Documentation

Returns the names of the fields within a given type of message.

The names appear in increasing order of field number, in case that helps type-level search algorithms, though at present it is likely that there is no benefit other than ensuring that declaration order is irrelevant.

Note that the names of fields and oneofs must be unique within their shared namespace (see https://protobuf.dev/reference/protobuf/proto3-spec/#message_definition).

In the context of a message type, maps its field names to their numbers.

In the context of a message type, maps the name of every field to its protobuf type.

In the context of a message type, maps the name of every field to the name of its containing oneof, or to "" if that field is not part of a oneof. Also maps the name of every oneof in the message to itself.

In the context of a message type, maps the name of every field and oneof to its Cardinality.

(Every oneof in the message is mapped to OneOf, as are those fields that are within oneofs.)

A compilation error message for when the given message does not contain a field with the given name.

A compilation error message for when the given message does not contain a field or oneof with the given name.

The packing of field that is repeated or is a map. Every encoding appends and element, and omission means zero elements.

Expresses how many values we expect a field to contain, what it means when its encoding is omitted, and if it is repeated, whether or not packing is preferred.

Each data constructor is chosen in such a way that it implies how many values are expected as arguments to field. This choice simplifies instantiation of type classes.

The type of a message field, but when the field is repeated, this is the element type.

Design Note: We do not use the same Haskell types recognized by MessageField because there more than one such type corresponds to protobuf type string. But see RecoverProtoType.

The type of the repeated key-value pair submessage implied by a map field.

We never need to construct values; instead we construct values of types such as Encoding (Association key value).

The key field is named "key" and the value field is named "value".

Yields the field presence of a mapped value of the given protobuf type.

Indicates the standard protobuf wrapper having the field type given by the type argument.

We never need to construct values; instead we construct values of types such as Encoding (Wrapper protoType) or Wrap a, where a is a corresponding native representation.

Note that if Google ever adds wrappers for "sint..." or "...fixed..." then this type constructor will naturally support such wrappers.

Given the Haskell type used by features such as MessageField to indicate the encoding of a message field.

Given the Haskell type used by features such as MessageField to indicate the encoding of a message field, returns the corresponding type of kind ProtoType, which for repeated types is the element type. This type family is not injective because multiple types are supported for fields of protobuf type string.

Inhabited by Haskell types used by features such as MessageField that correspond to particular protobuf types that are repeated in the specified way.

Helps to diagnose the absence of an instance for MessageFieldType for optional submessages by requiring that the second type parameter be Nested of the first. Please try to avoid using this type family directly; it is exported only to help explain compilation errors.

Helps to diagnose the absence of an instance for MessageFieldType for repeated submessages by requiring that the second type parameter be NestedVec of the first. Please try to avoid using this type family directly; it is exported only to help explain compilation errors.