(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 taget events on 'do_one_event' methos. 
    : 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 occurence 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 methods]
     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, doen'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 cannt 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 thead
       : sleeps 'no_event_wait' mili-seconds). 
       : 'loop_max == 800' and 'no_event_tick == 10' are defalut. 
       : 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 warinig message but ignore the exception.
       : If nil, no warning message and ignore the excepsion. 
       : 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 falsr 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 extention 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 regist the command once, after that, the
       : command can be called by _invoke. 

    _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. 

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 operateion for the current bindtag and 
  : starts the operation for the next buindtag for the current event).

(eof)
