Data structure used in the toolkit

In the MAYZ toolkit, data, such as parse trees and derivations, are represented with feature structures. This page explains the definitions of the feature structures.

• Feature structure representing a word
• Feature structure representing a parse tree
• Feature structure representing a derivation

Feature structure representing a word

word <- [bot] +
  [INPUT\string(0),        %% input word itself
   SURFACE\string(1),      %% preprocessed input word
   BASE\string(2),         %% base form of the input word
   INPUT_POS\string(5),    %% input POS itself
   POS\string(6),          %% preprocessed POS
   BASE_POS\string(7),     %% POS of the base form of the input word
   POSITION\integer(10)    %% the position of the input word
  ].

Feature structure representing a parse tree

A phrase structure of an input treebank (parse tree) is represented with the following feature structure.

%% head/argument/modifier marks
head_mark <- [bot].
non_head <- [head_mark].   %% other than 'head'
argument <- [non_head].    %% for argument
modifier <- [non_head].    %% for modifier
empty <- [head_mark].      %% for empty trees
non_empty <- [head_mark].  %% for non-empty trees
head <- [head_mark, non_empty].    %% head
non_head_empty <- [non_head, empty].    %% empty non-head
non_head_non_empty <- [non_head, non_empty].  %% non-empty non-head
argument_empty <- [argument, non_head_empty]. %% empty argument
argument_non_empty <- [argument, non_head_non_empty].  %% non-empty argument
modifier_empty <- [modifier, non_head_empty]. %% empty modifier
modifier_non_empty <- [modifier, non_head_non_empty].  %% non-empty modifier

%% representation of PropBank-style annotations
propbank_label <- [bot] +
  [PROP_ID\integer(0)].    %% ID number uniquely assigned in a sentence
propbank_arg <- [propbank_label] +  %% annotation for arguments
  [ARG_POS\string(1)].     %% argument label ("ARG1", ...)
propbank_rel <- [propbank_label] +  %% annotation for predicates
  [PRED_NAME\string(1),    %% name of a predicate
   PRED_SEM_ID\string(2)]. %% semantic ID of a predicate

%% list of 'propbank_label'
prop_list <- [list].
prop_cons <- [prop_list, cons] + [hd\propbank_label, tl\prop_list].
prop_nil <- [prop_list, nil].

%% a node in a parse tree
tree_node <- [bot] +
  [SYM\string(0),          %% symbol of the node
   FUNC\list(1),           %% function labels (SBJ, TPC, etc.)
   HEAD_MARK\head_mark(2), %% head/argument/modifier marks
   PROP_LIST\prop_list(5), %% for PropBank-style annotations
   NODE_SIGN\bot(10),      %% sign corresponding to the node
   ANNOT\bot(11)           %% other annotations
  ].
tree_node_nts <- [tree_node] +  %% nonterminal node
  [ID\list(3),             %% coindex ID assigned to the node
   SCHEMA_NAME\bot(4)      %% schema name
  ].
tree_node_term <- [tree_node] +  %% terminal node
  [WORD\word(3)].          %% word corresponding to the node
tree_node_empty <- [tree_node] +  %% empty terminal node
  [COIND\list(3),          %% coindex IDs
   EMPTY_WORD\string(4),   %% string representing an empty word
   COIND_NODE\list(5)      %% coindexed nodes
  ].

%% parse tree
tree_base <- [bot] +
  [TREE_NODE\tree_node(0)].  %% the node of the tree
tree <- [tree_base].       %% terminal/nonterminal of the tree
tree_nts <- [tree] +       %% nonterminal
  [TREE_NODE\tree_node_nts,
   TREE_DTRS\list(20)].    %% daughter trees
tree_term <- [tree] +      %% terminal
  [TREE_NODE\tree_node_term].
tree_empty <- [tree] +     %% empty terminal
  [TREE_NODE\tree_node_empty].

%% used for pattern matching of trees
tree_any <- [tree_base] +
  [ANY_TREES\list(10)].    %% a list of matched trees

Feature structure representing a derivation

derivation <- [bot] +                  %% node in a derivation
  [DERIV_SIGN\bot(5)].                 %% sign corresponding to the node
derivation_internal <- [derivation] +  %% internal node of a derivation
  [DERIV_SCHEMA\bot(0),                %% name of the applied schema
   DERIV_DTRS\list(10)].               %% daughter derivations
derivation_terminal <- [derivation] +  %% terminal node of a derivation
  [TERM_WORD\word(0),                  %% word corresponding to the node
   TERM_TEMPLATE\lex_template(1),      %% template name assigned to the word
   LEXENTRY_SIGN\bot(10),              %% sign of a lexical entry
   LEXEME_SIGN\bot(11)                 %% sign of a lexeme
  ].