requires a validation status.
  • HashType
    Every HoloHash is generic over HashType. Additionally, every HashableContent has an associated HashType. The HashType is the glue that binds together HashableContent with its hash.
  • HashableContent
    Any implementor of HashableContent may be used in a HoloHashed to pair data with its HoloHash representation. It also has an associated HashType.
  • HashableContentExtAsync
    Adds convenience methods for constructing HoloHash and HoloHashed from some HashableContent
  • HashableContentExtSync
    Adds convenience methods for constructing HoloHash and HoloHashed from some HashableContent
  • HostFnApiT
  • InlineZomeT
  • LinkTypesHelper
    A helper trait for finding the app defined link type from a ZomeIndex and LinkType.
  • PrimitiveHashType
    A PrimitiveHashType is one with a multihash prefix. In contrast, a non-primitive hash type could be one of several primitive types, e.g. an AnyDhtHash can represent one of three primitive types.
  • Serialize
    A data structure that can be serialized into any data format supported by Serde.
  • TryFrom
    Simple and safe type conversions that may fail in a controlled way under some circumstances. It is the reciprocal of TryInto.
  • TryInto
    An attempted conversion that consumes self, which may or may not be expensive.
  • U8Index
    Helper trait for types that are internally represented as u8 but need to be used as indicies into containers.
  • UnitEnum
    A utility trait for associating a data enum with a unit enum that has the same variants.

Functions

Type Aliases

Derive Macros