Demo/stdwin/miniedit.py

   1 #! /usr/bin/env python
   2
   3 # A miniature multi-window editor using STDWIN's text objects.
   4 #
   5 # Usage: miniedit [file] ...
   6 #
   7 # The user interface is similar to that of the miniedit demo application
   8 # in C that comes with STDWIN.
   9 #
  10 # XXX need to comment the functions
  11 # XXX Not yet implemented:
  12 #       disabling menu entries for inapplicable actions
  13 #       Find operations
  14
  15
  16 import sys
  17 import stdwin
  18 from stdwinevents import *
  19
  20
  21 # Constant: list of WE_COMMAND events that (may) change the text buffer
  22 # so we can decide whether to set the 'changed' flag.
  23 # Note that it is possible for such a command to fail (a backspace
  24 # at the beginning of the buffer) but we'll set the changed flag anyway
  25 # -- it's too complicated to check this condition right now.
  26 #
  27 changing = [WC_RETURN, WC_TAB, WC_BACKSPACE]
  28
  29
  30 # The list of currently open windows;
  31 # this is maintained so we can stop when there are no windows left
  32 #
  33 windows = []
  34
  35
  36 # A note on window data attributes (set by open_window):
  37 #
  38 # w.textobject  the window's text object
  39 # w.changed     true when the window's text is changed
  40 # w.filename    filename connected to the window; '' if none
  41
  42
  43 # Main program
  44 #
  45 def main():
  46         #
  47         # Set a reasonable default window size.
  48         # If we are using a fixed-width font this will open a 80x24 window;
  49         # for variable-width fonts we approximate this based on an average
  50         #
  51         stdwin.setdefwinsize(40*stdwin.textwidth('in'), 24*stdwin.lineheight())
  52         #
  53         # Create global menus (as local variables)
  54         #
  55         filemenu = make_file_menu(stdwin)
  56         editmenu = make_edit_menu(stdwin)
  57         findmenu = make_find_menu(stdwin)
  58         #
  59         # Get the list of files from the command line (maybe none)
  60         #
  61         files = sys.argv[1:]
  62         #
  63         # Open any files -- errors will be reported but do won't stop us
  64         #
  65         for filename in files:
  66                 open_file(filename)
  67         #
  68         # If there were no files, or none of them could be opened,
  69         # put up a dialog asking for a filename
  70         #
  71         if not windows:
  72                 try:
  73                         open_dialog(None)
  74                 except KeyboardInterrupt:
  75                         pass            # User cancelled
  76         #
  77         # If the dialog was cancelled, create an empty new window
  78         #
  79         if not windows:
  80                 new_window(None)
  81         #
  82         # Main event loop -- stop when we have no open windows left
  83         #
  84         while windows:
  85                 #
  86                 # Get the next event -- ignore interrupts
  87                 #
  88                 try:
  89                         type, window, detail = event = stdwin.getevent()
  90                 except KeyboardInterrupt:
  91                         type, window, detail = event = WE_NONE, None, None
  92                 #
  93                 # Event decoding switch
  94                 #
  95                 if not window:
  96                         pass            # Ignore such events
  97                 elif type == WE_MENU:
  98                         #
  99                         # Execute menu operation
 100                         #
 101                         menu, item = detail
 102                         try:
 103                                 menu.actions[item](window)
 104                         except KeyboardInterrupt:
 105                                 pass    # User cancelled
 106                 elif type == WE_CLOSE:
 107                         #
 108                         # Close a window
 109                         #
 110                         try:
 111                                 close_dialog(window)
 112                         except KeyboardInterrupt:
 113                                 pass    # User cancelled
 114                 elif type == WE_SIZE:
 115                         #
 116                         # A window was resized --
 117                         # let the text object recompute the line breaks
 118                         # and change the document size accordingly,
 119                         # so scroll bars will work
 120                         #
 121                         fix_textsize(window)
 122                 elif window.textobject.event(event):
 123                         #
 124                         # The event was eaten by the text object --
 125                         # set the changed flag if not already set
 126                         #
 127                         if type == WE_CHAR or \
 128                            type == WE_COMMAND and detail in changing:
 129                                 window.changed = 1
 130                                 fix_docsize(window)
 131                 #
 132                 # Delete all objects that may still reference the window
 133                 # in the event -- this is needed otherwise the window
 134                 # won't actually be closed and may receive further
 135                 # events, which will confuse the event decoder
 136                 #
 137                 del type, window, detail, event
 138
 139
 140 def make_file_menu(object):
 141         menu = object.menucreate('File')
 142         menu.actions = []
 143         additem(menu, 'New',            'N', new_window)
 144         additem(menu, 'Open..',         'O', open_dialog)
 145         additem(menu, '',               '',  None)
 146         additem(menu, 'Save',           'S', save_dialog)
 147         additem(menu, 'Save As..',      '',  save_as_dialog)
 148         additem(menu, 'Save a Copy..',  '',  save_copy_dialog)
 149         additem(menu, 'Revert',         'R', revert_dialog)
 150         additem(menu, 'Quit',           'Q', quit_dialog)
 151         return menu
 152
 153
 154 def make_edit_menu(object):
 155         menu = object.menucreate('Edit')
 156         menu.actions = []
 157         additem(menu, 'Cut',            'X', do_cut)
 158         additem(menu, 'Copy',           'C', do_copy)
 159         additem(menu, 'Paste',          'V', do_paste)
 160         additem(menu, 'Clear',          'B', do_clear)
 161         additem(menu, 'Select All',     'A', do_select_all)
 162         return menu
 163
 164
 165 def make_find_menu(object):
 166         menu = object.menucreate('Find')
 167         menu.actions = []
 168         # XXX
 169         return menu
 170
 171
 172 def additem(menu, text, shortcut, function):
 173         if shortcut:
 174                 menu.additem(text, shortcut)
 175         else:
 176                 menu.additem(text)
 177         menu.actions.append(function)
 178
 179
 180 def open_dialog(current_ignored):
 181         filename = stdwin.askfile('Open file:', '', 0)
 182         open_file(filename)
 183
 184
 185 def open_file(filename):
 186         try:
 187                 fp = open(filename, 'r')
 188         except RuntimeError:
 189                 stdwin.message(filename + ': cannot open')
 190                 return                  # Error, forget it
 191         try:
 192                 contents = fp.read()
 193         except RuntimeError:
 194                 stdwin.message(filename + ': read error')
 195                 return                  # Error, forget it
 196         del fp                          # Close the file
 197         open_window(filename, filename, contents)
 198
 199
 200 def new_window(current_ignored):
 201         open_window('', 'Untitled', '')
 202
 203
 204 def open_window(filename, title, contents):
 205         try:
 206                 window = stdwin.open(title)
 207         except RuntimeError:
 208                 stdwin.message('cannot open new window')
 209                 return                  # Error, forget it
 210         window.textobject = window.textcreate((0, 0), window.getwinsize())
 211         window.textobject.settext(contents)
 212         window.changed = 0
 213         window.filename = filename
 214         fix_textsize(window)
 215         windows.append(window)
 216
 217
 218 def quit_dialog(window):
 219         for window in windows[:]:
 220                 close_dialog(window)
 221
 222
 223 def close_dialog(window):
 224         if window.changed:
 225                 prompt = 'Save changes to ' + window.gettitle() + ' ?'
 226                 if stdwin.askync(prompt, 1):
 227                         save_dialog(window)
 228                         if window.changed:
 229                                 return  # Save failed (not) cancelled
 230         windows.remove(window)
 231         del window.textobject
 232
 233
 234 def save_dialog(window):
 235         if not window.filename:
 236                 save_as_dialog(window)
 237                 return
 238         if save_file(window, window.filename):
 239                 window.changed = 0
 240
 241
 242 def save_as_dialog(window):
 243         prompt = 'Save ' + window.gettitle() + ' as:'
 244         filename = stdwin.askfile(prompt, window.filename, 1)
 245         if save_file(window, filename):
 246                 window.filename = filename
 247                 window.settitle(filename)
 248                 window.changed = 0
 249
 250
 251 def save_copy_dialog(window):
 252         prompt = 'Save a copy of ' + window.gettitle() + ' as:'
 253         filename = stdwin.askfile(prompt, window.filename, 1)
 254         void = save_file(window, filename)
 255
 256
 257 def save_file(window, filename):
 258         try:
 259                 fp = open(filename, 'w')
 260         except RuntimeError:
 261                 stdwin.message(filename + ': cannot create')
 262                 return 0
 263         contents = window.textobject.gettext()
 264         try:
 265                 fp.write(contents)
 266         except RuntimeError:
 267                 stdwin.message(filename + ': write error')
 268                 return 0
 269         return 1
 270
 271
 272 def revert_dialog(window):
 273         if not window.filename:
 274                 stdwin.message('This window has no file to revert from')
 275                 return
 276         if window.changed:
 277                 prompt = 'Really read ' + window.filename + ' back from file?'
 278                 if not stdwin.askync(prompt, 1):
 279                         return
 280         try:
 281                 fp = open(window.filename, 'r')
 282         except RuntimeError:
 283                 stdwin.message(filename + ': cannot open')
 284                 return
 285         contents = fp.read()
 286         del fp                          # Close the file
 287         window.textobject.settext(contents)
 288         window.changed = 0
 289         fix_docsize(window)
 290
 291
 292 def fix_textsize(window):
 293         corner = window.getwinsize()
 294         area = (0, 0), (corner)
 295         window.textobject.move(area)
 296         fix_docsize(window)
 297
 298
 299 def fix_docsize(window):
 300         area = window.textobject.getrect()
 301         origin, corner = area
 302         width, height = corner
 303         window.setdocsize(0, height)
 304
 305
 306 def do_cut(window):
 307         selection = window.textobject.getfocustext()
 308         if not selection:
 309                 stdwin.fleep()          # Nothing to cut
 310         elif not window.setselection(WS_PRIMARY, selection):
 311                 stdwin.fleep()          # Window manager glitch...
 312         else:
 313                 stdwin.rotatecutbuffers(1)
 314                 stdwin.setcutbuffer(0, selection)
 315                 window.textobject.replace('')
 316                 window.changed = 1
 317                 fix_docsize(window)
 318
 319
 320 def do_copy(window):
 321         selection = window.textobject.getfocustext()
 322         if not selection:
 323                 stdwin.fleep()          # Nothing to cut
 324         elif not window.setselection(WS_PRIMARY, selection):
 325                 stdwin.fleep()          # Window manager glitch...
 326         else:
 327                 stdwin.rotatecutbuffers(1)
 328                 stdwin.setcutbuffer(0, selection)
 329
 330
 331 def do_paste(window):
 332         selection = stdwin.getselection(WS_PRIMARY)
 333         if not selection:
 334                 selection = stdwin.getcutbuffer(0)
 335         if not selection:
 336                 stdwin.fleep()          # Nothing to paste
 337         else:
 338                 window.textobject.replace(selection)
 339                 window.changed = 1
 340                 fix_docsize(window)
 341
 342 def do_clear(window):
 343         first, last = window.textobject.getfocus()
 344         if first == last:
 345                 stdwin.fleep()          # Nothing to clear
 346         else:
 347                 window.textobject.replace('')
 348                 window.changed = 1
 349                 fix_docsize(window)
 350
 351
 352 def do_select_all(window):
 353         window.textobject.setfocus(0, 0x7fffffff) # XXX Smaller on the Mac!
 354
 355
 356 main()