[antlr-interest] Generating XML from a antlr grammer!

[Scott Stanchfield]

I've started looking at creating an ANTLR 3.0 version of ANTXR
(http://javadude.com/antxr), in case that sounds interesting...

-- Scott 

> -----Original Message-----
> From: antlr-interest-bounces at antlr.org 
> [mailto:antlr-interest-bounces at antlr.org] On Behalf Of Oliver 
> Zeigermann
> Sent: Sunday, June 17, 2007 10:16 AM
> To: Johannes Luber
> Cc: antlr-interest at antlr.org
> Subject: Re: [antlr-interest] Generating XML from a antlr grammer!
> 
> Hi Johannes!
> 
> To me your solution looks nice. Maybe the error reporting 
> could be more beautiful ;)
> 
> Anyway, the only thing I could find was where the scope 
> begins (should be element in my opinion) and the check for 
> equality in endTag.
> 
> This grammar modified in the way described works for me:
> 
> parser grammar xmlParser;
> options {
>     tokenVocab=xmlLexer;
>     output=AST;
> }
> 
> tokens {
>     ELEMENT;
>     ATTRIBUTE;
> }
> 
> scope ElementScope {
> String currentElementName;
> }
> 
> document : element ;
> 
> element
> scope ElementScope;
>     : ( startTag^
>             (element
>             | PCDATA
>             )*
>             endTag!
>         | emptyElement
>         )
>     ;
> 
> startTag
>     : TAG_START_OPEN GENERIC_ID attribute* TAG_CLOSE
>             {$ElementScope::currentElementName = $GENERIC_ID.text; }
>         -> ^(ELEMENT GENERIC_ID attribute*)
>     ;
> 
> attribute : GENERIC_ID ATTR_EQ ATTR_VALUE -> ^(ATTRIBUTE GENERIC_ID
> ATTR_VALUE) ;
> 
> endTag!
>     : { 
> $ElementScope::currentElementName.equals(input.LT(2).getText()) }?
>  TAG_END_OPEN GENERIC_ID TAG_CLOSE
>     ;
> 
> emptyElement : TAG_START_OPEN GENERIC_ID attribute* TAG_EMPTY_CLOSE
>         -> ^(ELEMENT GENERIC_ID attribute*)
>     ;
> 
> 
> 
> 2007/6/11, Johannes Luber <jaluber at gmx.de>:
> > Oliver Zeigermann wrote:
> > > 2007/6/11, Johannes Luber <jaluber at gmx.de>:
> > >
> > > He, Johannes!
> > >
> > > Good observation.
> > >
> > > Maybe we can have a version that checks the order using 
> validating 
> > > semantic predicates. That really would be a good example 
> for their 
> > > use.
> > >
> > > What do you think?
> >
> > I've created an implementation (see grammar below), but the error 
> > reporting AND recovering is weak. For the XML file
> >
> > <doc>
> >     <assembly>
> >         <name>Util</Name>
> >     </assembly>
> > </doc>
> >
> > the following is being output:
> >
> > "line 3:18 rule endTag failed predicate: { 
> > $ElementScope::currentElementName == input.LA(2).text }?
> > line 4:4 rule endTag failed predicate: { 
> > $ElementScope::currentElementName == input.LA(2).text }?"
> >
> > The second message is a conundrum: If the value of 
> currentElementName 
> > is still "name", why does it accept the closing </doc>? 
> Maybe you have 
> > better idea regarding this problem.
> >
> > Best regards,
> > Johannes Luber
> >
> >
> > parser  grammar XMLParser;
> >
> > options {      tokenVocab=XMLLexer; }
> >
> > scope ElementScope {
> > String currentElementName;
> > }
> >
> > document  : element ;
> >
> > element
> >     : startTag
> >         (element
> >         | PCDATA
> >         )*
> >         endTag
> >     | emptyElement
> >     ;
> >
> > startTag
> > scope ElementScope;
> >         :       TAG_START_OPEN GENERIC_ID (attribute)* TAG_CLOSE {
> > $ElementScope::currentElementName = $GENERIC_ID.text; }
> >         ;
> >
> > attribute  : GENERIC_ID ATTR_EQ ATTR_VALUE ;
> >
> > endTag
> > scope ElementScope;
> >         :       { $ElementScope::currentElementName == 
> input.LT(2).getText() }?
> > TAG_END_OPEN GENERIC_ID TAG_CLOSE ;
> >
> > emptyElement : TAG_START_OPEN GENERIC_ID  (attribute)* 
> TAG_EMPTY_CLOSE 
> > ;
> >
>