lib/lyx2lyx/LyX.py

   1 # This file is part of lyx2lyx
   2 # -*- coding: utf-8 -*-
   3 # Copyright (C) 2002-2004 Dekel Tsur <dekel@lyx.org>
   4 # Copyright (C) 2002-2006 José Matos <jamatos@lyx.org>
   5 #
   6 # This program is free software; you can redistribute it and/or
   7 # modify it under the terms of the GNU General Public License
   8 # as published by the Free Software Foundation; either version 2
   9 # of the License, or (at your option) any later version.
  10 #
  11 # This program is distributed in the hope that it will be useful,
  12 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 # GNU General Public License for more details.
  15 #
  16 # You should have received a copy of the GNU General Public License
  17 # along with this program; if not, write to the Free Software
  18 # Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  19
  20 " The LyX module has all the rules related with different lyx file formats."
  21
  22 from parser_tools import get_value, check_token, find_token, \
  23      find_tokens, find_end_of
  24 import os.path
  25 import gzip
  26 import locale
  27 import sys
  28 import re
  29 import time
  30
  31 try:
  32     import lyx2lyx_version
  33     version__ = lyx2lyx_version.version
  34 except: # we are running from build directory so assume the last version
  35     version__ = '1.6.0svn'
  36
  37 default_debug__ = 2
  38
  39 ####################################################################
  40 # Private helper functions
  41
  42 def find_end_of_inset(lines, i):
  43     " Find beginning of inset, where lines[i] is included."
  44     return find_end_of(lines, i, "\\begin_inset", "\\end_inset")
  45
  46 def minor_versions(major, last_minor_version):
  47     """ Generate minor versions, using major as prefix and minor
  48     versions from 0 until last_minor_version, plus the generic version.
  49
  50     Example:
  51
  52       minor_versions("1.2", 4) ->
  53       [ "1.2", "1.2.0", "1.2.1", "1.2.2", "1.2.3"]
  54     """
  55     return [major] + [major + ".%d" % i for i in range(last_minor_version + 1)]
  56
  57
  58 # End of helper functions
  59 ####################################################################
  60
  61
  62 # Regular expressions used
  63 format_re = re.compile(r"(\d)[\.,]?(\d\d)")
  64 fileformat = re.compile(r"\\lyxformat\s*(\S*)")
  65 original_version = re.compile(r".*?LyX ([\d.]*)")
  66
  67 ##
  68 # file format information:
  69 #  file, supported formats, stable release versions
  70 format_relation = [("0_06",    [200], minor_versions("0.6" , 4)),
  71                    ("0_08",    [210], minor_versions("0.8" , 6) + ["0.7"]),
  72                    ("0_10",    [210], minor_versions("0.10", 7) + ["0.9"]),
  73                    ("0_12",    [215], minor_versions("0.12", 1) + ["0.11"]),
  74                    ("1_0",     [215], minor_versions("1.0" , 4)),
  75                    ("1_1",     [215], minor_versions("1.1" , 4)),
  76                    ("1_1_5",   [216], ["1.1.5","1.1.5.1","1.1.5.2","1.1"]),
  77                    ("1_1_6_0", [217], ["1.1.6","1.1.6.1","1.1.6.2","1.1"]),
  78                    ("1_1_6_3", [218], ["1.1.6.3","1.1.6.4","1.1"]),
  79                    ("1_2",     [220], minor_versions("1.2" , 4)),
  80                    ("1_3",     [221], minor_versions("1.3" , 7)),
  81                    ("1_4", range(222,246), minor_versions("1.4" , 5)),
  82                    ("1_5", range(246,277), minor_versions("1.5" , 6)),
  83                    ("1_6", range(277,346), minor_versions("1.6" , 0))]
  84
  85 ####################################################################
  86 # This is useful just for development versions                     #
  87 # if the list of supported formats is empty get it from last step  #
  88 if not format_relation[-1][1]:
  89     step, mode = format_relation[-1][0], "convert"
  90     convert = getattr(__import__("lyx_" + step), mode)
  91     format_relation[-1] = (step,
  92                            [conv[0] for conv in convert],
  93                            format_relation[-1][2])
  94 #                                                                  #
  95 ####################################################################
  96
  97 def formats_list():
  98     " Returns a list with supported file formats."
  99     formats = []
 100     for version in format_relation:
 101         for format in version[1]:
 102             if format not in formats:
 103                 formats.append(format)
 104     return formats
 105
 106
 107 def get_end_format():
 108     " Returns the more recent file format available."
 109     return format_relation[-1][1][-1]
 110
 111
 112 def get_backend(textclass):
 113     " For _textclass_ returns its backend."
 114     if textclass == "linuxdoc" or textclass == "manpage":
 115         return "linuxdoc"
 116     if textclass.startswith("docbook") or textclass.startswith("agu-"):
 117         return "docbook"
 118     return "latex"
 119
 120
 121 def trim_eol(line):
 122     " Remove end of line char(s)."
 123     if line[-2:-1] == '\r':
 124         return line[:-2]
 125     else:
 126         return line[:-1]
 127
 128
 129 def get_encoding(language, inputencoding, format, cjk_encoding):
 130     " Returns enconding of the lyx file"
 131     if format > 248:
 132         return "utf8"
 133     # CJK-LyX encodes files using the current locale encoding.
 134     # This means that files created by CJK-LyX can only be converted using
 135     # the correct locale settings unless the encoding is given as commandline
 136     # argument.
 137     if cjk_encoding == 'auto':
 138         return locale.getpreferredencoding()
 139     elif cjk_encoding:
 140         return cjk_encoding
 141     from lyx2lyx_lang import lang
 142     if inputencoding == "auto" or inputencoding == "default":
 143         return lang[language][3]
 144     if inputencoding == "":
 145         return "latin1"
 146     if inputencoding == "utf8x":
 147         return "utf8"
 148     # python does not know the alias latin9
 149     if inputencoding == "latin9":
 150         return "iso-8859-15"
 151     return inputencoding
 152
 153 ##
 154 # Class
 155 #
 156 class LyX_base:
 157     """This class carries all the information of the LyX file."""
 158
 159     def __init__(self, end_format = 0, input = "", output = "", error = "",
 160                  debug = default_debug__, try_hard = 0, cjk_encoding = '',
 161                  language = "english", encoding = "auto"):
 162
 163         """Arguments:
 164         end_format: final format that the file should be converted. (integer)
 165         input: the name of the input source, if empty resort to standard input.
 166         output: the name of the output file, if empty use the standard output.
 167         error: the name of the error file, if empty use the standard error.
 168         debug: debug level, O means no debug, as its value increases be more verbose.
 169         """
 170         self.choose_io(input, output)
 171
 172         if error:
 173             self.err = open(error, "w")
 174         else:
 175             self.err = sys.stderr
 176
 177         self.debug = debug
 178         self.try_hard = try_hard
 179         self.cjk_encoding = cjk_encoding
 180
 181         if end_format:
 182             self.end_format = self.lyxformat(end_format)
 183         else:
 184             self.end_format = get_end_format()
 185
 186         self.backend = "latex"
 187         self.textclass = "article"
 188         # This is a hack: We use '' since we don't know the default
 189         # layout of the text class. LyX will parse it as default layout.
 190         # FIXME: Read the layout file and use the real default layout
 191         self.default_layout = ''
 192         self.header = []
 193         self.preamble = []
 194         self.body = []
 195         self.status = 0
 196         self.encoding = encoding
 197         self.language = language
 198
 199
 200     def warning(self, message, debug_level= default_debug__):
 201         """ Emits warning to self.error, if the debug_level is less
 202         than the self.debug."""
 203         if debug_level <= self.debug:
 204             self.err.write("Warning: " + message + "\n")
 205
 206
 207     def error(self, message):
 208         " Emits a warning and exits if not in try_hard mode."
 209         self.warning(message)
 210         if not self.try_hard:
 211             self.warning("Quiting.")
 212             sys.exit(1)
 213
 214         self.status = 2
 215
 216
 217     def read(self):
 218         """Reads a file into the self.header and
 219         self.body parts, from self.input."""
 220
 221         while True:
 222             line = self.input.readline()
 223             if not line:
 224                 self.error("Invalid LyX file.")
 225
 226             line = trim_eol(line)
 227             if check_token(line, '\\begin_preamble'):
 228                 while 1:
 229                     line = self.input.readline()
 230                     if not line:
 231                         self.error("Invalid LyX file.")
 232
 233                     line = trim_eol(line)
 234                     if check_token(line, '\\end_preamble'):
 235                         break
 236
 237                     if line.split()[:0] in ("\\layout",
 238                                             "\\begin_layout", "\\begin_body"):
 239
 240                         self.warning("Malformed LyX file:"
 241                                      "Missing '\\end_preamble'."
 242                                      "\nAdding it now and hoping"
 243                                      "for the best.")
 244
 245                     self.preamble.append(line)
 246
 247             if check_token(line, '\\end_preamble'):
 248                 continue
 249
 250             line = line.strip()
 251             if not line:
 252                 continue
 253
 254             if line.split()[0] in ("\\layout", "\\begin_layout",
 255                                    "\\begin_body", "\\begin_deeper"):
 256                 self.body.append(line)
 257                 break
 258
 259             self.header.append(line)
 260
 261         i = find_token(self.header, '\\textclass', 0)
 262         if i == -1:
 263             self.warning("Malformed LyX file: Missing '\\textclass'.")
 264             i = find_token(self.header, '\\lyxformat', 0) + 1
 265             self.header[i:i] = ['\\textclass article']
 266
 267         self.textclass = get_value(self.header, "\\textclass", 0)
 268         self.backend = get_backend(self.textclass)
 269         self.format  = self.read_format()
 270         self.language = get_value(self.header, "\\language", 0,
 271                                   default = "english")
 272         self.inputencoding = get_value(self.header, "\\inputencoding",
 273                                        0, default = "auto")
 274         self.encoding = get_encoding(self.language,
 275                                      self.inputencoding, self.format,
 276                                      self.cjk_encoding)
 277         self.initial_version = self.read_version()
 278
 279         # Second pass over header and preamble, now we know the file encoding
 280         for i in range(len(self.header)):
 281             self.header[i] = self.header[i].decode(self.encoding)
 282         for i in range(len(self.preamble)):
 283             self.preamble[i] = self.preamble[i].decode(self.encoding)
 284
 285         # Read document body
 286         while 1:
 287             line = self.input.readline().decode(self.encoding)
 288             if not line:
 289                 break
 290             self.body.append(trim_eol(line))
 291
 292
 293     def write(self):
 294         " Writes the LyX file to self.output."
 295         self.set_version()
 296         self.set_format()
 297         self.set_textclass()
 298         if self.encoding == "auto":
 299             self.encoding = get_encoding(self.language, self.encoding,
 300                                          self.format, self.cjk_encoding)
 301         if self.preamble:
 302             i = find_token(self.header, '\\textclass', 0) + 1
 303             preamble = ['\\begin_preamble'] + self.preamble + ['\\end_preamble']
 304             header = self.header[:i] + preamble + self.header[i:]
 305         else:
 306             header = self.header
 307
 308         for line in header + [''] + self.body:
 309             self.output.write(line.encode(self.encoding)+"\n")
 310
 311
 312     def choose_io(self, input, output):
 313         """Choose input and output streams, dealing transparently with
 314         compressed files."""
 315
 316         if output:
 317             self.output = open(output, "wb")
 318         else:
 319             self.output = sys.stdout
 320
 321         if input and input != '-':
 322             self.dir = os.path.dirname(os.path.abspath(input))
 323             try:
 324                 gzip.open(input).readline()
 325                 self.input = gzip.open(input)
 326                 self.output = gzip.GzipFile(mode="wb", fileobj=self.output)
 327             except:
 328                 self.input = open(input)
 329         else:
 330             self.dir = ''
 331             self.input = sys.stdin
 332
 333
 334     def lyxformat(self, format):
 335         " Returns the file format representation, an integer."
 336         result = format_re.match(format)
 337         if result:
 338             format = int(result.group(1) + result.group(2))
 339         elif format == '2':
 340             format = 200
 341         else:
 342             self.error(str(format) + ": " + "Invalid LyX file.")
 343
 344         if format in formats_list():
 345             return format
 346
 347         self.error(str(format) + ": " + "Format not supported.")
 348         return None
 349
 350
 351     def read_version(self):
 352         """ Searchs for clues of the LyX version used to write the
 353         file, returns the most likely value, or None otherwise."""
 354
 355         for line in self.header:
 356             if line[0] != "#":
 357                 return None
 358
 359             line = line.replace("fix",".")
 360             result = original_version.match(line)
 361             if result:
 362                 # Special know cases: reLyX and KLyX
 363                 if line.find("reLyX") != -1 or line.find("KLyX") != -1:
 364                     return "0.12"
 365
 366                 res = result.group(1)
 367                 if not res:
 368                     self.warning(line)
 369                 #self.warning("Version %s" % result.group(1))
 370                 return res
 371         self.warning(str(self.header[:2]))
 372         return None
 373
 374
 375     def set_version(self):
 376         " Set the header with the version used."
 377         self.header[0] = " ".join(["#LyX %s created this file." % version__,
 378                                   "For more info see http://www.lyx.org/"])
 379         if self.header[1][0] == '#':
 380             del self.header[1]
 381
 382
 383     def read_format(self):
 384         " Read from the header the fileformat of the present LyX file."
 385         for line in self.header:
 386             result = fileformat.match(line)
 387             if result:
 388                 return self.lyxformat(result.group(1))
 389         else:
 390             self.error("Invalid LyX File.")
 391         return None
 392
 393
 394     def set_format(self):
 395         " Set the file format of the file, in the header."
 396         if self.format <= 217:
 397             format = str(float(self.format)/100)
 398         else:
 399             format = str(self.format)
 400         i = find_token(self.header, "\\lyxformat", 0)
 401         self.header[i] = "\\lyxformat %s" % format
 402
 403
 404     def set_textclass(self):
 405         i = find_token(self.header, "\\textclass", 0)
 406         self.header[i] = "\\textclass %s" % self.textclass
 407
 408
 409     #Note that the module will be added at the END of the extant ones
 410     def add_module(self, module):
 411       i = find_token(self.header, "\\begin_modules", 0)
 412       if i == -1:
 413         #No modules yet included
 414         i = find_token(self.header, "\\textclass", 0)
 415         if i == -1:
 416           self.warning("Malformed LyX document: No \\textclass!!")
 417           return
 418         modinfo = ["\\begin_modules", module, "\\end_modules"]
 419         self.header[i + 1: i + 1] = modinfo
 420         return
 421       j = find_token(self.header, "\\end_modules", i)
 422       if j == -1:
 423         self.warning("(add_module)Malformed LyX document: No \\end_modules.")
 424         return
 425       k = find_token(self.header, module, i)
 426       if k != -1 and k < j:
 427         return
 428       self.header.insert(j, module)
 429
 430
 431     def get_module_list(self):
 432       i = find_token(self.header, "\\begin_modules", 0)
 433       if (i == -1):
 434         return []
 435       j = find_token(self.header, "\\end_modules", i)
 436       return self.header[i + 1 : j]
 437
 438
 439     def set_module_list(self, mlist):
 440       modbegin = find_token(self.header, "\\begin_modules", 0)
 441       newmodlist = ['\\begin_modules'] + mlist + ['\\end_modules']
 442       if (modbegin == -1):
 443         #No modules yet included
 444         tclass = find_token(self.header, "\\textclass", 0)
 445         if tclass == -1:
 446           self.warning("Malformed LyX document: No \\textclass!!")
 447           return
 448         modbegin = tclass + 1
 449         self.header[modbegin:modbegin] = newmodlist
 450         return
 451       modend = find_token(self.header, "\\end_modules", modbegin)
 452       if modend == -1:
 453         self.warning("(set_module_list)Malformed LyX document: No \\end_modules.")
 454         return
 455       newmodlist = ['\\begin_modules'] + mlist + ['\\end_modules']
 456       self.header[modbegin:modend + 1] = newmodlist
 457
 458
 459     def set_parameter(self, param, value):
 460         " Set the value of the header parameter."
 461         i = find_token(self.header, '\\' + param, 0)
 462         if i == -1:
 463             self.warning('Parameter not found in the header: %s' % param, 3)
 464             return
 465         self.header[i] = '\\%s %s' % (param, str(value))
 466
 467
 468     def is_default_layout(self, layout):
 469         " Check whether a layout is the default layout of this class."
 470         # FIXME: Check against the real text class default layout
 471         if layout == 'Standard' or layout == self.default_layout:
 472             return 1
 473         return 0
 474
 475
 476     def convert(self):
 477         "Convert from current (self.format) to self.end_format."
 478         mode, convertion_chain = self.chain()
 479         self.warning("convertion chain: " + str(convertion_chain), 3)
 480
 481         for step in convertion_chain:
 482             steps = getattr(__import__("lyx_" + step), mode)
 483
 484             self.warning("Convertion step: %s - %s" % (step, mode),
 485                          default_debug__ + 1)
 486             if not steps:
 487                 self.error("The convertion to an older "
 488                 "format (%s) is not implemented." % self.format)
 489
 490             multi_conv = len(steps) != 1
 491             for version, table in steps:
 492                 if multi_conv and \
 493                    (self.format >= version and mode == "convert") or\
 494                    (self.format <= version and mode == "revert"):
 495                     continue
 496
 497                 for conv in table:
 498                     init_t = time.time()
 499                     try:
 500                         conv(self)
 501                     except:
 502                         self.warning("An error ocurred in %s, %s" %
 503                                      (version, str(conv)),
 504                                      default_debug__)
 505                         if not self.try_hard:
 506                             raise
 507                         self.status = 2
 508                     else:
 509                         self.warning("%lf: Elapsed time on %s" %
 510                                      (time.time() - init_t,
 511                                       str(conv)), default_debug__ +
 512                                      1)
 513                 self.format = version
 514                 if self.end_format == self.format:
 515                     return
 516
 517
 518     def chain(self):
 519         """ This is where all the decisions related with the
 520         convertion are taken.  It returns a list of modules needed to
 521         convert the LyX file from self.format to self.end_format"""
 522
 523         self.start =  self.format
 524         format = self.format
 525         correct_version = 0
 526
 527         for rel in format_relation:
 528             if self.initial_version in rel[2]:
 529                 if format in rel[1]:
 530                     initial_step = rel[0]
 531                     correct_version = 1
 532                     break
 533
 534         if not correct_version:
 535             if format <= 215:
 536                 self.warning("Version does not match file format, "
 537                              "discarding it. (Version %s, format %d)" %
 538                              (self.initial_version, self.format))
 539             for rel in format_relation:
 540                 if format in rel[1]:
 541                     initial_step = rel[0]
 542                     break
 543             else:
 544                 # This should not happen, really.
 545                 self.error("Format not supported.")
 546
 547         # Find the final step
 548         for rel in format_relation:
 549             if self.end_format in rel[1]:
 550                 final_step = rel[0]
 551                 break
 552         else:
 553             self.error("Format not supported.")
 554
 555         # Convertion mode, back or forth
 556         steps = []
 557         if (initial_step, self.start) < (final_step, self.end_format):
 558             mode = "convert"
 559             first_step = 1
 560             for step in format_relation:
 561                 if  initial_step <= step[0] <= final_step:
 562                     if first_step and len(step[1]) == 1:
 563                         first_step = 0
 564                         continue
 565                     steps.append(step[0])
 566         else:
 567             mode = "revert"
 568             relation_format = format_relation[:]
 569             relation_format.reverse()
 570             last_step = None
 571
 572             for step in relation_format:
 573                 if  final_step <= step[0] <= initial_step:
 574                     steps.append(step[0])
 575                     last_step = step
 576
 577             if last_step[1][-1] == self.end_format:
 578                 steps.pop()
 579
 580         self.warning("Convertion mode: %s\tsteps%s" %(mode, steps), 10)
 581         return mode, steps
 582
 583
 584     def get_toc(self, depth = 4):
 585         " Returns the TOC of this LyX document."
 586         paragraphs_filter = {'Title' : 0,'Chapter' : 1, 'Section' : 2,
 587                              'Subsection' : 3, 'Subsubsection': 4}
 588         allowed_insets = ['Quotes']
 589         allowed_parameters = ('\\paragraph_spacing', '\\noindent',
 590                               '\\align', '\\labelwidthstring',
 591                               "\\start_of_appendix", "\\leftindent")
 592         sections = []
 593         for section in paragraphs_filter.keys():
 594             sections.append('\\begin_layout %s' % section)
 595
 596         toc_par = []
 597         i = 0
 598         while 1:
 599             i = find_tokens(self.body, sections, i)
 600             if i == -1:
 601                 break
 602
 603             j = find_end_of(self.body,  i + 1, '\\begin_layout', '\\end_layout')
 604             if j == -1:
 605                 self.warning('Incomplete file.', 0)
 606                 break
 607
 608             section = self.body[i].split()[1]
 609             if section[-1] == '*':
 610                 section = section[:-1]
 611
 612             par = []
 613
 614             k = i + 1
 615             # skip paragraph parameters
 616             while not self.body[k].strip() or self.body[k].split()[0] \
 617                       in allowed_parameters:
 618                 k += 1
 619
 620             while k < j:
 621                 if check_token(self.body[k], '\\begin_inset'):
 622                     inset = self.body[k].split()[1]
 623                     end = find_end_of_inset(self.body, k)
 624                     if end == -1 or end > j:
 625                         self.warning('Malformed file.', 0)
 626
 627                     if inset in allowed_insets:
 628                         par.extend(self.body[k: end+1])
 629                     k = end + 1
 630                 else:
 631                     par.append(self.body[k])
 632                     k += 1
 633
 634             # trim empty lines in the end.
 635             while par and par[-1].strip() == '':
 636                 par.pop()
 637
 638             toc_par.append(Paragraph(section, par))
 639
 640             i = j + 1
 641
 642         return toc_par
 643
 644
 645 class File(LyX_base):
 646     " This class reads existing LyX files."
 647
 648     def __init__(self, end_format = 0, input = "", output = "", error = "",
 649                  debug = default_debug__, try_hard = 0, cjk_encoding = ''):
 650         LyX_base.__init__(self, end_format, input, output, error,
 651                           debug, try_hard, cjk_encoding)
 652         self.read()
 653
 654
 655 class NewFile(LyX_base):
 656     " This class is to create new LyX files."
 657     def set_header(self, **params):
 658         # set default values
 659         self.header.extend([
 660             "#LyX xxxx created this file."
 661             "For more info see http://www.lyx.org/",
 662             "\\lyxformat xxx",
 663             "\\begin_document",
 664             "\\begin_header",
 665             "\\textclass article",
 666             "\\language english",
 667             "\\inputencoding auto",
 668             "\\font_roman default",
 669             "\\font_sans default",
 670             "\\font_typewriter default",
 671             "\\font_default_family default",
 672             "\\font_sc false",
 673             "\\font_osf false",
 674             "\\font_sf_scale 100",
 675             "\\font_tt_scale 100",
 676             "\\graphics default",
 677             "\\paperfontsize default",
 678             "\\papersize default",
 679             "\\use_geometry false",
 680             "\\use_amsmath 1",
 681             "\\cite_engine basic",
 682             "\\use_bibtopic false",
 683             "\\paperorientation portrait",
 684             "\\secnumdepth 3",
 685             "\\tocdepth 3",
 686             "\\paragraph_separation indent",
 687             "\\defskip medskip",
 688             "\\quotes_language english",
 689             "\\papercolumns 1",
 690             "\\papersides 1",
 691             "\\paperpagestyle default",
 692             "\\tracking_changes false",
 693             "\\end_header"])
 694
 695         self.format = get_end_format()
 696         for param in params:
 697             self.set_parameter(param, params[param])
 698
 699
 700     def set_body(self, paragraphs):
 701         self.body.extend(['\\begin_body',''])
 702
 703         for par in paragraphs:
 704             self.body.extend(par.asLines())
 705
 706         self.body.extend(['','\\end_body', '\\end_document'])
 707
 708
 709 class Paragraph:
 710     # unfinished implementation, it is missing the Text and Insets
 711     # representation.
 712     " This class represents the LyX paragraphs."
 713     def __init__(self, name, body=[], settings = [], child = []):
 714         """ Parameters:
 715         name: paragraph name.
 716         body: list of lines of body text.
 717         child: list of paragraphs that descend from this paragraph.
 718         """
 719         self.name = name
 720         self.body = body
 721         self.settings = settings
 722         self.child = child
 723
 724     def asLines(self):
 725         """ Converts the paragraph to a list of strings, representing
 726         it in the LyX file."""
 727
 728         result = ['','\\begin_layout %s' % self.name]
 729         result.extend(self.settings)
 730         result.append('')
 731         result.extend(self.body)
 732         result.append('\\end_layout')
 733
 734         if not self.child:
 735             return result
 736
 737         result.append('\\begin_deeper')
 738         for node in self.child:
 739             result.extend(node.asLines())
 740         result.append('\\end_deeper')
 741
 742         return result