Every protocol buffer is an instance of Message. This class enables serialization by providing reflection of all of the fields that may be used by this type.

A tag that identifies a particular field of the message when converting to/from the wire format.

A description of a specific field of a protocol buffer.

The String parameter is the name of the field from the .proto file, as used in TextFormat, with the same behavior for groups as fieldsByTextFormatName. (Haddock doesn't support per-argument docs for GADTs.)

The original name of the field in the .proto file.

Whether the given field is required. Specifically, if its FieldAccessor is a Required PlainField.

A Lens for accessing the value of an individual field in a protocol buffer message.

The default value (if any) for a PlainField on the wire.

How a given repeated field is transmitted on the wire format.

A description of the type of a given field value.

A proto3 field type with an implicit default value.

This is distinct from, say, Default to avoid orphan instances, and because Bool doesn't necessarily have a good Default instance for general usage.

A class for protocol buffer enums that enables safe decoding.

Utility function for building a message from a default value. For example:

instance Default A where ...
x, y :: Lens' A Int
m :: A
m = build ((x .~ 5) . (y .~ 7))

A set of known message types. Can help encode/decode protobufs containing Data.ProtoLens.Any values in a more human-readable text format.

Registries can be combined using their Monoid instance.

See the withRegistry functions in TextFormat

Build a Registry containing a single proto type.

Example: > register (Proxy :: Proxy Proto.My.Proto.Type)

Look up a message type by name (e.g., "type.googleapis.com/google.protobuf.FloatValue"). The URL corresponds to the field google.protobuf.Any.type_url.

A helper lens for accessing optional fields. This is used as part of code generation, and should generally not be needed explicitly.

Note that maybeLens does not satisfy the lens laws, which expect that set l (view l x) == x. For example,

set (maybeLens 'a') (view (maybeLens 'a') Nothing) == Just 'a'

However, this is the behavior generally expected by users, and only matters if we're explicitly checking whether a field is set.

Reverse every repeated (list) field in the message.

During parsing, we store fields temporarily in reverse order, and then un-reverse them at the end. This helps avoid the quadratic blowup from repeatedly appending to lists. TODO: Benchmark how much of a problem this is in practice, and whether it's still a net win for small protobufs. If we decide on it more permanently, consider moving it to a more internal module.

A pair of an encoded field and a value.