
protobufs.pl -- Google's Protocol Buffers
Protocol buffers are Google's language-neutral, platform-neutral,
extensible mechanism for serializing structured data -- think XML, but
smaller, faster, and simpler. You define how you want your data to be
structured once. This takes the form of a template that describes the
data structure. You use this template to encode and decode your data
structure into wire-streams that may be sent-to or read-from your peers.
The underlying wire stream is platform independent, lossless, and may be
used to interwork with a variety of languages and systems regardless of
word size or endianness. Techniques exist to safely extend your data
structure without breaking deployed programs that are compiled against
the "old" format.
The idea behind Google's Protocol Buffers is that you define your
structured messages using a domain-specific language and tool set. In
SWI-Prolog, you define your message template as a list of predefined
Prolog terms that correspond to production rules in the Definite Clause
Grammar (DCG) that realizes the interpreter. Each production rule has an
equivalent rule in the protobuf grammar. The process is not unlike
specifiying the format of a regular expression. To encode a template to
a wire-stream, you pass a grounded template, X
, and variable, Y
, to
protobuf_message/2. To decode a wire-stream, Y
, you pass an ungrounded
template, X
, along with a grounded wire-stream, Y
, to
protobuf_message/2. The interpreter will unify the unbound variables in
the template with values decoded from the wire-stream.
For an overview and tutorial with examples, see protobufs_overview.txt
.
Examples of usage may also be found by inspecting test_protobufs.pl
.
- author
- - : Jeffrey Rosenwald (JeffRose@acm.org)
- See also
- - http://code.google.com/apis/protocolbuffers
- Compatibility
- - : SWI-Prolog
protobuf_message(?Template, ?Wire_stream) is semidet
protobuf_message(?Template, ?Wire_stream, ?Rest) is nondet- Marshalls and unmarshalls byte streams encoded using Google's
Protobuf grammars. protobuf_message/2 provides a bi-directional
parser that marshalls a Prolog structure to Wire_stream, according
to rules specified by Template. It can also unmarshall Wire_stream
into a Prolog structure according to the same grammar.
protobuf_message/3 provides a difference list version.
- Arguments:
-
Template | - is a protobuf grammar specification. On decode,
unbound variables in the Template are unified with their respective
values in the Wire_stream. On encode, Template must be ground. |
Wire_stream | - is a code list that was generated by a protobuf
encoder using an equivalent template. |
protobuf_message(?Template, ?Wire_stream) is semidet
protobuf_message(?Template, ?Wire_stream, ?Rest) is nondet- Marshalls and unmarshalls byte streams encoded using Google's
Protobuf grammars. protobuf_message/2 provides a bi-directional
parser that marshalls a Prolog structure to Wire_stream, according
to rules specified by Template. It can also unmarshall Wire_stream
into a Prolog structure according to the same grammar.
protobuf_message/3 provides a difference list version.
- Arguments:
-
Template | - is a protobuf grammar specification. On decode,
unbound variables in the Template are unified with their respective
values in the Wire_stream. On encode, Template must be ground. |
Wire_stream | - is a code list that was generated by a protobuf
encoder using an equivalent template. |