Converting Affix Files: Understanding the Affix File Format ------------------------------------------------------------ An affix is either a prefix or a suffix attached to root words to make other words. For example supply -> supplied by dropping the "y" and adding an "ied" (the suffix). Here is an example of how to define one specific suffix borrowed from the en_US.aff file used by the OpenOffice org spellchecker SFX D Y 4 SFX D 0 d e SFX D y ied [^aeiou]y SFX D 0 ed [^ey] SFX D 0 ed [aeiou]y This file is space delimited and case sensitive. So this information can be interpreted as follows: The first line has 4 fields: Field ----- 1 SFX - indicates this is a suffix 2 D - is the name of the character which represents this suffix 3 Y - indicates it can be combined with prefixes (cross product) 4 4 - indicates that sequence of 4 affix entries are needed to properly store the affix information The remaining lines describe the unique information for the 4 affix entries that make up this affix. Each line can be interpreted as follows: (note fields 1 and 2 are used as a check against line 1 info) Field ----- 1 SFX - indicates this is a suffix 2 D - is the name of the character which represents this affix 3 y - the string of chars to strip off before adding affix (a 0 here indicates the NULL string) 4 ied - the string of affix characters to add (a 0 here indicates the NULL string) 5 [^aeiou]y - the conditions which must be met before the affix can be applied Field 5 is interesting. Since this is a suffix, field 5 tells us that there are 2 conditions that must be met. The first condition is that the next to the last character in the word must *NOT* be any of the following "a", "e", "i", "o" or "u". The second condition is that the last character of the word must end in "y". Now for comparison purposes, here is the same information from the Ispell english.aff compression file which was used as the basis for the OOo one. flag *D: E > D # As in create > created [^AEIOU]Y > -Y,IED # As in imply > implied [^EY] > ED # As in cross > crossed [AEIOU]Y > ED # As in convey > conveyed The Ispell information has exactly the same information but in a slightly different (case-insensitive) format: Here are the ways to see the mapping from Ispell .aff format to our OOo format. 1. The ispell english.aff has flag D under the "suffix" section so you know it is a suffix. 2. The D is the character assigned to this suffix 3. * indicates that it can be combined with prefixes 4. Each line following the : describes the affix entries needed to define this suffix - The first field is the conditions that must be met. - The second field is after the > if a "-" occurs is the string to strip off (can be blank). - The third field is the string to add (the affix) In addition all chars in ispell aff files are in UPPERCASE. So the easiest way to create an OOo .aff file is to start with an Ispell .aff file (make sure you get the wordlist author's permission first). Then literally one by one, use a text editor to convert the information for each prefix and suffix into the OOo format (or write a perl script if need be). Note: MySpell does *NOT* support multi-byte characters. It needs both the affix file and the wordlist to use just one 8-bit character set which is then specified in the affix file. If the Ispell affix file and wordlist uses multiple bytes to indicate one character, a script or editor must be used to convert them to the proper single byte character encoding. For example, the Ispell german affix file uses the byte sequence u" to actually indicate the a u-umlaut character. All occurences of these multi-byte characters must be converted to their single byte encoding using the ISO-8859-1 character set in the affix file and the wordlist. FYI, the changes made to the format of the .aff file are necessary to support on-the-fly parsing of both the affix .aff file and the munched wordlists so that all dictionaries are literally stored as ISO text files with associated .aff files and not endian dependent binary hash tables dumped in some compile specific format. The code is then smart enough to build a hashtable on the fly just from the munched wordlist and the .aff file as long as the text files end in either \r\n or simply \n. There are two other things you need to add to the MySpell affix file. The first line specifies the character set used for both the wordlist and the affix file (should be all uppercase). For example: SET ISO8859-1 And the second line specifies the characters to be used in building suggestions for misspelled words. The should be listed in order or character frequency (highest to lowest). A good way to develop this string is to sort a simple character count of the wordlist. For example: TRY esianrtolcdugmphbyfvkw Converting an Ispell "munched" Wordlists ---------------------------------------- To convert an Ispell "munched" wordlist to the format needed by MySpell simply count the number of "root" words in the file and add that count to the first line of the file (this speeds loading the file since two passes are not needed).