(tof)
                                    2005/07/05  Hidetoshi NAGAI

This document discribes about the 'tcltklib' library. Although there
is the 'tcltk' library (tcltk.rb) under this directory, no description
in this document (because it is not maintained recently).

==============================================================
module TclTklib
  : Defines methods to do operations which are independed on
  : Tcl/Tk interpreters

  module TclTkLib::EventFlag
    : Defines flags to define target events on 'do_one_event' methods.
    : When to give, please use bit-operator (e.g. WINDOW | DONT_WAIT).

    [constants]
       NONE
         : Is 0. It means "there is no target". But on the real
         : operation, it is same to ALL.

       WINDOW
         : 'window' event is processed.

       FILE
         : 'file' event is processed.

       TIMER
         : 'timer' event is processed.

       IDLE
         : 'idle' operation (e.g. 're-draw'; the operations when the
         : other kinds of events doesn't occur) is processed.

       ALL
         : All kinds of events are processed.
         : Same to 'WINDOW | FILE | TIMER | IDLE'.

       DONT_WAIT
         : Without this flag, 'do_one_event' waits the occurrence of
         : a target event. With this flag, doesn't wait and returns
         : false if there is no target event for processing.

  module TclTkLib::VarAccessFlag
    : Defines flags to give '_get_variable' and so on. When to give,
    : please use bit-operator (e.g. GLOBAL_ONLY | LEAVE_ERR_MSG ).

    [constants]
       NONE
         : Is 0. It means "set no flag".

       GLOBAL_ONLY
         : (site Tcl/Tk's man page)
         : Under normal circumstances the procedures look up
         : variables as follows: If a procedure call is active
         : in interp, a variable is looked up at the current
         : level of procedure call. Otherwise, a variable is
         : looked up first in the current namespace,  then  in
         : the global namespace. However, if this bit is set
         : in flags then the variable is looked up only in the
         : global namespace even if there is a procedure call
         : active. If both GLOBAL_ONLY and NAMESPACE_ONLY are
         : given, GLOBAL_ONLY is ignored.
         :
         :  *** ATTENTION ***
         : Tcl7.6 doesn't have namespaces. So NAMESPACE_ONLY
         : is defined as 0, and then GLOBAL_ONLY is available
         : even if flag is (GLOBAL_ONLY | NAMESPACE_ONLY).

       NAMESPACE_ONLY
         : (site Tcl/Tk's man page)
         : Under normal circumstances the procedures look up
         : variables as follows: If a procedure call is active
         : in interp, a variable is looked up at the current
         : level of procedure call. Otherwise, a variable is
         : looked up first in the current namespace, then in
         : the global namespace. However, if this bit is set
         : in flags then the variable is looked up only in the
         : current namespace even if there is a procedure call
         : active.
         :
         :  *** ATTENTION ***
         : Tcl7.6 doesn't have namespaces. So NAMESPACE_ONLY
         : is defined as 0.

       LEAVE_ERR_MSG
         : (site Tcl/Tk's man page)
         : If an error is returned and this bit is set in flags,
         : then an error message will be left in the interpreter's
         : result, where it can be retrieved with Tcl_GetObjResult
         : or Tcl_GetStringResult. If this flag bit isn't set then
         : no error message is left and the interpreter's result
         : will not be modified.

       APPEND_VALUE
         : (site Tcl/Tk's man page)
         : If this bit is set then newValue is appended to the
         : current value, instead of replacing it. If the variable
         : is currently undefined, then this bit is ignored.

       LIST_ELEMENT
         : (site Tcl/Tk's man page)
         : If this bit is set, then newValue is converted to a
         : valid Tcl list element before setting (or appending
         : to) the variable. A separator space is appended before
         : the new list element unless the list element is going
         : to be the first element in a list or sublist (i.e. the
         : variable's current value is empty, or contains the
         : single character ``{'', or ends  in `` }'').

       PARSE_VARNAME
         : (site Tcl/Tk's man page)
         : If this bit is set when calling _set_variable and so
         : on, var_name argument may contain both an array and an
         : element name: if the name contains an open parenthesis
         : and ends with a close parenthesis, then the value
         : between the parentheses is treated as an element name
         : (which can have any string value) and the characters
         : before  the first open parenthesis are treated as the
         : name of an array variable. If the flag PARSE_VARNAME
         : is given, index_name argument should be 'nil' since the
         : array and element names are taken from var_name.
         :
         :  *** ATTENTION ***
         : Tcl7.6 doesn't have this flag. So PARSE_VARNAME is
         : defined as 0.

  module TclTkLib::RELEASE_TYPE
    : Defines release type number of Tcl/Tk

       ALPHA
         : ALPHA release

       BETA
         : BETA release

       FINAL
         : FINAL release

  [module methods]
     get_version()
        : return an array of major, minor, release-type number,
        : and patchlevel of current Tcl/Tk library.

     mainloop(check_root = true)
       : Starts the eventloop. If 'check_root' is true, this method
       : doesn't return when a root widget exists.
       : If 'check_root' is false, doesn't return by the other
       : reasons than exceptions.

    mainloop_thread?
       : Returns whether the current thread executes the eventloop.
       : If true, the eventloop is working on the current thread.
       : If no eventloop is working, this method returns nil.
       : And if the other thread executes the eventloop, returns false.
       :
       :  *** ATTENTION ***
       : When this methods returns false, it is dangerous to call a Tk
       : interpreter directly.

    mainloop_watchdog(check_root = true)
       : On the normal eventloop, some kinds of callback operations
       : cause deadlock. To avoid some of such deadlocks, this
       : method starts an eventloop and a watchdog-thread.

    do_one_event(flag = TclTkLib::EventFlag::ALL |
                          TclTkLib::EventFlag::DONT_WAIT)
       : Do one event for processing. When processed an event,
       : returns true.
       : If NOT set DONT_WAIT flag, this method waits occurrence of
       : a target event.
       : If set DONT_WAIT flag and no event for processing, returns
       : false immediately.
       : If $SAFE >= 4,  or $SAFE >= 1 and the flag is tainted,
       : force to set DONT_WAIT flag.

    set_eventloop_tick(timer_tick)
       : Define the interval of thread-switching with an integer
       : value of mili-seconds.
       : Default timer_tick is 0. It means that thread-switching
       : is based on the count of processed events.
       : ( see 'set_eventloop_weight' method )
       : However, if the eventloop thread is the only thread,
       : timer_tick cannot be set to 0. If 0, then is set to 100 ms
       : automatically (see NO_THREAD_INTERRUPT_TIME on tcltklib.c).
       : On $SAFE >= 4, cannot call this method.

    get_eventloop_tick
       : Get current value of 'timer_tick'

    set_no_event_wait(no_event_wait)
       : Define sleeping time of the eventloop when two or more
       : thread are running and there is no event for processing.
       : Default value is 20 (ms).
       : If the eventloop thread is the only thread, this value is
       : invalid.
       : On $SAFE >= 4, cannot call this method.

    get_no_event_wait
       : Get current value of 'no_event_wait'.

    set_eventloop_weight(loop_max, no_event_tick)
       : Define the weight parameters for the eventloop thread.
       : That is invalid when the eventloop is the only thread.
       : 'loop_max' is the max events for thread-switching.
       : 'no_event_tick' is the increment value of the event count
       : when no event for processing (And then, the eventloop thread
       : sleeps 'no_event_wait' mili-seconds).
       : 'loop_max == 800' and 'no_event_tick == 10' are default.
       : On $SAFE >= 4, cannot call this method.

    get_eventloop_weight
       : Get current values of 'loop_max' and 'no_event_tick'.

    mainloop_abort_on_exception=(bool)
       : Define whether the eventloop stops on exception or not.
       : If true (default value), stops on exception.
       : If false, show a waring message but ignore the exception.
       : If nil, no warning message and ignore the exception.
       : This parameter is sometimes useful when multiple Tk
       : interpreters are working. Because the only one eventloop
       : admins all Tk interpreters, sometimes exception on a
       : interpreter kills the eventloop thread. Even if such
       : situation, when abort_on_exception == false or nil,
       : the eventloop ignores the exception and continue to working.
       : On $SAFE >= 4, cannot call this method.

    mainloop_abort_on_exception
       : Get current status of that.

    num_of_mainwindows
       : Returns the number of main-windows (root-widget).
       : Because there is only one main-window for one Tk interpreter,
       : the value is same to the number of interpreters which has
       : available Tk functions.

    _merge_tklist(str, str, ... )
       : Get a Tcl's list string from arguments with a Tcl/Tk's
       : library function. Each arguemnt is converted to a valid
       : Tcl list element.

    _conv_listelement(str)
       : Convert the argument to a valid Tcl list element with
       : Tcl/Tk's library function.

    _toUTF8(str, encoding=nil)
    _fromUTF8(str, encoding=nil)
       : Call the function (which is internal function of Tcl/Tk) to
       : convert to/from a UTF8 string.

    _subst_UTF_backslash(str)
    _subst_Tcl_backslash(str)
       : Substitute backslash sequence with Tcl's rule (include \uhhhh;
       : give a sixteen-bit hexadecimal value for Unicode character).
       : _subst_Tcl_backslash method parses all backslash sequence.
       : _subst_UTF_backslash method parses \uhhhh only.

    encoding_system
    encoding_system=(encoding)
       : Get and set Tcl's system encoding.

    encoding
    encoding=(encoding)
       : alias of encoding_system / encoding_system=
       : ( probably, Ruby/Tk's tk.rb will override them )


class TclTkIp
  [class methods]
    new(ip_name=nil, options='')
       : Generate an instance of TclTkIp class.
       : If 'ip_name' argument is given as a string, it is the name
       : of the Tk interpreter which is shown by 'winfo interps'
       : command.
       : 'options' argument accepts a string which is the command
       : line options of wish; such as '-geometry' or '-use'.
       : The information is used to generate the root widget of the
       : interpreter.
       : ( e.g. TclTkIp.new('FOO', '-geometry 500x200 -use 0x2200009') )
       : If is given nil or false for the 'option' argument, generates
       : the Tcl interpreter without Tk library. Then the interpreter
       : doesn't need GUI environment. Therefore, even if a window
       : system doesn't exist or cannot be used, Ruby can control the
       : Tcl interpreter and the extension libraries loaded on the
       : interpreter.

  [instance methods]
    create_slave(name, safe=false)
       : Create a slave interpreter.
       : The parent of the interpreter is the receiver of this method.
       : The name of the slave interpreter is given by 'name' argument.
       : The 'safe' argument decides whether the slave interpreter is
       : created as a safe interpreter or not. If true, create a safe
       : interpreter. Default is false. However, if the parent
       : interpreter is a safe interpreter, the created interpreter is
       : a safe interpreter (ignore 'safe' argument value).
       : If $SAFE >= 4, can create a safe interpreter only.

    make_safe
       : Make the interpreter to the safe interpreter, and returns
       : self. If fail, raise RuntimeError.

    safe?
       : Check whether the interpreter is the safe interpreter.
       : If is the safe interpreter, returns true.

    allow_ruby_exit?
       : Return the mode whether 'exit' function of ruby or 'exit'
       : command of Tcl/Tk can quit the ruby process or not on the
       : interpreter. If false, such a command quit the interpreter
       : only.
       : The default value for a master interpreter is true, and
       : for a slave interpreter is false.

    allow_ruby_exit=(mode)
       : Change the mode of 'allow_ruby_exit?'.
       : If $SAFE >= 4 or the interpreter is a "safe" interpreter,
       : this is not permitted (raise an exception).

    delete
       : Delete the interpreter.
       : The deleted interpreter doesn't accept command and then
       : raise an exception.

    deleted?
       : Check whether the interpreter is already deleted.
       : If deleted, returns true.

    has_mainwindow?
       : Check whether the interpreter has a MainWindow (root widget).
       : If has, returns true. If doesn't, returns false.
       : If IP is already deleted, returns nil.

    restart
       : Restart Tk part of the interpreter.
       : Use this when you need Tk functions after destroying the
       : root widget.
       : On $SAFE >= 4, cannot call this method.

    _eval(str)
    _invoke(*args)
       : Estimates the arguments as a command on the Tk interpreter.
       : The argument of _eval is a script of Tcl/Tk.
       : Each argument of _invoke is a token of one command line of
       : Tcl/Tk.
       : Because the operation of _invoke doesn't through the
       : command line parser of Tk interpreter, the cost of
       : estimation is smaller than _eval. However, auto_load
       : mechanism of the Tk interpreter doesn't work on _invoke.
       : So _invoke can call only the command which already
       : registered on the interpreter by 'load' command and so on.
       : On _eval command, auto_load mechanism words. So if succeed
       : to _eval and register the command once, after that, the
       : command can be called by _invoke.

    _cancel_eval(str)
    _cancel_eval_unwind(str)
       : (Tcl/Tk8.6 or later)
       : Call Tcl_CancelEval() function, and cancel evaluation.

    _toUTF8(str, encoding=nil)
    _fromUTF8(str, encoding=nil)
       : Call the function (which is internal function of Tcl/Tk) to
       : convert to/from a UTF8 string.

    _thread_vwait(var_name)
    _thread_tkwait(mode, target)
       : 'vwait' or 'tkwait' with thread support.
       : The difference from normal 'vwait' or 'tkwait' command is
       : doing independent wait from the vwait stack when they are
       : called on the other thread than the eventloop thread.
       : In the case of Tcl/Tk's vwait / tkwait, if 2nd vwait /
       : tkwait is called on waiting for 1st vwait / tkwait,
       : returns the order of [2nd]->[1st] regardless of the order
       : of when the wait condition was fulfilled.
       : If _thread_vwait / _thread_tkwait is called on the
       : eventloop thread, there is no difference from vwait /
       : tkwait. But if called on the other thread than the
       : eventloop, stops the thread.  And when the wait condition
       : is fulfilled, the thread restarts. The meaning of
       : "independent from the vwait stack" is that the timing of
       : restarting is independent from the waiting status of the
       : other threads. That is, even if the eventloop thread is
       : waiting by vwait and is not fulfilled the condition,
       : _thread_vwait completes the waiting when its waiting
       : condition is fulfilled and the thread which stopped by
       : _thread_vwait can continue the operation.

    _return_value
       : Get the last result value on the interpreter.

    _get_variable(var_name, flag)
    _get_variable2(var_name, index_name, flag)
       : Get the current value of a variable. If specified a
       : index_name (see also the PARSE_VARNAME flag), get the
       : value of the index_name element.

    _set_variable(var_name, value, flag)
    _set_variable2(var_name, index_name, value, flag)
       : Create or modify a variable. If specified a index_name
       : (see also the PARSE_VARNAME flag), create or modify the
       : index_name element.

    _unset_variable(var_name)
    _unset_variable2(var_name, index_name)
       : Remove a variable. If specified a index_name (see also
       : the PARSE_VARNAME flag), remove the index_name element.

    _get_global_var(var_name)
    _get_global_var2(var_name, index_name)
    _set_global_var(var_name, value)
    _set_global_var2(var_name, index_name, value)
    _unset_global_var(var_name)
    _unset_global_var2(var_name, index_name)
       : Call the associated method with the flag argument
       : (GLOBAL_ONLY | LEAVE_ERR_MSG).

    _split_tklist(str)
       : Split the argument with Tcl/Tk's library function and
       : get an array as a list of Tcl list elements.

    _merge_tklist(str, str, ... )
       : Get a Tcl's list string from arguments with a Tcl/Tk's
       : library function. Each arguemnt is converted to a valid
       : Tcl list element.

    _conv_listelement(str)
       : Convert the argument to a valid Tcl list element with
       : Tcl/Tk's library function.

    mainloop
    mainloop_watchdog
       : If on the slave interpreter, never start an eventloop and
       : returns nil.
       : With the exception that, same to the TclTkLib module method
       : with the same name.

    do_one_event
       : With the exception that the argument is forced to set
       : DONT_WAIT flag on the slave interpreter, same to
       : TclTkLib#do_one_event.

    set_eventloop_tick
    get_eventloop_tick
    set_no_event_wait
    get_no_event_wait
    set_eventloop_weight
    get_eventloop_weight
    mainloop_abort_on_exception
    mainloop_abort_on_exception=
       : With the exception that it is ignored to set value on the
       : slave interpreter, same to the TclTkLib module method with
       : the same name.

    encoding_table
       : For Ruby m17n. Return encoding relation table between Ruby's
       : Encoding object and Tcl's encoding name.

class TkCallbackBreak < StandardError
class TkCallbackContinue < StandardError
  : They are exception classes to break or continue the Tk callback
  : operation.
  : If raise TkCallbackBreak on the callback procedure, Ruby returns
  : 'break' code to Tk interpreter (Then the Tk interpreter will
  : break the operation for the current event).
  : If raise TkCallbackContinue, returns 'continue' code (Then the Tk
  : interpreter will break the operation for the current bindtag and
  : starts the operation for the next bindtag for the current event).
  : However, current tcltklib supports Ruby's 'break' and 'next' to
  : get the same effect. That is, those classes are obsolete. Those
  : exist for backward compatibility.

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