1 ------------------------------------------------------------------------------
3 -- GNAT RUN-TIME COMPONENTS --
5 -- G N A T . S P E L L I N G _ C H E C K E R --
9 -- Copyright (C) 1998-2006, AdaCore --
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, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, 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
42 Expect : String) return Boolean
44 FN : constant Natural := Found'Length;
45 FF : constant Natural := Found'First;
46 FL : constant Natural := Found'Last;
48 EN : constant Natural := Expect'Length;
49 EF : constant Natural := Expect'First;
50 EL : constant Natural := Expect'Last;
53 -- If both strings null, then we consider this a match, but if one
54 -- is null and the other is not, then we definitely do not match
62 -- If first character does not match, then we consider that this is
63 -- definitely not a misspelling. An exception is when we expect a
64 -- letter O and found a zero.
66 elsif Found (FF) /= Expect (EF)
67 and then (Found (FF) /= '0'
68 or else (Expect (EF) /= 'o' and then Expect (EF) /= 'O'))
72 -- Not a bad spelling if both strings are 1-2 characters long
74 elsif FN < 3 and then EN < 3 then
77 -- Lengths match. Execute loop to check for a single error, single
78 -- transposition or exact match (we only fall through this loop if
79 -- one of these three conditions is found).
82 for J in 1 .. FN - 2 loop
83 if Expect (EF + J) /= Found (FF + J) then
85 -- If both mismatched characters are digits, then we do
86 -- not consider it a misspelling (e.g. B345 is not a
87 -- misspelling of B346, it is something quite different)
89 if Expect (EF + J) in '0' .. '9'
90 and then Found (FF + J) in '0' .. '9'
94 elsif Expect (EF + J + 1) = Found (FF + J + 1)
95 and then Expect (EF + J + 2 .. EL) = Found (FF + J + 2 .. FL)
99 elsif Expect (EF + J) = Found (FF + J + 1)
100 and then Expect (EF + J + 1) = Found (FF + J)
101 and then Expect (EF + J + 2 .. EL) = Found (FF + J + 2 .. FL)
111 -- At last character. Test digit case as above, otherwise we
112 -- have a match since at most this last character fails to match.
114 if Expect (EL) in '0' .. '9'
115 and then Found (FL) in '0' .. '9'
116 and then Expect (EL) /= Found (FL)
123 -- Length is 1 too short. Execute loop to check for single deletion
125 elsif FN = EN - 1 then
126 for J in 1 .. FN - 1 loop
127 if Found (FF + J) /= Expect (EF + J) then
128 return Found (FF + J .. FL) = Expect (EF + J + 1 .. EL);
132 -- If we fall through then the last character was missing, which
133 -- we consider to be a match (e.g. found xyz, expected xyza).
137 -- Length is 1 too long. Execute loop to check for single insertion
139 elsif FN = EN + 1 then
140 for J in 1 .. EN - 1 loop
141 if Found (FF + J) /= Expect (EF + J) then
142 return Found (FF + J + 1 .. FL) = Expect (EF + J .. EL);
146 -- If we fall through then the last character was an additional
147 -- character, which is a match (e.g. found xyza, expected xyz).
151 -- Length is completely wrong
156 end Is_Bad_Spelling_Of;
158 end GNAT.Spelling_Checker;