QXmlName

Synopsis

Functions

• def __eq__ (other)
• def __ne__ (other)
• def isNull ()
• def localName (query)
• def namespaceUri (query)
• def prefix (query)
• def toClarkName (query)

Static functions

• def fromClarkName (clarkName, namePool)
• def isNCName (candidate)

Detailed Description

The PySide.QtXmlPatterns.QXmlName class represents the name of an XML node, in an efficient, namespace-aware way.

PySide.QtXmlPatterns.QXmlName represents the name of an XML node in a way that is both efficient and safe for comparing names. Normally, an XML node represents an XML element or attribute, but PySide.QtXmlPatterns.QXmlName can also represent the names of other kinds of nodes, e.g., QAbstractXmlReceiver.processingInstruction() and QAbstractXmlReceiver.namespaceBinding() .

The name of an XML node has three components: The namespace URI , the local name , and the prefix . To see what these refer to in XML, consider the following snippet.

<book xmlns:dc='http://purl.org/dc/elements/1.1'
      xmlns='http://example.com/MyDefault'>
    <dc:title>Mobey Dick</dc:title> ...
</book>

For the element named book , PySide.QtXmlPatterns.QXmlName.localName() returns book , PySide.QtXmlPatterns.QXmlName.namespaceUri() returns http://example.com/MyDefault , and PySide.QtXmlPatterns.QXmlName.prefix() returns an empty string. For the element named title , PySide.QtXmlPatterns.QXmlName.localName() returns title , PySide.QtXmlPatterns.QXmlName.namespaceUri() returns http://purl.org/dc/elements/1.1 , and PySide.QtXmlPatterns.QXmlName.prefix() returns dc .

To ensure that operations with PySide.QtXmlPatterns.QXmlName are efficient, e.g., copying names and comparing them, each instance of PySide.QtXmlPatterns.QXmlName is associated with a name pool , which must be specified at PySide.QtXmlPatterns.QXmlName construction time. The three components of the PySide.QtXmlPatterns.QXmlName , i.e., the namespace URI, the local name, and the prefix, are stored in the name pool mapped to identifiers so they can be shared. For this reason, the only way to create a valid instance of PySide.QtXmlPatterns.QXmlName is to use the class constructor, where the name pool , local name, namespace URI, and prefix must all be specified.

Note that PySide.QtXmlPatterns.QXmlName ‘s default constructor constructs a null instance. It is typically used for allocating unused entries in collections of PySide.QtXmlPatterns.QXmlName .

A side effect of associating each instance of PySide.QtXmlPatterns.QXmlName with a name pool is that each instance of PySide.QtXmlPatterns.QXmlName is tied to the PySide.QtXmlPatterns.QXmlNamePool with which it was created. However, the PySide.QtXmlPatterns.QXmlName class does not keep track of the name pool, so all the accessor functions, e.g., PySide.QtXmlPatterns.QXmlName.namespaceUri() , PySide.QtXmlPatterns.QXmlName.prefix() , PySide.QtXmlPatterns.QXmlName.localName() , and PySide.QtXmlPatterns.QXmlName.toClarkName() require that the correct name pool be passed to them. Failure to provide the correct name pool to these accessor functions results in undefined behavior.

Note that a name pool is not an XML namespace. One name pool can represent instances of PySide.QtXmlPatterns.QXmlName from different XML namespaces, and the instances of PySide.QtXmlPatterns.QXmlName from one XML namespace can be distributed over multiple name pools .

Comparing QXmlNames

To determine what a PySide.QtXmlPatterns.QXmlName refers to, the namespace URI and the local name are used. The prefix is not used because the prefix is simply a shorthand name for use in place of the normally much longer namespace URI. Nor is the prefix used in name comparisons. For example, the following two element nodes represent the same element and compare equal.

<svg xmlns="http://www.w3.org/2000/svg"/>

<x:svg xmlns:x="http://www.w3.org/2000/svg"/>

Although the second name has the prefix x , the two names compare equal as instances of PySide.QtXmlPatterns.QXmlName , because the prefix is not used in the comparison.

A local name can never be an empty string, although the prefix and namespace URI can. If the prefix is not empty, the namespace URI cannot be empty. Local names and prefixes must be valid NCNames, e.g., abc.def or abc123 .

PySide.QtXmlPatterns.QXmlName represents what is sometimes called an expanded QName , or simply a QName.

See also

class PySide.QtXmlPatterns.QXmlName

class PySide.QtXmlPatterns.QXmlName(namePool, localName[, namespaceURI=""[, prefix=""]])

class PySide.QtXmlPatterns.QXmlName(QXmlName)

Parameters:

• namespaceURI – unicode
• prefix – unicode
• namePool – PySide.QtXmlPatterns.QXmlNamePool
• localName – unicode
• QXmlName – PySide.QtXmlPatterns.QXmlName

Constructs an uninitialized PySide.QtXmlPatterns.QXmlName . To build a valid PySide.QtXmlPatterns.QXmlName , you normally use the other constructor, which takes a name pool , namespace URI, local name, and prefix as parameters. But you can also use this constructor to build a null PySide.QtXmlPatterns.QXmlName and then assign an existing PySide.QtXmlPatterns.QXmlName to it.

See also

PySide.QtXmlPatterns.QXmlName.isNull()

Constructs a PySide.QtXmlPatterns.QXmlName instance that inserts localName , namespaceURI and prefix into namePool if they aren’t already there. The accessor functions PySide.QtXmlPatterns.QXmlName.namespaceUri() , PySide.QtXmlPatterns.QXmlName.prefix() , PySide.QtXmlPatterns.QXmlName.localName() , and PySide.QtXmlPatterns.QXmlName.toClarkName() must be passed the namePool used here, so the namePool must remain in scope while the accessor functions might be used. However, two instances can be compared with == or != and copied without the namePool .

The user guarantees that the string components are valid for a QName. In particular, the local name, and the prefix (if present), must be valid NCNames. The function PySide.QtXmlPatterns.QXmlName.isNCName() can be used to test validity of these names. The namespace URI should be an absolute URI. QUrl.isRelative() can be used to test whether the namespace URI is relative or absolute. Finally, providing a prefix is not valid when no namespace URI is provided.

namePool is not copied. Nor is the reference to it retained in this instance. This constructor inserts the three strings into namePool .

PySide.QtXmlPatterns.QXmlName.Constant

Various constants used in the QPatternist.NamePool and PySide.QtXmlPatterns.QXmlName .

Setting of the mask enums use essentially this:

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// Fills the bits from begin to end with 1s and leaves the rest as 0.

template<typename IntegralT>
inline IntegralT bitmask(IntegralT begin, IntegralT end)
{
   IntegralT filled_bits = (1 << (end - begin + 1)) - 1;
   return filled_bits << begin;
}

The masks, such as LocalNameMask , are positive. That is, for the area which the name resides, the bits are set.

static PySide.QtXmlPatterns.QXmlName.fromClarkName(clarkName, namePool)

Parameters:

• clarkName – unicode
• namePool – PySide.QtXmlPatterns.QXmlNamePool

Return type:

PySide.QtXmlPatterns.QXmlName

Converts clarkName into a PySide.QtXmlPatterns.QXmlName , inserts into namePool , and returns it.

A clark name is a way to present a full QName with only one string, where the namespace cannot contain braces. Here are a couple of examples:

Clark Name	Description
html	The local name html , in no namespace
http://www.w3.org/1999/xhtmlhtml	The local name html , in the XHTML namespace
http://www.w3.org/1999/xhtmlmy:html	The local name html , in the XHTML namespace, with the prefix my

If the namespace contains braces, the returned value is either invalid or has undefined content.

If clarkName is an invalid name, a default constructed PySide.QtXmlPatterns.QXmlName is returned.

See also

PySide.QtXmlPatterns.QXmlName.toClarkName()

static PySide.QtXmlPatterns.QXmlName.isNCName(candidate)

Parameters:candidate – unicode Return type:PySide.QtCore.bool

Returns true if candidate is an NCName . An NCName is a string that can be used as a name in XML and XQuery , e.g., the prefix or local name in an element or attribute, or the name of a variable.

See also

PySide.QtXmlPatterns.QXmlName.isNull()

Return type:PySide.QtCore.bool

Returns true if this PySide.QtXmlPatterns.QXmlName is not initialized with a valid combination of namespace URI , local name , and prefix .

A valid local name is always required. The prefix and namespace URI can be empty, but if the prefix is not empty, the namespace URI must not be empty. Local names and prefixes must be valid NCNames, e.g., abc.def or abc123 .

PySide.QtXmlPatterns.QXmlName.localName(query)

Parameters:query – PySide.QtXmlPatterns.QXmlNamePool Return type:unicode

Returns the local name.

Note that for efficiency, the local name string is not stored in the PySide.QtXmlPatterns.QXmlName but in the PySide.QtXmlPatterns.QXmlNamePool that was passed to the constructor. Hence, that same namePool must be passed to this function, so it can be used for looking up the local name.

PySide.QtXmlPatterns.QXmlName.namespaceUri(query)

Parameters:query – PySide.QtXmlPatterns.QXmlNamePool Return type:unicode

Returns the namespace URI.

Note that for efficiency, the namespace URI string is not stored in the PySide.QtXmlPatterns.QXmlName but in the PySide.QtXmlPatterns.QXmlNamePool that was passed to the constructor. Hence, that same namePool must be passed to this function, so it can be used for looking up the namespace URI.

PySide.QtXmlPatterns.QXmlName.__ne__(other)

Parameters:other – PySide.QtXmlPatterns.QXmlName Return type:PySide.QtCore.bool

Returns true if this PySide.QtXmlPatterns.QXmlName is not equal to other ; otherwise false. Two QXmlNames are equal if their namespace URIs are the same and their local names are the same. They are not equal if either their namespace URIs differ or their local names differ. Their prefixes are ignored.

Note that it is meaningless to compare two instances of PySide.QtXmlPatterns.QXmlName that were created with different name pools , but the attempt is not detected and the behavior is undefined.

See also

PySide.QtXmlPatterns.QXmlName.operator==()

PySide.QtXmlPatterns.QXmlName.__eq__(other)

Parameters:other – PySide.QtXmlPatterns.QXmlName Return type:PySide.QtCore.bool

Returns true if this PySide.QtXmlPatterns.QXmlName is equal to other ; otherwise false. Two QXmlNames are equal if their namespace URIs are the same and their local names are the same. The prefixes are ignored.

Note that it is meaningless to compare two instances of PySide.QtXmlPatterns.QXmlName that were created with different name pools , but the attempt is not detected and the behavior is undefined.

See also

PySide.QtXmlPatterns.QXmlName.operator!=()

PySide.QtXmlPatterns.QXmlName.prefix(query)

Parameters:query – PySide.QtXmlPatterns.QXmlNamePool Return type:unicode

Returns the prefix.

Note that for efficiency, the prefix string is not stored in the PySide.QtXmlPatterns.QXmlName but in the PySide.QtXmlPatterns.QXmlNamePool that was passed to the constructor. Hence, that same namePool must be passed to this function, so it can be used for looking up the prefix.

PySide.QtXmlPatterns.QXmlName.toClarkName(query)

Parameters:query – PySide.QtXmlPatterns.QXmlNamePool Return type:unicode

Returns this PySide.QtXmlPatterns.QXmlName formatted as a Clark Name. For example, if the local name is html , the prefix is x , and the namespace URI is http://www.w3.org/1999/xhtml/ , then the Clark Name returned is:

{http://www.w3.org/1999/xhtml/}x:html.

If the local name is MyWidget and the namespace is empty, the Clark Name returned is:

MyWidget

Note that for efficiency, the namespace URI, local name, and prefix strings are not stored in the PySide.QtXmlPatterns.QXmlName but in the PySide.QtXmlPatterns.QXmlNamePool that was passed to the constructor. Hence, that same namePool must be passed to this function, so it can be used for looking up the three string components.

This function can be useful for debugging.

See also

PySide.QtXmlPatterns.QXmlName.fromClarkName()