NAME¶
dom - Create an in-memory DOM tree from XML
SYNOPSIS¶
package require tdom
dom method ?arg arg ...?
DESCRIPTION ¶
This command provides the creation of complete DOM trees in memory. In the usual
case a string containing a XML information is parsed and converted into a DOM
tree.
method indicates a specific subcommand.
The valid methods are:
- dom parse ?options?
?data ?
- Parses the XML information and builds up the DOM tree in memory providing
a Tcl object command to this DOM document object. Example:
dom parse $xml doc
$doc documentElement root
parses the XML in the variable xml, creates the DOM tree in memory, make a
reference to the document object, visible in Tcl as a document object command,
and assigns this new object name to the variable doc. When doc gets freed, the
DOM tree and the associated Tcl command object (document and all node objects)
are freed automatically.
set document [dom parse $xml]
set root [$document documentElement]
parses the XML in the variable xml, creates the DOM tree in memory, make a
reference to the document object, visible in Tcl as a document object command,
and returns this new object name, which is then stored in
document. To
free the underlying DOM tree and the associative Tcl object commands (document
+ nodes + fragment nodes) the document object command has to be explicitly
deleted by:
or
The valid options are:
- -simple
- If -simple is specified, a simple but fast parser is used (conforms
not fully to XML recommendation). That should double parsing and DOM
generation speed. The encoding of the data is not transformed inside the
parser. The simple parser does not respect any encoding information in the
XML declaration. It skips over the internal DTD subset and ignores any
information in it. Therefor it doesn't include defaulted attribute values
into the tree, even if the according attribute declaration is in the
internal subset. It also doesn't expand internal or external entity
references other than the predefined entities and character
references.
- -html
- If -html is specified, a fast HTML parser is used, which tries to
even parse badly formed HTML into a DOM tree.
- -keepEmpties
- If -keepEmpties is specified, text nodes, which contain only
whitespaces, will be part of the resulting DOM tree. In default case (
-keepEmpties not given) those empty text nodes are removed at
parsing time.
- -channel <channel-ID>
- If -channel <channel-ID> is specified, the input to be parsed
is read from the specified channel. The encoding setting of the channel
(via fconfigure -encoding) is respected, ie the data read from the channel
are converted to UTF-8 according to the encoding settings, befor the data
is parsed.
- -baseurl <baseURI>
- If -baseurl <baseURI> is specified, the baseURI is used as
the base URI of the document. External entities referenced in the document
are resolved relative to this base URI. This base URI is also stored
within the DOM tree.
- -feedbackAfter <#bytes>
- If -feedbackAfter <#bytes> is specified, the tcl command
::dom::domParseFeedback is evaluated after parsing every #bytes. If you
use this option, you have to create a tcl proc named
::dom::domParseFeedback, otherwise you will get an error. Please notice,
that the calls of ::dom::domParseFeedback are not done exactly every
#bytes, but always at the first element start after every #bytes.
- -externalentitycommand <script>
- If -externalentitycommand <script> is specified, the
specified tcl script is called to resolve any external entities of the
document. The actual evaluated command consists of this option followed by
three arguments: the base uri, the system identifier of the entity and the
public identifier of the entity. The base uri and the public identifier
may be the empty list. The script has to return a tcl list consisting of
three elements. The first element of this list signals, how the external
entity is returned to the processor. At the moment, the two allowed types
are "string" and "channel". The second element of the
list has to be the (absolute) base URI of the external entity to be
parsed. The third element of the list are data, either the already read
data out of the external entity as string in the case of type
"string", or the name of a tcl channel, in the case of type
"channel". Note that if the script returns a tcl channel, it
will not be closed by the processor. It must be closed separately if it is
no longer required.
- -useForeignDTD <boolean>
- If <boolean> is true and the document does not have an external
subset, the parser will call the -externalentitycommand script with empty
values for the systemId and publicID arguments. Pleace notice, that, if
the document also doesn't have an internal subset, the
-startdoctypedeclcommand and -enddoctypedeclcommand scripts, if set, are
not called. The -useForeignDTD respects
- -paramentityparsing
<always|never|notstandalone>
- The -paramentityparsing option controls, if the parser tries to
resolve the external entities (including the external DTD subset) of the
document, while building the DOM tree. -paramentityparsing requires
an argument, which must be either "always", "never",
or "notstandalone". The value "always" means, that the
parser tries to resolves (recursively) all external entities of the XML
source. This is the default, in case -paramentityparsing is
omitted. The value "never" means, that only the given XML source
is parsed and no external entity (including the external subset) will be
resolved and parsed. The value "notstandalone" means, that all
external entities will be resolved and parsed, with the execption of
documents, which explicitly states standalone="yes" in their XML
declaration.
- dom createDocument
docElemName ?objVar?
- Creates a new DOM document object with one element node with node name
docElemName. The objVar controls the memory handling as
explained above.
- dom createDocumentNS uri
docElemName ?objVar?
- Creates a new DOM document object with one element node with node name
docElemName. Uri gives the namespace of the document element
to create. The objVar controls the memory handling as explained
above.
- dom createDocumentNode
?objVar?
- Creates a new, 'empty' DOM document object without any element node.
objVar controls the memory handling as explained above.
- dom setResultEncoding
?encodingName ?
- If encodingName is not given the current global result encoding is
returned. Otherwise the global result encoding is set to
encodingName. All character data, attribute values, etc. will then
be converted from UTF-8, which is delivered from the Expat XML parser, to
the given 8 bit encoding at XML/DOM parse time. Valid values for
encodingName are: utf-8, ascii, cp1250, cp1251, cp1252, cp1253,
cp1254, cp1255, cp1256, cp437, cp850, en, iso8859-1, iso8859-2, iso8859-3,
iso8859-4, iso8859-5, iso8859-6, iso8859-7, iso8859-8, iso8859-9,
koi8-r.
- dom createNodeCmd
?-returnNodeCmd?
(element|comment|text|cdata|pi)Node
commandName
- This method creates Tcl commands, which in turn create tDOM nodes. Tcl
commands created by this command are only avaliable inside a script given
to the domNode method appendFromScript. If a command created with
createNodeCmd is invoked in any other context, it will return
error. The created command commandName replaces any existing
command or procedure with that name. If the commandName includes
any namespace qualifiers, it is created in the specified namespace.
If such command is invoked inside a script given as argument to the domNode
method
appendFromScript, it creates a new node and appends this node at
the end of the child list of the invoking element node. If the option
-returnNodeCmd was given, the command returns the created node as Tcl
command. If this option was omitted, the command returns nothing. Each command
creates always the same type of node. Which type of node is created by the
command is determined by the first argument to the
createNodeCmd. The
syntax of the created command depends on the type of the node it creates.
If the first argument of the method is
elementNode, the created command
will create an element node. The tag name of the created node is
commandName without namespace qualifiers. The syntax of the created
command is:
elementNodeCmd ?attributeName attributeValue ...? ?script?
elementNodeCmd ?-attributeName attributeValue ...? ?script?
elementNodeCmd name_value_list script
The command syntax allows three different ways to specify the attributes of the
resulting element. These could be specified with
attributeName
attributeValue argument pairs, in an "option style" way with
-attriubteName attributeValue argument pairs (the '-' character is only
syntactical sugar and will be stripped off) or as a Tcl list with elements
interpreted as attribute name and the corresponding attribute value. The
attribute name elements in the list may have a leading '-' character, which
will be stripped off.
Every
elementNodeCmd accepts an optional Tcl script as last argument.
This script is evaluated as recursive
appendFromScript script with the
node created by the
elementNodeCmd as parent of all nodes created by
the script.
If the first argument of the method is
textNode, the command will create
a text node. The syntax of the created command is:
textNodeCmd ?-disableOutputEscaping? data
If the optional flag
-disableOutputEscaping is given, the escaping of the
ampersand character (&) and the left angle bracket (<) inside the data
is disabled. You should use this flag carefully.
If the first argument of the method is
commentNode, or
cdataNode,
the command will create an comment node or CDATA section node. The syntax of
the created command is:
If the first argument of the method is
piNode, the command will create a
processing instruction node. The syntax of the created command is:
- dom setStoreLineColumn
?boolean?
- If switched on, the DOM nodes will contain line and column position
information for the original XML document after parsing. The default is,
not to store line and column position information.
- dom setNameCheck
?boolean?
- If NameCheck is true, every method which expects an XML Name, a full
qualified name or a processing instructing target will check, if the given
string is valid according to his production rule. For commands created
with the createNodeCmd method to be used in the context of
appendFromScript the status of the flag at creation time decides.
If NameCheck is true at creation time, the command will check his
arguments, otherwise not. The setNameCheck set this flag. It
returns the current NameCheck flag state. The default state for NameCheck
is true.
- dom setTextCheck
?boolean?
- If TextCheck is true, every command which expects XML Chars, a comment, a
CDATA section value or a processing instructing value will check, if the
given string is valid according to his production rule. For commands
created with the createNodeCmd method to be used in the context of
appendFromScript the status of the flag at creation time decides.
If TextCheck is true at creation time, the command will check his
arguments, otherwise not.The setTextCheck method set this flag. It
returns the current TextCheck flag state. The default state for TextCheck
is true.
- dom setObjectCommands
?(automatic|token|command) ?
- Controls, if documents and nodes are created as tcl commands or as token
to be used with the domNode and domDoc commands. If the mode is
'automatic', then methods used at tcl commands will create tcl commands
and methods used at doc or node tokes will create tokens. If the mode is
'command' then always tcl commands will be created. If the mode is
'token', then always token will be created. The method returns the current
mode. This method is an experimental interface.
- dom isName name
- Returns 1, if name is a valid XML Name according to production 5 of
the XML 1.0 recommendation. This means, that name is a valid XML
element or attribute name. Otherwise it returns 0.
- dom isPIName name
- Returns 1, if name is a valid XML processing instruction target
according to production 17 of the XML 1.0 recommendation. Otherwise it
returns 0.
- dom isNCName name
- Returns 1, if name is a valid NCName according to production 4 of
the of the Namespaces in XML recommendation. Otherwise it returns 0.
- dom isQName name
- Returns 1, if name is a valid QName according to production 6 of
the of the Namespaces in XML recommendation. Otherwise it returns 0.
- dom isCharData
string
- Returns 1, if every character in string is a valid XML Char
according to production 2 of the XML 1.0 recommendation. Otherwise it
returns 0.
- dom isComment string
- Returns 1, if string is a valid comment according to production 15
of the XML 1.0 recommendation. Otherwise it returns 0.
- dom isCDATA string
- Returns 1, if string is valid according to production 20 of the XML
1.0 recommendation. Otherwise it returns 0.
- dom isPIValue string
- Returns 1, if string is valid according to production 16 of the XML
1.0 recommendation. Otherwise it returns 0.
KEYWORDS¶
XML, DOM, document, node, parsing