| [2] | 1 | """Generic output formatting.
|
|---|
| 2 |
|
|---|
| 3 | Formatter objects transform an abstract flow of formatting events into
|
|---|
| 4 | specific output events on writer objects. Formatters manage several stack
|
|---|
| 5 | structures to allow various properties of a writer object to be changed and
|
|---|
| 6 | restored; writers need not be able to handle relative changes nor any sort
|
|---|
| 7 | of ``change back'' operation. Specific writer properties which may be
|
|---|
| 8 | controlled via formatter objects are horizontal alignment, font, and left
|
|---|
| 9 | margin indentations. A mechanism is provided which supports providing
|
|---|
| 10 | arbitrary, non-exclusive style settings to a writer as well. Additional
|
|---|
| 11 | interfaces facilitate formatting events which are not reversible, such as
|
|---|
| 12 | paragraph separation.
|
|---|
| 13 |
|
|---|
| 14 | Writer objects encapsulate device interfaces. Abstract devices, such as
|
|---|
| 15 | file formats, are supported as well as physical devices. The provided
|
|---|
| 16 | implementations all work with abstract devices. The interface makes
|
|---|
| 17 | available mechanisms for setting the properties which formatter objects
|
|---|
| 18 | manage and inserting data into the output.
|
|---|
| 19 | """
|
|---|
| 20 |
|
|---|
| 21 | import sys
|
|---|
| 22 |
|
|---|
| 23 |
|
|---|
| 24 | AS_IS = None
|
|---|
| 25 |
|
|---|
| 26 |
|
|---|
| 27 | class NullFormatter:
|
|---|
| 28 | """A formatter which does nothing.
|
|---|
| 29 |
|
|---|
| 30 | If the writer parameter is omitted, a NullWriter instance is created.
|
|---|
| 31 | No methods of the writer are called by NullFormatter instances.
|
|---|
| 32 |
|
|---|
| 33 | Implementations should inherit from this class if implementing a writer
|
|---|
| 34 | interface but don't need to inherit any implementation.
|
|---|
| 35 |
|
|---|
| 36 | """
|
|---|
| 37 |
|
|---|
| 38 | def __init__(self, writer=None):
|
|---|
| 39 | if writer is None:
|
|---|
| 40 | writer = NullWriter()
|
|---|
| 41 | self.writer = writer
|
|---|
| 42 | def end_paragraph(self, blankline): pass
|
|---|
| 43 | def add_line_break(self): pass
|
|---|
| 44 | def add_hor_rule(self, *args, **kw): pass
|
|---|
| 45 | def add_label_data(self, format, counter, blankline=None): pass
|
|---|
| 46 | def add_flowing_data(self, data): pass
|
|---|
| 47 | def add_literal_data(self, data): pass
|
|---|
| 48 | def flush_softspace(self): pass
|
|---|
| 49 | def push_alignment(self, align): pass
|
|---|
| 50 | def pop_alignment(self): pass
|
|---|
| 51 | def push_font(self, x): pass
|
|---|
| 52 | def pop_font(self): pass
|
|---|
| 53 | def push_margin(self, margin): pass
|
|---|
| 54 | def pop_margin(self): pass
|
|---|
| 55 | def set_spacing(self, spacing): pass
|
|---|
| 56 | def push_style(self, *styles): pass
|
|---|
| 57 | def pop_style(self, n=1): pass
|
|---|
| 58 | def assert_line_data(self, flag=1): pass
|
|---|
| 59 |
|
|---|
| 60 |
|
|---|
| 61 | class AbstractFormatter:
|
|---|
| 62 | """The standard formatter.
|
|---|
| 63 |
|
|---|
| 64 | This implementation has demonstrated wide applicability to many writers,
|
|---|
| 65 | and may be used directly in most circumstances. It has been used to
|
|---|
| 66 | implement a full-featured World Wide Web browser.
|
|---|
| 67 |
|
|---|
| 68 | """
|
|---|
| 69 |
|
|---|
| 70 | # Space handling policy: blank spaces at the boundary between elements
|
|---|
| 71 | # are handled by the outermost context. "Literal" data is not checked
|
|---|
| 72 | # to determine context, so spaces in literal data are handled directly
|
|---|
| 73 | # in all circumstances.
|
|---|
| 74 |
|
|---|
| 75 | def __init__(self, writer):
|
|---|
| 76 | self.writer = writer # Output device
|
|---|
| 77 | self.align = None # Current alignment
|
|---|
| 78 | self.align_stack = [] # Alignment stack
|
|---|
| 79 | self.font_stack = [] # Font state
|
|---|
| 80 | self.margin_stack = [] # Margin state
|
|---|
| 81 | self.spacing = None # Vertical spacing state
|
|---|
| 82 | self.style_stack = [] # Other state, e.g. color
|
|---|
| 83 | self.nospace = 1 # Should leading space be suppressed
|
|---|
| 84 | self.softspace = 0 # Should a space be inserted
|
|---|
| 85 | self.para_end = 1 # Just ended a paragraph
|
|---|
| 86 | self.parskip = 0 # Skipped space between paragraphs?
|
|---|
| 87 | self.hard_break = 1 # Have a hard break
|
|---|
| 88 | self.have_label = 0
|
|---|
| 89 |
|
|---|
| 90 | def end_paragraph(self, blankline):
|
|---|
| 91 | if not self.hard_break:
|
|---|
| 92 | self.writer.send_line_break()
|
|---|
| 93 | self.have_label = 0
|
|---|
| 94 | if self.parskip < blankline and not self.have_label:
|
|---|
| 95 | self.writer.send_paragraph(blankline - self.parskip)
|
|---|
| 96 | self.parskip = blankline
|
|---|
| 97 | self.have_label = 0
|
|---|
| 98 | self.hard_break = self.nospace = self.para_end = 1
|
|---|
| 99 | self.softspace = 0
|
|---|
| 100 |
|
|---|
| 101 | def add_line_break(self):
|
|---|
| 102 | if not (self.hard_break or self.para_end):
|
|---|
| 103 | self.writer.send_line_break()
|
|---|
| 104 | self.have_label = self.parskip = 0
|
|---|
| 105 | self.hard_break = self.nospace = 1
|
|---|
| 106 | self.softspace = 0
|
|---|
| 107 |
|
|---|
| 108 | def add_hor_rule(self, *args, **kw):
|
|---|
| 109 | if not self.hard_break:
|
|---|
| 110 | self.writer.send_line_break()
|
|---|
| 111 | self.writer.send_hor_rule(*args, **kw)
|
|---|
| 112 | self.hard_break = self.nospace = 1
|
|---|
| 113 | self.have_label = self.para_end = self.softspace = self.parskip = 0
|
|---|
| 114 |
|
|---|
| 115 | def add_label_data(self, format, counter, blankline = None):
|
|---|
| 116 | if self.have_label or not self.hard_break:
|
|---|
| 117 | self.writer.send_line_break()
|
|---|
| 118 | if not self.para_end:
|
|---|
| 119 | self.writer.send_paragraph((blankline and 1) or 0)
|
|---|
| 120 | if isinstance(format, str):
|
|---|
| 121 | self.writer.send_label_data(self.format_counter(format, counter))
|
|---|
| 122 | else:
|
|---|
| 123 | self.writer.send_label_data(format)
|
|---|
| 124 | self.nospace = self.have_label = self.hard_break = self.para_end = 1
|
|---|
| 125 | self.softspace = self.parskip = 0
|
|---|
| 126 |
|
|---|
| 127 | def format_counter(self, format, counter):
|
|---|
| 128 | label = ''
|
|---|
| 129 | for c in format:
|
|---|
| 130 | if c == '1':
|
|---|
| 131 | label = label + ('%d' % counter)
|
|---|
| 132 | elif c in 'aA':
|
|---|
| 133 | if counter > 0:
|
|---|
| 134 | label = label + self.format_letter(c, counter)
|
|---|
| 135 | elif c in 'iI':
|
|---|
| 136 | if counter > 0:
|
|---|
| 137 | label = label + self.format_roman(c, counter)
|
|---|
| 138 | else:
|
|---|
| 139 | label = label + c
|
|---|
| 140 | return label
|
|---|
| 141 |
|
|---|
| 142 | def format_letter(self, case, counter):
|
|---|
| 143 | label = ''
|
|---|
| 144 | while counter > 0:
|
|---|
| 145 | counter, x = divmod(counter-1, 26)
|
|---|
| 146 | # This makes a strong assumption that lowercase letters
|
|---|
| 147 | # and uppercase letters form two contiguous blocks, with
|
|---|
| 148 | # letters in order!
|
|---|
| 149 | s = chr(ord(case) + x)
|
|---|
| 150 | label = s + label
|
|---|
| 151 | return label
|
|---|
| 152 |
|
|---|
| 153 | def format_roman(self, case, counter):
|
|---|
| 154 | ones = ['i', 'x', 'c', 'm']
|
|---|
| 155 | fives = ['v', 'l', 'd']
|
|---|
| 156 | label, index = '', 0
|
|---|
| 157 | # This will die of IndexError when counter is too big
|
|---|
| 158 | while counter > 0:
|
|---|
| 159 | counter, x = divmod(counter, 10)
|
|---|
| 160 | if x == 9:
|
|---|
| 161 | label = ones[index] + ones[index+1] + label
|
|---|
| 162 | elif x == 4:
|
|---|
| 163 | label = ones[index] + fives[index] + label
|
|---|
| 164 | else:
|
|---|
| 165 | if x >= 5:
|
|---|
| 166 | s = fives[index]
|
|---|
| 167 | x = x-5
|
|---|
| 168 | else:
|
|---|
| 169 | s = ''
|
|---|
| 170 | s = s + ones[index]*x
|
|---|
| 171 | label = s + label
|
|---|
| 172 | index = index + 1
|
|---|
| 173 | if case == 'I':
|
|---|
| 174 | return label.upper()
|
|---|
| 175 | return label
|
|---|
| 176 |
|
|---|
| 177 | def add_flowing_data(self, data):
|
|---|
| 178 | if not data: return
|
|---|
| 179 | prespace = data[:1].isspace()
|
|---|
| 180 | postspace = data[-1:].isspace()
|
|---|
| 181 | data = " ".join(data.split())
|
|---|
| 182 | if self.nospace and not data:
|
|---|
| 183 | return
|
|---|
| 184 | elif prespace or self.softspace:
|
|---|
| 185 | if not data:
|
|---|
| 186 | if not self.nospace:
|
|---|
| 187 | self.softspace = 1
|
|---|
| 188 | self.parskip = 0
|
|---|
| 189 | return
|
|---|
| 190 | if not self.nospace:
|
|---|
| 191 | data = ' ' + data
|
|---|
| 192 | self.hard_break = self.nospace = self.para_end = \
|
|---|
| 193 | self.parskip = self.have_label = 0
|
|---|
| 194 | self.softspace = postspace
|
|---|
| 195 | self.writer.send_flowing_data(data)
|
|---|
| 196 |
|
|---|
| 197 | def add_literal_data(self, data):
|
|---|
| 198 | if not data: return
|
|---|
| 199 | if self.softspace:
|
|---|
| 200 | self.writer.send_flowing_data(" ")
|
|---|
| 201 | self.hard_break = data[-1:] == '\n'
|
|---|
| 202 | self.nospace = self.para_end = self.softspace = \
|
|---|
| 203 | self.parskip = self.have_label = 0
|
|---|
| 204 | self.writer.send_literal_data(data)
|
|---|
| 205 |
|
|---|
| 206 | def flush_softspace(self):
|
|---|
| 207 | if self.softspace:
|
|---|
| 208 | self.hard_break = self.para_end = self.parskip = \
|
|---|
| 209 | self.have_label = self.softspace = 0
|
|---|
| 210 | self.nospace = 1
|
|---|
| 211 | self.writer.send_flowing_data(' ')
|
|---|
| 212 |
|
|---|
| 213 | def push_alignment(self, align):
|
|---|
| 214 | if align and align != self.align:
|
|---|
| 215 | self.writer.new_alignment(align)
|
|---|
| 216 | self.align = align
|
|---|
| 217 | self.align_stack.append(align)
|
|---|
| 218 | else:
|
|---|
| 219 | self.align_stack.append(self.align)
|
|---|
| 220 |
|
|---|
| 221 | def pop_alignment(self):
|
|---|
| 222 | if self.align_stack:
|
|---|
| 223 | del self.align_stack[-1]
|
|---|
| 224 | if self.align_stack:
|
|---|
| 225 | self.align = align = self.align_stack[-1]
|
|---|
| 226 | self.writer.new_alignment(align)
|
|---|
| 227 | else:
|
|---|
| 228 | self.align = None
|
|---|
| 229 | self.writer.new_alignment(None)
|
|---|
| 230 |
|
|---|
| [391] | 231 | def push_font(self, font):
|
|---|
| 232 | size, i, b, tt = font
|
|---|
| [2] | 233 | if self.softspace:
|
|---|
| 234 | self.hard_break = self.para_end = self.softspace = 0
|
|---|
| 235 | self.nospace = 1
|
|---|
| 236 | self.writer.send_flowing_data(' ')
|
|---|
| 237 | if self.font_stack:
|
|---|
| 238 | csize, ci, cb, ctt = self.font_stack[-1]
|
|---|
| 239 | if size is AS_IS: size = csize
|
|---|
| 240 | if i is AS_IS: i = ci
|
|---|
| 241 | if b is AS_IS: b = cb
|
|---|
| 242 | if tt is AS_IS: tt = ctt
|
|---|
| 243 | font = (size, i, b, tt)
|
|---|
| 244 | self.font_stack.append(font)
|
|---|
| 245 | self.writer.new_font(font)
|
|---|
| 246 |
|
|---|
| 247 | def pop_font(self):
|
|---|
| 248 | if self.font_stack:
|
|---|
| 249 | del self.font_stack[-1]
|
|---|
| 250 | if self.font_stack:
|
|---|
| 251 | font = self.font_stack[-1]
|
|---|
| 252 | else:
|
|---|
| 253 | font = None
|
|---|
| 254 | self.writer.new_font(font)
|
|---|
| 255 |
|
|---|
| 256 | def push_margin(self, margin):
|
|---|
| 257 | self.margin_stack.append(margin)
|
|---|
| 258 | fstack = filter(None, self.margin_stack)
|
|---|
| 259 | if not margin and fstack:
|
|---|
| 260 | margin = fstack[-1]
|
|---|
| 261 | self.writer.new_margin(margin, len(fstack))
|
|---|
| 262 |
|
|---|
| 263 | def pop_margin(self):
|
|---|
| 264 | if self.margin_stack:
|
|---|
| 265 | del self.margin_stack[-1]
|
|---|
| 266 | fstack = filter(None, self.margin_stack)
|
|---|
| 267 | if fstack:
|
|---|
| 268 | margin = fstack[-1]
|
|---|
| 269 | else:
|
|---|
| 270 | margin = None
|
|---|
| 271 | self.writer.new_margin(margin, len(fstack))
|
|---|
| 272 |
|
|---|
| 273 | def set_spacing(self, spacing):
|
|---|
| 274 | self.spacing = spacing
|
|---|
| 275 | self.writer.new_spacing(spacing)
|
|---|
| 276 |
|
|---|
| 277 | def push_style(self, *styles):
|
|---|
| 278 | if self.softspace:
|
|---|
| 279 | self.hard_break = self.para_end = self.softspace = 0
|
|---|
| 280 | self.nospace = 1
|
|---|
| 281 | self.writer.send_flowing_data(' ')
|
|---|
| 282 | for style in styles:
|
|---|
| 283 | self.style_stack.append(style)
|
|---|
| 284 | self.writer.new_styles(tuple(self.style_stack))
|
|---|
| 285 |
|
|---|
| 286 | def pop_style(self, n=1):
|
|---|
| 287 | del self.style_stack[-n:]
|
|---|
| 288 | self.writer.new_styles(tuple(self.style_stack))
|
|---|
| 289 |
|
|---|
| 290 | def assert_line_data(self, flag=1):
|
|---|
| 291 | self.nospace = self.hard_break = not flag
|
|---|
| 292 | self.para_end = self.parskip = self.have_label = 0
|
|---|
| 293 |
|
|---|
| 294 |
|
|---|
| 295 | class NullWriter:
|
|---|
| 296 | """Minimal writer interface to use in testing & inheritance.
|
|---|
| 297 |
|
|---|
| 298 | A writer which only provides the interface definition; no actions are
|
|---|
| 299 | taken on any methods. This should be the base class for all writers
|
|---|
| 300 | which do not need to inherit any implementation methods.
|
|---|
| 301 |
|
|---|
| 302 | """
|
|---|
| 303 | def __init__(self): pass
|
|---|
| 304 | def flush(self): pass
|
|---|
| 305 | def new_alignment(self, align): pass
|
|---|
| 306 | def new_font(self, font): pass
|
|---|
| 307 | def new_margin(self, margin, level): pass
|
|---|
| 308 | def new_spacing(self, spacing): pass
|
|---|
| 309 | def new_styles(self, styles): pass
|
|---|
| 310 | def send_paragraph(self, blankline): pass
|
|---|
| 311 | def send_line_break(self): pass
|
|---|
| 312 | def send_hor_rule(self, *args, **kw): pass
|
|---|
| 313 | def send_label_data(self, data): pass
|
|---|
| 314 | def send_flowing_data(self, data): pass
|
|---|
| 315 | def send_literal_data(self, data): pass
|
|---|
| 316 |
|
|---|
| 317 |
|
|---|
| 318 | class AbstractWriter(NullWriter):
|
|---|
| 319 | """A writer which can be used in debugging formatters, but not much else.
|
|---|
| 320 |
|
|---|
| 321 | Each method simply announces itself by printing its name and
|
|---|
| 322 | arguments on standard output.
|
|---|
| 323 |
|
|---|
| 324 | """
|
|---|
| 325 |
|
|---|
| 326 | def new_alignment(self, align):
|
|---|
| 327 | print "new_alignment(%r)" % (align,)
|
|---|
| 328 |
|
|---|
| 329 | def new_font(self, font):
|
|---|
| 330 | print "new_font(%r)" % (font,)
|
|---|
| 331 |
|
|---|
| 332 | def new_margin(self, margin, level):
|
|---|
| 333 | print "new_margin(%r, %d)" % (margin, level)
|
|---|
| 334 |
|
|---|
| 335 | def new_spacing(self, spacing):
|
|---|
| 336 | print "new_spacing(%r)" % (spacing,)
|
|---|
| 337 |
|
|---|
| 338 | def new_styles(self, styles):
|
|---|
| 339 | print "new_styles(%r)" % (styles,)
|
|---|
| 340 |
|
|---|
| 341 | def send_paragraph(self, blankline):
|
|---|
| 342 | print "send_paragraph(%r)" % (blankline,)
|
|---|
| 343 |
|
|---|
| 344 | def send_line_break(self):
|
|---|
| 345 | print "send_line_break()"
|
|---|
| 346 |
|
|---|
| 347 | def send_hor_rule(self, *args, **kw):
|
|---|
| 348 | print "send_hor_rule()"
|
|---|
| 349 |
|
|---|
| 350 | def send_label_data(self, data):
|
|---|
| 351 | print "send_label_data(%r)" % (data,)
|
|---|
| 352 |
|
|---|
| 353 | def send_flowing_data(self, data):
|
|---|
| 354 | print "send_flowing_data(%r)" % (data,)
|
|---|
| 355 |
|
|---|
| 356 | def send_literal_data(self, data):
|
|---|
| 357 | print "send_literal_data(%r)" % (data,)
|
|---|
| 358 |
|
|---|
| 359 |
|
|---|
| 360 | class DumbWriter(NullWriter):
|
|---|
| 361 | """Simple writer class which writes output on the file object passed in
|
|---|
| 362 | as the file parameter or, if file is omitted, on standard output. The
|
|---|
| 363 | output is simply word-wrapped to the number of columns specified by
|
|---|
| 364 | the maxcol parameter. This class is suitable for reflowing a sequence
|
|---|
| 365 | of paragraphs.
|
|---|
| 366 |
|
|---|
| 367 | """
|
|---|
| 368 |
|
|---|
| 369 | def __init__(self, file=None, maxcol=72):
|
|---|
| 370 | self.file = file or sys.stdout
|
|---|
| 371 | self.maxcol = maxcol
|
|---|
| 372 | NullWriter.__init__(self)
|
|---|
| 373 | self.reset()
|
|---|
| 374 |
|
|---|
| 375 | def reset(self):
|
|---|
| 376 | self.col = 0
|
|---|
| 377 | self.atbreak = 0
|
|---|
| 378 |
|
|---|
| 379 | def send_paragraph(self, blankline):
|
|---|
| 380 | self.file.write('\n'*blankline)
|
|---|
| 381 | self.col = 0
|
|---|
| 382 | self.atbreak = 0
|
|---|
| 383 |
|
|---|
| 384 | def send_line_break(self):
|
|---|
| 385 | self.file.write('\n')
|
|---|
| 386 | self.col = 0
|
|---|
| 387 | self.atbreak = 0
|
|---|
| 388 |
|
|---|
| 389 | def send_hor_rule(self, *args, **kw):
|
|---|
| 390 | self.file.write('\n')
|
|---|
| 391 | self.file.write('-'*self.maxcol)
|
|---|
| 392 | self.file.write('\n')
|
|---|
| 393 | self.col = 0
|
|---|
| 394 | self.atbreak = 0
|
|---|
| 395 |
|
|---|
| 396 | def send_literal_data(self, data):
|
|---|
| 397 | self.file.write(data)
|
|---|
| 398 | i = data.rfind('\n')
|
|---|
| 399 | if i >= 0:
|
|---|
| 400 | self.col = 0
|
|---|
| 401 | data = data[i+1:]
|
|---|
| 402 | data = data.expandtabs()
|
|---|
| 403 | self.col = self.col + len(data)
|
|---|
| 404 | self.atbreak = 0
|
|---|
| 405 |
|
|---|
| 406 | def send_flowing_data(self, data):
|
|---|
| 407 | if not data: return
|
|---|
| 408 | atbreak = self.atbreak or data[0].isspace()
|
|---|
| 409 | col = self.col
|
|---|
| 410 | maxcol = self.maxcol
|
|---|
| 411 | write = self.file.write
|
|---|
| 412 | for word in data.split():
|
|---|
| 413 | if atbreak:
|
|---|
| 414 | if col + len(word) >= maxcol:
|
|---|
| 415 | write('\n')
|
|---|
| 416 | col = 0
|
|---|
| 417 | else:
|
|---|
| 418 | write(' ')
|
|---|
| 419 | col = col + 1
|
|---|
| 420 | write(word)
|
|---|
| 421 | col = col + len(word)
|
|---|
| 422 | atbreak = 1
|
|---|
| 423 | self.col = col
|
|---|
| 424 | self.atbreak = data[-1].isspace()
|
|---|
| 425 |
|
|---|
| 426 |
|
|---|
| 427 | def test(file = None):
|
|---|
| 428 | w = DumbWriter()
|
|---|
| 429 | f = AbstractFormatter(w)
|
|---|
| 430 | if file is not None:
|
|---|
| 431 | fp = open(file)
|
|---|
| 432 | elif sys.argv[1:]:
|
|---|
| 433 | fp = open(sys.argv[1])
|
|---|
| 434 | else:
|
|---|
| 435 | fp = sys.stdin
|
|---|
| 436 | for line in fp:
|
|---|
| 437 | if line == '\n':
|
|---|
| 438 | f.end_paragraph(1)
|
|---|
| 439 | else:
|
|---|
| 440 | f.add_flowing_data(line)
|
|---|
| 441 | f.end_paragraph(0)
|
|---|
| 442 |
|
|---|
| 443 |
|
|---|
| 444 | if __name__ == '__main__':
|
|---|
| 445 | test()
|
|---|
