The character variant generation feature allows FTR to treat typographical variants of the same word as equivalent for search purposes. This ensures that potential mismatches due to subtleties in language or other external restrictions are avoided. For example, FTR can be instructed to include the German word, Frühling as an equivalent form of the word Fruehling in a query.
Character variant generation is controlled by the set of rules contained in a character variant rules file. The rules can contain instructions for removing or inserting accents, and instructions for modifying the suffix of a query term. SearchServer supports English, French, German, and other European language character variants.
There are three character variant rules files supplied with FTR. The FULTEXT.FTL character variant rules file appends the suffixes s and 's to each word. The GERMAN.FTL character variant rules file supports the typographic equivalents used for ä, ö, ü, and ß.
The FRENCH.FTL character variant rules file equates accented characters with a non-accented counterpart. For example, the character e is replaced by the three accented forms é, ê, and è.
You can modify one of these three sample character variant rules files or you can create a new character variant rules file using a text editor. You can compile the rules with a thesaurus source file into a thesaurus object file using the fthmake utility program. For more information on compiling a thesaurus, see Compiling a Thesaurus File.