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/** @page tcl-howto Tcl Scripting HOWTO

@section Intoduction

NOTA BENE: This documentation is badly out of date for 2.x.

The libpurple Tcl interface provides a Tcl API for many useful libpurple

functions. Like the perl API, the Tcl API does not provide access to

every corner of libpurple exposed by the @e C interface. It does,

however, provide a very powerful interface to many of libpurple'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 purple Tcl script by libpurple 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 purple (or Pidgin, or finch, or ...) signals

(more about this below) and definitions of procedures to be executed

when those signals occur.

@section details Interpreter Details

libpurple 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 purple-specific functions are provided in a statically-linked

package called @c purple; this means that if you spawn a child

interpreter and wish to use the purple-specific functions, you will need

to execute <tt>load {} purple</tt> in that interpreter.

@section internals purple Internal Procedures and Variables

All of the information provided for your use by purple will be in the @c

::purple namespace. This means that in order to access it you will either

have to import the purple namespace (e.g. via the command <tt>namespace

import purple::*</tt>) or reference it explicitly. The following

descriptions will reference it explicitly for clarity.

@li Variables

@code

purple::version

@endcode

This contains the version of the libpurple library which loaded the

script.

@li Commands

@code

purple::account alias account

purple::account connect account

purple::account connection account

purple::account disconnect account

purple::account find username protocol

purple::account handle

purple::account isconnected account

purple::account list ?option?

purple::account protocol account

purple::account username account

@endcode

The @c purple::account command consists of a set of subcommands

pertaining to purple 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 purple::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>purple::account username</tt> and <tt>purple::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>purple::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

libpurple. 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-aim")

for the given account.

The @c username subcommand returns the username for the account

@c account.

@code

purple::buddy alias buddy

purple::buddy handle

purple::buddy info ( buddy | account username )

purple::buddy list

@endcode

@c purple::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>purple::signal connect</tt>).

@c info causes the purple-using UI 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

purple::connection account gc

purple::connection displayname gc

purple::connection handle

purple::connection list

purple::connection state

@endcode

@c purple::connection is a collection of subcommands pertaining to

account connections.

@c account returns the purple account associated with @c gc. This

account is the same account used by @c purple::account and other

commands.

@c displayname returns the display name (duh) of @c gc as reported by

<tt>purple_connection_get_display_name(gc)</tt>.

@c handle returns the purple connections instance handle. (See

<tt>purple::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 purple::connection subcommands or other commands requiring a gc.

@c state returns the PurpleConnectionState of this account as one of

the strings "connected", "disconnected", or "connecting".

@code

purple::conv_send account who text

@endcode

@c purple::conv is simply a convenience wrapper for @c purple::send_im and

<tt>purple::conversation write</tt>. It sends the IM, determines the from

and to arguments for <tt>purple::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 purple::conv_send</tt> at

a Purple Commander prompt.

Note that an error in either @c purple::send_im or <tt>purple::conversation

write</tt> will not be caught by this procedure, and will be propagated

to the caller.

@code

purple::conversation find ?-account account? name

purple::conversation handle

purple::conversation list

purple::conversation new ?-chat? ?-im? account name

purple::conversation write conversation style from to text

@endcode

@c purple::conversation provides an API for dealing with

conversations. Given that libpurple clients are instant messenger

programs, 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>purple::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 purple user (style @c send), being sent to the purple 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

purple::core handle

purple::core quit

@endcode

This command exposes functionality provided by the purple core API.

<tt>purple::core handle</tt> returns a handle to the purple core for signal

connection. (See <tt>purple::signal connect</tt>).

@c quit exits the libpurple client cleanly, and should be used in

preference to the tcl @c exit command. (Note that @c exit has not

been removed, however.)

@code

purple::debug level category message

@endcode

Equivalent to the C purple_debug function, this command outputs

debugging information to the libpurple UI's debug window (or,

typically, stdout if that UI 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 purple_debug), no trailing \\n is

required. (However, embedded newlines may be generated with \\n).

@code

purple::notify ?type? title primary secondary

@endcode

Also a direct equivalent to a C function, purple_notify, this command

causes libpurple 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 purple

UI being used, but @c title should generally be the title of the

window, and @c primary and @c secondary text within that window; in

the Pidgin UI, @c primary is slightly larger than @c secondary and

displayed in a @b boldface font.

@code

purple::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

purple::signal connect instance signal args proc

purple::signal disconnect instance signal

@endcode

@c purple::signal is a set of subcommands for dealing with purple

signals.

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 libpurple. @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>purple::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

purple::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 name of the buddy 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

purple::signal connect [purple::conversation handle] receiving-im-msg {

if {[ string match "*shizzle*" $event::buffer ]} {

purple::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 libpurple'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

pidgin/pidgin