"""

MultiCall - a class which inherits its methods from a Tkinter widget (Text, for

example), but enables multiple calls of functions per virtual event - all

matching events will be called, not only the most specific one. This is done

by wrapping the event functions - event_add, event_delete and event_info.

MultiCall recognizes only a subset of legal event sequences. Sequences which

are not recognized are treated by the original Tk handling mechanism. A

more-specific event will be called before a less-specific event.

The recognized sequences are complete one-event sequences (no emacs-style

Ctrl-X Ctrl-C, no shortcuts like <3>), for all types of events.

Key/Button Press/Release events can have modifiers.

The recognized modifiers are Shift, Control, Option and Command for Mac, and

Control, Alt, Shift, Meta/M for other platforms.

For all events which were handled by MultiCall, a new member is added to the

event instance passed to the binded functions - mc_type. This is one of the

event type constants defined in this module (such as MC_KEYPRESS).

For Key/Button events (which are handled by MultiCall and may receive

modifiers), another member is added - mc_state. This member gives the state

of the recognized modifiers, as a combination of the modifier constants

also defined in this module (for example, MC_SHIFT).

Using these members is absolutely portable.

The order by which events are called is defined by these rules:

1. A more-specific event will be called before a less-specific event.

2. A recently-binded event will be called before a previously-binded event,

   unless this conflicts with the first rule.

Each function will be called at most once for each event.

"""

import sys

import string

import re

import Tkinter

# the event type constants, which define the meaning of mc_type

MC_KEYPRESS=0; MC_KEYRELEASE=1; MC_BUTTONPRESS=2; MC_BUTTONRELEASE=3;

MC_ACTIVATE=4; MC_CIRCULATE=5; MC_COLORMAP=6; MC_CONFIGURE=7;

MC_DEACTIVATE=8; MC_DESTROY=9; MC_ENTER=10; MC_EXPOSE=11; MC_FOCUSIN=12;

MC_FOCUSOUT=13; MC_GRAVITY=14; MC_LEAVE=15; MC_MAP=16; MC_MOTION=17;

MC_MOUSEWHEEL=18; MC_PROPERTY=19; MC_REPARENT=20; MC_UNMAP=21; MC_VISIBILITY=22;

# the modifier state constants, which define the meaning of mc_state

MC_SHIFT = 1<<0; MC_CONTROL = 1<<2; MC_ALT = 1<<3; MC_META = 1<<5

MC_OPTION = 1<<6; MC_COMMAND = 1<<7

# define the list of modifiers, to be used in complex event types.

if sys.platform == "darwin" and sys.executable.count(".app"):

    _modifiers = (("Shift",), ("Control",), ("Option",), ("Command",))

    _modifier_masks = (MC_SHIFT, MC_CONTROL, MC_OPTION, MC_COMMAND)

else:

    _modifiers = (("Control",), ("Alt",), ("Shift",), ("Meta", "M"))

    _modifier_masks = (MC_CONTROL, MC_ALT, MC_SHIFT, MC_META)

# a dictionary to map a modifier name into its number

_modifier_names = dict([(name, number)

                         for number in range(len(_modifiers))

                         for name in _modifiers[number]])

# A binder is a class which binds functions to one type of event. It has two

# methods: bind and unbind, which get a function and a parsed sequence, as

# returned by _parse_sequence(). There are two types of binders:

# _SimpleBinder handles event types with no modifiers and no detail.

# No Python functions are called when no events are binded.

# _ComplexBinder handles event types with modifiers and a detail.

# A Python function is called each time an event is generated.

class _SimpleBinder:

    def __init__(self, type, widget, widgetinst):

        self.type = type

        self.sequence = '<'+_types[type][0]+'>'

        self.widget = widget

        self.widgetinst = widgetinst

        self.bindedfuncs = []

        self.handlerid = None

    def bind(self, triplet, func):

        if not self.handlerid:

            def handler(event, l = self.bindedfuncs, mc_type = self.type):

                event.mc_type = mc_type

                wascalled = {}

                for i in range(len(l)-1, -1, -1):

                    func = l[i]

                    if func not in wascalled:

                        wascalled[func] = True

                        r = func(event)

                        if r:

                            return r

            self.handlerid = self.widget.bind(self.widgetinst,

                                              self.sequence, handler)

        self.bindedfuncs.append(func)

    def unbind(self, triplet, func):

        self.bindedfuncs.remove(func)

        if not self.bindedfuncs:

            self.widget.unbind(self.widgetinst, self.sequence, self.handlerid)

            self.handlerid = None

    def __del__(self):

        if self.handlerid:

            self.widget.unbind(self.widgetinst, self.sequence, self.handlerid)

# An int in range(1 << len(_modifiers)) represents a combination of modifiers

# (if the least significent bit is on, _modifiers[0] is on, and so on).

# _state_subsets gives for each combination of modifiers, or *state*,

# a list of the states which are a subset of it. This list is ordered by the

# number of modifiers is the state - the most specific state comes first.

_states = range(1 << len(_modifiers))

_state_names = [reduce(lambda x, y: x + y,

                       [_modifiers[i][0]+'-' for i in range(len(_modifiers))

                        if (1 << i) & s],

                       "")

                for s in _states]

_state_subsets = map(lambda i: filter(lambda j: not (j & (~i)), _states),

                      _states)

for l in _state_subsets:

    l.sort(lambda a, b, nummod = lambda x: len(filter(lambda i: (1<<i) & x,

                                                      range(len(_modifiers)))):

           nummod(b) - nummod(a))

# _state_codes gives for each state, the portable code to be passed as mc_state

_state_codes = [reduce(lambda x, y: x | y,

                       [_modifier_masks[i] for i in range(len(_modifiers))

                        if (1 << i) & s],

                       0)

                for s in _states]

class _ComplexBinder:

    # This class binds many functions, and only unbinds them when it is deleted.

    # self.handlerids is the list of seqs and ids of binded handler functions.

    # The binded functions sit in a dictionary of lists of lists, which maps

    # a detail (or None) and a state into a list of functions.

    # When a new detail is discovered, handlers for all the possible states

    # are binded.

    def __create_handler(self, lists, mc_type, mc_state):

        def handler(event, lists = lists,

                    mc_type = mc_type, mc_state = mc_state,

                    ishandlerrunning = self.ishandlerrunning,

                    doafterhandler = self.doafterhandler):

            ishandlerrunning[:] = [True]

            event.mc_type = mc_type

            event.mc_state = mc_state

            wascalled = {}

            r = None

            for l in lists:

                for i in range(len(l)-1, -1, -1):

                    func = l[i]

                    if func not in wascalled:

                        wascalled[func] = True

                        r = l[i](event)

                        if r:

                            break

                if r:

                    break

            ishandlerrunning[:] = []

            # Call all functions in doafterhandler and remove them from list

            while doafterhandler:

                doafterhandler.pop()()

            if r:

                return r

        return handler

    def __init__(self, type, widget, widgetinst):

        self.type = type

        self.typename = _types[type][0]

        self.widget = widget

        self.widgetinst = widgetinst

        self.bindedfuncs = {None: [[] for s in _states]}

        self.handlerids = []

        # we don't want to change the lists of functions while a handler is

        # running - it will mess up the loop and anyway, we usually want the

        # change to happen from the next event. So we have a list of functions

        # for the handler to run after it finishes calling the binded functions.

        # It calls them only once.

        # ishandlerrunning is a list. An empty one means no, otherwise - yes.

        # this is done so that it would be mutable.

        self.ishandlerrunning = []

        self.doafterhandler = []

        for s in _states:

            lists = [self.bindedfuncs[None][i] for i in _state_subsets[s]]

            handler = self.__create_handler(lists, type, _state_codes[s])

            seq = '<'+_state_names[s]+self.typename+'>'

            self.handlerids.append((seq, self.widget.bind(self.widgetinst,

                                                          seq, handler)))

    def bind(self, triplet, func):

        if not self.bindedfuncs.has_key(triplet[2]):

            self.bindedfuncs[triplet[2]] = [[] for s in _states]

            for s in _states:

                lists = [ self.bindedfuncs[detail][i]

                          for detail in (triplet[2], None)

                          for i in _state_subsets[s]       ]

                handler = self.__create_handler(lists, self.type,

                                                _state_codes[s])

                seq = "<%s%s-%s>"% (_state_names[s], self.typename, triplet[2])

                self.handlerids.append((seq, self.widget.bind(self.widgetinst,

                                                              seq, handler)))

        doit = lambda: self.bindedfuncs[triplet[2]][triplet[0]].append(func)

        if not self.ishandlerrunning:

            doit()

        else:

            self.doafterhandler.append(doit)

    def unbind(self, triplet, func):

        doit = lambda: self.bindedfuncs[triplet[2]][triplet[0]].remove(func)

        if not self.ishandlerrunning:

            doit()

        else:

            self.doafterhandler.append(doit)

    def __del__(self):

        for seq, id in self.handlerids:

            self.widget.unbind(self.widgetinst, seq, id)

# define the list of event types to be handled by MultiEvent. the order is

# compatible with the definition of event type constants.

_types = (

    ("KeyPress", "Key"), ("KeyRelease",), ("ButtonPress", "Button"),

    ("ButtonRelease",), ("Activate",), ("Circulate",), ("Colormap",),

    ("Configure",), ("Deactivate",), ("Destroy",), ("Enter",), ("Expose",),

    ("FocusIn",), ("FocusOut",), ("Gravity",), ("Leave",), ("Map",),

    ("Motion",), ("MouseWheel",), ("Property",), ("Reparent",), ("Unmap",),

    ("Visibility",),

)

# which binder should be used for every event type?

_binder_classes = (_ComplexBinder,) * 4 + (_SimpleBinder,) * (len(_types)-4)

# A dictionary to map a type name into its number

_type_names = dict([(name, number)

                     for number in range(len(_types))

                     for name in _types[number]])

_keysym_re = re.compile(r"^\w+$")

_button_re = re.compile(r"^[1-5]$")

def _parse_sequence(sequence):

    """Get a string which should describe an event sequence. If it is

    successfully parsed as one, return a tuple containing the state (as an int),

    the event type (as an index of _types), and the detail - None if none, or a

    string if there is one. If the parsing is unsuccessful, return None.

    """

    if not sequence or sequence[0] != '<' or sequence[-1] != '>':

        return None

    words = string.split(sequence[1:-1], '-')

    modifiers = 0

    while words and words[0] in _modifier_names:

        modifiers |= 1 << _modifier_names[words[0]]

        del words[0]

    if words and words[0] in _type_names:

        type = _type_names[words[0]]

        del words[0]

    else:

        return None

    if _binder_classes[type] is _SimpleBinder:

        if modifiers or words:

            return None

        else:

            detail = None

    else:

        # _ComplexBinder

        if type in [_type_names[s] for s in ("KeyPress", "KeyRelease")]:

            type_re = _keysym_re

        else:

            type_re = _button_re

        if not words:

            detail = None

        elif len(words) == 1 and type_re.match(words[0]):

            detail = words[0]

        else:

            return None

    return modifiers, type, detail

def _triplet_to_sequence(triplet):

    if triplet[2]:

        return '<'+_state_names[triplet[0]]+_types[triplet[1]][0]+'-'+ \

               triplet[2]+'>'

    else:

        return '<'+_state_names[triplet[0]]+_types[triplet[1]][0]+'>'

_multicall_dict = {}

def MultiCallCreator(widget):

    """Return a MultiCall class which inherits its methods from the

    given widget class (for example, Tkinter.Text). This is used

    instead of a templating mechanism.

    """

    if widget in _multicall_dict:

        return _multicall_dict[widget]

    class MultiCall (widget):

        assert issubclass(widget, Tkinter.Misc)

        def __init__(self, *args, **kwargs):

            apply(widget.__init__, (self,)+args, kwargs)

            # a dictionary which maps a virtual event to a tuple with:

            #  0. the function binded

            #  1. a list of triplets - the sequences it is binded to

            self.__eventinfo = {}

            self.__binders = [_binder_classes[i](i, widget, self)

                              for i in range(len(_types))]

        def bind(self, sequence=None, func=None, add=None):

            #print "bind(%s, %s, %s) called." % (sequence, func, add)

            if type(sequence) is str and len(sequence) > 2 and \

               sequence[:2] == "<<" and sequence[-2:] == ">>":

                if sequence in self.__eventinfo:

                    ei = self.__eventinfo[sequence]

                    if ei[0] is not None:

                        for triplet in ei[1]:

                            self.__binders[triplet[1]].unbind(triplet, ei[0])

                    ei[0] = func

                    if ei[0] is not None:

                        for triplet in ei[1]:

                            self.__binders[triplet[1]].bind(triplet, func)

                else:

                    self.__eventinfo[sequence] = [func, []]

            return widget.bind(self, sequence, func, add)

        def unbind(self, sequence, funcid=None):

            if type(sequence) is str and len(sequence) > 2 and \

               sequence[:2] == "<<" and sequence[-2:] == ">>" and \

               sequence in self.__eventinfo:

                func, triplets = self.__eventinfo[sequence]

                if func is not None:

                    for triplet in triplets:

                        self.__binders[triplet[1]].unbind(triplet, func)

                    self.__eventinfo[sequence][0] = None

            return widget.unbind(self, sequence, funcid)

        def event_add(self, virtual, *sequences):

            #print "event_add(%s,%s) was called"%(repr(virtual),repr(sequences))

            if virtual not in self.__eventinfo:

                self.__eventinfo[virtual] = [None, []]

            func, triplets = self.__eventinfo[virtual]

            for seq in sequences:

                triplet = _parse_sequence(seq)

                if triplet is None:

                    #print >> sys.stderr, "Seq. %s was added by Tkinter."%seq

                    widget.event_add(self, virtual, seq)

                else:

                    if func is not None:

                        self.__binders[triplet[1]].bind(triplet, func)

                    triplets.append(triplet)

        def event_delete(self, virtual, *sequences):

            if virtual not in self.__eventinfo:

                return

            func, triplets = self.__eventinfo[virtual]

            for seq in sequences:

                triplet = _parse_sequence(seq)

                if triplet is None:

                    #print >> sys.stderr, "Seq. %s was deleted by Tkinter."%seq

                    widget.event_delete(self, virtual, seq)

                else:

                    if func is not None:

                        self.__binders[triplet[1]].unbind(triplet, func)

                    triplets.remove(triplet)

        def event_info(self, virtual=None):

            if virtual is None or virtual not in self.__eventinfo:

                return widget.event_info(self, virtual)

            else:

                return tuple(map(_triplet_to_sequence,

                                 self.__eventinfo[virtual][1])) + \

                       widget.event_info(self, virtual)

        def __del__(self):

            for virtual in self.__eventinfo:

                func, triplets = self.__eventinfo[virtual]

                if func:

                    for triplet in triplets:

                        self.__binders[triplet[1]].unbind(triplet, func)

    _multicall_dict[widget] = MultiCall

    return MultiCall

if __name__ == "__main__":

    # Test

    root = Tkinter.Tk()

    text = MultiCallCreator(Tkinter.Text)(root)

    text.pack()

    def bindseq(seq, n=[0]):

        def handler(event):

            print seq

        text.bind("<<handler%d>>"%n[0], handler)

        text.event_add("<<handler%d>>"%n[0], seq)

        n[0] += 1

    bindseq("<Key>")

    bindseq("<Control-Key>")

    bindseq("<Alt-Key-a>")

    bindseq("<Control-Key-a>")

    bindseq("<Alt-Control-Key-a>")

    bindseq("<Key-b>")

    bindseq("<Control-Button-1>")

    bindseq("<Alt-Button-1>")

    bindseq("<FocusOut>")

    bindseq("<Enter>")

    bindseq("<Leave>")

    root.mainloop()