The Program fxviz

	Description
	An Example
	Summary of Options
	Tributes

Description

fxviz [option ...] [infile]

node type	color	information	unfolds into
comment	yellow	file position	-
processing instruction	orange	file position	-
element	light blue	file position	attributes
text	beige	file position	data segments
attribute	light green	-	-
attribute value	beige	attribute type	-

A text node is usually the result of merging several adjacent text fragments into a single one. It is, however, possible to unfold a text node into the sequence of fragments it consists of.

Simimlarly, an element node can be unfolded such that each of its attributes is represented by its own attribute node as a child of the element.

An Example

Consider the follwing XML document test.xml:

<!DOCTYPE a [
<!ELEMENT a ANY>
<!ELEMENT b ANY>
<!-- comment in DTD -->
<!ATTLIST a x NMTOKEN "foo"
	    y ID      #IMPLIED>
<!ATTLIST b x (yes|no) #REQUIRED	
	    y IDREFS   #IMPLIED>
]>

<?foo pi in prolog ?>
<a x="yup" y="i-1">
  <!-- comment in a -->
  <b x="yes" y="i-1">
    This is text with another <a>a element with an empty <b/> </a>, 
    a character reference &#x3C; and a <![CDATA[CDATA section]]>
  </b> 
  <?foo pi in a ?>
</a>
<!-- comment in epilog -->

The graph description produced by fxviz will display the document tree as follows:

Each node in the tree is connected to each of its children by an edge. Additionally, the nodes are annotated this their starting postions in the XML source. These positions can be viewed by selecting Node Information => Source Position in the vcg menu:

Text nodes are merged such that no text node has another text node as a direct sibling. If you wish to see how a merged text node is composed of text fragments, apply vcg's Unfold Subgraph function to that node. For the second text-node in the b-element this results in:

Additional information about attributes of elements is also available by applying vcg's Unfold Subgraph function to the element node: the attributes are removed from the element node's label, and for each attribute a new attribute node is inserted before the element's content. Each attribute node is labeled with the attribute name and has as a single child the attribute value:

The values of defaulted attributed are marked, and unspecified attributes are either marked as implied or missing:

Finally, if you are interested in the attribute type of some specified attribute, use the Node Information => Attribute Type function:

Summary of Command Line Options

• A file name specifying the input document. Only one input document may be specified.
• A long option of the form --key[=arg]
• A short option of the form -k, where k consists of single character. If k consists of more than one character, each character is assumed to be a short option itself (e.g., -vic equals -v -i -c).
• A short option with argument of the form -k arg, where k consists of a single character.
• A negative short option of the form -nk, where k consists of single character. If k consists of more than one character, each character is assumed to be a negative short option itself (e.g., -nvic equals -nv -ni -nc). If k is empty, then we have the (non-negative) short option -n.
• The string --. This option is ignored, except that all remaining options are interpreted as file names, whether they start with - or not.

-o fname

--output=fname

Write all output, except for errors and warnings, to the file named fname. If fname is -, the standard output is used. Defaults to -.

Tributes