1 ------------------------------------------------------------------------------
3 -- GNAT RUNTIME COMPONENTS --
5 -- G N A T . S P E L L I N G _ C H E C K E R --
9 -- Copyright (C) 1998-2003 Ada Core Technologies, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 2, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 59 Temple Place - Suite 330, Boston, --
20 -- MA 02111-1307, USA. --
22 -- As a special exception, if other files instantiate generics from this --
23 -- unit, or you link this unit with other files to produce an executable, --
24 -- this unit does not by itself cause the resulting executable to be --
25 -- covered by the GNU General Public License. This exception does not --
26 -- however invalidate any other reasons why the executable file might be --
27 -- covered by the GNU Public License. --
29 -- GNAT was originally developed by the GNAT team at New York University. --
30 -- Extensive contributions were provided by Ada Core Technologies Inc. --
32 ------------------------------------------------------------------------------
34 package body GNAT.Spelling_Checker is
36 ------------------------
37 -- Is_Bad_Spelling_Of --
38 ------------------------
40 function Is_Bad_Spelling_Of
45 FN : constant Natural := Found'Length;
46 FF : constant Natural := Found'First;
47 FL : constant Natural := Found'Last;
49 EN : constant Natural := Expect'Length;
50 EF : constant Natural := Expect'First;
51 EL : constant Natural := Expect'Last;
54 -- If both strings null, then we consider this a match, but if one
55 -- is null and the other is not, then we definitely do not match
63 -- If first character does not match, then definitely not misspelling
65 elsif Found (FF) /= Expect (EF) then
68 -- Not a bad spelling if both strings are 1-2 characters long
70 elsif FN < 3 and then EN < 3 then
73 -- Lengths match. Execute loop to check for a single error, single
74 -- transposition or exact match (we only fall through this loop if
75 -- one of these three conditions is found).
78 for J in 1 .. FN - 2 loop
79 if Expect (EF + J) /= Found (FF + J) then
81 -- If both mismatched characters are digits, then we do
82 -- not consider it a misspelling (e.g. B345 is not a
83 -- misspelling of B346, it is something quite different)
85 if Expect (EF + J) in '0' .. '9'
86 and then Found (FF + J) in '0' .. '9'
90 elsif Expect (EF + J + 1) = Found (FF + J + 1)
91 and then Expect (EF + J + 2 .. EL) = Found (FF + J + 2 .. FL)
95 elsif Expect (EF + J) = Found (FF + J + 1)
96 and then Expect (EF + J + 1) = Found (FF + J)
97 and then Expect (EF + J + 2 .. EL) = Found (FF + J + 2 .. FL)
107 -- At last character. Test digit case as above, otherwise we
108 -- have a match since at most this last character fails to match.
110 if Expect (EL) in '0' .. '9'
111 and then Found (FL) in '0' .. '9'
112 and then Expect (EL) /= Found (FL)
119 -- Length is 1 too short. Execute loop to check for single deletion
121 elsif FN = EN - 1 then
122 for J in 1 .. FN - 1 loop
123 if Found (FF + J) /= Expect (EF + J) then
124 return Found (FF + J .. FL) = Expect (EF + J + 1 .. EL);
128 -- If we fall through then the last character was missing, which
129 -- we consider to be a match (e.g. found xyz, expected xyza).
133 -- Length is 1 too long. Execute loop to check for single insertion
135 elsif FN = EN + 1 then
136 for J in 1 .. EN - 1 loop
137 if Found (FF + J) /= Expect (EF + J) then
138 return Found (FF + J + 1 .. FL) = Expect (EF + J .. EL);
142 -- If we fall through then the last character was an additional
143 -- character, which is a match (e.g. found xyza, expected xyz).
147 -- Length is completely wrong
153 end Is_Bad_Spelling_Of;
155 end GNAT.Spelling_Checker;