sgml_parse(+Parser, 
+Options)Parse an XML file. The parser can operate in two input and two output 
modes. Output is either a structured term as described with
load_structure/2 
or call-backs on predefined events. The first is especially suitable for 
manipulating not-too-large documents, while the latter provides a 
primitive means for handling very large documents.
Input is a stream. A full description of the option-list is below.
- document(-Term)
- A variable that will be unified with a list describing the content of 
the document (see load_structure/2).
- source(+Stream)
- An input stream that is read. This option must be given.
- content_length(+Characters)
- Stop parsing after Characters. This option is useful to parse 
input embedded in envelopes, such as the HTTP protocol.
- cdata(+Representation)
- Specify the representation of cdata elements. Supported are
atom(default), andstring. See load_structure/3 
for details.
- parse(+Unit)
- Defines how much of the input is parsed. This option is used to parse 
only parts of a file.
- file
- Default. Parse everything upto the end of the input.
- element
- The parser stops after reading the first element. Using
source(Stream), this implies reading is stopped as soon as 
the element is complete, and another call may be issued on the same 
stream to read the next element.
- content
- The value contentis likeelementbut assumes 
the element has already been opened. It may be used in a call-back fromcall(on_begin, Pred)
to parse individual 
elements after validating their headers.
- declaration
- This may be used to stop the parser after reading the first declaration. 
This is especially useful to parse only the doctypedeclaration.
- input
- This option is intended to be used in conjunction with the
allowed(Elements)option of get_sgml_parser/2. 
It disables the parser's default to complete the parse-tree by closing 
all open elements.
 
- max_errors(+MaxErrors)
- Set the maximum number of errors. If this number is exceeded further 
writes to the stream will yield an I/O error exception. Printing of 
errors is suppressed after reaching this value. The default is 50. Using max_errors(-1)makes the parser continue, no matter how many errors it encounters.
error(limit_exceeded(max_errors, Max), _)
 
- syntax_errors(+ErrorMode)
- Defines how syntax errors are handled.
- quiet
- Suppress all messages.
- print
- Default. Pass messages to print_message/2.
- style
- Print dubious input such as attempts for redefinitions in the DTD using print_message/2 
with severity
informational.
 
- xml_no_ns(+Mode)
- Error handling if an XML namespace is not defined. Default generates an 
error. If quiet, the error is suppressed. Can be used 
together withcall(urlns, Closure)to provide external 
expansion of namespaces. See also section 
3.3.1.
- call(+Event, :PredicateName)
- Issue call-backs on the specified events. PredicateName is 
the name of the predicate to call on this event, possibly prefixed with 
a module identifier. If the handler throws an exception, parsing is 
stopped and sgml_parse/2 
re-throws the exception. The defined events are:
- begin
- An open-tag has been parsed. The named handler is called with three 
arguments: Handler(+Tag, +Attributes, +Parser).
- end
- A close-tag has been parsed. The named handler is called with two 
arguments: Handler(+Tag, +Parser).
- cdata
- CDATA has been parsed. The named handler is called with two arguments:
Handler(+CDATA, +Parser), where CDATA is an atom 
representing the data.
- pi
- A processing instruction has been parsed. The named handler is called 
with two arguments: Handler(+Text, +Parser), 
where
Text is the text of the processing instruction.
- decl
- A declaration (<!...>) has been read. The named 
handler is called with two arguments:Handler(+Text, 
+Parser), where Text is the text of the declaration 
with comments removed.
This option is expecially useful for highlighting declarations and 
comments in editor support, where the location of the declaration is 
extracted using
get_sgml_parser/2. 
- error
- An error has been encountered. the named handler is called with three 
arguments: Handler(+Severity, +Message, +Parser), 
where
Severity is one ofwarningorerrorand
Message is an atom representing the diagnostic message. The 
location of the error can be determined using get_sgml_parser/2
If this option is present, errors and warnings are not reported using
print_message/3 
- xmlns
- When parsing an in xmlnsmode, a new namespace declaraction 
is pushed on the environment. The named handler is called with three 
arguments:Handler(+NameSpace, +URL, +Parser). 
See section 3.3.1 for details.
- urlns
- When parsing an in xmlnsmode, this predicate can be used 
to map a url into either a canonical URL for this namespace or another 
internal identifier. See section 3.3.1 
for details.