diff options
Diffstat (limited to 'Doc/libsgmllib.tex')
| -rw-r--r-- | Doc/libsgmllib.tex | 105 |
1 files changed, 76 insertions, 29 deletions
diff --git a/Doc/libsgmllib.tex b/Doc/libsgmllib.tex index 129bdd9..23d8504 100644 --- a/Doc/libsgmllib.tex +++ b/Doc/libsgmllib.tex @@ -12,7 +12,7 @@ exists as a basis for the \code{htmllib} module. \stmodindex{htmllib} In particular, the parser is hardcoded to recognize the following -elements: +constructs: \begin{itemize} @@ -22,13 +22,15 @@ Opening and closing tags of the form ``\code{</\var{tag}>}'', respectively. \item -Character references of the form ``\code{\&\#\var{name};}''. +Numeric character references of the form ``\code{\&\#\var{name};}''. \item Entity references of the form ``\code{\&\var{name};}''. \item -SGML comments of the form ``\code{<!--\var{text}>}''. +SGML comments of the form ``\code{<!--\var{text}-->}''. Note that +spaces, tabs, and newlines are allowed between the trailing +``\code{>}'' and the immediately preceeding ``\code{--}''. \end{itemize} @@ -63,41 +65,83 @@ define additional processing at the end of the input, but the redefined version should always call \code{SGMLParser.close()}. \end{funcdesc} +\begin{funcdesc}{handle_starttag}{tag\, method\, attributes} +This method is called to handle start tags for which either a +\code{start_\var{tag}()} or \code{do_\var{tag}()} method has been +defined. The \code{tag} argument is the name of the tag converted to +lower case, and the \code{method} argument is the bound method which +should be used to support semantic interpretation of the start tag. +The \var{attributes} argument is a list of (\var{name}, \var{value}) +pairs containing the attributes found inside the tag's \code{<>} +brackets. The \var{name} has been translated to lower case and double +quotes and backslashes in the \var{value} have been interpreted. For +instance, for the tag \code{<A HREF="http://www.cwi.nl/">}, this +method would be called as \code{unknown_starttag('a', [('href', +'http://www.cwi.nl/')])}. The base implementation simply calls +\code{method} with \code{attributes} as the only argument. +\end{funcdesc} + +\begin{funcdesc}{handle_endtag}{tag\, method} + +This method is called to handle endtags for which an +\code{end_\var{tag}()} method has been defined. The \code{tag} +argument is the name of the tag converted to lower case, and the +\code{method} argument is the bound method which should be used to +support semantic interpretation of the end tag. If no +\code{end_\var{tag}()} method is defined for the closing element, this +handler is not called. The base implementation simply calls +\code{method}. +\end{funcdesc} + +\begin{funcdesc}{handle_data}{data} +This method is called to process arbitrary data. It is intended to be +overridden by a derived class; the base class implementation does +nothing. +\end{funcdesc} + \begin{funcdesc}{handle_charref}{ref} This method is called to process a character reference of the form -``\code{\&\#\var{ref};}'' where \var{ref} is a decimal number in the +``\code{\&\#\var{ref};}''. In the base implementation, \var{ref} must +be a decimal number in the range 0-255. It translates the character to \ASCII{} and calls the method \code{handle_data()} with the character as argument. If \var{ref} is invalid or out of range, the method -\code{unknown_charref(\var{ref})} is called instead. +\code{unknown_charref(\var{ref})} is called to handle the error. A +subclass must override this method to provide support for named +character entities. \end{funcdesc} \begin{funcdesc}{handle_entityref}{ref} -This method is called to process an entity reference of the form -``\code{\&\var{ref};}'' where \var{ref} is an alphabetic entity +This method is called to process a general entity reference of the form +``\code{\&\var{ref};}'' where \var{ref} is an general entity reference. It looks for \var{ref} in the instance (or class) -variable \code{entitydefs} which should give the entity's translation. +variable \code{entitydefs} which should be a mapping from entity names +to corresponding translations. If a translation is found, it calls the method \code{handle_data()} with the translation; otherwise, it calls the method -\code{unknown_entityref(\var{ref})}. +\code{unknown_entityref(\var{ref})}. The default \code{entitydefs} +defines translations for \code{\&}, \code{\&apos}, \code{\>}, +\code{\<}, and \code{\"}. \end{funcdesc} -\begin{funcdesc}{handle_data}{data} -This method is called to process arbitrary data. It is intended to be -overridden by a derived class; the base class implementation does -nothing. +\begin{funcdesc}{handle_comment}{comment} +This method is called when a comment is encountered. The +\code{comment} argument is a string containing the text between the +``\code{<!--}'' and ``\code{-->}'' delimiters, but not the delimiters +themselves. For example, the comment ``\code{<!--text-->}'' will +cause this method to be called with the argument \code{'text'}. The +default method does nothing. +\end{funcdesc} + +\begin{funcdesc}{report_unbalanced}{tag} +This method is called when an end tag is found which does not +correspond to any open element. \end{funcdesc} \begin{funcdesc}{unknown_starttag}{tag\, attributes} This method is called to process an unknown start tag. It is intended to be overridden by a derived class; the base class implementation -does nothing. The \var{attributes} argument is a list of -(\var{name}, \var{value}) pairs containing the attributes found inside -the tag's \code{<>} brackets. The \var{name} has been translated to -lower case and double quotes and backslashes in the \var{value} have -been interpreted. For instance, for the tag -\code{<A HREF="http://www.cwi.nl/">}, this method would be -called as \code{unknown_starttag('a', [('href', 'http://www.cwi.nl/')])}. +does nothing. \end{funcdesc} \begin{funcdesc}{unknown_endtag}{tag} @@ -107,9 +151,9 @@ does nothing. \end{funcdesc} \begin{funcdesc}{unknown_charref}{ref} -This method is called to process an unknown character reference. It -is intended to be overridden by a derived class; the base class -implementation does nothing. +This method is called to process unresolvable numeric character +references. It is intended to be overridden by a derived class; the +base class implementation does nothing. \end{funcdesc} \begin{funcdesc}{unknown_entityref}{ref} @@ -127,22 +171,25 @@ case: \begin{funcdesc}{start_\var{tag}}{attributes} This method is called to process an opening tag \var{tag}. It has preference over \code{do_\var{tag}()}. The \var{attributes} argument -has the same meaning as described for \code{unknown_tag()} above. +has the same meaning as described for \code{handle_starttag()} above. \end{funcdesc} \begin{funcdesc}{do_\var{tag}}{attributes} This method is called to process an opening tag \var{tag} that does not come with a matching closing tag. The \var{attributes} argument -has the same meaning as described for \code{unknown_tag()} above. +has the same meaning as described for \code{handle_starttag()} above. \end{funcdesc} \begin{funcdesc}{end_\var{tag}}{} This method is called to process a closing tag \var{tag}. \end{funcdesc} -Note that the parser maintains a stack of opening tags for which no -matching closing tag has been found yet. Only tags processed by -\code{start_\var{tag}()} are pushed on this stack. Definition of a +Note that the parser maintains a stack of open elements for which no +end tag has been found yet. Only tags processed by +\code{start_\var{tag}()} are pushed on this stack. Definition of an \code{end_\var{tag}()} method is optional for these tags. For tags processed by \code{do_\var{tag}()} or by \code{unknown_tag()}, no -\code{end_\var{tag}()} method must be defined. +\code{end_\var{tag}()} method must be defined; if defined, it will not +be used. If both \code{start_\var{tag}()} and \code{do_\var{tag}()} +methods exist for a tag, the \code{start_\var{tag}()} method takes +precedence. |