Minor changelog updates

[pidgin-git.git] / doc / TCL-HOWTO.dox

/** @page tcl-howto Tcl Scripting HOWTO

@section Intoduction

NOTA BENE: This documentation is badly out of date for 2.x.

The Gaim Tcl interface provides a Tcl API for many useful gaim
functions.  Like the perl API, the Tcl API does not provide
access to every corner of gaim exposed by the @e C interface.  It does,
however, provide a very powerful interface to many of Gaim's functions
through a simple to learn and extend scripting language.

If you are not familiar with Tcl, you will probably find it somewhat
different from what you are used to.  Despite being somewhat unique
(more akin to shell programming than other traditional scripting
languages such as @e perl or @e python), it is simple to learn for
beginners and experienced programmers alike.  There are numerous books
on the subject; we will not discuss it any further here.

@section start Getting Started

The only requirement placed on a Gaim Tcl script by Gaim is the
existence of a procedure called @c plugin_init.  This procedure has
some limitations placed upon it; it will be parsed and evaluated before
the rest of the Tcl script, so it cannot reference any other variables
or procedures declared in the script.  In practice this is not a
problem, as the only thing this procedure should do is return a simple
list containing five items: the @b name of the script, its @b version
number, a @b summary (just a few words) of its function, a short (longer
than the summary, but no more than a couple of sentences if possible)
@b description, the @b author, and a @b URL to web page.  For example:

@code
proc plugin_init { } {
  return [ list "Example Plugin" \
                "1.0" \
                "Example plugin registration" \
                "Example of how to register a plugin for the Tcl HOWTO" \
                "Ethan Blanton <eblanton@cs.purdue.edu>" \
                "http://pidgin.im/" ]
}
@endcode

The rest of the script will generally be registration to recieve
notification of various Gaim signals (more about this below) and
definitions of procedures to be executed when those signals occur.

@section details Interpreter Details

Gaim initializes and drives the Tcl event loop (similar to Tk),
meaning that commands like @c fileevent and @c after are available and
do not require @c vwait etc.  The @c vwait actually seems to be somewhat
broken due to a bug somewhere in the Tcl/Glib event loop glue, and it
should not be used for now.

The gaim-specific functions are provided in a statically-linked
package called @c gaim; this means that if you spawn a child
interpreter and wish to use the gaim-specific functions, you will need
to execute <tt>load {} gaim</tt> in that interpreter.

@section internals Gaim Internal Procedures and Variables

All of the information provided for your use by Gaim will be in the @c
::gaim namespace.  This means that in order to access it you will either
have to import the gaim namespace (e.g. via the command <tt>namespace
import gaim::*</tt>) or reference it explicitly.  The following
descriptions will reference it explicitly for clarity.

@li Variables

@code
gaim::version
@endcode

  This contains the version of the gaim process which loaded the
  script.

@li Commands

@code
gaim::account alias account
gaim::account connect account
gaim::account connection account
gaim::account disconnect account
gaim::account find username protocol
gaim::account handle
gaim::account isconnected account
gaim::account list ?option?
gaim::account protocol account
gaim::account username account
@endcode

  The @c gaim::account command consists of a set of subcommands
  pertaining to gaim accounts.

  @c alias returns the alias for the account @c account.  If there is no
  alias for the given account, it returns the empty string.

  The subcommand @c connect connects the named account if it is not
  connected, and does nothing if it is.  In either case, it returns
  the @c gc for the account.

  @c connection returns the @c gc of the given account if it is connected,
  or 0 if it is not.  This @c gc is the gc used by gaim::connection and
  other functions.

  @c disconnect disconnects the given @c account if it is connected, or
  does nothing if it is.

  @c find finds an account by its @c username and @c protocol (as returned by
  <tt>gaim::account username</tt> and <tt>gaim::account protocol</tt>) and 
  returns the account if found, or 0 otherwise.

  @c handle returns the instance handle required to connect to account
  signals.  (See <tt>gaim::signal connect</tt>).

  The @c isconnected query returns true if the given account is
  connected and false otherwise.

  The @c list subcommand returns a list of all of the accounts known to
  Gaim.  The elements of this lists are accounts appropriate for the
  @c account argument of the other subcommands.  The @c -all option
  (default) returns all accounts, while the @c -online option returns
  only those accounts which are online.

  The @c protocol subcommand returns the protocol ID (e.g. "prpl-msn")
  for the given account.

  The @c username subcommand returns the username for the account
  @c account.

@code
gaim::buddy alias buddy
gaim::buddy handle
gaim::buddy info ( buddy | account username )
gaim::buddy list
@endcode

  @c gaim::buddy is a set of commands for retrieving information about
  buddies and manipulating the buddy list.  For the purposes of Tcl,
  a "buddy" is currently a list of several elements, the first of
  which being the type.  The currently recognized types are "group",
  "buddy", and "chat".  A group node looks like:
@code
        { group name { buddies } }
@endcode
  A buddy node is:
@code
        { buddy name account }
@endcode
  And a chat node is:
@code
        { chat alias account }
@endcode

  The @c alias subcommand returns the alias for the given buddy if it
  exists, or the empty string if it does not.

  @c handle returns the blist handle for the purposes of connecting
  signals to buddy list events.  (See <tt>gaim::signal connect</tt>).

  @c info causes gaim to display the info dialog for the given buddy.
  Since it is possible to request user info for a buddy not in your
  buddy list, you may also specify a buddy by his or her username and
  the account through which you wish to retrieve info.

  @c list returns a list of @c group structures, filled out with buddies
  and chats as described above.

@code
gaim::connection account gc
gaim::connection displayname gc
gaim::connection handle
gaim::connection list
@endcode

  @c gaim::connection is a collection of subcommands pertaining to
  account connections.

  @c account returns the Gaim account associated with @c gc.  This
  account is the same account used by @c gaim::account and other
  commands.

  @c displayname returns the display name (duh) of @c gc as reported by
  <tt>gaim_connection_get_display_name(gc)</tt>.

  @c handle returns the gaim connections instance handle.  (See
  <tt>gaim::signal connect</tt>).

  @c list returns a list of all known connections.  The elements of
  this list are appropriate as @c gc arguments to the other
  @c gaim::connection subcommands or other commands requiring a gc.

@code
gaim::conv_send account who text
@endcode

  @c gaim::conv is simply a convenience wrapper for @c gaim::send_im and
  <tt>gaim::conversation write</tt>.  It sends the IM, determines the from
  and to arguments for <tt>gaim::conversation write</tt>, and prints the text
  sent to the conversation as one would expect.  For the curious, you
  may view the source for it by typing <tt>info body gaim::conv_send</tt> at
  a Gaim Commander prompt.

  Note that an error in either @c gaim::send_im or <tt>gaim::conversation
  write</tt> will not be caught by this procedure, and will be propagated
  to the caller.

@code
gaim::conversation find ?-account account? name
gaim::conversation handle
gaim::conversation list
gaim::conversation new ?-chat? ?-im? account name
gaim::conversation write conversation style from to text
@endcode

  @c gaim::conversation provides an API for dealing with conversations.
  Given that Gaim is an instant messenger program, you'll probably
  spend a lot of time here.

  The command @c find attempts to find an existing conversation with
  username @c name.  If the @c -account option is given, it refines its
  search to include only conversations on that account.

  @c handle returns the conversations instance handle for the purposes
  of signal connection.  (See <tt>gaim::signal connect</tt>).

  @c list returns a list of all currently open conversations.

  The @c new subcommand can be used to create a new conversation with
  a specified user on a specified account if one does not exist, or
  retrieve the existing conversation if it does.  The @c -chat and
  @c -im options specify whether the created conversation should be a
  chat or a standard IM, respectively.

  @c write is used to write to the specified conversation.  The @c style
  argument specifies how the text should be printed -- as text coming
  from the gaim user (style @c send), being sent to the gaim user
  (style @c recv), or as a system message (such as "so-and-so has
  signed off", style @c system).  From is the name to whom the text
  should be attributed -- you probably want to check for aliases here,
  lest you confuse the user.  @c text is the text to print.

@code
gaim::core handle
gaim::core quit
@endcode

  This command exposes functionality provided by the gaim core API.

  <tt>gaim::core handle</tt> returns a handle to the gaim core for signal
  connection.  (See <tt>gaim::signal connect</tt>).

  @c quit exits gaim cleanly, and should be used in preference to the
  tcl @c exit command.  (Note that @c exit has not been removed,
  however.)

@code
gaim::debug level category message
@endcode

  Equivalent to the C gaim_debug function, this command outputs
  debugging information to the gaim debug window (or stdout if gaim is
  invoked with -d|--debug).  The valid levels are, in increasing level
  of severity, @c -misc, @c -info, @c -warning, and, or @c -error.  @c
  category is a short (a few characters ... for instance, "tcl" or "tcl
  plugin") "topic" type name for this message, and @c message is the text
  of the message. In the style of Tcl @e puts (and differing from
  @e gaim_debug), no trailing \\n is required.  (However, embedded newlines
  may be generated with \\n).

@code
gaim::notify ?type? title primary secondary
@endcode

  Also a direct equivalent to a C function, gaim_notify, this command
  causes gaim to present the provided notification information to the
  user via some appropriate UI method.  The @c type argument, if
  present, must be one of @c -error, @c -warning, or @c -info. The following
  three arguments' absolute meanings may vary with the Gaim UI being
  used (presently only a Gtk2 UI is available), but @c title should
  generally be the title of the window, and @c primary and @c secondary
  text within that window; in the Gtk2 UI, @c primary is slightly
  larger than @c secondary and displayed in a @b boldface font.

@code
gaim::send_im gc who text
@endcode

  This sends an IM in the fashion of serv_send_im.  @c gc is the GC of
  the connection on which you wish to send (as returned by most event
  handlers), @c who is the nick of the buddy to which you wish to send,
  and @c text is the text of the message.

@code
gaim::signal connect instance signal args proc
gaim::signal disconnect instance signal
@endcode

  @c gaim::signal is a set of subcommands for dealing with gaim signals
  (known as "events" prior to gaim 0.68).

  The @c connect subcommand registers the procedure @c proc as a handler
  for the signal @c signal on the instance @c instance.  @c instance
  should be an instance handle as returned by one of the @c handle
  commands from the various parts of gaim. @c args and @ proc are as in
  the Tcl @e proc command; note that the number of arguments in @c args
  must match the number of arguments emitted by the signal exactly,
  although you need not use them all.  The procedure @c proc may be
  either a simple command or a procedure in curly brackets.  Note that
  only one procedure may be associated with each signal; an attempt to
  connect a second procedure to the same signal will remove the
  existing binding and replace it with the new procedure.
  <tt>gaim::signal connect</tt> returns 0 on success and 1 on failure.

  @c disconnect removes any existing signal handler for the named
  signal and instance.

@code
gaim::unload
@endcode

  This unloads the current plugin.  Note that preferences will not be
  updated (yet).

@section Signals

Check the signals documentation for the meaning of these signals; this is
intended to be a list only of their arguments.  Signal callbacks will
be made in their own namespace, and arguments to those signal
callbacks will live in the namespace @c event underneath that
namespace.  To briefly illustrate, the signal @c receiving-im-msg is
provided with three arguments; the account on which the IM was
received, the screen name of the user sending the IM, and the text of
the IM.  These arguments live in the variables @c event::account,
@c event::sender, and @c event::buffer, respectively.  Therefore a callback
which notifies the user of an incoming IM containing the word 'shizzle'
might look like this:

@code
gaim::signal connect [gaim::conversation handle] receiving-im-msg {
        if {[ string match "*shizzle*" $event::buffer ]} {
                gaim::notify -info "tcl plugin" "Fo' shizzle" \
                        "$event::sender is down with the shizzle"
        }
}
@endcode

Note that for some signals (notably @c receiving-im-msg, @c sending-im-msg,
and their chat counterparts), changes to the event arguments will
change the message itself from Gaim's vantage.  For those signals
whose return value is meaningful, returning a value from the Tcl event
will return that value as it would in C.

*/

// vim: syntax=c tw=72 et