QuiXML

# The QuiXML API

A fast Ruby XML API written in C with pretty-printing, entity en-/decoding, marshalling and regex addressing.

Copyright © 2003 Sean O'Dell <sean@celsoft.com>
QuiXML is released under the GNU General Public License

Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with the Invariant Sections being "About The Author" and "GNU Free Documentation License", no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License".

### Table of Contents

> QuiXML Programming Examples

> How QuiXML Parses and Outputs XML
> How QuiXML::Tree Stores Its Data Internally
> Transmuting Attribute Data
> Element Path Addressing

> Module and Class Reference

> About The Author

> GNU Free Documentation License

### About QuiXML

> QuiXML is an XML library for Ruby written in C, utilizing the expat library for parsing XML string buffers. It uses only Ruby native data structures to store its XML data internally, so how they are generated is completely open. The library both parses and generates XML, maintaining XML structure or performing pretty printing and automatically encoding/decoding special characters (<, >, &, ', and "). Transmutations to/from attribute string values and Ruby objects can occur when reading/writing XML, allowing for a limited degree of object marshalling. Element path addressing makes it easy to find one or more nodes using literal strings, regular expressions or any other object which supports Ruby case-equality to match against XML node names and attributes.

> A Snippet of Sample Code:

>     require "quixml"

>     # parse an XML file
>     tree = QuiXML::parse(File::readlines("file.xml"))

>     # iterate through a range of nodes
>     tree.find_all([".", ["account", "id", [0..200]]]) do | node |
>     end

>     # add a new node to the root
>     node = QuiXML::create_node("account")
>     node["attributes"]["id"] = 12345
>     tree.root["children"] << node

### QuiXML Programming Examples

> When programming with QuiXML, always start with:

>     require "quixml"

> Examples

> > Creating a New, Empty XML Tree
> > Parsing an XML File
> > Writing XML to a File
> > Generating New XML Content
> > Merging XML
> > Finding a Node
> > Finding All Matching Nodes
> > Get the Text Content of a Node

> Creating a New, Empty XML Tree

>     require "quixml"

>     # creates a new, empty XML tree
>     tree = QuiXML::Tree.new

> Parsing an XML File

>     # creates a new tree by parsing an XML file
>     tree = QuiXML::parse(File::readlines("file.xml"))

> Writing XML to a File

>     # writes a tree's content as XML with pretty-printing
>     File::open("newfile.xml", File::RDWR|File::CREAT) do | file |
>       file.print(tree.to_xml(QuiXML::PRETTY))
>     end

> Generating New XML Content

>     # creates a new, empty XML tree, adds a root node
>     # and adds two child nodes to the root node
>     tree = QuiXML::Tree.new
>     tree.root = QuiXML::create_node("root")
>     tree.root["children"] << QuiXML::create_node("child")
>     tree.root["children"] << QuiXML::create_node("another_child")

> Merging XML

>     # creates a new tree after parsing an XML file
>     # then parses an XML buffer and adds it as a child node to root
>     tree = QuiXML::parse("file.xml")
>     tree.root["children"] << QuiXML::parse_node(xmlbuffer)

> Finding a Node

>     # find a node named /root/account with an attribute named id
>     # which has a value of 42
>     node = tree.find_first(".", ["account", "id", 42])

> Finding All Matching Nodes

>     # iterates through all nodes named /root/account
>     tree.find_all(".", "account") do | node |
>     end

> Get the Text Content of a Node

>     # returns the text content of a node named /root/account/name
>     # where account has an attribute named id
>     # which has a value of 42
>     node = tree.text_of(".", ["account", "id", 42], "name")

### How QuiXML Parses and Outputs XML

> QuiXML allows XML nodes to have mixed content; that is, any node may have text and any number of child elements together in the same node. However, QuiXML follows the convention "text content must appear before child nodes." It can, and will, write out the same exact XML that it reads, if the XML follows that convention.

> QuiXML stores the text content for every node in a single text property (a string) and children as an array of nodes (hashes). A problem arises when an XML buffer with nodes which have snippets of text content appearing after child nodes. Because QuiXML stores all text content in a single variable, it's not possible to preserve the exact format of XML buffers formatted this way.

> When generating XML, QuiXML always outputs each node by writing all of its text content first, and then all of its child nodes.

> The methods parse, parse_node and to_xml each take an optional flags parameter, allowing more control over text content when parsing and generating XML. You may select one of the pre-defined OR values, for simplicity, or build a set of your own flags.

> flags may be any of the following values OR'd (|) together:

> > QuiXML::CONSERVATIVE (usually the default)
> >   An alias for QuiXML::KEEP_MIXED. This is the safest flag because it will harvest ALL text content, even if the content appears after child nodes. However, thereafter, the content will always appear before child nodes, so there is a chance the XML will change format initially. Nonetheless, subsequent reads/writes will never add or strip any text content, so the XML is preserved precisely.
> > QuiXML::PERFECT
> >   No flags are set. Performs just like QuiXML::CONSERVATIVE, but forces the XML to adhere to the "text before child nodes" convention and will not harvest any text appearing after the first child.
> > QuiXML::READABLE
> >   An alias for QuiXML::INDENT_TAGS. Performs just like QuiXML::PERFECT except that, after the first child node is written (thereby protecting the text content), all subsequent child nodes are indented with tabs.
> > QuiXML::PRETTY
> >   An OR of all flags. Very human-readable, but very destructive to the format of your data.
> > QuiXML::STRIP_START
> >   When reading, strips all whitespace from the beginning of text. Does nothing when writing.
> > QuiXML::STRIP_END
> >   When reading, strips all whitespace from the end of text. Does nothing when writing.
> > QuiXML::KEEP_MIXED
> >   When reading, all content, even text appearing after child nodes, will be harvested. If omitted, parsing text content stops where the first child node appears. Does nothing when writing.
> > QuiXML::NEWLINE_TEXT
> >   When writing, writes a newline character immediately after writing the text content (once per node). Does nothing when reading.
> > QuiXML::INDENT_TAGS
> >   When writing, indents every tag with 2 space characters for every level it is nested within the tree. If QuiXML::NEWLINE_TEXT is not set, the first child node will not be indented. Does nothing when reading.

### How QuiXML::Tree Stores Its Data Internally

> QuiXML::Tree stores all of its data as a tree of nested nodes, mimicing the way XML data is organized. Each node on the tree is a small hash containing up to four items (properties): name, attributes, text and children.

> The top node of a QuiXML::Tree object is stored as an instance variable named root. The root node is a complete node just like any other, except it has no parent and is accessible directly as a member of a tree object. WARNING: you are free to set root to point to any object you wish and QuiXML will not attempt to validate its contents in any way, although errors will be given if it is not constructed with at least the basic requirements, given below.

> QuiXML node members

> Each node is a hash with the following members:

> name: the name property is required of every node. This is a string which represents the name of the XML tag, and for obvious reasons, must be present and must conform to the standard for XML tag names.
> attributes: the attributes property is optional. If present, it is a hash containing all the XML attributes associated with the element. Attributes are always in the form name=value. Each attribute name must conform to XML standards for attributes.
> text: the text property is optional. If present, it is a string containing the body data of the element.
> children: the children property is optional. If present, it is an array of nodes (QuiXML-style node hashes) which represent the nested child nodes of this node.

> Here's an example of what a very small QuiXML data tree looks like, starting at the root node:

>     root =
>     {
>       "name" => "aaa",
>       "text" => "content for aaa",
>       "attributes" =>
>       {
>         "attr" => "attrvalue1"
>       },
>       "children" =>
>       [
>         {
>           "name" => "bbb",
>           "text" => "content for bbb",
>           "attributes" =>
>           {
>             "attr" => "attrvalue2"
>           }
>         },
>         {
>           "name" => "ccc",
>           "text" => "content for ccc",
>           "attributes" =>
>           {
>             "attr" => "attrvalue3"
>           }
>         }
>       ]
>     }

> The above looks like this in XML:

>     <aaa "attr"="attrvalue1">content for aaa
>       <bbb "attr"="attrvalue2">content for bbb</bbb>
>       <ccc "attr"="attrvalue3">content for ccc</ccc>
>     </aaa>

> Accessing the attribute "attr" in the element "ccc" could look something like this:

>     qxml.root["children"][1]["attributes"]["attr"]

> Although, if any objects were nil anywhere in that long sub-script reference, you would get an exception. A better, safer way to access that same attribute would be to use an addressing method.

### Transmuting Attribute Data

> Transmutation blocks can marshal Ruby objects when parsing in or writing out XML attributes. This can make XML more human-readable by allowing attributes which are represented as strings in XML to be stored internally as Ruby objects. For example, an attribute stored internally as a Ruby boolean true or false value can be represented by the strings "true" or "false" in XML. These transmutations can be performed both when parsing XML into or generating XML from a QuiXML::Tree object.

> QuiXML::Tree nodes allow their attributes property (a hash) to associate string names with any Ruby objects, but when reading and writing XML, those objects are treated as strings. By default, when writing an attribute to an XML string buffer, it is written using the string representation of the object and, inversely, when reading XML, all attributes are read in and stored as strings.

> You can override this behavior by providing a transmutation block when calling the parse, parse_node and to_xml methods.

> For example, let's create a very simple XML buffer and parse it:

>     require "quixml"

>     qxml = QuiXML::Tree.new

>     qxml.parse("<root \"isrootnode\"=\"yes\">")

> This results in a tree which has this representation internally:

>     root =
>     {
>       "name" => "root",
>       "attributes" =>
>       {
>         "isrootnode" => "yes"
>       }
>     }

> Notice how the attribute "isrootnode" is read in as a string. If we knew that the attribute was a boolean, why not read the attribute in as a real Ruby true or false value?

> Here is an example of how a transmutation block can do this:

>     qxml.parse("<root \"isrootnode\"=\"true\">") do
>       | name, value |

>       case name
>         when "isrootnode"
>           value = value == "yes" ? true : false
>       end

>       value
>     end

> The above shows how, when an attribute named "isrootnode" is found, a test is performed to see if the string value is "yes," in which case a real Ruby true value is returned. If the test fails, a real Ruby false is returned.

> The internal representation now looks like this:

>     root =
>     {
>       "name" => "root",
>       "attributes" =>
>       {
>         "isrootnode" => true
>       }
>     }

> You will notice now that "isrootnode" is stored internally as a real Ruby true value.

> We can also provide a transmutation block when generating XML for objects that may not have a to_s method suitable for storing as an XML attribute.

> For example, suppose we wanted to store "isrootnode" not as "true" or "false" but "yes" or "no." A transmutation block to do this would look like this:

>     xml = qxml.to_xml do | name, value |

>       case name
>         when "isrootnode"
>           value = value ? "yes" : "no"
>       end

>       value
>     end

> This would output the tree as this XML string buffer:

>     <root "isrootnode"="yes" />

> When the same transmutations need to occur in different places in code, it may be convenient to store the blocks as Proc objects and passed to parse, parse_node or to_xml as needed. For example:

>     parse_transmutator = Proc.new do | name, value |
>       case name
>         when "isrootnode"
>           value = value == "yes" ? true : false
>       end

>       value
>     end

>     qxml.parse("<root \"isrootnode\"=\"yes\">",
>       &parse_transmutator)

> This would give us a tree with a Ruby true/false value for the "isrootnode" attribute.

### Element Path Addressing

> The QuiXML::Tree methods find_all, find_first, text_of, attributes_of and children_of all require a special search sytnax used to find one or more nodes in the tree.

> To each of these functions, you pass a series of values (a variable number of arguments) which are used to perform tests on each node of the tree. The values can be literal strings, regular expressions or any other expression which is capable of performing case-equality tests. At the time of this writing, the author is aware of only the following built-in Ruby objects which support case-equality testing and which are likely to be useful as addressing tests: Date, Range, Regexp and String.

> Let's look at example of how we might test and print the attribute of an element using the example tree hierarchy from above using conventional methods, sans protective expressions:

>     # unsafe method
>     qxml.root["children"].each do | node |
>       if node["attributes"]["attrname"] == "attrvalue3" then
>         print ("#{node['attributes']['attrname']}\n")
>       end
>     end

> A major problem with accessing the tree's nodes this way is we cannot be certain that ["children"], ["attributes"] or ["attrname"] even exists. If any of them are missing from the tree, an error will occur.

> A better way to access that same element might be:

>     # a safer way
>     qxml.find_all("aaa", [//, "attrname", "attrvalue3"]) do | node |
>       print ("#{node['attributes']['attrname']}\n")
>     end

> This essentially does the same thing, except that the block will only return for elements which are children of root node "aaa" and have an attribute named "attrname" which match the literal string "attrvalue3".

> Addressing syntax

> An element address expression is a series of values passed to find_all or find_first.

> To test a node's name, pass any expression (except an array which indicates an attribute test) which supports case-equality testing.

> To test a node's name and attribute value at the same time, pass an array which contains exactly three items, and in this order: [ node test, attribute name, attribute test ]. Both the node and attribute test may be any case-equality test. The attribute name, however, must be a literal string and will match only attributes with the exact name given.

> > NOTE: if the attribute value test (third item) is nil, then a special test is performed. If the node name matches its test and the node has no attribute with the name given, the entire test is a match).

> An example test series (addressing):

>     ".",                           # root node test
>     /[bc]/,                          # child node test
>     [ /^ccc/, "attr", "eee".."fff" ] # child node/attribute test

> Note that the first test appears as "."; a single period always matches the first (root) node of the tree.

> Now let's analyze a code example using our previous example tree:

>     qxml.find_first(".", [//, "attr", "attrvalue3"])

> In the above series, the first test "aaa" is a literal string, and will be tried against the name of the tree's root node. The second test is tried against both the node names of only immediate children of "aaa" as well as the value (if any)

> A little raw theory

> Addressing tests always begins testing against the root node, unlike XPath, which lets you apply your test to the first matching element anywhere in the tree. The first test must ALWAYS contain an expression which will match the root node, or the find_ method is guaranteed to return no matches at all ("." always matches the root node).

> Each test in the series is tried against elements which are nested exactly as deep as the test itself is within the series, and only elements whose ancestors have all matched are tried. In order for an element to return as a "full match", it must match the test for its level and every ancestor in its hierarchy must match theirs and there must be no more tests in the series to perform on descendants of the element. If an element is a "full match" and has descendants (for which no more tests are available) that has no bearing on its status; it is still a full match and its descendents will remain so.

> You can place simple node name tests and node name/attribute tests (3-item array) anywhere in the series you wish.

### Module and Class Reference

QuiXML Module Methods

> create_node ( name ) -> aNewNode
> parse ( string <, flags > ) { | name, value | block } -> aNewQuiXMLTree
> parse_node ( string <, flags > ) { | name, value | block } -> aNewNode
> with_node ( node ) { | tree | block } -> aNewQuiXMLTree

QuiXML::Tree Class Methods

> new ( < rootnode > ) -> aNewQuiXMLTree

QuiXML::Tree Instance Methods

> attributes_of ( < case < , case < , ... > > > ) -> theAttributes
> children_of ( < case < , case < , ... > > > ) -> theChildren
> find_all ( < case < , case < , ... > > > ) { | node | block } -> anArray
> find_first ( < case < , case < , ... > > > ) -> aNode
> parse ( string <, flags > ) { | name, value | block } -> theRootNode
> root -> theRootNode
> root= -> theRootNode
> text_of ( < case < , case < , ... > > > ) -> theText
> to_xml { | name, value | block } -> aString

QuiXML Module Methods

create_node
  QuiXML::create_node( name ) -> aNewNode

Creates a new, empty node which has the name given. This node is a hash containing native Ruby data types for its attributes, children and text content.

example:

>     tree = QuiXML::Tree.new
>     tree.root = QuiXML::create_node

parse
  QuiXML::parse( string <, flags > ) { | name, value | block } -> aNewQuiXMLTree

Parses a string buffer which should contain only valid XML and returns a new QuiXML::Tree object. If a block is provided, it is called for every attribute encountered, passing its name and current string value and will set the internal value of the attribute to the last object returned by the block.
Optional parameter flags determines how XML is parsed. QuiXML::CONSERVATIVE is default. See How QuiXML Parses and Outputs XML.

example:

>     tree = QuiXML::parse(File::readlines("file.xml")) do | name, value |
>       case name
>         when "id"
>           value = value.to_i
>       end
>       value
>     end

parse_node
  QuiXML::parse_node( string <, flags > ) { | name, value | block } -> aNewNode

Parses a string buffer which should contain only valid XML and returns a new top (root) node for the tree as a hash containing all the basic node properties (name, attributes, children and text). If a block is provided, it is called for every attribute encountered, passing its name and current string value and will set the internal value of the attribute to the last object returned by the block.
Optional parameter flags determines how XML is parsed. QuiXML::CONSERVATIVE is default. See How QuiXML Parses and Outputs XML.

example:

>     children = tree.children_of(".", ["account", "id", 42], "ext_data")
>     children << QuiXML::parse_node(xml_buffer) if (children)

with_node
  QuiXML::with_node( node ) { | tree | block } -> aNewQuiXMLTree

Creates a new QuiXML::Tree object using the given node as its root, and then passes the new tree as a parameter to the block given.

example:

>     node = tree.find_first(".", ["account", "id", 42])
>     QuiXML::with_node(node) do | sub_tree |
>       sub_tree.find_all("notes", "note") do | note_node |
>         print "#{note_node['text']}\n"
>       end
>     end

QuiXML::Tree Class Methods

new
  QuiXML::Tree.new( < rootnode > ) -> aNewQuiXMLTree

Creates a new QuiXML tree object. If rootnode is provided, it will be used as the root node for the tree, otherwise the root node will be empty (nil).

example:

>     tree = QuiXML::Tree.new

QuiXML::Tree Instance Methods

attributes_of
  tree.attributes_of( < case < , case < , ... > > > ) -> theAttributes

Returns the attributes (a hash) of the first node which matches the entire series of case-equality tests. If no match is found, returns nil. See Element Path Addressing.

example:

>     attrs = tree.attributes_of(".", ["account", "id", 42])
>     attrs["date_processed"] = Time.now if (attrs)

children_of
  tree.children_of( < case < , case < , ... > > > ) -> theChildren

Returns the child nodes (an array) of the first node which matches the entire series of case-equality tests. If no match is found, returns nil. See Element Path Addressing.

example:

>     children = tree.children_of(".", ["account", "id", 42], "notes")
>     children << QuiXML::create_node("note") if (attrs)

find_all
  tree.find_all( < case < , case < , ... > > > ) { | node | block } -> anArray

Returns an array containing every node that matches the entire series of case-equality tests. If no match is found, returns an empty array. If a block is given, it is called for every matching node found, passing the node as a parameter. See Element Path Addressing.

example:

>     tree.find_all(".", ["account", "id", [0..200]]) do | node |
>       process_account(node)
>     end

find_first
  tree.find_first( < case < , case < , ... > > > ) -> aNode

Returns the first node (a hash) which matches the entire series of case-equality tests. If no match is found, returns nil. See Element Path Addressing.

example:

>     node = tree.find_first(".", [ "account", "id", 42 ])
>     process_account(node) if (node)

parse
  tree.parse( string <, flags > ) { | name, value | block } -> theRootNode

Parses a string buffer which should contain only valid XML and returns the tree's new root node. If a block is provided, it is called for every attribute encountered, passing its name and current string value and will set the internal value of the attribute to the last object returned by the block.
Optional parameter flags determines how XML is parsed. QuiXML::CONSERVATIVE is default. See How QuiXML Parses and Outputs XML.

example:

>     tree = QuiXML::Tree.new
>     tree.parse(File::readlines("file.xml")) do | name, value |
>       case name
>         when "id"
>           value = value.to_i
>       end
>       value
>     end

root
  tree.root -> theRootNode

Returns the hash object stored at the root node.

example:

>     tree = QuiXML::parse(File::readlines("file.xml"))
>     tree.root["children"] << QuiXML::create_node

root=
  tree.root= -> theRootNode

Sets the root node to an arbitrary object, which should be a hash object of a structure QuiXML recognizes.

example:

>     tree = QuiXML::Tree.new
>     tree.root = QuiXML::create_node

text_of
  tree.text_of( < case < , case < , ... > > > ) -> theText

Returns the text content (a string) of the first node which matches the entire series of case-equality tests. If no match is found, returns nil. See Element Path Addressing.

example:

>     content = tree.text_of(".", ["account", "id", 42], "name")
>     print ("account name: #{content}\n")

to_xml
  tree.to_xml{ | name, value | block } -> aString

Creates a valid XML string buffer which represents the entire data tree stored internally starting at the root node. If a block is provided, it is called for every attribute encountered, passing its name and current value and will change the outputted value of the attribute to the string representation of the last object returned by the block.
Optional parameter flags determines how XML is generated. QuiXML::CONSERVATIVE is default. See How QuiXML Parses and Outputs XML.

example:

>     print tree.to_xml(QuiXML::PRETTY) do | name, value |
>       case name
>         when "id"
>           value = value.to_s
>       end
>       value
>     end

### About The Author

> QuiXML and "The QuiXML API" were written by Sean O'Dell <sean@celsoft.com>, the sole developer at Celtech Software (www.celsoft.com) and admin/programmer at a small Ruby-centric web hosting company called Atomic Systems (www.atomicsystems.com).

### GNU Free Documentation License

> Version 1.2, November 2002

>     Copyright (C) 2000,2001,2002  Free Software Foundation, Inc.
>     59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
>     Everyone is permitted to copy and distribute verbatim copies
>     of this license document, but changing it is not allowed.

> 0. PREAMBLE

> The purpose of this License is to make a manual, textbook, or other functional and useful document "free" in the sense of freedom: to assure everyone the effective freedom to copy and redistribute it, with or without modifying it, either commercially or noncommercially. Secondarily, this License preserves for the author and publisher a way to get credit for their work, while not being considered responsible for modifications made by others.

> This License is a kind of "copyleft", which means that derivative works of the document must themselves be free in the same sense. It complements the GNU General Public License, which is a copyleft license designed for free software.

> We have designed this License in order to use it for manuals for free software, because free software needs free documentation: a free program should come with manuals providing the same freedoms that the software does. But this License is not limited to software manuals; it can be used for any textual work, regardless of subject matter or whether it is published as a printed book. We recommend this License principally for works whose purpose is instruction or reference.

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> A "Transparent" copy of the Document means a machine-readable copy, represented in a format whose specification is available to the general public, that is suitable for revising the document straightforwardly with generic text editors or (for images composed of pixels) generic paint programs or (for drawings) some widely available drawing editor, and that is suitable for input to text formatters or for automatic translation to a variety of formats suitable for input to text formatters. A copy made in an otherwise Transparent file format whose markup, or absence of markup, has been arranged to thwart or discourage subsequent modification by readers is not Transparent. An image format is not Transparent if used for any substantial amount of text. A copy that is not "Transparent" is called "Opaque".

> Examples of suitable formats for Transparent copies include plain ASCII without markup, Texinfo input format, LaTeX input format, SGML or XML using a publicly available DTD, and standard-conforming simple HTML, PostScript or PDF designed for human modification. Examples of transparent image formats include PNG, XCF and JPG. Opaque formats include proprietary formats that can be read and edited only by proprietary word processors, SGML or XML for which the DTD and/or processing tools are not generally available, and the machine-generated HTML, PostScript or PDF produced by some word processors for output purposes only.

> The "Title Page" means, for a printed book, the title page itself, plus such following pages as are needed to hold, legibly, the material this License requires to appear in the title page. For works in formats which do not have any title page as such, "Title Page" means the text near the most prominent appearance of the work's title, preceding the beginning of the body of the text.

> A section "Entitled XYZ" means a named subunit of the Document whose title either is precisely XYZ or contains XYZ in parentheses following text that translates XYZ in another language. (Here XYZ stands for a specific section name mentioned below, such as "Acknowledgements", "Dedications", "Endorsements", or "History".) To "Preserve the Title" of such a section when you modify the Document means that it remains a section "Entitled XYZ" according to this definition.

> The Document may include Warranty Disclaimers next to the notice which states that this License applies to the Document. These Warranty Disclaimers are considered to be included by reference in this License, but only as regards disclaiming warranties: any other implication that these Warranty Disclaimers may have is void and has no effect on the meaning of this License.

> 2. VERBATIM COPYING

> You may copy and distribute the Document in any medium, either commercially or noncommercially, provided that this License, the copyright notices, and the license notice saying this License applies to the Document are reproduced in all copies, and that you add no other conditions whatsoever to those of this License. You may not use technical measures to obstruct or control the reading or further copying of the copies you make or distribute. However, you may accept compensation in exchange for copies. If you distribute a large enough number of copies you must also follow the conditions in section 3.

> You may also lend copies, under the same conditions stated above, and you may publicly display copies.

> 3. COPYING IN QUANTITY

> If you publish printed copies (or copies in media that commonly have printed covers) of the Document, numbering more than 100, and the Document's license notice requires Cover Texts, you must enclose the copies in covers that carry, clearly and legibly, all these Cover Texts: Front-Cover Texts on the front cover, and Back-Cover Texts on the back cover. Both covers must also clearly and legibly identify you as the publisher of these copies. The front cover must present the full title with all words of the title equally prominent and visible. You may add other material on the covers in addition. Copying with changes limited to the covers, as long as they preserve the title of the Document and satisfy these conditions, can be treated as verbatim copying in other respects.

> If the required texts for either cover are too voluminous to fit legibly, you should put the first ones listed (as many as fit reasonably) on the actual cover, and continue the rest onto adjacent pages.

> If you publish or distribute Opaque copies of the Document numbering more than 100, you must either include a machine-readable Transparent copy along with each Opaque copy, or state in or with each Opaque copy a computer-network location from which the general network-using public has access to download using public-standard network protocols a complete Transparent copy of the Document, free of added material. If you use the latter option, you must take reasonably prudent steps, when you begin distribution of Opaque copies in quantity, to ensure that this Transparent copy will remain thus accessible at the stated location until at least one year after the last time you distribute an Opaque copy (directly or through your agents or retailers) of that edition to the public.

> It is requested, but not required, that you contact the authors of the Document well before redistributing any large number of copies, to give them a chance to provide you with an updated version of the Document.

> 4. MODIFICATIONS

> You may copy and distribute a Modified Version of the Document under the conditions of sections 2 and 3 above, provided that you release the Modified Version under precisely this License, with the Modified Version filling the role of the Document, thus licensing distribution and modification of the Modified Version to whoever possesses a copy of it. In addition, you must do these things in the Modified Version:

> - A. Use in the Title Page (and on the covers, if any) a title distinct from that of the Document, and from those of previous versions (which should, if there were any, be listed in the History section of the Document). You may use the same title as a previous version if the original publisher of that version gives permission.
> - B. List on the Title Page, as authors, one or more persons or entities responsible for authorship of the modifications in the Modified Version, together with at least five of the principal authors of the Document (all of its principal authors, if it has fewer than five), unless they release you from this requirement.
> - C. State on the Title page the name of the publisher of the Modified Version, as the publisher.
> - D. Preserve all the copyright notices of the Document.
> - E. Add an appropriate copyright notice for your modifications adjacent to the other copyright notices.
> - F. Include, immediately after the copyright notices, a license notice giving the public permission to use the Modified Version under the terms of this License, in the form shown in the Addendum below.
> - G. Preserve in that license notice the full lists of Invariant Sections and required Cover Texts given in the Document's license notice.
> - H. Include an unaltered copy of this License.
> - I. Preserve the section Entitled "History", Preserve its Title, and add to it an item stating at least the title, year, new authors, and publisher of the Modified Version as given on the Title Page. If there is no section Entitled "History" in the Document, create one stating the title, year, authors, and publisher of the Document as given on its Title Page, then add an item describing the Modified Version as stated in the previous sentence.
> - J. Preserve the network location, if any, given in the Document for public access to a Transparent copy of the Document, and likewise the network locations given in the Document for previous versions it was based on. These may be placed in the "History" section. You may omit a network location for a work that was published at least four years before the Document itself, or if the original publisher of the version it refers to gives permission.
> - K. For any section Entitled "Acknowledgements" or "Dedications", Preserve the Title of the section, and preserve in the section all the substance and tone of each of the contributor acknowledgements and/or dedications given therein.
> - L. Preserve all the Invariant Sections of the Document, unaltered in their text and in their titles. Section numbers or the equivalent are not considered part of the section titles.
> - M. Delete any section Entitled "Endorsements". Such a section may not be included in the Modified Version.
> - N. Do not retitle any existing section to be Entitled "Endorsements" or to conflict in title with any Invariant Section.
> - O. Preserve any Warranty Disclaimers.

> If the Modified Version includes new front-matter sections or appendices that qualify as Secondary Sections and contain no material copied from the Document, you may at your option designate some or all of these sections as invariant. To do this, add their titles to the list of Invariant Sections in the Modified Version's license notice. These titles must be distinct from any other section titles.

> You may add a section Entitled "Endorsements", provided it contains nothing but endorsements of your Modified Version by various parties--for example, statements of peer review or that the text has been approved by an organization as the authoritative definition of a standard.

> You may add a passage of up to five words as a Front-Cover Text, and a passage of up to 25 words as a Back-Cover Text, to the end of the list of Cover Texts in the Modified Version. Only one passage of Front-Cover Text and one of Back-Cover Text may be added by (or through arrangements made by) any one entity. If the Document already includes a cover text for the same cover, previously added by you or by arrangement made by the same entity you are acting on behalf of, you may not add another; but you may replace the old one, on explicit permission from the previous publisher that added the old one.

> The author(s) and publisher(s) of the Document do not by this License give permission to use their names for publicity for or to assert or imply endorsement of any Modified Version.

> 5. COMBINING DOCUMENTS

> You may combine the Document with other documents released under this License, under the terms defined in section 4 above for modified versions, provided that you include in the combination all of the Invariant Sections of all of the original documents, unmodified, and list them all as Invariant Sections of your combined work in its license notice, and that you preserve all their Warranty Disclaimers.

> The combined work need only contain one copy of this License, and multiple identical Invariant Sections may be replaced with a single copy. If there are multiple Invariant Sections with the same name but different contents, make the title of each such section unique by adding at the end of it, in parentheses, the name of the original author or publisher of that section if known, or else a unique number. Make the same adjustment to the section titles in the list of Invariant Sections in the license notice of the combined work.

> In the combination, you must combine any sections Entitled "History" in the various original documents, forming one section Entitled "History"; likewise combine any sections Entitled "Acknowledgements", and any sections Entitled "Dedications". You must delete all sections Entitled "Endorsements."

> 6. COLLECTIONS OF DOCUMENTS

> You may make a collection consisting of the Document and other documents released under this License, and replace the individual copies of this License in the various documents with a single copy that is included in the collection, provided that you follow the rules of this License for verbatim copying of each of the documents in all other respects.

> You may extract a single document from such a collection, and distribute it individually under this License, provided you insert a copy of this License into the extracted document, and follow this License in all other respects regarding verbatim copying of that document.

> 7. AGGREGATION WITH INDEPENDENT WORKS

> A compilation of the Document or its derivatives with other separate and independent documents or works, in or on a volume of a storage or distribution medium, is called an "aggregate" if the copyright resulting from the compilation is not used to limit the legal rights of the compilation's users beyond what the individual works permit. When the Document is included in an aggregate, this License does not apply to the other works in the aggregate which are not themselves derivative works of the Document.

> If the Cover Text requirement of section 3 is applicable to these copies of the Document, then if the Document is less than one half of the entire aggregate, the Document's Cover Texts may be placed on covers that bracket the Document within the aggregate, or the electronic equivalent of covers if the Document is in electronic form. Otherwise they must appear on printed covers that bracket the whole aggregate.

> 8. TRANSLATION

> Translation is considered a kind of modification, so you may distribute translations of the Document under the terms of section 4. Replacing Invariant Sections with translations requires special permission from their copyright holders, but you may include translations of some or all Invariant Sections in addition to the original versions of these Invariant Sections. You may include a translation of this License, and all the license notices in the Document, and any Warranty Disclaimers, provided that you also include the original English version of this License and the original versions of those notices and disclaimers. In case of a disagreement between the translation and the original version of this License or a notice or disclaimer, the original version will prevail.

> If a section in the Document is Entitled "Acknowledgements", "Dedications", or "History", the requirement (section 4) to Preserve its Title (section 1) will typically require changing the actual title.

> 9. TERMINATION

> You may not copy, modify, sublicense, or distribute the Document except as expressly provided for under this License. Any other attempt to copy, modify, sublicense or distribute the Document is void, and will automatically terminate your rights under this License. However, parties who have received copies, or rights, from you under this License will not have their licenses terminated so long as such parties remain in full compliance.

> 10. FUTURE REVISIONS OF THIS LICENSE

> The Free Software Foundation may publish new, revised versions of the GNU Free Documentation License from time to time. Such new versions will be similar in spirit to the present version, but may differ in detail to address new problems or concerns. See http://www.gnu.org/copyleft/.

> Each version of the License is given a distinguishing version number. If the Document specifies that a particular numbered version of this License "or any later version" applies to it, you have the option of following the terms and conditions either of that specified version or of any later version that has been published (not as a draft) by the Free Software Foundation. If the Document does not specify a version number of this License, you may choose any version ever published (not as a draft) by the Free Software Foundation.

The QuiXML API, Copyright © 2003 Sean O'Dell <sean@celsoft.com>
This document is released under the GNU Free Documentation License