jupytersketcher/Lib/site-packages/nltk/test/unit/test_tgrep.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# Natural Language Toolkit: TGrep search
#
# Copyright (C) 2001-2020 NLTK Project
# Author: Will Roberts <wildwilhelm@gmail.com>
# URL: <http://nltk.org/>
# For license information, see LICENSE.TXT

'''
Unit tests for nltk.tgrep.
'''


import unittest

from nltk.tree import ParentedTree
from nltk import tgrep


class TestSequenceFunctions(unittest.TestCase):

    '''
    Class containing unit tests for nltk.tgrep.
    '''

    def test_tokenize_simple(self):
        '''
        Simple test of tokenization.
        '''
        tokens = tgrep.tgrep_tokenize('A .. (B !< C . D) | ![<< (E , F) $ G]')
        self.assertEqual(
            tokens,
            [
                'A',
                '..',
                '(',
                'B',
                '!',
                '<',
                'C',
                '.',
                'D',
                ')',
                '|',
                '!',
                '[',
                '<<',
                '(',
                'E',
                ',',
                'F',
                ')',
                '$',
                'G',
                ']',
            ],
        )

    def test_tokenize_encoding(self):
        '''
        Test that tokenization handles bytes and strs the same way.
        '''
        self.assertEqual(
            tgrep.tgrep_tokenize(b'A .. (B !< C . D) | ![<< (E , F) $ G]'),
            tgrep.tgrep_tokenize('A .. (B !< C . D) | ![<< (E , F) $ G]'),
        )

    def test_tokenize_link_types(self):
        '''
        Test tokenization of basic link types.
        '''
        self.assertEqual(tgrep.tgrep_tokenize('A<B'), ['A', '<', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A>B'), ['A', '>', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A<3B'), ['A', '<3', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A>3B'), ['A', '>3', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A<,B'), ['A', '<,', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A>,B'), ['A', '>,', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A<-3B'), ['A', '<-3', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A>-3B'), ['A', '>-3', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A<-B'), ['A', '<-', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A>-B'), ['A', '>-', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A<\'B'), ['A', '<\'', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A>\'B'), ['A', '>\'', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A<:B'), ['A', '<:', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A>:B'), ['A', '>:', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A<<B'), ['A', '<<', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A>>B'), ['A', '>>', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A<<,B'), ['A', '<<,', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A>>,B'), ['A', '>>,', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A<<\'B'), ['A', '<<\'', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A>>\'B'), ['A', '>>\'', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A<<:B'), ['A', '<<:', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A>>:B'), ['A', '>>:', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A.B'), ['A', '.', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A,B'), ['A', ',', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A..B'), ['A', '..', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A,,B'), ['A', ',,', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A$B'), ['A', '$', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A$.B'), ['A', '$.', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A$,B'), ['A', '$,', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A$..B'), ['A', '$..', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A$,,B'), ['A', '$,,', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!<B'), ['A', '!', '<', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!>B'), ['A', '!', '>', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!<3B'), ['A', '!', '<3', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!>3B'), ['A', '!', '>3', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!<,B'), ['A', '!', '<,', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!>,B'), ['A', '!', '>,', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!<-3B'), ['A', '!', '<-3', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!>-3B'), ['A', '!', '>-3', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!<-B'), ['A', '!', '<-', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!>-B'), ['A', '!', '>-', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!<\'B'), ['A', '!', '<\'', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!>\'B'), ['A', '!', '>\'', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!<:B'), ['A', '!', '<:', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!>:B'), ['A', '!', '>:', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!<<B'), ['A', '!', '<<', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!>>B'), ['A', '!', '>>', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!<<,B'), ['A', '!', '<<,', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!>>,B'), ['A', '!', '>>,', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!<<\'B'), ['A', '!', '<<\'', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!>>\'B'), ['A', '!', '>>\'', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!<<:B'), ['A', '!', '<<:', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!>>:B'), ['A', '!', '>>:', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!.B'), ['A', '!', '.', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!,B'), ['A', '!', ',', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!..B'), ['A', '!', '..', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!,,B'), ['A', '!', ',,', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!$B'), ['A', '!', '$', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!$.B'), ['A', '!', '$.', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!$,B'), ['A', '!', '$,', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!$..B'), ['A', '!', '$..', 'B'])
        self.assertEqual(tgrep.tgrep_tokenize('A!$,,B'), ['A', '!', '$,,', 'B'])

    def test_tokenize_examples(self):
        '''
        Test tokenization of the TGrep2 manual example patterns.
        '''
        self.assertEqual(tgrep.tgrep_tokenize('NP < PP'), ['NP', '<', 'PP'])
        self.assertEqual(tgrep.tgrep_tokenize('/^NP/'), ['/^NP/'])
        self.assertEqual(
            tgrep.tgrep_tokenize('NP << PP . VP'), ['NP', '<<', 'PP', '.', 'VP']
        )
        self.assertEqual(
            tgrep.tgrep_tokenize('NP << PP | . VP'), ['NP', '<<', 'PP', '|', '.', 'VP']
        )
        self.assertEqual(
            tgrep.tgrep_tokenize('NP !<< PP [> NP | >> VP]'),
            ['NP', '!', '<<', 'PP', '[', '>', 'NP', '|', '>>', 'VP', ']'],
        )
        self.assertEqual(
            tgrep.tgrep_tokenize('NP << (PP . VP)'),
            ['NP', '<<', '(', 'PP', '.', 'VP', ')'],
        )
        self.assertEqual(
            tgrep.tgrep_tokenize('NP <\' (PP <, (IN < on))'),
            ['NP', '<\'', '(', 'PP', '<,', '(', 'IN', '<', 'on', ')', ')'],
        )
        self.assertEqual(
            tgrep.tgrep_tokenize('S < (A < B) < C'),
            ['S', '<', '(', 'A', '<', 'B', ')', '<', 'C'],
        )
        self.assertEqual(
            tgrep.tgrep_tokenize('S < ((A < B) < C)'),
            ['S', '<', '(', '(', 'A', '<', 'B', ')', '<', 'C', ')'],
        )
        self.assertEqual(
            tgrep.tgrep_tokenize('S < (A < B < C)'),
            ['S', '<', '(', 'A', '<', 'B', '<', 'C', ')'],
        )
        self.assertEqual(tgrep.tgrep_tokenize('A<B&.C'), ['A', '<', 'B', '&', '.', 'C'])

    def test_tokenize_quoting(self):
        '''
        Test tokenization of quoting.
        '''
        self.assertEqual(
            tgrep.tgrep_tokenize('"A<<:B"<<:"A $.. B"<"A>3B"<C'),
            ['"A<<:B"', '<<:', '"A $.. B"', '<', '"A>3B"', '<', 'C'],
        )

    def test_tokenize_nodenames(self):
        '''
        Test tokenization of node names.
        '''
        self.assertEqual(tgrep.tgrep_tokenize('Robert'), ['Robert'])
        self.assertEqual(tgrep.tgrep_tokenize('/^[Bb]ob/'), ['/^[Bb]ob/'])
        self.assertEqual(tgrep.tgrep_tokenize('*'), ['*'])
        self.assertEqual(tgrep.tgrep_tokenize('__'), ['__'])
        # test tokenization of NLTK tree position syntax
        self.assertEqual(tgrep.tgrep_tokenize('N()'), ['N(', ')'])
        self.assertEqual(tgrep.tgrep_tokenize('N(0,)'), ['N(', '0', ',', ')'])
        self.assertEqual(tgrep.tgrep_tokenize('N(0,0)'), ['N(', '0', ',', '0', ')'])
        self.assertEqual(
            tgrep.tgrep_tokenize('N(0,0,)'), ['N(', '0', ',', '0', ',', ')']
        )

    def test_tokenize_macros(self):
        '''
        Test tokenization of macro definitions.
        '''
        self.assertEqual(
            tgrep.tgrep_tokenize(
                '@ NP /^NP/;\n@ NN /^NN/;\n@NP [!< NP | < @NN] !$.. @NN'
            ),
            [
                '@',
                'NP',
                '/^NP/',
                ';',
                '@',
                'NN',
                '/^NN/',
                ';',
                '@NP',
                '[',
                '!',
                '<',
                'NP',
                '|',
                '<',
                '@NN',
                ']',
                '!',
                '$..',
                '@NN',
            ],
        )

    def test_node_simple(self):
        '''
        Test a simple use of tgrep for finding nodes matching a given
        pattern.
        '''
        tree = ParentedTree.fromstring(
            '(S (NP (DT the) (JJ big) (NN dog)) ' '(VP bit) (NP (DT a) (NN cat)))'
        )
        self.assertEqual(list(tgrep.tgrep_positions('NN', [tree])), [[(0, 2), (2, 1)]])
        self.assertEqual(
            list(tgrep.tgrep_nodes('NN', [tree])), [[tree[0, 2], tree[2, 1]]]
        )
        self.assertEqual(
            list(tgrep.tgrep_positions('NN|JJ', [tree])), [[(0, 1), (0, 2), (2, 1)]]
        )

    def test_node_printing(self):
        '''Test that the tgrep print operator ' is properly ignored.'''
        tree = ParentedTree.fromstring('(S (n x) (N x))')
        self.assertEqual(
            list(tgrep.tgrep_positions('N', [tree])),
            list(tgrep.tgrep_positions('\'N', [tree])),
        )
        self.assertEqual(
            list(tgrep.tgrep_positions('/[Nn]/', [tree])),
            list(tgrep.tgrep_positions('\'/[Nn]/', [tree])),
        )

    def test_node_encoding(self):
        '''
        Test that tgrep search strings handles bytes and strs the same
        way.
        '''
        tree = ParentedTree.fromstring(
            '(S (NP (DT the) (JJ big) (NN dog)) ' '(VP bit) (NP (DT a) (NN cat)))'
        )
        self.assertEqual(
            list(tgrep.tgrep_positions(b'NN', [tree])),
            list(tgrep.tgrep_positions(b'NN', [tree])),
        )
        self.assertEqual(
            list(tgrep.tgrep_nodes(b'NN', [tree])),
            list(tgrep.tgrep_nodes('NN', [tree])),
        )
        self.assertEqual(
            list(tgrep.tgrep_positions(b'NN|JJ', [tree])),
            list(tgrep.tgrep_positions('NN|JJ', [tree])),
        )

    def test_node_nocase(self):
        '''
        Test selecting nodes using case insensitive node names.
        '''
        tree = ParentedTree.fromstring('(S (n x) (N x))')
        self.assertEqual(list(tgrep.tgrep_positions('"N"', [tree])), [[(1,)]])
        self.assertEqual(list(tgrep.tgrep_positions('i@"N"', [tree])), [[(0,), (1,)]])

    def test_node_quoted(self):
        '''
        Test selecting nodes using quoted node names.
        '''
        tree = ParentedTree.fromstring('(N ("N" x) (N" x) ("\\" x))')
        self.assertEqual(list(tgrep.tgrep_positions('"N"', [tree])), [[()]])
        self.assertEqual(list(tgrep.tgrep_positions('"\\"N\\""', [tree])), [[(0,)]])
        self.assertEqual(list(tgrep.tgrep_positions('"N\\""', [tree])), [[(1,)]])
        self.assertEqual(list(tgrep.tgrep_positions('"\\"\\\\\\""', [tree])), [[(2,)]])

    def test_node_regex(self):
        '''
        Test regex matching on nodes.
        '''
        tree = ParentedTree.fromstring('(S (NP-SBJ x) (NP x) (NNP x) (VP x))')
        # This is a regular expression that matches any node whose
        # name starts with NP, including NP-SBJ:
        self.assertEqual(list(tgrep.tgrep_positions('/^NP/', [tree])), [[(0,), (1,)]])

    def test_node_regex_2(self):
        '''
        Test regex matching on nodes.
        '''
        tree = ParentedTree.fromstring('(S (SBJ x) (SBJ1 x) (NP-SBJ x))')
        self.assertEqual(list(tgrep.tgrep_positions('/^SBJ/', [tree])), [[(0,), (1,)]])
        # This is a regular expression that matches any node whose
        # name includes SBJ, including NP-SBJ:
        self.assertEqual(
            list(tgrep.tgrep_positions('/SBJ/', [tree])), [[(0,), (1,), (2,)]]
        )

    def test_node_tree_position(self):
        '''
        Test matching on nodes based on NLTK tree position.
        '''
        tree = ParentedTree.fromstring('(S (NP-SBJ x) (NP x) (NNP x) (VP x))')
        # test all tree positions that are not leaves
        leaf_positions = set(
            tree.leaf_treeposition(x) for x in range(len(tree.leaves()))
        )
        tree_positions = [x for x in tree.treepositions() if x not in leaf_positions]
        for position in tree_positions:
            node_id = 'N{0}'.format(position)
            tgrep_positions = list(tgrep.tgrep_positions(node_id, [tree]))
            self.assertEqual(len(tgrep_positions[0]), 1)
            self.assertEqual(tgrep_positions[0][0], position)

    def test_node_noleaves(self):
        '''
        Test node name matching with the search_leaves flag set to False.
        '''
        tree = ParentedTree.fromstring('(S (A (T x)) (B (N x)))')
        self.assertEqual(
            list(tgrep.tgrep_positions('x', [tree])), [[(0, 0, 0), (1, 0, 0)]]
        )
        self.assertEqual(list(tgrep.tgrep_positions('x', [tree], False)), [[]])

    def tests_rel_dominance(self):
        '''
        Test matching nodes based on dominance relations.
        '''
        tree = ParentedTree.fromstring('(S (A (T x)) (B (N x)))')
        self.assertEqual(list(tgrep.tgrep_positions('* < T', [tree])), [[(0,)]])
        self.assertEqual(list(tgrep.tgrep_positions('* < T > S', [tree])), [[(0,)]])
        self.assertEqual(
            list(tgrep.tgrep_positions('* !< T', [tree])),
            [[(), (0, 0), (0, 0, 0), (1,), (1, 0), (1, 0, 0)]],
        )
        self.assertEqual(list(tgrep.tgrep_positions('* !< T > S', [tree])), [[(1,)]])
        self.assertEqual(list(tgrep.tgrep_positions('* > A', [tree])), [[(0, 0)]])
        self.assertEqual(list(tgrep.tgrep_positions('* > B', [tree])), [[(1, 0)]])
        self.assertEqual(
            list(tgrep.tgrep_positions('* !> B', [tree])),
            [[(), (0,), (0, 0), (0, 0, 0), (1,), (1, 0, 0)]],
        )
        self.assertEqual(
            list(tgrep.tgrep_positions('* !> B >> S', [tree])), [[(0,), (0, 0), (1,)]]
        )
        self.assertEqual(
            list(tgrep.tgrep_positions('* >> S', [tree])),
            [[(0,), (0, 0), (1,), (1, 0)]],
        )
        self.assertEqual(
            list(tgrep.tgrep_positions('* >>, S', [tree])), [[(0,), (0, 0)]]
        )
        self.assertEqual(
            list(tgrep.tgrep_positions('* >>\' S', [tree])), [[(1,), (1, 0)]]
        )
        # Known issue:
        # self.assertEqual(list(tgrep.tgrep_positions('* !>> S', [tree])),
        #                 [[()]])
        self.assertEqual(list(tgrep.tgrep_positions('* << T', [tree])), [[(), (0,)]])
        self.assertEqual(list(tgrep.tgrep_positions('* <<\' T', [tree])), [[(0,)]])
        self.assertEqual(list(tgrep.tgrep_positions('* <<1 N', [tree])), [[(1,)]])
        self.assertEqual(
            list(tgrep.tgrep_positions('* !<< T', [tree])),
            [[(0, 0), (0, 0, 0), (1,), (1, 0), (1, 0, 0)]],
        )
        tree = ParentedTree.fromstring('(S (A (T x)) (B (T x) (N x )))')
        self.assertEqual(list(tgrep.tgrep_positions('* <: T', [tree])), [[(0,)]])
        self.assertEqual(list(tgrep.tgrep_positions('* < T', [tree])), [[(0,), (1,)]])
        self.assertEqual(
            list(tgrep.tgrep_positions('* !<: T', [tree])),
            [[(), (0, 0), (0, 0, 0), (1,), (1, 0), (1, 0, 0), (1, 1), (1, 1, 0)]],
        )
        self.assertEqual(list(tgrep.tgrep_positions('* !<: T > S', [tree])), [[(1,)]])
        tree = ParentedTree.fromstring('(S (T (A x) (B x)) (T (C x)))')
        self.assertEqual(list(tgrep.tgrep_positions('* >: T', [tree])), [[(1, 0)]])
        self.assertEqual(
            list(tgrep.tgrep_positions('* !>: T', [tree])),
            [[(), (0,), (0, 0), (0, 0, 0), (0, 1), (0, 1, 0), (1,), (1, 0, 0)]],
        )
        tree = ParentedTree.fromstring(
            '(S (A (B (C (D (E (T x))))))' ' (A (B (C (D (E (T x))) (N x)))))'
        )
        self.assertEqual(
            list(tgrep.tgrep_positions('* <<: T', [tree])),
            [
                [
                    (0,),
                    (0, 0),
                    (0, 0, 0),
                    (0, 0, 0, 0),
                    (0, 0, 0, 0, 0),
                    (1, 0, 0, 0),
                    (1, 0, 0, 0, 0),
                ]
            ],
        )
        self.assertEqual(
            list(tgrep.tgrep_positions('* >>: A', [tree])),
            [
                [
                    (0, 0),
                    (0, 0, 0),
                    (0, 0, 0, 0),
                    (0, 0, 0, 0, 0),
                    (0, 0, 0, 0, 0, 0),
                    (1, 0),
                    (1, 0, 0),
                ]
            ],
        )

    def test_bad_operator(self):
        '''
        Test error handling of undefined tgrep operators.
        '''
        tree = ParentedTree.fromstring('(S (A (T x)) (B (N x)))')
        self.assertRaises(
            tgrep.TgrepException, list, tgrep.tgrep_positions('* >>> S', [tree])
        )

    def test_comments(self):
        '''
        Test that comments are correctly filtered out of tgrep search
        strings.
        '''
        tree = ParentedTree.fromstring('(S (NN x) (NP x) (NN x))')
        search1 = '''
        @ NP /^NP/;
        @ NN /^NN/;
        @NN
        '''
        self.assertEqual(list(tgrep.tgrep_positions(search1, [tree])), [[(0,), (2,)]])
        search2 = '''
        # macros
        @ NP /^NP/;
        @ NN /^NN/;

        # search string
        @NN
        '''
        self.assertEqual(list(tgrep.tgrep_positions(search2, [tree])), [[(0,), (2,)]])

    def test_rel_sister_nodes(self):
        '''
        Test matching sister nodes in a tree.
        '''
        tree = ParentedTree.fromstring('(S (A x) (B x) (C x))')
        self.assertEqual(list(tgrep.tgrep_positions('* $. B', [tree])), [[(0,)]])
        self.assertEqual(list(tgrep.tgrep_positions('* $.. B', [tree])), [[(0,)]])
        self.assertEqual(list(tgrep.tgrep_positions('* $, B', [tree])), [[(2,)]])
        self.assertEqual(list(tgrep.tgrep_positions('* $,, B', [tree])), [[(2,)]])
        self.assertEqual(list(tgrep.tgrep_positions('* $ B', [tree])), [[(0,), (2,)]])

    def tests_rel_indexed_children(self):
        '''
        Test matching nodes based on their index in their parent node.
        '''
        tree = ParentedTree.fromstring('(S (A x) (B x) (C x))')
        self.assertEqual(list(tgrep.tgrep_positions('* >, S', [tree])), [[(0,)]])
        self.assertEqual(list(tgrep.tgrep_positions('* >1 S', [tree])), [[(0,)]])
        self.assertEqual(list(tgrep.tgrep_positions('* >2 S', [tree])), [[(1,)]])
        self.assertEqual(list(tgrep.tgrep_positions('* >3 S', [tree])), [[(2,)]])
        self.assertEqual(list(tgrep.tgrep_positions('* >\' S', [tree])), [[(2,)]])
        self.assertEqual(list(tgrep.tgrep_positions('* >-1 S', [tree])), [[(2,)]])
        self.assertEqual(list(tgrep.tgrep_positions('* >-2 S', [tree])), [[(1,)]])
        self.assertEqual(list(tgrep.tgrep_positions('* >-3 S', [tree])), [[(0,)]])
        tree = ParentedTree.fromstring(
            '(S (D (A x) (B x) (C x)) (E (B x) (C x) (A x)) ' '(F (C x) (A x) (B x)))'
        )
        self.assertEqual(list(tgrep.tgrep_positions('* <, A', [tree])), [[(0,)]])
        self.assertEqual(list(tgrep.tgrep_positions('* <1 A', [tree])), [[(0,)]])
        self.assertEqual(list(tgrep.tgrep_positions('* <2 A', [tree])), [[(2,)]])
        self.assertEqual(list(tgrep.tgrep_positions('* <3 A', [tree])), [[(1,)]])
        self.assertEqual(list(tgrep.tgrep_positions('* <\' A', [tree])), [[(1,)]])
        self.assertEqual(list(tgrep.tgrep_positions('* <-1 A', [tree])), [[(1,)]])
        self.assertEqual(list(tgrep.tgrep_positions('* <-2 A', [tree])), [[(2,)]])
        self.assertEqual(list(tgrep.tgrep_positions('* <-3 A', [tree])), [[(0,)]])

    def test_rel_precedence(self):
        '''
        Test matching nodes based on precedence relations.
        '''
        tree = ParentedTree.fromstring(
            '(S (NP (NP (PP x)) (NP (AP x)))'
            ' (VP (AP (X (PP x)) (Y (AP x))))'
            ' (NP (RC (NP (AP x)))))'
        )
        self.assertEqual(
            list(tgrep.tgrep_positions('* . X', [tree])), [[(0,), (0, 1), (0, 1, 0)]]
        )
        self.assertEqual(
            list(tgrep.tgrep_positions('* . Y', [tree])), [[(1, 0, 0), (1, 0, 0, 0)]]
        )
        self.assertEqual(
            list(tgrep.tgrep_positions('* .. X', [tree])),
            [[(0,), (0, 0), (0, 0, 0), (0, 1), (0, 1, 0)]],
        )
        self.assertEqual(
            list(tgrep.tgrep_positions('* .. Y', [tree])),
            [[(0,), (0, 0), (0, 0, 0), (0, 1), (0, 1, 0), (1, 0, 0), (1, 0, 0, 0)]],
        )
        self.assertEqual(
            list(tgrep.tgrep_positions('* , X', [tree])), [[(1, 0, 1), (1, 0, 1, 0)]]
        )
        self.assertEqual(
            list(tgrep.tgrep_positions('* , Y', [tree])),
            [[(2,), (2, 0), (2, 0, 0), (2, 0, 0, 0)]],
        )
        self.assertEqual(
            list(tgrep.tgrep_positions('* ,, X', [tree])),
            [[(1, 0, 1), (1, 0, 1, 0), (2,), (2, 0), (2, 0, 0), (2, 0, 0, 0)]],
        )
        self.assertEqual(
            list(tgrep.tgrep_positions('* ,, Y', [tree])),
            [[(2,), (2, 0), (2, 0, 0), (2, 0, 0, 0)]],
        )

    def test_examples(self):
        '''
        Test the Basic Examples from the TGrep2 manual.
        '''
        tree = ParentedTree.fromstring('(S (NP (AP x)) (NP (PP x)))')
        # This matches any NP node that immediately dominates a PP:
        self.assertEqual(list(tgrep.tgrep_positions('NP < PP', [tree])), [[(1,)]])

        tree = ParentedTree.fromstring('(S (NP x) (VP x) (NP (PP x)) (VP x))')
        # This matches an NP that dominates a PP and is immediately
        # followed by a VP:
        self.assertEqual(list(tgrep.tgrep_positions('NP << PP . VP', [tree])), [[(2,)]])

        tree = ParentedTree.fromstring(
            '(S (NP (AP x)) (NP (PP x)) ' '(NP (DET x) (NN x)) (VP x))'
        )
        # This matches an NP that dominates a PP or is immediately
        # followed by a VP:
        self.assertEqual(
            list(tgrep.tgrep_positions('NP << PP | . VP', [tree])), [[(1,), (2,)]]
        )

        tree = ParentedTree.fromstring(
            '(S (NP (NP (PP x)) (NP (AP x)))'
            ' (VP (AP (NP (PP x)) (NP (AP x))))'
            ' (NP (RC (NP (AP x)))))'
        )
        # This matches an NP that does not dominate a PP. Also, the NP
        # must either have a parent that is an NP or be dominated by a
        # VP:
        self.assertEqual(
            list(tgrep.tgrep_positions('NP !<< PP [> NP | >> VP]', [tree])),
            [[(0, 1), (1, 0, 1)]],
        )

        tree = ParentedTree.fromstring(
            '(S (NP (AP (PP x) (VP x))) ' '(NP (AP (PP x) (NP x))) (NP x))'
        )
        # This matches an NP that dominates a PP which itself is
        # immediately followed by a VP. Note the use of parentheses to
        # group ". VP" with the PP rather than with the NP:
        self.assertEqual(
            list(tgrep.tgrep_positions('NP << (PP . VP)', [tree])), [[(0,)]]
        )

        tree = ParentedTree.fromstring(
            '(S (NP (DET a) (NN cat) (PP (IN on) (NP x)))'
            ' (NP (DET a) (NN cat) (PP (IN on) (NP x)) (PP x))'
            ' (NP x))'
        )
        # This matches an NP whose last child is a PP that begins with
        # the preposition "on":
        self.assertEqual(
            list(tgrep.tgrep_positions('NP <\' (PP <, (IN < on))', [tree])), [[(0,)]]
        )

        tree = ParentedTree.fromstring(
            '(S (S (C x) (A (B x))) (S (C x) (A x)) ' '(S (D x) (A (B x))))'
        )
        # The following pattern matches an S which has a child A and
        # another child that is a C and that the A has a child B:
        self.assertEqual(
            list(tgrep.tgrep_positions('S < (A < B) < C', [tree])), [[(0,)]]
        )

        tree = ParentedTree.fromstring(
            '(S (S (A (B x) (C x))) (S (S (C x) (A (B x)))))'
        )
        # However, this pattern means that S has child A and that A
        # has children B and C:
        self.assertEqual(
            list(tgrep.tgrep_positions('S < ((A < B) < C)', [tree])), [[(0,)]]
        )

        # It is equivalent to this:
        self.assertEqual(
            list(tgrep.tgrep_positions('S < (A < B < C)', [tree])), [[(0,)]]
        )

    def test_use_macros(self):
        '''
        Test defining and using tgrep2 macros.
        '''
        tree = ParentedTree.fromstring(
            '(VP (VB sold) (NP (DET the) '
            '(NN heiress)) (NP (NN deed) (PREP to) '
            '(NP (DET the) (NN school) (NN house))))'
        )
        self.assertEqual(
            list(
                tgrep.tgrep_positions(
                    '@ NP /^NP/;\n@ NN /^NN/;\n@NP !< @NP !$.. @NN', [tree]
                )
            ),
            [[(1,), (2, 2)]],
        )
        # use undefined macro @CNP
        self.assertRaises(
            tgrep.TgrepException,
            list,
            tgrep.tgrep_positions(
                '@ NP /^NP/;\n@ NN /^NN/;\n@CNP !< @NP !$.. @NN', [tree]
            ),
        )

    def test_tokenize_node_labels(self):
        '''Test tokenization of labeled nodes.'''
        self.assertEqual(
            tgrep.tgrep_tokenize('S < @SBJ < (@VP < (@VB $.. @OBJ))'),
            [
                'S',
                '<',
                '@SBJ',
                '<',
                '(',
                '@VP',
                '<',
                '(',
                '@VB',
                '$..',
                '@OBJ',
                ')',
                ')',
            ],
        )
        self.assertEqual(
            tgrep.tgrep_tokenize('S < @SBJ=s < (@VP=v < (@VB $.. @OBJ))'),
            [
                'S',
                '<',
                '@SBJ',
                '=',
                's',
                '<',
                '(',
                '@VP',
                '=',
                'v',
                '<',
                '(',
                '@VB',
                '$..',
                '@OBJ',
                ')',
                ')',
            ],
        )

    def test_tokenize_segmented_patterns(self):
        '''Test tokenization of segmented patterns.'''
        self.assertEqual(
            tgrep.tgrep_tokenize('S < @SBJ=s < (@VP=v < (@VB $.. @OBJ)) : =s .. =v'),
            [
                'S',
                '<',
                '@SBJ',
                '=',
                's',
                '<',
                '(',
                '@VP',
                '=',
                'v',
                '<',
                '(',
                '@VB',
                '$..',
                '@OBJ',
                ')',
                ')',
                ':',
                '=s',
                '..',
                '=v',
            ],
        )

    def test_labeled_nodes(self):
        '''
        Test labeled nodes.

        Test case from Emily M. Bender.
        '''
        search = '''
            # macros
            @ SBJ /SBJ/;
            @ VP /VP/;
            @ VB /VB/;
            @ VPoB /V[PB]/;
            @ OBJ /OBJ/;

            # 1 svo
            S < @SBJ=s < (@VP=v < (@VB $.. @OBJ)) : =s .. =v'''
        sent1 = ParentedTree.fromstring(
            '(S (NP-SBJ I) (VP (VB eat) (NP-OBJ (NNS apples))))'
        )
        sent2 = ParentedTree.fromstring(
            '(S (VP (VB eat) (NP-OBJ (NNS apples))) (NP-SBJ I))'
        )
        search_firsthalf = search.split('\n\n')[0] + 'S < @SBJ < (@VP < (@VB $.. @OBJ))'
        search_rewrite = 'S < (/.*SBJ/ $.. (/VP/ < (/VB/ $.. /.*OBJ/)))'

        self.assertTrue(list(tgrep.tgrep_positions(search_firsthalf, [sent1]))[0])
        self.assertTrue(list(tgrep.tgrep_positions(search, [sent1]))[0])
        self.assertTrue(list(tgrep.tgrep_positions(search_rewrite, [sent1]))[0])
        self.assertEqual(
            list(tgrep.tgrep_positions(search, [sent1])),
            list(tgrep.tgrep_positions(search_rewrite, [sent1])),
        )
        self.assertTrue(list(tgrep.tgrep_positions(search_firsthalf, [sent2]))[0])
        self.assertFalse(list(tgrep.tgrep_positions(search, [sent2]))[0])
        self.assertFalse(list(tgrep.tgrep_positions(search_rewrite, [sent2]))[0])
        self.assertEqual(
            list(tgrep.tgrep_positions(search, [sent2])),
            list(tgrep.tgrep_positions(search_rewrite, [sent2])),
        )

    def test_multiple_conjs(self):
        '''
        Test that multiple (3 or more) conjunctions of node relations are
        handled properly.
        '''
        sent = ParentedTree.fromstring('((A (B b) (C c)) (A (B b) (C c) (D d)))')
        # search = '(A < B < C < D)'
        # search_tworels = '(A < B < C)'
        self.assertEqual(
            list(tgrep.tgrep_positions('(A < B < C < D)', [sent])), [[(1,)]]
        )
        self.assertEqual(
            list(tgrep.tgrep_positions('(A < B < C)', [sent])), [[(0,), (1,)]]
        )

    def test_trailing_semicolon(self):
        '''
        Test that semicolons at the end of a tgrep2 search string won't
        cause a parse failure.
        '''
        tree = ParentedTree.fromstring(
            '(S (NP (DT the) (JJ big) (NN dog)) ' '(VP bit) (NP (DT a) (NN cat)))'
        )
        self.assertEqual(list(tgrep.tgrep_positions('NN', [tree])), [[(0, 2), (2, 1)]])
        self.assertEqual(list(tgrep.tgrep_positions('NN;', [tree])), [[(0, 2), (2, 1)]])
        self.assertEqual(
            list(tgrep.tgrep_positions('NN;;', [tree])), [[(0, 2), (2, 1)]]
        )


if __name__ == '__main__':
    unittest.main()