Added methods for obtaining an effective parrent and children.

Vincent Kriz · Vincent Kriz · commit 216245d6bd45 · 2016-12-19T15:46:32.000+01:00
diff --git a/udapi/block/zellig_harris/enhancedeps.py b/udapi/block/zellig_harris/enhancedeps.py
@@ -0,0 +1,129 @@
+#!/usr/bin/env python
+
+from udapi.core.block import Block
+
+
+def eparent(node):
+    """
+    Return an effective parent for the given node.
+
+    The rule for the effective parent - when the current node A has a deprel 'conj' to its parent B,
+    return  B.parent, otherwise return A.parent.
+
+    :param node: An input node.
+    :return: An effective parent.
+    :rtype: udapi.core.node.Node
+
+    """
+    if node.deprel == 'conj':
+        return node.parent.parent
+
+    return node.parent
+
+
+def echildren(node):
+    """
+    Return a list with node's effective children.
+
+    :param node: An input node.
+    :return: A list with node's effective children.
+    :rtype: list
+
+    """
+    target_deprels = ['subj', 'subjpass', 'dobj', 'iobj', 'compl']
+    node_parent = eparent(node)
+    echildren = node.children
+
+    for candidate_child in node_parent.children:
+        # Check if a candidate node C has the target deprel.
+        if candidate_child.deprel not in target_deprels:
+            continue
+
+        # Check if such deprel is not in the current node children already.
+        no_such_deprel = True
+        for current_child in node.children:
+            if current_child.deprel == candidate_child.deprel:
+                no_such_deprel = False
+                break
+
+        # If there is no such deprel, we can add a new secondary dependence.
+        if no_such_deprel:
+            echildren.append(candidate_child)
+
+
+def enhance_deps(node, new_dependence):
+    """
+    Add a new dependence to the node.deps, but firstly check
+    if there is no such dependence already.
+
+    :param node: A node to be enhanced.
+    :param new_dependence: A new dependence to be add into node.deps.
+
+    """
+    for existing_dependence in node.deps:
+        if existing_dependence['parent'] == new_dependence['parent'] and \
+           existing_dependence['deprel'] == new_dependence['deprel']:
+            return
+
+    node.deps.append(new_dependence)
+
+
+class EnhanceDeps(Block):
+    """
+    Identify new relations between nodes in the dependency tree (an analogy of effective parents/children from PML).
+    Add these new relations into secondary dependencies slot.
+
+    """
+
+    def __init__(self, args=None):
+        """
+        Initialization.
+
+        :param args: A dict of optional parameters.
+
+        """
+        super(Block, self).__init__()
+
+        if args is None:
+            args = {}
+
+    def process_node(self, node):
+        """
+        Enhance secondary dependencies by application of the following rules:
+        1. when the current node A has a deprel 'conj' to its parent B, create a new secondary dependence
+           (B.parent, B.deprel) to A
+        2. when the current node A has a deprel 'conj' to its parent B, look at B.children C
+           when C.deprel is in {subj, subjpass, iobj, dobj, compl} and there is no A.children D
+           such that C.deprel == D.deprel, add a new secondary dependence (A, C.deprel) to C
+
+        :param node: A node to be process.
+
+        """
+        # Both rules require node.deprel to be 'conj'.
+        if node.deprel != 'conj':
+            return
+
+        # Node's parent should not be root.
+        if node.parent.is_root():
+            return
+
+        # Apply rule (1)
+        enhance_deps(node, {'parent': node.parent.parent, 'deprel': node.parent.deprel})
+
+        # Apply rule (2)
+        target_deprels = ['subj', 'subjpass', 'dobj', 'iobj', 'compl']
+        for candidate_child in node.parent.children:
+            # Check if a candidate node C has the target deprel.
+            if candidate_child.deprel not in target_deprels:
+                continue
+
+            # Check if such deprel is not in the current node children already.
+            no_such_deprel = True
+            for current_child in node.children:
+                if current_child.deprel == candidate_child.deprel:
+                    no_such_deprel = False
+                    break
+
+            # If there is no such deprel, we can add a new secondary dependence.
+            if no_such_deprel:
+                enhance_deps(candidate_child, {'parent': node, 'deprel': candidate_child.deprel})
