[Tik-devel] FAQ: HOW TO USE THE FILTER SYSTEM (for cvs and future releases)

[Alfred E. <alf...@ho...>]

FAQ:   HOW TO USE THE FILTER SYSTEM



1. Q:  When is it appropriate to use toc filters?
   Q:  When is it appropriate to use preproc filters?

   A:  Basically, if you're writing a component with filters, you want to
       directly access the toc functions to avoid calling the 
preproc_register
       function before it's loaded.  If you're writing a package, or just
       adding some of your own filters, you want to use the preproc 
functions.


2. Q:  How do I make my own filters?

   A:  First thing to do is to create a function that contains your filter
       code:

            proc Some_filter {msg args} {
                ....Some code
                return $filtered_msg
            }

       msg          = the incoming text
       args         = additional arguments, like the $id used by some chat
                      filters
       filtered_msg = the text once you're done with it

       Then you need to register it:

            toc_register_filter connName type Some_filter

                  for components or

            preproc::register connName type Some_filter optional_comments

       connName           = $::SCREENNAME or * (usually *)
       type               = type of filter [see #3]
       Some_filter        = your function name
       optional_comments  = variable containing comments for preproc filters


3. Q:  What are the filter types?

   A:  These are available for both the toc and preproc functions

       IM_OUT       --  outgoing IM's
       IM_IN        --  incoming IM's
       CHAT_OUT     --  outgoing CHAT's
       CHAT_IN      --  incoming CHAT's

       These are for available for just preproc

       OUT          --  both outgoing IM's and CHAT's
       IN           --  both incoming IM's and CHAT's


4. Q:  How do I unload filters when my package is unloaded?

   A:  You use:

             toc_unregister_filter connName type func

       for components and

             preproc::unregister connName type func

       for packages and all else.

       connName    = $::SCREENNAME or * (usually *)
       type        = type of filter [see #3]
       func        = name of your filter function




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