Form1 is converted back to the original wire stream, then the predicate non-deterimisticly attempts to convert the wire stream to a string or length_delimited term (or both: the lattter always succeeds).

The possible conversions are: message(Tag,Segments) => string(Tag,String) message(Tag,Segments) => length_delimited(Tag,Codes) string(Tag,String) => length_delimited(Tag,Codes) length_delimited(Tag,Codes) => length_delimited(Tag,Codes)

Note that for fixed32, fixed64, only the signed integer forms are given; if you want the floating point forms, then you need to do use int64_float64_when/2 and int32_float32_when/2.

For example:

?- protobuf_segment_convert(
       message(10,[fixed64(13,7309475598860382318)]),
       string(10,"inputType")).
?- protobuf_segment_convert(
       message(10,[fixed64(13,7309475598860382318)]),
       length_delimited(10,[105,110,112,117,116,84,121,112,101])).
?- protobuf_segment_convert(
       string(10, "inputType"),
       length_delimited(10,[105,110,112,117,116,84,121,112,101])).
?- forall(protobuf_segment_convert(string(1999,"\x1\\x0\\x0\\x0\\x2\\x0\\x0\\x0\"),Z), writeln(Z)).
      string(1999,)
      packed(1999,fixed64([8589934593]))
      packed(1999,fixed32([1,2]))
      packed(1999,varint([1,0,0,0,2,0,0,0]))
      length_delimited(1999,[1,0,0,0,2,0,0,0])

These come from:

Codes = [82,9,105,110,112,117,116,84,121,112,101],
protobuf_message(protobuf([embedded(T1, protobuf([integer64(T2, I)]))]), Codes),
protobuf_message(protobuf([string(T,S)]), Codes).
   T = 10, T1 = 10, T2 = 13,
   I = 7309475598860382318,
   S = "inputType".

bug

- This predicate is preliminary and may change as additional functionality is added.

- This predicate will sometimes generate unexpected choice points, Such as from protobuf_segment_convert(message(10,...), string(10,...))

Arguments:

Form1	- message(Tag,Pieces), string(Tag,String), length_delimited(Tag,Codes), varint(Tag,Value), fixed64(Tag,Value), fixed32(Tag,Value).
Form2	- similar to Form1.