[antlr-interest] XPA and ANTLR

[ooobles]

Hi all,

It's been a while since I've got to play with ANTLR in a new way. 
I've been happily making up new grammars for a while now. :)  I now
have the new challenge of parsing XML. After writing a 1200line parser
that reads over a dom4j tree, I decided there must be a better way. 
Thankfully, I found XPA and have started writing a tree walker for
reading XML Schemas (XSD).

One thing I find with tree walkers is that I can't be sure if I missed
nodes in the tree.  A tree walker can silently skip child nodes
because the grammar has already been met.  Is there any way to force
the parser to report an error when additional nodes have been found in
the tree?

I've been using one of the XPA examples to write the tree parser (see
below). It *seems* to read XSD, but I'm quite sure it is skipping
some elements.

As an aside, has anyone already written an XSD parser that generates a
 nice internal model? :)  I'm guessing I'll need to do a few passes
over the XSD files to resolve all the data types, groups, elements, etc.

Thanks,
David.

PS I read over a few other messages mentioning that there arn't many
fans of XML here.  I'm definately not a fan either, but when you
work in a group that only does XML, you don't get much choice. :) 

-------------- XSD Tree Parser ----------------

class ComponentTreeParser extends TreeParser;
options 
{
   buildAST = true;
   ASTLabelType = "XMLAST";
}

// enable wildcard processing for xtal and 
// set wildcard element type to "<wildcard>"
tokens 
{
    "<wildcard>";
}

schema : #(c:"<xsd:schema>" ( schemaImport | schemaInclude	| element |
complexType | complexContent | groupDef )* )
    ;

schemaImport : imp:"<xsd:import>" 
	;

schemaInclude : inc:"<xsd:include>"
	;	

groupDef: #("<xsd:group>" sequence )
	;

annotation: #("<xsd:annotation>" documentation )
	;	

documentation: "<xsd:documentation>"
	;

complexType: #( "<xsd:complexType>"  ( annotation | sequence |
attribute | simpleContent | complexContent )* )
	;

complexContent: #( "<xsd:complxContent>" extension )
	;

simpleContent: #( "<xsd:simpleContent>" extension )
	;
	
extension: #( "<xsd:extension>" ( attribute | sequence ) )
	;
	
sequence: #( "<xsd:sequence>" ( sequence | element | choice | groupRef
)* )
	;
	
choice: #( "<xsd:choice>" ( element | sequence )* )
	;	

groupRef: "<xsd:group>" 	
	;
	
attribute: #( "<xsd:attribute>" (simpleType)? )
	;	
	
simpleType: #( "<xsd:simpleType>" restriction )	
	;
	
restriction: #( "<xsd:restriction>" enumeration )
	;
	
enumeration: "<xsd:enumeration>"	
	;






 
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