1/* Find near-matches for identifiers.
2 Copyright (C) 2015-2017 Free Software Foundation, Inc.
3
4This file is part of GCC.
5
6GCC is free software; you can redistribute it and/or modify it under
7the terms of the GNU General Public License as published by the Free
8Software Foundation; either version 3, or (at your option) any later
9version.
10
11GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12WARRANTY; without even the implied warranty of MERCHANTABILITY or
13FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14for more details.
15
16You should have received a copy of the GNU General Public License
17along with GCC; see the file COPYING3. If not see
18<http://www.gnu.org/licenses/>. */
19
20#include "config.h"
21#include "system.h"
22#include "coretypes.h"
23#include "tm.h"
24#include "tree.h"
25#include "cpplib.h"
26#include "spellcheck-tree.h"
27#include "selftest.h"
28#include "stringpool.h"
29
30/* Calculate Levenshtein distance between two identifiers. */
31
32edit_distance_t
33levenshtein_distance (tree ident_s, tree ident_t)
34{
35 gcc_assert (TREE_CODE (ident_s) == IDENTIFIER_NODE);
36 gcc_assert (TREE_CODE (ident_t) == IDENTIFIER_NODE);
37
38 return levenshtein_distance (IDENTIFIER_POINTER (ident_s),
39 IDENTIFIER_LENGTH (ident_s),
40 IDENTIFIER_POINTER (ident_t),
41 IDENTIFIER_LENGTH (ident_t));
42}
43
44/* Given TARGET, an identifier, and CANDIDATES, a vec of identifiers,
45 determine which element within CANDIDATES has the lowest edit
46 distance to TARGET. If there are multiple elements with the
47 same minimal distance, the first in the vector wins.
48
49 If more than half of the letters were misspelled, the suggestion is
50 likely to be meaningless, so return NULL_TREE for this case. */
51
52tree
53find_closest_identifier (tree target, const auto_vec<tree> *candidates)
54{
55 gcc_assert (TREE_CODE (target) == IDENTIFIER_NODE);
56
57 best_match<tree, tree> bm (target);
58 int i;
59 tree identifier;
60 FOR_EACH_VEC_ELT (*candidates, i, identifier)
61 {
62 gcc_assert (TREE_CODE (identifier) == IDENTIFIER_NODE);
63 bm.consider (identifier);
64 }
65
66 return bm.get_best_meaningful_candidate ();
67}
68
69#if CHECKING_P
70
71namespace selftest {
72
73/* Selftests. */
74
75/* Verify that find_closest_identifier is sane. */
76
77static void
78test_find_closest_identifier ()
79{
80 auto_vec<tree> candidates;
81
82 /* Verify that it can handle an empty vec. */
83 ASSERT_EQ (NULL, find_closest_identifier (get_identifier (""), &candidates));
84
85 /* Verify that it works sanely for non-empty vecs. */
86 tree apple = get_identifier ("apple");
87 tree banana = get_identifier ("banana");
88 tree cherry = get_identifier ("cherry");
89 candidates.safe_push (apple);
90 candidates.safe_push (banana);
91 candidates.safe_push (cherry);
92
93 ASSERT_EQ (apple, find_closest_identifier (get_identifier ("app"),
94 &candidates));
95 ASSERT_EQ (banana, find_closest_identifier (get_identifier ("banyan"),
96 &candidates));
97 ASSERT_EQ (cherry, find_closest_identifier (get_identifier ("berry"),
98 &candidates));
99 ASSERT_EQ (NULL,
100 find_closest_identifier (get_identifier ("not like the others"),
101 &candidates));
102}
103
104/* Run all of the selftests within this file. */
105
106void
107spellcheck_tree_c_tests ()
108{
109 test_find_closest_identifier ();
110}
111
112} // namespace selftest
113
114#endif /* #if CHECKING_P */
115