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5. Customizing Aspell next up previous contents
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5. Customizing Aspell

The behavior of Aspell can be changed by any number of options which can be specified at either the command line, the environmental variable ASPELL_CONF, a personal configuration file, or a global configuration file. Options specified on the command line override options specified by the environmental variable. Options specified by the environmental variable override options specified by either of the configurations files. Finally options specified by the personal configuration file override options specified in the global configuration file. Options specified in the environmental variable ASPELL_CONF, a personal configuration file, or a global configuration file will take effect no matter how Aspell is used which includes being used by other applications.

Aspell has three basic type of options: boolean, value, and list. Boolean options are either enabled or disabled, value options take a specific value, and list options can either have entries added or removed from the list.

5.1 Specifying Options

5.1.1 At the Command Line

All options specified at the command line have the following basic format:

where the '=' can be replaced by whitespace.

However some options also have single letter abbreviations of the form:

-«letter»[«optional whitespace»«value»] Boolean

To enable a boolean option simply special the option with out any corresponding value. For example to ignore accents when checking words use ``--ignore-accents''. To disable a boolean option prefix the option name with a ``dont-''. For example to not ignore accents when checking words use ``--dont-ignore-accents''.

If a boolean option has a single letter abbreviation simply give the letter corresponding to either enabling or disabling the option with out any corresponding value. For example to consider run-together words legal use ``-C'' or to consider them illegal use ``-B'' Value

To specify a value option simply specify the option with its corresponding value. For example to set the filter mode to Tex use ``--mode=tex''.

If a value option has a single letter shortcut simply specify the single letter short cut with its corresponding value. For example to use a large american dictionary use ``-d american-lrg''. List

To add a value to the list prefix the option name with a ``add-'' and then specify the value to add. For example to add the URL filter use ``--add-filter url''. To remove a value from a list option prefix the option name with a ``rem-'' and then specify the value to remove. For example to remove the URL filter use ``--rem-filter url''. To remove all items from a list prefix the option name with a ``rem-all'' without specify any value. For example to remove all filters use ``--rem-all-filter''.

5.1.2 Via a Configuration File

Aspell can also accept options via a personal or global configuration file. The exact files to used are specified by the options per-conf and conf respectfully but the personal configuration file is normally ``.aspell.conf'' located in the HOME directory and the global one is normally ``aspell.conf'' which is located in the etc directory which is normally ``/usr/etc'' or ``/usr/local/etc''. To find out the particular values for your particular system use ``aspell dump config''.

Each line of the configuration file has the format:

«option» [«value»]
There may any number of spaces between the option and the value however it can only be spaces, ie there is no '=' between the option name and the value.

Comments may also be included by preceding them with a '#' as anything from a ``#'' to a newline is ignored. Blank lines are also allowed.

Values set in the personal configuration file override those in the global file. Options specified at either the command line or via an environmental variable override those specified by either configuration file. Boolean

To specify a boolean option simply include the option followed by a ``true'' to enable it or a ``false'' to disable it. For example to allow run-together words use ``run-together true''. Value

To specify a value option simply include the option followed by the corresponding option. For example to set the default language to german use ``lang german''. List

To add a value to the list prefix the option name with a ``add-'' and then specify the value to add. For example to add the URL filter use ``add-filter url''. To remove a value from a list option prefix the option name with a ``rem-'' and then specify the value to remove. For example to remove the URL filter use ``rem-filter url''. To remove all items from a list prefix the option name with a ``rem-all'' without specify any value. For example to remove all filters use ``rem-all-filter''.

5.1.3 Via an Environmental Variable

The environmental variable ASPELL_CONF may also be used and it overrides any options set in the configuration file. The format of the string is exactly the same as the configuration file except that semicolons ( ; ) are used instead of newlines.

5.2 The Options

The following is a list of available options broken down by category. Each entry has the following format:

«option»[,«single letter abbreviations»]
(«type») «description»

Where single letter options are specified as they would appear at the command line, ie with the preceding dash. Boolean single letter options are specified in the following format:

-«abbreviation to enable»|-«abbreviation to disable»
«Option» is one of the following: boolean, string, file, dir, integer, or list. String, file, dir, and integer types are all value options which can only take a specific type of value.

5.2.1 Basic Options

(file) main configuration file
(dir) location of main configuration file
(dir) location of language data files
(dir) alternative location of language data files. This directory is searched before data-dir. It defaults to the same directory the actual main word list is in (which is not necessarily dict-dir).
(list) add or removes a filter
(dir) location for personal files
(integer) ignore words <= n chars
(boolean) ignore case when checking words
(boolean)ignore accents when checking words
(boolean) ignore commands to store replacement pairs
(boolean) save the replacement word list on save all
(string) default language to use when creating a dictionary or all else fails
(string) language code to use when selecting a dictionary, it follows the same format of the LANG environmental variable on most systems. In fact it defaults to the value of the LANG environmental variable if it is set.
(string) sets the filter mode. Mode is one if none, url, email, sgml, or tex. (The short cut options '-e' may be used for email, '-H' for Html/Sgml, or '-t' for Tex)
(file) personal configuration file
(file) personal word list file name
(dir) prefix directory
(boolean) set the prefix based on executable location (only works on Win32 and when compiled with --enable-win32-relocatable)
(file) replacements list file name
(file) the base name of the keyboard definition file to use (see section 5.4.4)
(mode) suggestion mode = ultra | fast | normal | bad-spellers (see section 5.4.5)

5.2.2 Dictionary Options

The following options may be used to control which dictionaries to use and how they behave (see section 5.4.1 for more information):

(string) base name of the main dictionary to use. The default Aspell installation provided the following dictionaries: american, british, and canadian.
(dir) location of the main word list
(list) extra dictionaries to use
(boolean) strip accents from all words in the dictionary

5.2.3 Run-together Word Options

These may be used to control the behavior of run-together words (see section 7.4 for more information):

(boolean) consider run-together words legal
(integer) maximum numbers that can be strung together
(integer) minimal length of interior words

5.2.4 Filter Options

These options modify the behavior of the various filters (see section 5.4.2 for more information):

(list) email quote characters
(integer) num chars that can appear before the quote char
(list) sgml tags to always check.
(list) sgml file extensions.
(list) TEX commands
(boolean) check TEX comments

5.2.5 Aspell Utility Options

These options are may only be specified at the command line as there are aspell utility specific:

(boolean) create a backup file by appending ``.bak'' to the file name. (Only applies when the command is check)
(boolean) time load time and suggest time in pipe mode.
(boolean) reverse the order of the suggestions list.

5.3 Dumping Configuration Values

To find out the current value of all the options use the command ``aspell dump config''. This will dump the current configuration to standard output. The format of the contents dumped is such that it can be used as either the global or personal configuration file.

5.4 Notes on various Options

5.4.1 Pertaining to which word lists to use How Aspell Selects an Appropriate Dictionary

Aspell will go through the following steps to find an appropriate dictionary:

  1. If the master options is set in any fashion (via the command line, the ASPELL_CONF environmental variable, or a configuration file) look for a dictionary of that name. If one could not be found complain.
  2. If the language-tag (not lang) option or LANG environmental variable is set and master option is not then use it (giving preference to language-tag over LANG) to search for an appropriate dictionary. Aspell will use the same strategy that Pspell does, which is based on the installed .pwli files, to find an appropriate word list. For more information of how this is done see the Pspell manual.
  3. If 2 fails than look for a dictionary of the same name of current setting of the lang options. This will currently work even if the language name is invalid, but this fact should not be relied upon as it is an implementation detail.
  4. Finally, if all else fails, complain. About Multi Dictionaries

As with precious versions of aspell you can specify the main dictionary to use via the -d or --master option. However as of Aspell .32 you can now also:

  1. Specify more than word list to use with the extra-dicts option.
  2. Optionally have all accents striped form the word lists using strip-accents option. This is not the same thing as the ignore-accents option. As enabling the ignore-accents would accept both cafe and café (notice the accent on the e), but only enabling strip-accents would only accent cafe, even if café is in the original dictionary. Specify strip-accents is just like using a word list with out the accents.
  3. Specify special ``multi'' dictionaries.
A ``multi'' dictionary is a special file which basically a list of dictionary files to use. A multi dictionary must end is .multi and has roughly the same format of a configuration file where the two valid keys are add and strip-accents. The add key is used for adding individual word lists, or other ``multi'' files. The strip-accents key is used to control if accents are striped from the dictionaries. Unlike the global strip-accent option this option only effects word lists that came after the option. For example:

strip-accents yes
add english
strip-accents no
add must-accent
will strip accents from the english word list but not the must-accent word list. If the global strip-accents option is specified the local strip-accents options are ignored. Provided Word Lists

Aspell now provides multi dictionaries for three variates of english: american-med, british-med, and canadian-med. The word lists themselves all contain accented words however the strip-accents option is enabled by default for all the individual word lists. If you wish to use the accented words you can set the global strip-accents option to false or create a new multi word list.

Great care has been taken so that that only one spelling for any particular word is included in the main list. When two variants were considered equal I randomly picked one for inclusion in the main word list. Unfortunately this means that my choice in how to spell a word may not match your choice. If this is the case you can try to include one of the special variant dictionaries with the add-extra-dict option. You can chose from english-variant-0, english-variant-1, and english-variant-2. Each of these word lists included all the others from the previous variant level, thus there is no need to include more than one. English-variant-0 includes most variants which are considered almost equal, english-variant-1 include variants which are also generally considered acceptable, and english-variant-2 contains variants which are seldom used. These special variant dictionaries are an experimental feature so please let me know if you take advantage of them. If no one seams to be using them I may no longer provide them in a future release of Aspell.

Many other dictionary sizes and varieties can be created. See the scowl/ directory in the source distribution for information on the different varieties you can create and section 4 for how to create an individual dictionary.

5.4.2 Notes on Various Filters and Filter Modes

Aspell now has rudimentary filter support. You can either select from individual filters or chose a filter mode. To select a filter mode use the mode option. You may chose from none, url, email, sgml, and tex. The default mode is url. Individual filters can be added with the option add-filter and remove with the rem-filter option. The currently available filters are url, email, sgml, tex as well as a bunch of filters which translate the text from one format to another. None Mode

This mode is exactly what it says. It turns off all filters. Url Filter/Mode

The url filter/mode skips over URL's, host names, and email addresses. Because this filter is almost always useful and rarely does any harm it is enabled in all modes except none. To turn it off either select the none mode or use rem-filter option after the desired mode is selected. Email Filter/Mode

The email filter/mode skips over quoted text. It currently does not support skipping over headers however a future version should. In the mean time I suggest you use Aspell with Newsbody which can be found at http://home.worldonline.dk/~byrial/newsbody/. The option email-skip controls the number of characters that can appear before the email quote char, the default is 10. The option add|rem-email-quote controls the characters that are considered quote characters, the default is ``>' and '|'. SGML Filter/Mode

The sgml filter/mode will skip over sgml commands. It currently does not handle nested < > unless they are in quotes. It also does it handle the null end tag (net) minimization feature of sgml such as

The option add|rem-sgml-check controls which sgml tags should always be checked. The default is ``alt''.

The option add|rem-sgml-extension controls which file extensions are recognized as sgml/html files. The default is html, htm, php, and sgml. The extension are not case sensitive so extensions like .HTM will also be recognized.

The sgml mode also enables a filter which will recognize sgml charter commands such as &amp; and convert it into the proper iso8859-1 character. Currently only the iso8859-1 character set is used however in future versions it will convert it to the encoding that is specified in the language date file. You can specifically turn on this filter by enable the SGML&«charset»/«charset» filter. TEX Filter/Mode

The tex (all lowercase) filter/mode skips over TEX commands and parameters and/or options to certain command. It also skips over TEX comments by default. The option [dont-]tex-check-comments controls whether or not aspel will skip over TEX comments. The option add|rem-tex-command controls which TEX commands should have certain parameters and/or options also skipped over. Commands that are not specified will have all there parameters and/or options checked. The format for each item is

«command»  «a list of p,P,o and Os»
The first item is simple the command name. The second item controls which parameters to skip over. A 'p' skips over a parameter while a 'P' won't. Similar an 'o' will skip over an optional parameter while a 'O' won't. The first letter on the list will apply to the first parameter, the second letter will apply to the second parameter etc. If there are more parameters than letters Aspell will simply check them as normal. For example the option

add-tex-command rule pp
will skip over the first two parameters of the ``rule'' command while the option

add-tex-command foo Pop
will check the first parameter of the ``foo'' command, skip over the next optional parameter, if it is present, and will skip over the second parameter -- even if the optional parameter is not present -- and will check any additional parameters.

A'*' at the end of the command is simply ignored. For example the option

enlargethispage p
will ignore the first parameter in both enlargethispage and enlargethispage*.

To remove a command simple use the rem-tex-command option. For example

rem-tex-command foo
will remove the command foo, if present, from the list of TEX commands.

5.4.3 Notes on the Prefix Option

The prefix option is there to allow Aspell to easily be relocated. Changing prefix will change all directory names relative to the new prefix that are not explicitly set. For example if prefix was ``/usr/local/aspell'' and dict-dir has a default value of ``/usr/local/aspell/dict'' than changing prefix to ``/opt/aspell'' will also change the default value of dict-dir to ``/opt/aspell/dict''. Note that modifying prefix will only effect the default compiled in values of directories. If a directory option is explicitly given a value than changing the value of prefix has no effect on that directory option.

5.4.4 Notes on Typo-Analysis and the Keyboard Definition File

Aspell .33 and better will, in general, give a higher priority to certain misspelling which are likely to be due to typos such as ``teh'' instead of ``the'' or ``hapoy'' instead of ``happy''. However in order to do this well Aspell needs to know the layout of the keyboard. The keyboard definition file simply identifies keys that are right next to each other. The file has an extension of .kbd and each line consists of two letters corresponding to two keys that are right next to each other. For example the line ``as'' will indicate that 'a' and 's' are right next to each other. If ``as'' is listed as a entry it is not necessary to list ``sa'' as an entry as that will be done automatically. Also by ``right next to each other'' I mean to keys that are close enough together that it is easy to type one instead of the other. On most keyboards this means keys that are to the left or to the right of each other and not keys that are below or above it.

The default for this option is normally ``standard''. However the default can be changed via the language data file. The normal default, ``standard'', should work well for most QWERTY like keyboard layouts. It may need minor adjusting for foreign keyboards and will need to be completely rewritten for a Dvorak layout. When creating a keyboard definition file for a foreign language please keep in mind that Aspell completely ignores accents when scoring words so that the key 'o' and 'ö' will appear to be the same key to aspell even if they are in fact separate keys on your keyboard.

5.4.5 Notes on the Different Suggestion Modes

In order to understand what these suggestion modes do, a basic understanding of how aspell works is required. See section 8 for that. The suggestion modes are as follows.

This method will use the fastest method available to come up with decent suggestions. This currently means that it will look for soundslikes within one edit distance apart without doing any typo analysis. It is slower than Ispell by a factor of 1.5 to 2 when a single word list is used. It speed is only minor affected by the size of the word list, if at all, but it is strongly effected by the number of word lists use. In this mode Aspell gets about 87% of the words from my small test kernel of misspelled words. (Go to http://aspell.sourceforge.net/testfor more info on the test kernel as well as comparisons of this version of Aspell with previous versions and other spell checkers.)
This method is like ultra except that it also performs typo analysis unless it is turned off by setting the keyboard to none. The typo analysis brings words which are likely to be due to typos to the beginning of the list but slows things down by a factor of about two. This mode should get around the same number of words that the ultra method does.
This method looks for soundslikes within two edit distance apart and perform typo-analysis unless it is turned off. Is is around 10 times slower than fast mode with the english word list but returns better suggestions. Its speed is directly proportional to the size of the word list. This mode gets 93% of the words.
This method also looks for soundslikes within two edit distances apart but is more tailored for the bad speller where as fast or normal are more tailed to strike a good balance between typos and true misspellings. This mode never performs typo-analysis and returns a huge number of words for the really bad spellers who can't seam to get the spelling anything close to what it should be. If the misspelled word looks anything like the correct spelling it is bound to be found somewhere on the list of 100 or more suggestions. This mode gets 98% of the words.

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Next: 6. Writing programs to Up: Aspell .33.7.1 alpha A Previous: 4. Managing Word Lists   Contents
Kevin Atkinson 2001-08-19