1 """ |
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2 Implements the tree containing pages and their metadata |
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3 """ |
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4 |
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5 import tree_parse |
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6 |
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7 # path to file containing the page metadata tree |
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8 PAGE_TREE_FILE = "pages/list" |
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9 |
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10 class PageTreeError (Exception) : |
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11 """ |
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12 Error parsing/loading the page tree |
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13 """ |
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14 |
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15 pass |
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16 |
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17 class PageInfo (object) : |
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18 """ |
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19 Contains metainformation about a page |
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20 """ |
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21 |
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22 def __init__ (self, parent, name, title, children=None) : |
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23 """ |
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24 Initialize, children defaults to empty list |
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25 """ |
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26 |
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27 # store |
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28 self.parent = parent |
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29 self.name = name |
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30 self.title = title |
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31 self.children = children if children else [] |
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32 |
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33 # no url get |
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34 self._url = None |
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35 |
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36 def set_parent (self, parent) : |
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37 """ |
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38 Set a parent where non was set before |
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39 """ |
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40 |
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41 assert self.parent is None |
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42 |
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43 self.parent = parent |
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44 |
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45 def add_child (self, child) : |
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46 """ |
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47 Add a PageInfo child |
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48 """ |
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49 |
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50 self.children.append(child) |
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51 |
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52 def get_child (self, name) : |
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53 """ |
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54 Look up a child by name, returning None if not found |
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55 """ |
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56 |
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57 return dict((c.name, c) for c in self.children).get(name) |
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58 |
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59 def get_ancestry (self) : |
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60 """ |
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61 Returns a list of this page's parents and the page itself, but not root |
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62 """ |
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63 |
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64 # collect in reverse order |
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65 ancestry = [] |
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66 |
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67 # starting from self |
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68 item = self |
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69 |
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70 # add all items, but not root |
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71 while item and item.parent : |
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72 ancestry.append(item) |
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73 |
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74 item = item.parent |
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75 |
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76 # reverse |
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77 ancestry.reverse() |
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78 |
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79 # done |
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80 return ancestry |
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81 |
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82 @property |
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83 def url (self) : |
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84 """ |
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85 Build this page's URL |
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86 """ |
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87 |
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88 # cached? |
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89 if self._url : |
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90 return self._url |
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91 |
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92 segments = [item.name for item in self.get_ancestry()] |
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93 |
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94 # add empty segment if dir |
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95 if self.children : |
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96 segments.append('') |
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97 |
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98 # join |
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99 url = '/'.join(segments) |
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100 |
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101 # cache |
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102 self._url = url |
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103 |
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104 # done |
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105 return url |
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106 |
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107 class PageTree (object) : |
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108 """ |
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109 The tree of pages, rooted at .root. |
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110 |
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111 Use load_page_tree to initialize the global page_tree instance, and then use that |
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112 """ |
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113 |
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114 def __init__ (self) : |
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115 """ |
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116 Empty PageList, must call load_page_list to initialize, once |
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117 """ |
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118 |
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119 def _load (self, path) : |
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120 """ |
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121 Processes the lines in the given file |
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122 """ |
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123 |
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124 # parse tree |
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125 tree = tree_parse.parse(path, ':') |
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126 |
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127 if not tree : |
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128 raise PageTreeError("No root node found") |
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129 |
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130 def _create_node (parent, item) : |
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131 """ |
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132 Creates and returns a PageInfo from the given parent node and (line_number, line, children) tuple item |
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133 """ |
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134 |
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135 # unpack |
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136 line_number, line, children = item |
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137 |
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138 # parse line |
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139 url = title = None |
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140 |
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141 try : |
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142 url, title = line.split(':') |
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143 |
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144 except : |
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145 raise PageTreeError("Invalid line: %s:%d: %r" % (path, line_number, line)) |
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146 |
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147 # remove whitespace |
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148 url = url.strip() |
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149 title = title.strip() |
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150 |
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151 # create PageInfo |
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152 node = PageInfo(parent, url, title) |
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153 |
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154 # set node children |
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155 node.children = [ |
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156 _create_node(node, child_item) for child_item in children |
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157 ] |
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158 |
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159 # return |
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160 return node |
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161 |
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162 # translate |
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163 self.root = _create_node(None, tree) |
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164 |
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165 # *evil cackle* |
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166 self.root.children.insert(0, self.root) |
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167 |
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168 def get_page (self, url) : |
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169 """ |
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170 Lookup the given page URL, and return the matching PageInfo object, or None, if not found |
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171 """ |
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172 |
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173 # start from root |
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174 node = self.root |
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175 |
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176 # traverse the object tree |
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177 for segment in url.split('/') : |
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178 if segment : |
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179 node = node.get_child(segment) |
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180 |
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181 if not node : |
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182 return None |
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183 |
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184 # return |
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185 return node |
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186 |
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187 def get_siblings (self, url) : |
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188 """ |
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189 Get the list of siblings for the given url, including the given page itself |
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190 """ |
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191 |
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192 # look up the page itself |
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193 page = self.get_page(url) |
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194 |
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195 # specialcase root/unknown node |
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196 if page and page.parent : |
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197 return page.parent.children |
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198 |
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199 else : |
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200 return self.root.children |
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201 |
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202 def dump (self) : |
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203 """ |
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204 Returns a string representation of the tree |
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205 """ |
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206 |
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207 def _print_node (indent, node) : |
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208 return '\n'.join('%s%s' % (' '*indent, line) for line in [ |
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209 "%-15s : %s" % (node.name, node.title) |
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210 ] + [ |
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211 _print_node(indent + 4, child) for child in node.children if child != node |
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212 ]) |
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213 |
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214 return _print_node(0, self.root) |
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215 |
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216 # global singleton PageList instance |
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217 page_tree = PageTree() |
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218 |
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219 def load () : |
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220 """ |
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221 Load the global singleton PageInfo instance |
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222 """ |
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223 |
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224 page_tree._load(PAGE_TREE_FILE) |
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225 |
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