gcc/spellcheck-tree.c

   1 /* Find near-matches for identifiers.
   2    Copyright (C) 2015-2018 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 3, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along 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
  32 edit_distance_t
  33 levenshtein_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
  52 tree
  53 find_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
  71 namespace selftest {
  72
  73 /* Selftests.  */
  74
  75 /* Verify that find_closest_identifier is sane.  */
  76
  77 static void
  78 test_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
 106 void
 107 spellcheck_tree_c_tests ()
 108 {
 109   test_find_closest_identifier ();
 110 }
 111
 112 } // namespace selftest
 113
 114 #endif /* #if CHECKING_P */