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# Source Code for Package epydoc.markup

      1  #
      2  # epydoc package file
      3  #
      4  # A python documentation Module
      5  # Edward Loper
      6  #
      7  # $Id: __init__.py 1577 2007-03-09 23:26:21Z dvarrazzo $
      8  #
      9
     10  """
     11  Markup language support for docstrings.  Each submodule defines a
     12  parser for a single markup language.  These parsers convert an
     13  object's docstring to a L{ParsedDocstring}, a standard intermediate
     14  representation that can be used to generate output.
     15  C{ParsedDocstring}s support the following operations:
     16    - output generation (L{to_plaintext()<ParsedDocstring.to_plaintext>},
     17      L{to_html()<ParsedDocstring.to_html>}, and
     18      L{to_latex()<ParsedDocstring.to_latex>}).
     19    - Summarization (L{summary()<ParsedDocstring.summary>}).
     20    - Field extraction (L{split_fields()<ParsedDocstring.split_fields>}).
     21    - Index term extraction (L{index_terms()<ParsedDocstring.index_terms>}.
     22
     23  The L{parse()} function provides a single interface to the
     24  C{epydoc.markup} package: it takes a docstring and the name of a
     25  markup language; delegates to the appropriate parser; and returns the
     26  parsed docstring (along with any errors or warnings that were
     27  generated).
     28
     29  The C{ParsedDocstring} output generation methods (C{to_M{format}()})
     30  use a L{DocstringLinker} to link the docstring output with the rest of
     31  the documentation that epydoc generates.  C{DocstringLinker}s are
     32  currently responsible for translating two kinds of crossreference:
     33    - index terms (L{translate_indexterm()
     34      <DocstringLinker.translate_indexterm>}).
     35    - identifier crossreferences (L{translate_identifier_xref()
     36      <DocstringLinker.translate_identifier_xref>}).
     37
     38  A parsed docstring's fields can be extracted using the
     39  L{ParsedDocstring.split_fields()} method.  This method divides a
     40  docstring into its main body and a list of L{Field}s, each of which
     41  encodes a single field.  The field's bodies are encoded as
     42  C{ParsedDocstring}s.
     43
     44  Markup errors are represented using L{ParseError}s.  These exception
     45  classes record information about the cause, location, and severity of
     46  each error.
     47
     48  @sort: parse, ParsedDocstring, Field, DocstringLinker
     49  @group Errors and Warnings: ParseError
     50  @group Utility Functions: parse_type_of
     51  @var SCRWIDTH: The default width with which text will be wrapped
     52        when formatting the output of the parser.
     53  @type SCRWIDTH: C{int}
     54  @var _parse_warnings: Used by L{_parse_warn}.
     55  """
     56  __docformat__ = 'epytext en'
     57
     58  import re, types, sys
     59  from epydoc import log
     60  from epydoc.util import plaintext_to_html, plaintext_to_latex
     61  import epydoc
     62  from epydoc.compat import *
     63
     64  ##################################################
     65  ## Contents
     66  ##################################################
     67  #
     68  # 1. parse() dispatcher
     69  # 2. ParsedDocstring abstract base class
     70  # 3. Field class
     71  # 4. Docstring Linker
     72  # 5. ParseError exceptions
     73  # 6. Misc helpers
     74  #
     75
     76  ##################################################
     77  ## Dispatcher
     78  ##################################################
     79
     80  _markup_language_registry = {
     81      'restructuredtext': 'epydoc.markup.restructuredtext',
     82      'epytext': 'epydoc.markup.epytext',
     83      'plaintext': 'epydoc.markup.plaintext',
     84      'javadoc': 'epydoc.markup.javadoc',
     85      }
     86
     87 -def register_markup_language(name, parse_function):
     88      """
     89      Register a new markup language named C{name}, which can be parsed
     90      by the function C{parse_function}.
     91
     92      @param name: The name of the markup language.  C{name} should be a
     93      simple identifier, such as C{'epytext'} or C{'restructuredtext'}.
     94      Markup language names are case insensitive.
     95
     96      @param parse_function: A function which can be used to parse the
     97          markup language, and returns a L{ParsedDocstring}.  It should
     98          have the following signature:
     99
    100              >>> def parse(s, errors):
    101              ...     'returns a ParsedDocstring'
    102
    103          Where:
    104              - C{s} is the string to parse.  (C{s} will be a unicode
    105                string.)
    106              - C{errors} is a list; any errors that are generated
    107                during docstring parsing should be appended to this
    108                list (as L{ParseError} objects).
    109      """
    110      _markup_language_registry[name.lower()] = parse_function
    111
    112  MARKUP_LANGUAGES_USED = set()
    113
    114 -def parse(docstring, markup='plaintext', errors=None, **options):
    115      """
    116      Parse the given docstring, and use it to construct a
    117      C{ParsedDocstring}.  If any fatal C{ParseError}s are encountered
    118      while parsing the docstring, then the docstring will be rendered
    119      as plaintext, instead.
    120
    121      @type docstring: C{string}
    122      @param docstring: The docstring to encode.
    123      @type markup: C{string}
    124      @param markup: The name of the markup language that is used by
    125          the docstring.  If the markup language is not supported, then
    126          the docstring will be treated as plaintext.  The markup name
    127          is case-insensitive.
    128      @param errors: A list where any errors generated during parsing
    129          will be stored.  If no list is specified, then fatal errors
    130          will generate exceptions, and non-fatal errors will be
    131          ignored.
    132      @type errors: C{list} of L{ParseError}
    133      @rtype: L{ParsedDocstring}
    134      @return: A L{ParsedDocstring} that encodes the contents of
    135          C{docstring}.
    136      @raise ParseError: If C{errors} is C{None} and an error is
    137          encountered while parsing.
    138      """
    139      # Initialize errors list.
    140      raise_on_error = (errors is None)
    141      if errors == None: errors = []
    142
    143      # Normalize the markup language name.
    144      markup = markup.lower()
    145
    146      # Is the markup language valid?
    147      if not re.match(r'\w+', markup):
    148          _parse_warn('Bad markup language name %r.  Treating '
    149                      'docstrings as plaintext.' % markup)
    150          import epydoc.markup.plaintext as plaintext
    151          return plaintext.parse_docstring(docstring, errors, **options)
    152
    153      # Is the markup language supported?
    154      if markup not in _markup_language_registry:
    155          _parse_warn('Unsupported markup language %r.  Treating '
    156                      'docstrings as plaintext.' % markup)
    157          import epydoc.markup.plaintext as plaintext
    158          return plaintext.parse_docstring(docstring, errors, **options)
    159
    160      # Get the parse function.
    161      parse_docstring = _markup_language_registry[markup]
    162
    163      # If it's a string, then it names a function to import.
    164      if isinstance(parse_docstring, basestring):
    165          try: exec('from %s import parse_docstring' % parse_docstring)
    166          except ImportError, e:
    167              _parse_warn('Error importing %s for markup language %s: %s' %
    168                          (parse_docstring, markup, e))
    169              import epydoc.markup.plaintext as plaintext
    170              return plaintext.parse_docstring(docstring, errors, **options)
    171          _markup_language_registry[markup] = parse_docstring
    172
    173      # Keep track of which markup languages have been used so far.
    174      MARKUP_LANGUAGES_USED.add(markup)
    175
    176      # Parse the docstring.
    177      try: parsed_docstring = parse_docstring(docstring, errors, **options)
    178      except KeyboardInterrupt: raise
    179      except Exception, e:
    180          if epydoc.DEBUG: raise
    181          log.error('Internal error while parsing a docstring: %s; '
    182                    'treating docstring as plaintext' % e)
    183          import epydoc.markup.plaintext as plaintext
    184          return plaintext.parse_docstring(docstring, errors, **options)
    185
    186      # Check for fatal errors.
    187      fatal_errors = [e for e in errors if e.is_fatal()]
    188      if fatal_errors and raise_on_error: raise fatal_errors[0]
    189      if fatal_errors:
    190          import epydoc.markup.plaintext as plaintext
    191          return plaintext.parse_docstring(docstring, errors, **options)
    192
    193      return parsed_docstring
    194
    195  # only issue each warning once:
    196  _parse_warnings = {}
    197 -def _parse_warn(estr):
    198      """
    199      Print a warning message.  If the given error has already been
    200      printed, then do nothing.
    201      """
    202      global _parse_warnings
    203      if estr in _parse_warnings: return
    204      _parse_warnings[estr] = 1
    205      log.warning(estr)
    206
    207  ##################################################
    208  ## ParsedDocstring
    209  ##################################################
    210 -class ParsedDocstring:
    211      """
    212      A standard intermediate representation for parsed docstrings that
    213      can be used to generate output.  Parsed docstrings are produced by
    214      markup parsers (such as L{epytext.parse} or L{javadoc.parse}).
    215      C{ParsedDocstring}s support several kinds of operation:
    216        - output generation (L{to_plaintext()}, L{to_html()}, and
    217          L{to_latex()}).
    218        - Summarization (L{summary()}).
    219        - Field extraction (L{split_fields()}).
    220        - Index term extraction (L{index_terms()}.
    221
    222      The output generation methods (C{to_M{format}()}) use a
    223      L{DocstringLinker} to link the docstring output with the rest
    224      of the documentation that epydoc generates.
    225
    226      Subclassing
    227      ===========
    228      The only method that a subclass is I{required} to implement is
    229      L{to_plaintext()}; but it is often useful to override the other
    230      methods.  The default behavior of each method is described below:
    231        - C{to_I{format}}: Calls C{to_plaintext}, and uses the string it
    232          returns to generate verbatim output.
    233        - C{summary}: Returns C{self} (i.e., the entire docstring).
    234        - C{split_fields}: Returns C{(self, [])} (i.e., extracts no
    235          fields).
    236        - C{index_terms}: Returns C{[]} (i.e., extracts no index terms).
    237
    238      If and when epydoc adds more output formats, new C{to_I{format}}
    239      methods will be added to this base class; but they will always
    240      be given a default implementation.
    241      """
    242 -    def split_fields(self, errors=None):
    243          """
    244          Split this docstring into its body and its fields.
    245
    246          @return: A tuple C{(M{body}, M{fields})}, where C{M{body}} is
    247              the main body of this docstring, and C{M{fields}} is a list
    248              of its fields.  If the resulting body is empty, return
    249              C{None} for the body.
    250          @rtype: C{(L{ParsedDocstring}, list of L{Field})}
    251          @param errors: A list where any errors generated during
    252              splitting will be stored.  If no list is specified, then
    253              errors will be ignored.
    254          @type errors: C{list} of L{ParseError}
    255          """
    256          # Default behavior:
    257          return self, []
    258
    259 -    def summary(self):
    260          """
    261          @return: A pair consisting of a short summary of this docstring and a
    262              boolean value indicating whether there is further documentation
    263              in addition to the summary. Typically, the summary consists of the
    264              first sentence of the docstring.
    265          @rtype: (L{ParsedDocstring}, C{bool})
    266          """
    267          # Default behavior:
    268          return self, False
    269
    270 -    def concatenate(self, other):
    271          """
    272          @return: A new parsed docstring containing the concatination
    273              of this docstring and C{other}.
    274          @raise ValueError: If the two parsed docstrings are
    275              incompatible.
    276          """
    277          return ConcatenatedDocstring(self, other)
    278
    279 -    def __add__(self, other): return self.concatenate(other)
    280
    281 -    def to_html(self, docstring_linker, **options):
    282          """
    283          Translate this docstring to HTML.
    284
    285          @param docstring_linker: An HTML translator for crossreference
    286              links into and out of the docstring.
    287          @type docstring_linker: L{DocstringLinker}
    288          @param options: Any extra options for the output.  Unknown
    289              options are ignored.
    290          @return: An HTML fragment that encodes this docstring.
    291          @rtype: C{string}
    292          """
    293          # Default behavior:
    294          plaintext = plaintext_to_html(self.to_plaintext(docstring_linker))
    295          return '<pre class="literalblock">\n%s\n</pre>\n' % plaintext
    296
    297 -    def to_latex(self, docstring_linker, **options):
    298          """
    299          Translate this docstring to LaTeX.
    300
    301          @param docstring_linker: A LaTeX translator for crossreference
    302              links into and out of the docstring.
    303          @type docstring_linker: L{DocstringLinker}
    304          @param options: Any extra options for the output.  Unknown
    305              options are ignored.
    306          @return: A LaTeX fragment that encodes this docstring.
    307          @rtype: C{string}
    308          """
    309          # Default behavior:
    310          plaintext = plaintext_to_latex(self.to_plaintext(docstring_linker))
    311          return '\\begin{alltt}\n%s\\end{alltt}\n\n' % plaintext
    312
    313 -    def to_plaintext(self, docstring_linker, **options):
    314          """
    315          Translate this docstring to plaintext.
    316
    317          @param docstring_linker: A plaintext translator for
    318              crossreference links into and out of the docstring.
    319          @type docstring_linker: L{DocstringLinker}
    320          @param options: Any extra options for the output.  Unknown
    321              options are ignored.
    322          @return: A plaintext fragment that encodes this docstring.
    323          @rtype: C{string}
    324          """
    325          raise NotImplementedError, 'ParsedDocstring.to_plaintext()'
    326
    327 -    def index_terms(self):
    328          """
    329          @return: The list of index terms that are defined in this
    330              docstring.  Each of these items will be added to the index
    331              page of the documentation.
    332          @rtype: C{list} of C{ParsedDocstring}
    333          """
    334          # Default behavior:
    335          return []
    336
    337  ##################################################
    338  ## Concatenated Docstring
    339  ##################################################
    340 -class ConcatenatedDocstring:
    341 -    def __init__(self, *parsed_docstrings):
    342          self._parsed_docstrings = [pds for pds in parsed_docstrings
    343                                     if pds is not None]
    344
    345 -    def split_fields(self, errors=None):
    346          bodies = []
    347          fields = []
    348          for doc in self._parsed_docstrings:
    349              b,f = doc.split_fields()
    350              bodies.append(b)
    351              fields.extend(f)
    352
    353          return ConcatenatedDocstring(*bodies), fields
    354
    355 -    def summary(self):
    356          return self._parsed_docstrings[0].summary()
    357
    358 -    def to_html(self, docstring_linker, **options):
    359          htmlstring = ''
    360          for doc in self._parsed_docstrings:
    361              htmlstring += doc.to_html(docstring_linker, **options)
    362          return htmlstring
    363
    364 -    def to_latex(self, docstring_linker, **options):
    365          latexstring = ''
    366          for doc in self._parsed_docstrings:
    367              latexstring += doc.to_latex(docstring_linker, **options)
    368          return latexstring
    369
    370 -    def to_plaintext(self, docstring_linker, **options):
    371          textstring = ''
    372          for doc in self._parsed_docstrings:
    373              textstring += doc.to_plaintext(docstring_linker, **options)
    374          return textstring
    375
    376 -    def index_terms(self):
    377          terms = []
    378          for doc in self._parsed_docstrings:
    379              terms += doc.index_terms()
    380          return terms
    381
    382  ##################################################
    383  ## Fields
    384  ##################################################
    385 -class Field:
    386      """
    387      The contents of a docstring's field.  Docstring fields are used
    388      to describe specific aspects of an object, such as a parameter of
    389      a function or the author of a module.  Each field consists of a
    390      tag, an optional argument, and a body:
    391        - The tag specifies the type of information that the field
    392          encodes.
    393        - The argument specifies the object that the field describes.
    394          The argument may be C{None} or a C{string}.
    395        - The body contains the field's information.
    396
    397      Tags are automatically downcased and stripped; and arguments are
    398      automatically stripped.
    399      """
    400 -    def __init__(self, tag, arg, body):
    401          self._tag = tag.lower().strip()
    402          if arg is None: self._arg = None
    403          else: self._arg = arg.strip()
    404          self._body = body
    405
    406 -    def tag(self):
    407          """
    408          @return: This field's tag.
    409          @rtype: C{string}
    410          """
    411          return self._tag
    412
    413 -    def arg(self):
    414          """
    415          @return: This field's argument, or C{None} if this field has
    416              no argument.
    417          @rtype: C{string} or C{None}
    418          """
    419          return self._arg
    420
    421 -    def body(self):
    422          """
    423          @return: This field's body.
    424          @rtype: L{ParsedDocstring}
    425          """
    426          return self._body
    427
    428 -    def __repr__(self):
    429          if self._arg is None:
    430              return '<Field @%s: ...>' % self._tag
    431          else:
    432              return '<Field @%s %s: ...>' % (self._tag, self._arg)
    433
    434  ##################################################
    435  ## Docstring Linker (resolves crossreferences)
    436  ##################################################
    437 -class DocstringLinker:
    438      """
    439      A translator for crossreference links into and out of a
    440      C{ParsedDocstring}.  C{DocstringLinker} is used by
    441      C{ParsedDocstring} to convert these crossreference links into
    442      appropriate output formats.  For example,
    443      C{DocstringLinker.to_html} expects a C{DocstringLinker} that
    444      converts crossreference links to HTML.
    445      """
    446 -    def translate_indexterm(self, indexterm):
    447          """
    448          Translate an index term to the appropriate output format.  The
    449          output will typically include a crossreference anchor.
    450
    451          @type indexterm: L{ParsedDocstring}
    452          @param indexterm: The index term to translate.
    453          @rtype: C{string}
    454          @return: The translated index term.
    455          """
    456          raise NotImplementedError, 'DocstringLinker.translate_indexterm()'
    457
    458 -    def translate_identifier_xref(self, identifier, label=None):
    459          """
    460          Translate a crossreference link to a Python identifier to the
    461          appropriate output format.  The output will typically include
    462          a reference or pointer to the crossreference target.
    463
    464          @type identifier: C{string}
    465          @param identifier: The name of the Python identifier that
    466              should be linked to.
    467          @type label: C{string} or C{None}
    468          @param label: The label that should be used for the identifier,
    469              if it's different from the name of the identifier.
    470          @rtype: C{string}
    471          @return: The translated crossreference link.
    472          """
    473          raise NotImplementedError, 'DocstringLinker.translate_xref()'
    474
    475  ##################################################
    476  ## ParseError exceptions
    477  ##################################################
    478
    479 -class ParseError(Exception):
    480      """
    481      The base class for errors generated while parsing docstrings.
    482
    483      @ivar _linenum: The line on which the error occured within the
    484          docstring.  The linenum of the first line is 0.
    485      @type _linenum: C{int}
    486      @ivar _offset: The line number where the docstring begins.  This
    487          offset is added to C{_linenum} when displaying the line number
    488          of the error.  Default value: 1.
    489      @type _offset: C{int}
    490      @ivar _descr: A description of the error.
    491      @type _descr: C{string}
    492      @ivar _fatal: True if this is a fatal error.
    493      @type _fatal: C{boolean}
    494      """
    495 -    def __init__(self, descr, linenum=None, is_fatal=1):
    496          """
    497          @type descr: C{string}
    498          @param descr: A description of the error.
    499          @type linenum: C{int}
    500          @param linenum: The line on which the error occured within
    501              the docstring.  The linenum of the first line is 0.
    502          @type is_fatal: C{boolean}
    503          @param is_fatal: True if this is a fatal error.
    504          """
    505          self._descr = descr
    506          self._linenum = linenum
    507          self._fatal = is_fatal
    508          self._offset = 1
    509
    510 -    def is_fatal(self):
    511          """
    512          @return: true if this is a fatal error.  If an error is fatal,
    513              then epydoc should ignore the output of the parser, and
    514              parse the docstring as plaintext.
    515          @rtype: C{boolean}
    516          """
    517          return self._fatal
    518
    519 -    def linenum(self):
    520          """
    521          @return: The line number on which the error occured (including
    522          any offset).  If the line number is unknown, then return
    523          C{None}.
    524          @rtype: C{int} or C{None}
    525          """
    526          if self._linenum is None: return None
    527          else: return self._offset + self._linenum
    528
    529 -    def set_linenum_offset(self, offset):
    530          """
    531          Set the line number offset for this error.  This offset is the
    532          line number where the docstring begins.  This offset is added
    533          to C{_linenum} when displaying the line number of the error.
    534
    535          @param offset: The new line number offset.
    536          @type offset: C{int}
    537          @rtype: C{None}
    538          """
    539          self._offset = offset
    540
    541 -    def descr(self):
    542          return self._descr
    543
    544 -    def __str__(self):
    545          """
    546          Return a string representation of this C{ParseError}.  This
    547          multi-line string contains a description of the error, and
    548          specifies where it occured.
    549
    550          @return: the informal representation of this C{ParseError}.
    551          @rtype: C{string}
    552          """
    553          if self._linenum is not None:
    554              return 'Line %s: %s' % (self._linenum+self._offset, self.descr())
    555          else:
    556              return self.descr()
    557
    558 -    def __repr__(self):
    559          """
    560          Return the formal representation of this C{ParseError}.
    561          C{ParseError}s have formal representations of the form::
    562             <ParseError on line 12>
    563
    564          @return: the formal representation of this C{ParseError}.
    565          @rtype: C{string}
    566          """
    567          if self._linenum is None:
    568              return '<ParseError on line %d' % self._offset
    569          else:
    570              return '<ParseError on line %d>' % (self._linenum+self._offset)
    571
    572 -    def __cmp__(self, other):
    573          """
    574          Compare two C{ParseError}s, based on their line number.
    575            - Return -1 if C{self.linenum<other.linenum}
    576            - Return +1 if C{self.linenum>other.linenum}
    577            - Return 0 if C{self.linenum==other.linenum}.
    578          The return value is undefined if C{other} is not a
    579          ParseError.
    580
    581          @rtype: C{int}
    582          """
    583          if not isinstance(other, ParseError): return -1000
    584          return cmp(self._linenum+self._offset,
    585                     other._linenum+other._offset)
    586
    587  ##################################################
    588  ## Misc helpers
    589  ##################################################
    590  # These are used by multiple markup parsers
    591
    592 -def parse_type_of(obj):
    593      """
    594      @return: A C{ParsedDocstring} that encodes the type of the given
    595      object.
    596      @rtype: L{ParsedDocstring}
    597      @param obj: The object whose type should be returned as DOM document.
    598      @type obj: any
    599      """
    600      # This is a bit hackish; oh well. :)
    601      from epydoc.markup.epytext import ParsedEpytextDocstring
    602      from xml.dom.minidom import Document
    603      doc = Document()
    604      epytext = doc.createElement('epytext')
    605      para = doc.createElement('para')
    606      doc.appendChild(epytext)
    607      epytext.appendChild(para)
    608
    609      if type(obj) is types.InstanceType:
    610          link = doc.createElement('link')
    611          name = doc.createElement('name')
    612          target = doc.createElement('target')
    613          para.appendChild(link)
    614          link.appendChild(name)
    615          link.appendChild(target)
    616          name.appendChild(doc.createTextNode(str(obj.__class__.__name__)))
    617          target.appendChild(doc.createTextNode(str(obj.__class__)))
    618      else:
    619          code = doc.createElement('code')
    620          para.appendChild(code)
    621          code.appendChild(doc.createTextNode(type(obj).__name__))
    622      return ParsedEpytextDocstring(doc)
    623