1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
Demo/tkinter/guido/ss1.py
"""SS1 -- a spreadsheet."""

import os
import re
import sys
import cgi
import rexec
from xml.parsers import expat

LEFT, CENTER, RIGHT = "LEFT", "CENTER", "RIGHT"

def ljust(x, n):
    return x.ljust(n)
def center(x, n):
    return x.center(n)
def rjust(x, n):
    return x.rjust(n)
align2action = {LEFT: ljust, CENTER: center, RIGHT: rjust}

align2xml = {LEFT: "left", CENTER: "center", RIGHT: "right"}
xml2align = {"left": LEFT, "center": CENTER, "right": RIGHT}

align2anchor = {LEFT: "w", CENTER: "center", RIGHT: "e"}

def sum(seq):
    total = 0
    for x in seq:
        if x is not None:
            total += x
    return total

class Sheet:

    def __init__(self):
        self.cells = {} # {(x, y): cell, ...}
        self.rexec = rexec.RExec()
        m = self.rexec.add_module('__main__')
        m.cell = self.cellvalue
        m.cells = self.multicellvalue
        m.sum = sum

    def cellvalue(self, x, y):
        cell = self.getcell(x, y)
        if hasattr(cell, 'recalc'):
            return cell.recalc(self.rexec)
        else:
            return cell

    def multicellvalue(self, x1, y1, x2, y2):
        if x1 > x2:
            x1, x2 = x2, x1
        if y1 > y2:
            y1, y2 = y2, y1
        seq = []
        for y in range(y1, y2+1):
            for x in range(x1, x2+1):
                seq.append(self.cellvalue(x, y))
        return seq

    def getcell(self, x, y):
        return self.cells.get((x, y))

    def setcell(self, x, y, cell):
        assert x > 0 and y > 0
        assert isinstance(cell, BaseCell)
        self.cells[x, y] = cell

    def clearcell(self, x, y):
        try:
            del self.cells[x, y]
        except KeyError:
            pass

    def clearcells(self, x1, y1, x2, y2):
        for xy in self.selectcells(x1, y1, x2, y2):
            del self.cells[xy]

    def clearrows(self, y1, y2):
        self.clearcells(0, y1, sys.maxint, y2)

    def clearcolumns(self, x1, x2):
        self.clearcells(x1, 0, x2, sys.maxint)

    def selectcells(self, x1, y1, x2, y2):
        if x1 > x2:
            x1, x2 = x2, x1
        if y1 > y2:
            y1, y2 = y2, y1
        return [(x, y) for x, y in self.cells
                if x1 <= x <= x2 and y1 <= y <= y2]

    def movecells(self, x1, y1, x2, y2, dx, dy):
        if dx == 0 and dy == 0:
            return
        if x1 > x2:
            x1, x2 = x2, x1
        if y1 > y2:
            y1, y2 = y2, y1
        assert x1+dx > 0 and y1+dy > 0
        new = {}
        for x, y in self.cells:
            cell = self.cells[x, y]
            if hasattr(cell, 'renumber'):
                cell = cell.renumber(x1, y1, x2, y2, dx, dy)
            if x1 <= x <= x2 and y1 <= y <= y2:
                x += dx
                y += dy
            new[x, y] = cell
        self.cells = new

    def insertrows(self, y, n):
        assert n > 0
        self.movecells(0, y, sys.maxint, sys.maxint, 0, n)

    def deleterows(self, y1, y2):
        if y1 > y2:
            y1, y2 = y2, y1
        self.clearrows(y1, y2)
        self.movecells(0, y2+1, sys.maxint, sys.maxint, 0, y1-y2-1)

    def insertcolumns(self, x, n):
        assert n > 0
        self.movecells(x, 0, sys.maxint, sys.maxint, n, 0)

    def deletecolumns(self, x1, x2):
        if x1 > x2:
            x1, x2 = x2, x1
        self.clearcells(x1, x2)
        self.movecells(x2+1, 0, sys.maxint, sys.maxint, x1-x2-1, 0)

    def getsize(self):
        maxx = maxy = 0
        for x, y in self.cells:
            maxx = max(maxx, x)
            maxy = max(maxy, y)
        return maxx, maxy

    def reset(self):
        for cell in self.cells.itervalues():
            if hasattr(cell, 'reset'):
                cell.reset()

    def recalc(self):
        self.reset()
        for cell in self.cells.itervalues():
            if hasattr(cell, 'recalc'):
                cell.recalc(self.rexec)

    def display(self):
        maxx, maxy = self.getsize()
        width, height = maxx+1, maxy+1
        colwidth = [1] * width
        full = {}
        # Add column heading labels in row 0
        for x in range(1, width):
            full[x, 0] = text, alignment = colnum2name(x), RIGHT
            colwidth[x] = max(colwidth[x], len(text))
        # Add row labels in column 0
        for y in range(1, height):
            full[0, y] = text, alignment = str(y), RIGHT
            colwidth[0] = max(colwidth[0], len(text))
        # Add sheet cells in columns with x>0 and y>0
        for (x, y), cell in self.cells.iteritems():
            if x <= 0 or y <= 0:
                continue
            if hasattr(cell, 'recalc'):
                cell.recalc(self.rexec)
            if hasattr(cell, 'format'):
                text, alignment = cell.format()
                assert isinstance(text, str)
                assert alignment in (LEFT, CENTER, RIGHT)
            else:
                text = str(cell)
                if isinstance(cell, str):
                    alignment = LEFT
                else:
                    alignment = RIGHT
            full[x, y] = (text, alignment)
            colwidth[x] = max(colwidth[x], len(text))
        # Calculate the horizontal separator line (dashes and dots)
        sep = ""
        for x in range(width):
            if sep:
                sep += "+"
            sep += "-"*colwidth[x]
        # Now print The full grid
        for y in range(height):
            line = ""
            for x in range(width):
                text, alignment = full.get((x, y)) or ("", LEFT)
                text = align2action[alignment](text, colwidth[x])
                if line:
                    line += '|'
                line += text
            print line
            if y == 0:
                print sep

    def xml(self):
        out = ['<spreadsheet>']
        for (x, y), cell in self.cells.iteritems():
            if hasattr(cell, 'xml'):
                cellxml = cell.xml()
            else:
                cellxml = '<value>%s</value>' % cgi.escape(cell)
            out.append('<cell row="%s" col="%s">\n  %s\n</cell>' %
                       (y, x, cellxml))
        out.append('</spreadsheet>')
        return '\n'.join(out)

    def save(self, filename):
        text = self.xml()
        f = open(filename, "w")
        f.write(text)
        if text and not text.endswith('\n'):
            f.write('\n')
        f.close()

    def load(self, filename):
        f = open(filename, 'r')
        SheetParser(self).parsefile(f)
        f.close()

class SheetParser:

    def __init__(self, sheet):
        self.sheet = sheet

    def parsefile(self, f):
        parser = expat.ParserCreate()
        parser.StartElementHandler = self.startelement
        parser.EndElementHandler = self.endelement
        parser.CharacterDataHandler = self.data
        parser.ParseFile(f)

    def startelement(self, tag, attrs):
        method = getattr(self, 'start_'+tag, None)
        if method:
            for key, value in attrs.iteritems():
                attrs[key] = str(value) # XXX Convert Unicode to 8-bit
            method(attrs)
        self.texts = []

    def data(self, text):
        text = str(text) # XXX Convert Unicode to 8-bit
        self.texts.append(text)

    def endelement(self, tag):
        method = getattr(self, 'end_'+tag, None)
        if method:
            method("".join(self.texts))

    def start_cell(self, attrs):
        self.y = int(attrs.get("row"))
        self.x = int(attrs.get("col"))

    def start_value(self, attrs):
        self.fmt = attrs.get('format')
        self.alignment = xml2align.get(attrs.get('align'))

    start_formula = start_value

    def end_int(self, text):
        try:
            self.value = int(text)
        except:
            self.value = None

    def end_long(self, text):
        try:
            self.value = long(text)
        except:
            self.value = None

    def end_double(self, text):
        try:
            self.value = float(text)
        except:
            self.value = None

    def end_complex(self, text):
        try:
            self.value = complex(text)
        except:
            self.value = None

    def end_string(self, text):
        try:
            self.value = text
        except:
            self.value = None

    def end_value(self, text):
        if isinstance(self.value, BaseCell):
            self.cell = self.value
        elif isinstance(self.value, str):
            self.cell = StringCell(self.value,
                                   self.fmt or "%s",
                                   self.alignment or LEFT)
        else:
            self.cell = NumericCell(self.value,
                                    self.fmt or "%s",
                                    self.alignment or RIGHT)

    def end_formula(self, text):
        self.cell = FormulaCell(text,
                                self.fmt or "%s",
                                self.alignment or RIGHT)

    def end_cell(self, text):
        self.sheet.setcell(self.x, self.y, self.cell)

class BaseCell:
    __init__ = None # Must provide
    """Abstract base class for sheet cells.

    Subclasses may but needn't provide the following APIs:

    cell.reset() -- prepare for recalculation
    cell.recalc(rexec) -> value -- recalculate formula
    cell.format() -> (value, alignment) -- return formatted value
    cell.xml() -> string -- return XML
    """

class NumericCell(BaseCell):

    def __init__(self, value, fmt="%s", alignment=RIGHT):
        assert isinstance(value, (int, long, float, complex))
        assert alignment in (LEFT, CENTER, RIGHT)
        self.value = value
        self.fmt = fmt
        self.alignment = alignment

    def recalc(self, rexec):
        return self.value

    def format(self):
        try:
            text = self.fmt % self.value
        except:
            text = str(self.value)
        return text, self.alignment

    def xml(self):
        method = getattr(self, '_xml_' + type(self.value).__name__)
        return '<value align="%s" format="%s">%s</value>' % (
                align2xml[self.alignment],
                self.fmt,
                method())

    def _xml_int(self):
        if -2**31 <= self.value < 2**31:
            return '<int>%s</int>' % self.value
        else:
            return self._xml_long()

    def _xml_long(self):
        return '<long>%s</long>' % self.value

    def _xml_float(self):
        return '<double>%s</double>' % repr(self.value)

    def _xml_complex(self):
        return '<complex>%s</double>' % repr(self.value)

class StringCell(BaseCell):

    def __init__(self, text, fmt="%s", alignment=LEFT):
        assert isinstance(text, (str, unicode))
        assert alignment in (LEFT, CENTER, RIGHT)
        self.text = text
        self.fmt = fmt
        self.alignment = alignment

    def recalc(self, rexec):
        return self.text

    def format(self):
        return self.text, self.alignment

    def xml(self):
        s = '<value align="%s" format="%s"><string>%s</string></value>'
        return s % (
            align2xml[self.alignment],
            self.fmt,
            cgi.escape(self.text))

class FormulaCell(BaseCell):

    def __init__(self, formula, fmt="%s", alignment=RIGHT):
        assert alignment in (LEFT, CENTER, RIGHT)
        self.formula = formula
        self.translated = translate(self.formula)
        self.fmt = fmt
        self.alignment = alignment
        self.reset()

    def reset(self):
        self.value = None

    def recalc(self, rexec):
        if self.value is None:
            try:
                # A hack to evaluate expressions using true division
                rexec.r_exec("from __future__ import division\n" +
                             "__value__ = eval(%s)" % repr(self.translated))
                self.value = rexec.r_eval("__value__")
            except:
                exc = sys.exc_info()[0]
                if hasattr(exc, "__name__"):
                    self.value = exc.__name__
                else:
                    self.value = str(exc)
        return self.value

    def format(self):
        try:
            text = self.fmt % self.value
        except:
            text = str(self.value)
        return text, self.alignment

    def xml(self):
        return '<formula align="%s" format="%s">%s</formula>' % (
            align2xml[self.alignment],
            self.fmt,
            self.formula)

    def renumber(self, x1, y1, x2, y2, dx, dy):
        out = []
        for part in re.split('(\w+)', self.formula):
            m = re.match('^([A-Z]+)([1-9][0-9]*)$', part)
            if m is not None:
                sx, sy = m.groups()
                x = colname2num(sx)
                y = int(sy)
                if x1 <= x <= x2 and y1 <= y <= y2:
                    part = cellname(x+dx, y+dy)
            out.append(part)
        return FormulaCell("".join(out), self.fmt, self.alignment)

def translate(formula):
    """Translate a formula containing fancy cell names to valid Python code.

    Examples:
        B4 -> cell(2, 4)
        B4:Z100 -> cells(2, 4, 26, 100)
    """
    out = []
    for part in re.split(r"(\w+(?::\w+)?)", formula):
        m = re.match(r"^([A-Z]+)([1-9][0-9]*)(?::([A-Z]+)([1-9][0-9]*))?$", part)
        if m is None:
            out.append(part)
        else:
            x1, y1, x2, y2 = m.groups()
            x1 = colname2num(x1)
            if x2 is None:
                s = "cell(%s, %s)" % (x1, y1)
            else:
                x2 = colname2num(x2)
                s = "cells(%s, %s, %s, %s)" % (x1, y1, x2, y2)
            out.append(s)
    return "".join(out)

def cellname(x, y):
    "Translate a cell coordinate to a fancy cell name (e.g. (1, 1)->'A1')."
    assert x > 0 # Column 0 has an empty name, so can't use that
    return colnum2name(x) + str(y)

def colname2num(s):
    "Translate a column name to number (e.g. 'A'->1, 'Z'->26, 'AA'->27)."
    s = s.upper()
    n = 0
    for c in s:
        assert 'A' <= c <= 'Z'
        n = n*26 + ord(c) - ord('A') + 1
    return n

def colnum2name(n):
    "Translate a column number to name (e.g. 1->'A', etc.)."
    assert n > 0
    s = ""
    while n:
        n, m = divmod(n-1, 26)
        s = chr(m+ord('A')) + s
    return s

import Tkinter as Tk

class SheetGUI:

    """Beginnings of a GUI for a spreadsheet.

    TO DO:
    - clear multiple cells
    - Insert, clear, remove rows or columns
    - Show new contents while typing
    - Scroll bars
    - Grow grid when window is grown
    - Proper menus
    - Undo, redo
    - Cut, copy and paste
    - Formatting and alignment
    """

    def __init__(self, filename="sheet1.xml", rows=10, columns=5):
        """Constructor.

        Load the sheet from the filename argument.
        Set up the Tk widget tree.
        """
        # Create and load the sheet
        self.filename = filename
        self.sheet = Sheet()
        if os.path.isfile(filename):
            self.sheet.load(filename)
        # Calculate the needed grid size
        maxx, maxy = self.sheet.getsize()
        rows = max(rows, maxy)
        columns = max(columns, maxx)
        # Create the widgets
        self.root = Tk.Tk()
        self.root.wm_title("Spreadsheet: %s" % self.filename)
        self.beacon = Tk.Label(self.root, text="A1",
                               font=('helvetica', 16, 'bold'))
        self.entry = Tk.Entry(self.root)
        self.savebutton = Tk.Button(self.root, text="Save",
                                    command=self.save)
        self.cellgrid = Tk.Frame(self.root)
        # Configure the widget lay-out
        self.cellgrid.pack(side="bottom", expand=1, fill="both")
        self.beacon.pack(side="left")
        self.savebutton.pack(side="right")
        self.entry.pack(side="left", expand=1, fill="x")
        # Bind some events
        self.entry.bind("<Return>", self.return_event)
        self.entry.bind("<Shift-Return>", self.shift_return_event)
        self.entry.bind("<Tab>", self.tab_event)
        self.entry.bind("<Shift-Tab>", self.shift_tab_event)
        self.entry.bind("<Delete>", self.delete_event)
        self.entry.bind("<Escape>", self.escape_event)
        # Now create the cell grid
        self.makegrid(rows, columns)
        # Select the top-left cell
        self.currentxy = None
        self.cornerxy = None
        self.setcurrent(1, 1)
        # Copy the sheet cells to the GUI cells
        self.sync()

    def delete_event(self, event):
        if self.cornerxy != self.currentxy and self.cornerxy is not None:
            self.sheet.clearcells(*(self.currentxy + self.cornerxy))
        else:
            self.sheet.clearcell(*self.currentxy)
        self.sync()
        self.entry.delete(0, 'end')
        return "break"

    def escape_event(self, event):
        x, y = self.currentxy
        self.load_entry(x, y)

    def load_entry(self, x, y):
        cell = self.sheet.getcell(x, y)
        if cell is None:
            text = ""
        elif isinstance(cell, FormulaCell):
            text = '=' + cell.formula
        else:
            text, alignment = cell.format()
        self.entry.delete(0, 'end')
        self.entry.insert(0, text)
        self.entry.selection_range(0, 'end')

    def makegrid(self, rows, columns):
        """Helper to create the grid of GUI cells.

        The edge (x==0 or y==0) is filled with labels; the rest is real cells.
        """
        self.rows = rows
        self.columns = columns
        self.gridcells = {}
        # Create the top left corner cell (which selects all)
        cell = Tk.Label(self.cellgrid, relief='raised')
        cell.grid_configure(column=0, row=0, sticky='NSWE')
        cell.bind("<ButtonPress-1>", self.selectall)
        # Create the top row of labels, and confiure the grid columns
        for x in range(1, columns+1):
            self.cellgrid.grid_columnconfigure(x, minsize=64)
            cell = Tk.Label(self.cellgrid, text=colnum2name(x), relief='raised')
            cell.grid_configure(column=x, row=0, sticky='WE')
            self.gridcells[x, 0] = cell
            cell.__x = x
            cell.__y = 0
            cell.bind("<ButtonPress-1>", self.selectcolumn)
            cell.bind("<B1-Motion>", self.extendcolumn)
            cell.bind("<ButtonRelease-1>", self.extendcolumn)
            cell.bind("<Shift-Button-1>", self.extendcolumn)
        # Create the leftmost column of labels
        for y in range(1, rows+1):
            cell = Tk.Label(self.cellgrid, text=str(y), relief='raised')
            cell.grid_configure(column=0, row=y, sticky='WE')
            self.gridcells[0, y] = cell
            cell.__x = 0
            cell.__y = y
            cell.bind("<ButtonPress-1>", self.selectrow)
            cell.bind("<B1-Motion>", self.extendrow)
            cell.bind("<ButtonRelease-1>", self.extendrow)
            cell.bind("<Shift-Button-1>", self.extendrow)
        # Create the real cells
        for x in range(1, columns+1):
            for y in range(1, rows+1):
                cell = Tk.Label(self.cellgrid, relief='sunken',
                                bg='white', fg='black')
                cell.grid_configure(column=x, row=y, sticky='NSWE')
                self.gridcells[x, y] = cell
                cell.__x = x
                cell.__y = y
                # Bind mouse events
                cell.bind("<ButtonPress-1>", self.press)
                cell.bind("<B1-Motion>", self.motion)
                cell.bind("<ButtonRelease-1>", self.release)
                cell.bind("<Shift-Button-1>", self.release)

    def selectall(self, event):
        self.setcurrent(1, 1)
        self.setcorner(sys.maxint, sys.maxint)

    def selectcolumn(self, event):
        x, y = self.whichxy(event)
        self.setcurrent(x, 1)
        self.setcorner(x, sys.maxint)

    def extendcolumn(self, event):
        x, y = self.whichxy(event)
        if x > 0:
            self.setcurrent(self.currentxy[0], 1)
            self.setcorner(x, sys.maxint)

    def selectrow(self, event):
        x, y = self.whichxy(event)
        self.setcurrent(1, y)
        self.setcorner(sys.maxint, y)

    def extendrow(self, event):
        x, y = self.whichxy(event)
        if y > 0:
            self.setcurrent(1, self.currentxy[1])
            self.setcorner(sys.maxint, y)

    def press(self, event):
        x, y = self.whichxy(event)
        if x > 0 and y > 0:
            self.setcurrent(x, y)

    def motion(self, event):
        x, y = self.whichxy(event)
        if x > 0 and y > 0:
            self.setcorner(x, y)

    release = motion

    def whichxy(self, event):
        w = self.cellgrid.winfo_containing(event.x_root, event.y_root)
        if w is not None and isinstance(w, Tk.Label):
            try:
                return w.__x, w.__y
            except AttributeError:
                pass
        return 0, 0

    def save(self):
        self.sheet.save(self.filename)

    def setcurrent(self, x, y):
        "Make (x, y) the current cell."
        if self.currentxy is not None:
            self.change_cell()
        self.clearfocus()
        self.beacon['text'] = cellname(x, y)
        self.load_entry(x, y)
        self.entry.focus_set()
        self.currentxy = x, y
        self.cornerxy = None
        gridcell = self.gridcells.get(self.currentxy)
        if gridcell is not None:
            gridcell['bg'] = 'yellow'

    def setcorner(self, x, y):
        if self.currentxy is None or self.currentxy == (x, y):
            self.setcurrent(x, y)
            return
        self.clearfocus()
        self.cornerxy = x, y
        x1, y1 = self.currentxy
        x2, y2 = self.cornerxy or self.currentxy
        if x1 > x2:
            x1, x2 = x2, x1
        if y1 > y2:
            y1, y2 = y2, y1
        for (x, y), cell in self.gridcells.iteritems():
            if x1 <= x <= x2 and y1 <= y <= y2:
                cell['bg'] = 'lightBlue'
        gridcell = self.gridcells.get(self.currentxy)
        if gridcell is not None:
            gridcell['bg'] = 'yellow'
        self.setbeacon(x1, y1, x2, y2)

    def setbeacon(self, x1, y1, x2, y2):
        if x1 == y1 == 1 and x2 == y2 == sys.maxint:
            name = ":"
        elif (x1, x2) == (1, sys.maxint):
            if y1 == y2:
                name = "%d" % y1
            else:
                name = "%d:%d" % (y1, y2)
        elif (y1, y2) == (1, sys.maxint):
            if x1 == x2:
                name = "%s" % colnum2name(x1)
            else:
                name = "%s:%s" % (colnum2name(x1), colnum2name(x2))
        else:
            name1 = cellname(*self.currentxy)
            name2 = cellname(*self.cornerxy)
            name = "%s:%s" % (name1, name2)
        self.beacon['text'] = name


    def clearfocus(self):
        if self.currentxy is not None:
            x1, y1 = self.currentxy
            x2, y2 = self.cornerxy or self.currentxy
            if x1 > x2:
                x1, x2 = x2, x1
            if y1 > y2:
                y1, y2 = y2, y1
            for (x, y), cell in self.gridcells.iteritems():
                if x1 <= x <= x2 and y1 <= y <= y2:
                    cell['bg'] = 'white'

    def return_event(self, event):
        "Callback for the Return key."
        self.change_cell()
        x, y = self.currentxy
        self.setcurrent(x, y+1)
        return "break"

    def shift_return_event(self, event):
        "Callback for the Return key with Shift modifier."
        self.change_cell()
        x, y = self.currentxy
        self.setcurrent(x, max(1, y-1))
        return "break"

    def tab_event(self, event):
        "Callback for the Tab key."
        self.change_cell()
        x, y = self.currentxy
        self.setcurrent(x+1, y)
        return "break"

    def shift_tab_event(self, event):
        "Callback for the Tab key with Shift modifier."
        self.change_cell()
        x, y = self.currentxy
        self.setcurrent(max(1, x-1), y)
        return "break"

    def change_cell(self):
        "Set the current cell from the entry widget."
        x, y = self.currentxy
        text = self.entry.get()
        cell = None
        if text.startswith('='):
            cell = FormulaCell(text[1:])
        else:
            for cls in int, long, float, complex:
                try:
                    value = cls(text)
                except:
                    continue
                else:
                    cell = NumericCell(value)
                    break
        if cell is None and text:
            cell = StringCell(text)
        if cell is None:
            self.sheet.clearcell(x, y)
        else:
            self.sheet.setcell(x, y, cell)
        self.sync()

    def sync(self):
        "Fill the GUI cells from the sheet cells."
        self.sheet.recalc()
        for (x, y), gridcell in self.gridcells.iteritems():
            if x == 0 or y == 0:
                continue
            cell = self.sheet.getcell(x, y)
            if cell is None:
                gridcell['text'] = ""
            else:
                if hasattr(cell, 'format'):
                    text, alignment = cell.format()
                else:
                    text, alignment = str(cell), LEFT
                gridcell['text'] = text
                gridcell['anchor'] = align2anchor[alignment]


def test_basic():
    "Basic non-gui self-test."
    import os
    a = Sheet()
    for x in range(1, 11):
        for y in range(1, 11):
            if x == 1:
                cell = NumericCell(y)
            elif y == 1:
                cell = NumericCell(x)
            else:
                c1 = cellname(x, 1)
                c2 = cellname(1, y)
                formula = "%s*%s" % (c1, c2)
                cell = FormulaCell(formula)
            a.setcell(x, y, cell)
##    if os.path.isfile("sheet1.xml"):
##        print "Loading from sheet1.xml"
##        a.load("sheet1.xml")
    a.display()
    a.save("sheet1.xml")

def test_gui():
    "GUI test."
    if sys.argv[1:]:
        filename = sys.argv[1]
    else:
        filename = "sheet1.xml"
    g = SheetGUI(filename)
    g.root.mainloop()

if __name__ == '__main__':
    #test_basic()
    test_gui()