The XML C parser and toolkit of Gnome

The parser returns a tree built during the document analysis. Thevaluereturned is an xmlDocPtr(i.e., a pointer toanxmlDocstructure). This structure contains informationsuchas the file name, the document type, and achildrenpointerwhich is the root of the document (or moreexactly the first child under theroot which is the document). The tree ismade of xmlNodes,chained in double-linked lists of siblingsand with a children<->parentrelationship. An xmlNode can also carryproperties (a chain of xmlAttrstructures). An attribute may have a valuewhich is a list of TEXT orENTITY_REF nodes.

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

In the source package there is a small program (not installed bydefault)called xmllintwhich parses XML files given asargument andprints them back as parsed. This is useful for detecting errorsboth in XMLcode and in the XML parser itself. It has an option--debugwhich prints the actual in-memory structure of thedocument; here is theresult with the examplegivenbefore:

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