pokedex/db/rst.py

   1 # encoding: utf8
   2 r"""Functionality for handling reStructuredText fields in the database.
   3
   4 This module defines the following extra text roles.  By default, they merely
   5 bold the contents of the tag.  Calling code may redefine them with
   6 `docutils.parsers.rst.roles.register_local_role`.  Docutils role extensions
   7 are, apparently, global.
   8
   9 `ability`
  10 `item`
  11 `move`
  12 `pokemon`
  13     These all wrap objects of the corresponding type.  They're intended to be
  14     used to link to these items.
  15
  16 `mechanic`
  17     This is a general-purpose reference role.  The Web Pokédex uses these to
  18     link to pages on mechanics.  Amongst the things tagged with this are:
  19     * Stats, e.g., Attack, Speed
  20     * Major status effects, e.g., paralysis, freezing
  21     * Minor status effects not unique to a single move, e.g., confusion
  22     * Battle mechanics, e.g., "regular damage", "lowers/raises" a stat
  23
  24 `data`
  25     Depends on context.  Created for move effect chances; some effects contain
  26     text like "Has a \:data\:\`move.effect_chance\` chance to...".  Here, the
  27     enclosed text is taken as a reference to a column on the associated move.
  28     Other contexts may someday invent their own constructs.
  29
  30     This is actually implemented by adding a `_pokedex_handle_data` attribute
  31     to the reST document itself, which the `data` role handler attempts to
  32     call.  This function takes `rawtext` and `text` as arguments and should
  33     return a reST node.
  34 """
  35
  36 from docutils.frontend import OptionParser
  37 from docutils.io import Output
  38 import docutils.nodes
  39 from docutils.parsers.rst import Parser, roles
  40 import docutils.utils
  41 from docutils.writers.html4css1 import Writer as HTMLWriter
  42
  43 ### Subclasses of bits of docutils, to munge it into doing what I want
  44 class HTMLFragmentWriter(HTMLWriter):
  45     """Translates reST to HTML, but only as a fragment.  Enclosing <body>,
  46     <head>, and <html> tags are omitted.
  47     """
  48
  49     def apply_template(self):
  50         subs = self.interpolation_dict()
  51         return subs['body']
  52
  53 class UnicodeOutput(Output):
  54     """reST Unicode output.  The distribution only has a StringOutput, and I
  55     want me some Unicode.
  56     """
  57
  58     def write(self, data):
  59         """Returns data (a Unicode string) unaltered."""
  60         return data
  61
  62
  63 ### Text roles
  64
  65 def generic_role(name, rawtext, text, lineno, inliner, options={}, content=[]):
  66     node = docutils.nodes.strong(text, rawtext, **options)
  67     return [node], []
  68
  69 roles.register_local_role('ability', generic_role)
  70 roles.register_local_role('item', generic_role)
  71 roles.register_local_role('move', generic_role)
  72 roles.register_local_role('pokemon', generic_role)
  73 roles.register_local_role('mechanic', generic_role)
  74
  75 def data_role(name, rawtext, text, lineno, inliner, options={}, content=[]):
  76     document = inliner.document
  77     node = document._pokedex_handle_data(rawtext, text)
  78     return [node], []
  79
  80 roles.register_local_role('data', data_role)
  81
  82
  83 ### Public classes
  84
  85 class RstString(object):
  86     """Wraps a reStructuredText string.  Stringifies to the original text, but
  87     may be translated to HTML with .to_html().
  88     """
  89
  90     def __init__(self, source_text, document_properties={}):
  91         """
  92         `document_properties`
  93             List of extra properties to attach to the reST document object.
  94         """
  95         self.source_text = source_text
  96         self.document_properties = document_properties
  97         self._rest_document = None
  98
  99     def __unicode__(self):
 100         return self.source_text
 101
 102     @property
 103     def rest_document(self):
 104         """reST parse tree of the source text.
 105
 106         This property is lazy-loaded.
 107         """
 108
 109         # Return it if we have it
 110         if self._rest_document:
 111             return self._rest_document
 112
 113         parser = Parser()
 114         settings = OptionParser(components=(Parser,HTMLWriter)).get_default_values()
 115         document = docutils.utils.new_document('pokedex', settings)
 116
 117         # Add properties (in this case, probably just the data role handler)
 118         document.__dict__.update(self.document_properties)
 119
 120         # PARSE
 121         parser.parse(self.source_text, document)
 122
 123         self._rest_document = document
 124         return document
 125
 126     @property
 127     def as_html(self):
 128         """Returns the string as HTML4."""
 129
 130         document = self.rest_document
 131         destination = UnicodeOutput()
 132
 133         writer = HTMLFragmentWriter()
 134         return writer.write(document, destination)
 135
 136
 137 class MoveEffectProperty(object):
 138     """Property that wraps a move effect.  Used like this:
 139
 140         MoveClass.effect = MoveEffectProperty()
 141
 142         some_move.effect            # returns an RstString
 143         some_move.effect.as_html    # returns a chunk of HTML
 144
 145     This class also performs `%` substitution on the effect, replacing
 146     `%(effect_chance)d` with the move's actual effect chance.  Also this is a
 147     lie and it doesn't yet.
 148     """
 149
 150     def __get__(self, move, move_class):
 151         # Attach a function for handling the `data` role
 152         # XXX make this a little more fault-tolerant..  maybe..
 153         def data_role_func(rawtext, text):
 154             assert text[0:5] == 'move.'
 155             newtext = getattr(move, text[5:])
 156             return docutils.nodes.Text(newtext, rawtext)
 157
 158         return RstString(move.move_effect.effect,
 159                          document_properties=dict(
 160                              _pokedex_handle_data=data_role_func))