Action against software patentsGnome2 LogoW3C LogoRed Hat Logo
Made with Libxml2 Logo

The XML C parser and toolkit of Gnome

The tree output

Developer Menu
API Indexes
Related links

The parser returns a tree built during the document analysis. The valuereturned is an xmlDocPtr(i.e., a pointer to anxmlDocstructure). This structure contains information suchas the file name, the document type, and a childrenpointerwhich is the root of the document (or more exactly the first child under theroot which is the document). The tree is made of xmlNodes,chained in double-linked lists of siblings and with a children<->parentrelationship. An xmlNode can also carry properties (a chain of xmlAttrstructures). An attribute may have a value which is a list of TEXT orENTITY_REF nodes.

Here is an example (erroneous with respect to the XML spec since thereshould be only one ELEMENT under the root):

 structure.gif

In the source package there is a small program (not installed by default)called xmllintwhich parses XML files given as argument andprints them back as parsed. This is useful for detecting errors both in XMLcode and in the XML parser itself. It has an option --debugwhich prints the actual in-memory structure of the document; here is theresult with the examplegiven before:

DOCUMENT
version=1.0
standalone=true
  ELEMENT EXAMPLE
    ATTRIBUTE prop1
      TEXT
      content=gnome is great
    ATTRIBUTE prop2
      ENTITY_REF
      TEXT
      content= linux too 
    ELEMENT head
      ELEMENT title
        TEXT
        content=Welcome to Gnome
    ELEMENT chapter
      ELEMENT title
        TEXT
        content=The Linux adventure
      ELEMENT p
        TEXT
        content=bla bla bla ...
      ELEMENT image
        ATTRIBUTE href
          TEXT
          content=linus.gif
      ELEMENT p
        TEXT
        content=...

This should be useful for learning the internal representation model.

Daniel Veillard