docs/latex/wx/htparser.tex

   1 %
   2 % automatically generated by HelpGen from
   3 % htmlparser.tex at 14/Mar/99 20:13:37
   4 %
   5
   6 \section{\class{wxHtmlParser}}\label{wxhtmlparser}
   7
   8 This class handles the {\bf generic} parsing of HTML document: it scans
   9 the document and divide it into blocks of tags (where one block
  10 consists of begining and ending tag and of text between these
  11 two tags).
  12
  13 It is independent from wxHtmlWindow and can be used as stand-alone parser
  14 (Julian Smart's idea of speech-only HTML viewer or wget-like utility -
  15 see InetGet sample for example).
  16
  17 It uses system of tag handlers to parse the HTML document. Tag handlers
  18 are not staticaly shared by all instances but are created for each
  19 wxHtmlParser instance. The reason is that the handler may contain
  20 document-specific temporary data used during parsing (e.g. complicated
  21 structures like tables).
  22
  23 Typically the user calls only the \helpref{Parse}{wxhtmlparserparse} method.
  24
  25 \wxheading{Derived from}
  26
  27 wxObject
  28
  29 \wxheading{See also}
  30
  31 \helpref{Cells Overview}{cells},
  32 \helpref{Tag Handlers Overview}{handlers},
  33 \helpref{wxHtmlTag}{wxhtmltag}
  34
  35 \latexignore{\rtfignore{\wxheading{Members}}}
  36
  37 \membersection{wxHtmlParser::wxHtmlParser}\label{wxhtmlparserwxhtmlparser}
  38
  39 \func{}{wxHtmlParser}{\void}
  40
  41 Constructor.
  42
  43 \membersection{wxHtmlParser::AddTag}\label{wxhtmlparseraddtag}
  44
  45 \func{void}{AddTag}{\param{const wxHtmlTag\& }{tag}}
  46
  47 This may (and may not) be overwriten in derived class.
  48
  49 This method is called each time new tag is about to be added.
  50 {\it tag} contains information about the tag. (See \helpref{wxHtmlTag}{wxhtmltag}
  51 for details.)
  52
  53 Default (wxHtmlParser) behaviour is this:
  54 First it finds a handler capable of handling this tag and then it calls
  55 handler's HandleTag method.
  56
  57 \membersection{wxHtmlParser::AddTagHandler}\label{wxhtmlparseraddtaghandler}
  58
  59 \func{virtual void}{AddTagHandler}{\param{wxHtmlTagHandler }{*handler}}
  60
  61 Adds handler to the internal list (\& hash table) of handlers. This
  62 method should not be called directly by user but rather by derived class'
  63 constructor.
  64
  65 This adds the handler to this {\bf instance} of wxHtmlParser, not to
  66 all objects of this class! (Static front-end to AddTagHandler is provided
  67 by wxHtmlWinParser).
  68
  69 All handlers are deleted on object deletion.
  70
  71 \membersection{wxHtmlParser::AddText}\label{wxhtmlparseraddword}
  72
  73 \func{virtual void}{AddWord}{\param{const char* }{txt}}
  74
  75 Must be overwriten in derived class.
  76
  77 This method is called by \helpref{DoParsing}{wxhtmlparserdoparsing}
  78 each time a part of text is parsed. {\it txt} is NOT only one word, it is
  79 substring of input. It is not formatted or preprocessed (so white spaces are
  80 unmodified).
  81
  82 \membersection{wxHtmlParser::DoParsing}\label{wxhtmlparserdoparsing}
  83
  84 \func{void}{DoParsing}{\param{int }{begin\_pos}, \param{int }{end\_pos}}
  85
  86 \func{void}{DoParsing}{\void}
  87
  88 Parses the m\_Source from begin\_pos to end\_pos-1.
  89 (in noparams version it parses whole m\_Source)
  90
  91 \membersection{wxHtmlParser::DoneParser}\label{wxhtmlparserdoneparser}
  92
  93 \func{virtual void}{DoneParser}{\void}
  94
  95 This must be called after DoParsing().
  96
  97 \membersection{wxHtmlParser::GetFS}\label{wxhtmlparsergetfs}
  98
  99 \constfunc{wxFileSystem*}{GetFS}{\void}
 100
 101 Returns pointer to the file system. Because each tag handler has
 102 reference to it's parent parser it can easily request the file by
 103 calling
 104
 105 \begin{verbatim}
 106 wxFSFile *f = m_Parser -> GetFS() -> OpenFile("image.jpg");
 107 \end{verbatim}
 108
 109 \membersection{wxHtmlParser::GetProduct}\label{wxhtmlparsergetproduct}
 110
 111 \func{virtual wxObject*}{GetProduct}{\void}
 112
 113 Returns product of parsing. Returned value is result of parsing
 114 of the document. The type of this result depends on internal
 115 representation in derived parser (but it must be derived from wxObject!).
 116
 117 See wxHtmlWinParser for details.
 118
 119 \membersection{wxHtmlParser::GetSource}\label{wxhtmlparsergetsource}
 120
 121 \func{wxString*}{GetSource}{\void}
 122
 123 Returns pointer to the source being parsed.
 124
 125
 126 \membersection{wxHtmlParser::InitParser}\label{wxhtmlparserinitparser}
 127
 128 \func{virtual void}{InitParser}{\param{const wxString\& }{source}}
 129
 130 Setups the parser for parsing the {\it source} string. (Should be overriden
 131 in derived class)
 132
 133 \membersection{wxHtmlParser::Parse}\label{wxhtmlparserparse}
 134
 135 \func{wxObject*}{Parse}{\param{const wxString\& }{source}}
 136
 137 Proceeds parsing of the document. This is end-user method. You can simply
 138 call it when you need to obtain parsed output (which is parser-specific)
 139
 140 The method does these things:
 141
 142 \begin{enumerate}\itemsep=0pt
 143 \item calls \helpref{InitParser(source)}{wxhtmlparserinitparser}
 144 \item calls \helpref{DoParsing}{wxhtmlparserdoparsing}
 145 \item calls \helpref{GetProduct}{wxhtmlparsergetproduct}
 146 \item calls \helpref{DoneParser}{wxhtmlparserdoneparser}
 147 \item returns value returned by GetProduct
 148 \end{enumerate}
 149
 150 You shouldn't use InitParser, DoParsing, GetProduct or DoneParser directly.
 151
 152
 153
 154 \membersection{wxHtmlParser::PushTagHandler}\label{wxhtmlparserpushtaghandler}
 155
 156 \func{void}{PushTagHandler}{\param{wxHtmlTagHandler* }{handler}, \param{wxString }{tags}}
 157
 158 Forces the handler to handle additional tags
 159 (not returned by \helpref{GetSupportedTags}{wxhtmltaghandlergetsupportedtags}).
 160 The handler should already be added to this parser.
 161
 162 \wxheading{Parameters}
 163
 164 \docparam{handler}{the handler}
 165 \docparam{tags}{List of tags (in same format as GetSupportedTags's return value). The parser
 166 will redirect these tags to {\it handler} (until call to \helpref{PopTagHandler}{wxhtmlparserpoptaghandler}). }
 167
 168 \wxheading{Example}
 169
 170 Imagine you want to parse following pseudo-html structure:
 171
 172 \begin{verbatim}
 173 <myitems>
 174     <param name="one" value="1">
 175     <param name="two" value="2">
 176 </myitems>
 177
 178 <execute>
 179     <param program="text.exe">
 180 </execute>
 181 \end{verbatim}
 182
 183 It is obvious that you cannot use only one tag handler for <param> tag.
 184 Instead you must use context-sensitive handlers for <param> inside <myitems>
 185 and <param> inside <execute>.
 186
 187 This is the prefered solution:
 188
 189 \begin{verbatim}
 190 TAG_HANDLER_BEGIN(MYITEM, "MYITEMS")
 191     TAG_HANDLER_PROC(tag)
 192     {
 193         // ...something...
 194
 195         m_Parser -> PushTagHandler(this, "PARAM");
 196         ParseInner(tag);
 197         m_Parser -> PopTagHandler();
 198
 199         // ...something...
 200      }
 201 TAG_HANDLER_END(MYITEM)
 202 \end{verbatim}
 203
 204
 205 \membersection{wxHtmlParser::PopTagHandler}\label{wxhtmlparserpoptaghandler}
 206
 207 \func{void}{PopTagHandler}{\void}
 208
 209 Restores parser's state before last call to
 210 \helpref{PushTagHandler}{wxhtmlparserpushtaghandler}.
 211
 212
 213 \membersection{wxHtmlParser::SetFS}\label{wxhtmlparsersetfs}
 214
 215 \func{void}{SetFS}{\param{wxFileSystem }{*fs}}
 216
 217 Sets the virtual file system that will be used to request additional
 218 files. (For example {\tt <IMG>} tag handler requests wxFSFile with the
 219 image data.)
 220