text: #Copyright ReportLab Europe Ltd. 2000-2017
  #see license.txt for license details
  #history http://www.reportlab.co.uk/cgi-bin/viewcvs.cgi/public/reportlab/trunk/reportlab/lib/yaml.py
  # parses "Yet Another Markup Language" into a list of tuples.
  # Each tuple says what the data is e.g.
  # ('Paragraph', 'Heading1', 'Why Reportlab Rules')
  # and the pattern depends on type.
  """
  .h1 Welcome to YAML!
  YAML is "Yet Another Markup Language" - a markup language
  which is easier to type in than XML, yet gives us a
  reasonable selection of formats.
  
  The general rule is that if a line begins with a '.',
  it requires special processing. Otherwise lines
  are concatenated to paragraphs, and blank lines
  separate paragraphs.
  
  If the line ".foo bar bletch" is encountered,
  it immediately ends and writes out any current
  paragraph.
  
  It then looks for a parser method called 'foo';
  if found, it is called with arguments (bar, bletch).
  
  If this is not found, it assumes that 'foo' is a
  paragraph style, and the text for the first line
  of the paragraph is 'bar bletch'.  It would be
  up to the formatter to decide whether on not 'foo'
  was a valid paragraph.
  
  Special commands understood at present are:
  dot image filename
  - adds the image to the document
  dot beginPre Code
  - begins a Preformatted object in style 'Code'
  dot endPre
  - ends a preformatted object.
  """
  __version__='3.3.0'
  
  import sys
  
  #modes:
  PLAIN = 1
  PREFORMATTED = 2
  
  BULLETCHAR = '\267'  # assumes font Symbol, but works on all platforms
  
  class BaseParser:
      """"Simplest possible parser with only the most basic options.
  
      This defines the line-handling abilities and basic mechanism.
      The class YAMLParser includes capabilities for a fairly rich
      story."""
  
      def __init__(self):
          self.reset()
  
      def reset(self):
          self._lineNo = 0
          self._style = 'Normal'  # the default
          self._results = []
          self._buf = []
          self._mode = PLAIN
  
      def parseFile(self, filename):
          #returns list of objects
          data = open(filename, 'r').readlines()
  
          for line in data:
              #strip trailing newlines
              self.readLine(line[:-1])
          self.endPara()
          return self._results
  
      def parseText(self, textBlock):
          "Parses the a possible multi-line text block"
          lines = textBlock.split('\n')
          for line in lines:
              self.readLine(line)
          self.endPara()
          return self._results
  
      def readLine(self, line):
          #this is the inner loop
          self._lineNo = self._lineNo + 1
          stripped = line.lstrip()
          if len(stripped) == 0:
              if self._mode == PLAIN:
                  self.endPara()
              else:  #preformatted, append it
                  self._buf.append(line)
          elif line[0]=='.':
              # we have a command of some kind
              self.endPara()
              words = stripped[1:].split()
              cmd, args = words[0], words[1:]
  
              #is it a parser method?
              if hasattr(self.__class__, cmd):
                  #this was very bad; any type error in the method was hidden
                  #we have to hack the traceback
                  try:
                      getattr(self,cmd)(*args)
                  except TypeError as err:
                      sys.stderr.write("Parser method: %s(*%s) %s at line %d\n" % (cmd, args, err, self._lineNo))
                      raise
              else:
                  # assume it is a paragraph style -
                  # becomes the formatter's problem
                  self.endPara()  #end the last one
                  words = stripped.split(' ', 1)
                  assert len(words)==2, "Style %s but no data at line %d" % (words[0], self._lineNo)
                  (styletag, data) = words
                  self._style = styletag[1:]
                  self._buf.append(data)
          else:
              #we have data, add to para
              self._buf.append(line)
  
      def endPara(self):
          #ends the current paragraph, or preformatted block
  
          text = ' '.join(self._buf)
          if text:
              if self._mode == PREFORMATTED:
                  #item 3 is list of lines
                  self._results.append(('PREFORMATTED', self._style,
                                   '\n'.join(self._buf)))
              else:
                  self._results.append(('PARAGRAPH', self._style, text))
          self._buf = []
          self._style = 'Normal'
  
      def beginPre(self, stylename):
          self._mode = PREFORMATTED
          self._style = stylename
  
      def endPre(self):
          self.endPara()
          self._mode = PLAIN
  
      def image(self, filename):
          self.endPara()
          self._results.append(('IMAGE', filename))
  
  
  class Parser(BaseParser):
      """This adds a basic set of "story" components compatible with HTML & PDF.
  
      Images, spaces"""
  
      def vSpace(self, points):
          """Inserts a vertical spacer"""
          self._results.append(('VSpace', points))
  
      def pageBreak(self):
          """Inserts a frame break"""
          self._results.append(('PageBreak','blah'))  # must be a tuple
  
      def custom(self, moduleName, funcName):
          """Goes and gets the Python object and adds it to the story"""
          self.endPara()
          self._results.append(('Custom',moduleName, funcName))
  
      def nextPageTemplate(self, templateName):
          self._results.append(('NextPageTemplate',templateName))
  
  def parseFile(filename):
      p = Parser()
      return p.parseFile(filename)
  
  def parseText(textBlock):
      p = Parser()
      return p.parseText(textBlock)
  
  
  if __name__=='__main__': #NORUNTESTS
      if len(sys.argv) != 2:
          results = parseText(__doc__)
      else:
          results = parseFile(sys.argv[1])
      import pprint
      pprint.pprint(results)
  