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Notes-on-Various-Options.html#Notes-on-Various-OptionsNotes on Various Options 4.4.1 Notes on Various Filters and Filter Modes
Aspell now has filter support.  You can either select from individual
filters or choose a filter mode.  To select a filter mode use the
mode option.  You may choose from `none', `url',
`
email', `sgml', `ccpp', `tex' and any other
available on your system.  The default mode is `
url'.  Individual
filters can be added with the option 
add-filter and removed
with the 
rem-filter option.  The currently available filters
are `
url', `email', `sgml' and `tex', `latex'
(alias for `
tex'), `nroff', `context', as well as a
bunch of filters which translate the text from one format to another.
   
To check which filters are available use aspell dump filters. 
To check which filter modes are available use 
aspell dump
modes
.  The aspell help command will also list all available
filter and filter modes.
4.4.1.1 None Filter Mode
The none mode is exactly what it says.  It turns off all filters.
4.4.1.2 URL Filter
The url filter/mode skips over URLs, 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.
4.4.1.3 Email Filter
The email filter mode skips over quoted text.  It currently
does not support skipping over headers however a future version
should.  In the meantime I suggest you use Aspell with Newsbody which
can be found at 
http://home.worldonline.dk/~byrial/newsbody/http://home.worldonline.dk/~byrial/newsbody/ . 
The option 
email-skip controls the number of characters that
can appear before the email quote character, the default is 10.  The
option 
add|rem-email-quote controls the characters that are
considered quote characters, the defaults are `
>' and `|'.
4.4.1.4 SGML Filter
The SGML filter allows you to spell check SGML, HTML, XHTML, and XML
files. In most cases everything within a tag `
<tag attrib=value
attrib2="a whole sentence">
' will be skipped by the spell checker. The
SGML/HTML/XML that Aspell supports is a slight superset of most DTDs
(Document Type Definitions) and can spell check the often non-conforming
HTML found on the web.
   
Two configuration options, sgml-skip and sgml-check,
allow you to control what is spell checked. The tag and attribute names
specified are case insensitive.
     
sgml-skipThis is a list of tags whose contents will also be skipped by the spell
checker.  For example, if you wish to leave a misspelling in a document
and not have them flagged as misspellings, you could surround them with
a <nospellcheck> tag:
     
            <TD><FONT size=2><NOSPELLCHECK>leviosa</NOSPELLCHECK>
            is what Mr. Potter said</FONT></TD>
     
     
And put that word in the skip config directive:
     
          add-sgml-skip nospellcheck
     
     
sgml-checkThis is a list of attributes whose values you do want spell checked. By
default, 'alt' (<img> alternate text) is a member of the check list
since it is text that is seen by a web page viewer. You may also want
'value' to be on the check list since that is the text put on buttons:
     
          add-sgml-check value
     
     
In this case `<input type=button value="Donr">' will be flagged as a
misspelling. 
   
This filter will also translate SGML characters of the form
`
&#num;'.  Other SGML characters such as `&amp;' will simply
be skipped over so that the word `
amp', for example, will not be
spell checked.  Eventually full support for properly translating SGML
characters will be added.
4.4.1.5 HTML Filter
The html filter is like the SGML Filter Mode but specialized for
HTML.  By default, 'script' and 'style' are members of the skip list in
HTML mode.
4.4.1.6 TeX/LaTeX Filter
The tex (all lowercase) filter mode skips over TeX
commands and parameters and/or options to certain commands.  It also
skips over TeX comments by default.  The option
[dont-]tex-check-comments controls whether or not Aspell will
skip over TeX comments.  The option 
add|rem-tex-commandcontrols which TeX commands should have certain parameters and/or
options also skipped over.  Commands that are not specified will have
all their parameters and/or options checked.  The format for each item
is
     <command> <a list of p,P,o and Os>
   
The first item is simply the command name.  The second item controls
which parameters to skip over.  A 'p' skips over a parameter while a
'P' doesn't.  Similar an 'o' will skip over an optional parameter
while a 'O' doesn'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.
   
The TeX filter mode is also available via latex alias name.
4.4.1.7 Texinfo Filter
The texinfo filter allows you to spell check Texinfo files. 
It will skip over any Texinfo commands and their parameters when
appropriate.  It will also skip over some Texinfo environments such as
example.  The list option texinfo-ignorecontrols which commands to ignore the parameters of and the list option
texinfo-ignore-env controls which Texinfo
environments to ignore.
   
The Texinfo filter has special code to deal with the @tableand related commands.  It will apply the formatting command to each of
the 
@item or @itemx commands just like Texinfo
will.  This means that if the formatting command is 
@codeand and the 
@code command is a member of the
texinfo-ignore option than the Texinfo filter will ignore the
parameter of the 
@item command as if the parameter was also
the parameter of the 
@code command.
   
The Texinfo filter will also skip over the `\input texinfo' line.
4.4.1.8 Nroff Filter
The nroff filter mode allows you to check the spelling of
Nroff documents. The mode is enabled by giving
--add-filter=nroff or -n command line option to
aspell. It is also automatically enabled if the first three
characters of the file being checked are 
.\" (a nroff comment
marker) or the file name ends in a one of the following suffixes:
     
single decimal digit from `0' to `9'
letter `n'
`tmac'
This filter mode skips following nroff language
elements:
     
Comments
Requests
Names of nroff registers (both traditional two-letter
names and GNU nroff long names)
Arguments to the following requests: ds, de, nr,
do, so. 
Arguments to font switch (\f) and size switch (\s)
escapes
Arguments to extended charset escape in both traditional
(
\() and extended (\[comp1 comp2 ...]) form. 
4.4.1.9 Context Filter
The context filter allows Aspell to distinguish between visible
and invisible contexts.  The visible ones will be spell checked and
the invisible ones will be ignored.  The contexts are distinguished by
the fact that the visible/invisible ones are delimited by specific and
unique delimiter characters or character sequences.  Whether the
delimited contexts should be visible or invisible only stated by the
value of the 
[dont-]context-visible-first option and not by
the delimiters.
   
The context delimiters are specified as pairs of delimiters via the
add|rem-context-delimiters option.  The delimiters enclosing
a specific context are specified as a space separated pair.  If more
than one delimiter pair is specified by one call of
add|rem-context-delimiters they have to be combined to a
comma separated list.  To indicate that a context is always closed by
end of line use 
\0 sequence as closing delimiter.
4.4.1.10 Ccpp Filter Mode
The ccpp filter mode will limit spell checking to C/C++ comments
and string literals. Any code in between will be left alone.
   
