/* Copyright 2016 Google Inc. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
==============================================================================*/

// Protocol buffer specification for sentence analysis.

syntax = "proto2";
option optimize_for = LITE_RUNTIME;

package chrome_lang_id;

// A Sentence contains the raw text contents of a sentence, as well as an
// analysis.
message Sentence {
  // Identifier for sentence.
  optional string id = 1;

  // Raw text contents of the sentence.
  optional string text = 2;

  // Tokenization of the sentence.
  repeated Token token = 3;

  extensions 1000 to max;
}

// A sentence token marks a span of bytes in the sentence text as a token
// or word.
message Token {
  // Token word form.
  required string word = 1;

  // Start position of token in text.
  required int32 start = 2;

  // End position of token in text. Gives index of last byte, not one past
  // the last byte. If token came from lexer, excludes any trailing HTML tags.
  required int32 end = 3;

  // Head of this token in the dependency tree: the id of the token which has an
  // arc going to this one. If it is the root token of a sentence, then it is
  // set to -1.
  optional int32 head = 4 [default = -1];

  // Part-of-speech tag for token.
  optional string tag = 5;

  // Coarse-grained word category for token.
  optional string category = 6;

  // Label for dependency relation between this token and its head.
  optional string label = 7;

  // Break level for tokens that indicates how it was separated from the
  // previous token in the text.
  enum BreakLevel {
    NO_BREAK = 0;         // No separation between tokens.
    SPACE_BREAK = 1;      // Tokens separated by space.
    LINE_BREAK = 2;       // Tokens separated by line break.
    SENTENCE_BREAK = 3;   // Tokens separated by sentence break.
  }

  optional BreakLevel break_level = 8 [default = SPACE_BREAK];

  extensions 1000 to max;
}