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{Include files}
  30
  31 <wx/html/htmlpars.h>
  32
  33 \wxheading{See also}
  34
  35 \helpref{Cells Overview}{cells},
  36 \helpref{Tag Handlers Overview}{handlers},
  37 \helpref{wxHtmlTag}{wxhtmltag}
  38
  39 \latexignore{\rtfignore{\wxheading{Members}}}
  40
  41 \membersection{wxHtmlParser::wxHtmlParser}\label{wxhtmlparserwxhtmlparser}
  42
  43 \func{}{wxHtmlParser}{\void}
  44
  45 Constructor.
  46
  47 \membersection{wxHtmlParser::AddTag}\label{wxhtmlparseraddtag}
  48
  49 \func{void}{AddTag}{\param{const wxHtmlTag\& }{tag}}
  50
  51 This may (and may not) be overwriten in derived class.
  52
  53 This method is called each time new tag is about to be added.
  54 {\it tag} contains information about the tag. (See \helpref{wxHtmlTag}{wxhtmltag}
  55 for details.)
  56
  57 Default (wxHtmlParser) behaviour is this:
  58 First it finds a handler capable of handling this tag and then it calls
  59 handler's HandleTag method.
  60
  61 \membersection{wxHtmlParser::AddTagHandler}\label{wxhtmlparseraddtaghandler}
  62
  63 \func{virtual void}{AddTagHandler}{\param{wxHtmlTagHandler }{*handler}}
  64
  65 Adds handler to the internal list (\& hash table) of handlers. This
  66 method should not be called directly by user but rather by derived class'
  67 constructor.
  68
  69 This adds the handler to this {\bf instance} of wxHtmlParser, not to
  70 all objects of this class! (Static front-end to AddTagHandler is provided
  71 by wxHtmlWinParser).
  72
  73 All handlers are deleted on object deletion.
  74
  75 \membersection{wxHtmlParser::AddText}\label{wxhtmlparseraddword}
  76
  77 \func{virtual void}{AddWord}{\param{const char* }{txt}}
  78
  79 Must be overwriten in derived class.
  80
  81 This method is called by \helpref{DoParsing}{wxhtmlparserdoparsing}
  82 each time a part of text is parsed. {\it txt} is NOT only one word, it is
  83 substring of input. It is not formatted or preprocessed (so white spaces are
  84 unmodified).
  85
  86 \membersection{wxHtmlParser::DoParsing}\label{wxhtmlparserdoparsing}
  87
  88 \func{void}{DoParsing}{\param{int }{begin\_pos}, \param{int }{end\_pos}}
  89
  90 \func{void}{DoParsing}{\void}
  91
  92 Parses the m\_Source from begin\_pos to end\_pos-1.
  93 (in noparams version it parses whole m\_Source)
  94
  95 \membersection{wxHtmlParser::DoneParser}\label{wxhtmlparserdoneparser}
  96
  97 \func{virtual void}{DoneParser}{\void}
  98
  99 This must be called after DoParsing().
 100
 101 \membersection{wxHtmlParser::GetFS}\label{wxhtmlparsergetfs}
 102
 103 \constfunc{wxFileSystem*}{GetFS}{\void}
 104
 105 Returns pointer to the file system. Because each tag handler has
 106 reference to it is parent parser it can easily request the file by
 107 calling
 108
 109 \begin{verbatim}
 110 wxFSFile *f = m_Parser -> GetFS() -> OpenFile("image.jpg");
 111 \end{verbatim}
 112
 113 \membersection{wxHtmlParser::GetProduct}\label{wxhtmlparsergetproduct}
 114
 115 \func{virtual wxObject*}{GetProduct}{\void}
 116
 117 Returns product of parsing. Returned value is result of parsing
 118 of the document. The type of this result depends on internal
 119 representation in derived parser (but it must be derived from wxObject!).
 120
 121 See wxHtmlWinParser for details.
 122
 123 \membersection{wxHtmlParser::GetSource}\label{wxhtmlparsergetsource}
 124
 125 \func{wxString*}{GetSource}{\void}
 126
 127 Returns pointer to the source being parsed.
 128
 129
 130 \membersection{wxHtmlParser::InitParser}\label{wxhtmlparserinitparser}
 131
 132 \func{virtual void}{InitParser}{\param{const wxString\& }{source}}
 133
 134 Setups the parser for parsing the {\it source} string. (Should be overridden
 135 in derived class)
 136
 137 \membersection{wxHtmlParser::Parse}\label{wxhtmlparserparse}
 138
 139 \func{wxObject*}{Parse}{\param{const wxString\& }{source}}
 140
 141 Proceeds parsing of the document. This is end-user method. You can simply
 142 call it when you need to obtain parsed output (which is parser-specific)
 143
 144 The method does these things:
 145
 146 \begin{enumerate}\itemsep=0pt
 147 \item calls \helpref{InitParser(source)}{wxhtmlparserinitparser}
 148 \item calls \helpref{DoParsing}{wxhtmlparserdoparsing}
 149 \item calls \helpref{GetProduct}{wxhtmlparsergetproduct}
 150 \item calls \helpref{DoneParser}{wxhtmlparserdoneparser}
 151 \item returns value returned by GetProduct
 152 \end{enumerate}
 153
 154 You shouldn't use InitParser, DoParsing, GetProduct or DoneParser directly.
 155
 156
 157
 158 \membersection{wxHtmlParser::PushTagHandler}\label{wxhtmlparserpushtaghandler}
 159
 160 \func{void}{PushTagHandler}{\param{wxHtmlTagHandler* }{handler}, \param{wxString }{tags}}
 161
 162 Forces the handler to handle additional tags
 163 (not returned by \helpref{GetSupportedTags}{wxhtmltaghandlergetsupportedtags}).
 164 The handler should already be added to this parser.
 165
 166 \wxheading{Parameters}
 167
 168 \docparam{handler}{the handler}
 169 \docparam{tags}{List of tags (in same format as GetSupportedTags's return value). The parser
 170 will redirect these tags to {\it handler} (until call to \helpref{PopTagHandler}{wxhtmlparserpoptaghandler}). }
 171
 172 \wxheading{Example}
 173
 174 Imagine you want to parse following pseudo-html structure:
 175
 176 \begin{verbatim}
 177 <myitems>
 178     <param name="one" value="1">
 179     <param name="two" value="2">
 180 </myitems>
 181
 182 <execute>
 183     <param program="text.exe">
 184 </execute>
 185 \end{verbatim}
 186
 187 It is obvious that you cannot use only one tag handler for <param> tag.
 188 Instead you must use context-sensitive handlers for <param> inside <myitems>
 189 and <param> inside <execute>.
 190
 191 This is the preferred solution:
 192
 193 \begin{verbatim}
 194 TAG_HANDLER_BEGIN(MYITEM, "MYITEMS")
 195     TAG_HANDLER_PROC(tag)
 196     {
 197         // ...something...
 198
 199         m_Parser -> PushTagHandler(this, "PARAM");
 200         ParseInner(tag);
 201         m_Parser -> PopTagHandler();
 202
 203         // ...something...
 204      }
 205 TAG_HANDLER_END(MYITEM)
 206 \end{verbatim}
 207
 208
 209 \membersection{wxHtmlParser::PopTagHandler}\label{wxhtmlparserpoptaghandler}
 210
 211 \func{void}{PopTagHandler}{\void}
 212
 213 Restores parser's state before last call to
 214 \helpref{PushTagHandler}{wxhtmlparserpushtaghandler}.
 215
 216
 217 \membersection{wxHtmlParser::SetFS}\label{wxhtmlparsersetfs}
 218
 219 \func{void}{SetFS}{\param{wxFileSystem }{*fs}}
 220
 221 Sets the virtual file system that will be used to request additional
 222 files. (For example {\tt <IMG>} tag handler requests wxFSFile with the
 223 image data.)
 224