[antlr-interest] Token Stream Rewriting

[Fabien Hermenier]

Yes it was a String. In my previous mail, I've explained the List was an 
error, so the trace was not fine.
You say it as to return a Tree; I will work on this. I think I didn't 
understood the example on the webpage.

Thanks for your help.
Fabien.

Le 22/06/11 00:45, Bart Kiers a écrit :
> Is it _really_ returning a String
>
> *  private String merge(String s1, List lst, String s2) {*
> *    ...*
> *    return ...*
> *  }*
>
> ?
> Not an Object _you think_ is a String:
>
> *  private Object merge(String s1, List lst, String s2) {*
> *    ...*
> *    return ...*
> *  }*
>
> ?
> I ask because the stack-trace you posted: "Caused by: 
> java.lang.ClassCastException: java.util.ArrayList" seems to suggest it 
> is an ArrayList.
> Either way: a String or an ArrayList, both are wrong: that method 
> needs to return a Tree.
>
> Bart.
>
>
> On Wed, Jun 22, 2011 at 8:39 AM, Fabien Hermenier 
> <hermenierfabien at gmail.com <mailto:hermenierfabien at gmail.com>> wrote:
>
>     merge(...) is returning a String.
>
>     Fabien.
>
>     Le 22/06/11 00:36, Bart Kiers a écrit :
>>     Fabien, but what is the return type of  this `merge(...)`
>>     method? Could you post the method? Or even better: post a SSCCE
>>     <http://sscce.org>that causes such an exception?
>>
>>     Regards,
>>
>>     Bart.
>>
>>
>>     On Wed, Jun 22, 2011 at 8:30 AM, Fabien Hermenier
>>     <hermenierfabien at gmail.com <mailto:hermenierfabien at gmail.com>> wrote:
>>
>>         In fact, I've badly readed the help. So yet, it is running a
>>         String that
>>         should be tokenized (then translated into tree I suppose) at
>>         run time.
>>
>>         Le 22/06/11 00:28, Bart Kiers a écrit :
>>         > Is your `merge(String, List, String)` method returning
>>         > a java.util.ArrayList instead of a Tree?
>>         >
>>         > Regards,
>>         >
>>         > Bart.
>>         >
>>         >
>>         > On Wed, Jun 22, 2011 at 8:04 AM, Fabien Hermenier
>>         > <hermenierfabien at gmail.com
>>         <mailto:hermenierfabien at gmail.com>
>>         <mailto:hermenierfabien at gmail.com
>>         <mailto:hermenierfabien at gmail.com>>> wrote:
>>         >
>>         >     Hi
>>         >
>>         >     I have some troubles with token stream rewriting. Below
>>         is the
>>         >     piece of
>>         >     ANTLR code. I have a grammar, with an AST as output and
>>         Java
>>         >     as the target. I want to insert a sequence of token
>>         into the stream.
>>         >
>>         >     I have followed the page
>>         >
>>         http://www.antlr.org/wiki/display/~admin/2007/06/28/Token+stream+rewriting+with+rewrite+rules
>>         <http://www.antlr.org/wiki/display/%7Eadmin/2007/06/28/Token+stream+rewriting+with+rewrite+rules>
>>         >
>>         <http://www.antlr.org/wiki/display/%7Eadmin/2007/06/28/Token+stream+rewriting+with+rewrite+rules>
>>         >     and adapted the example that interest me. A piece of
>>         the code is
>>         >     following. Basically, in the alternative of
>>         'explodedSet', I get the
>>         >     return values of other rules and do some stuff in the merge
>>         >     method. This
>>         >     one returns a list of String as explained in the online
>>         example.
>>         >
>>         >
>>         >     explodedSet: '{' (setContent (',' setContent)*)? '}' ->
>>         ^(EXPLODED_SET
>>         >     setContent+)
>>         >         | {List l = new LinkedList();}LEFTY
>>         >     r1=brace_content{l.add($r1.ret);} (','
>>         >     r2=brace_content{l.add($r2.ret);})* RIGHTY
>>         >         -> {
>>         >         merge($LEFTY.text,l,$RIGHTY.text)
>>         >         };
>>         >
>>         >     brace_content returns [List ret]:
>>         >              st=number ('..' ed=number)? {$ret = new
>>         LinkedList(); for
>>         >     (int
>>         >     i = $st.val; i <= $ed.val; i++) {$ret.add(i);}}
>>         >                | NAME {$ret = new LinkedList();
>>         $ret.add($NAME.text);};
>>         >
>>         >     The code compiles well but at runtime, I've got this
>>         exception:
>>         >
>>         >     Caused by: java.lang.ClassCastException:
>>         java.util.ArrayList cannot be
>>         >     cast to org.antlr.runtime.tree.Tree
>>         >         at
>>         >    
>>         org.antlr.runtime.tree.BaseTreeAdaptor.addChild(BaseTreeAdaptor.java:107)
>>         >         at Parser.explodedSet(Parser.java:560)
>>         >
>>         >     So, the return value of merge does not seems to be
>>         converted into
>>         >     tokens
>>         >     nor Tree. Does someone has an idea ?
>>         >
>>         >
>>         >     Fabien.
>>         >
>>         >     List: http://www.antlr.org/mailman/listinfo/antlr-interest
>>         >     Unsubscribe:
>>         >
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>>         >
>>         >
>>
>>
>>         --
>>         Fabien Hermenier
>>         Postdoctoral researcher at Flux
>>         http://sites.google.com/site/hermenierfabien/home
>>
>>
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>>
>
>
>     -- 
>     Fabien Hermenier
>     Postdoctoral researcher at Flux
>     http://sites.google.com/site/hermenierfabien/home
>
>


-- 
Fabien Hermenier
Postdoctoral researcher at Flux
http://sites.google.com/site/hermenierfabien/home