[antlr-interest] Re: TokenStreamRewriteEngine class and samples of its usage

[kumarsriram]

>> Hi. You need to set the token object to be TokenWithIndex as 
well :)

Thanks a lot for the quick response. But I'm not sure I understand. 
How do I SET the token object? In my code, I'm GETTING the token 
object from the TokenStreamRewriteEngine instance. 

I tried the following code as well:

Mylexer = new MyLexer(new StringReader(inputStr));
System.out.println("Input string is " + inputStr);
TokenStreamRewriteEngine writer = new TokenStreamRewriteEngine
(lexer);
CommonToken dollarInput = new CommonToken(12, "$input"); //12 is the 
index of the toke "$input" in the lexer
writer.replace(dollarInput, "get");

When I execute, I get the following exception:

java.lang.ClassCastException
	at antlr.TokenStreamRewriteEngine.replace
(TokenStreamRewriteEngine.java:269)
	at antlr.TokenStreamRewriteEngine.replace
(TokenStreamRewriteEngine.java:257)
	at NomisParserTest.main(NomisParserTest.java:32)
exception: java.lang.ClassCastException


Help appreciated. Thanks.

Sriram




--- In antlr-interest at yahoogroups.com, Terence Parr <parrt at c...> 
wrote:
> 
> On May 26, 2004, at 7:04 PM, kumarsriram wrote:
> 
> > Hi,
> >
> > I'm a novice to ANTLR. I'm trying to write an expression parser
> > (extension to the one that is provided in the ANTLR examples). I
> > have a case where I need to replace some input characters
> > ("$input.xyz" should be replaced with "getXYZ()"). I figured out
> > that I could use TokenStreamRewriteEngine to do that. But when I 
use
> > it in my program, I end up with ClassCastExceptions whenever I
> > invoke nextToken() method on the engine instance. Has anyone used
> > TokenStreamRewriteEngine before? BTW, am I taking the correct
> > approach?
> >
> > I have tested my Lexer and Parser and they seem to be work fine.
> >
> > Have enclosed my test code.
> >
> > MyLexer lexer = new MyLexer(new StringBufferInputStream
(inputStr));
> > System.out.println("Input string is " + inputStr);
> > TokenStreamRewriteEngine writer = new TokenStreamRewriteEngine
> > (lexer);
> > Token t = writer.nextToken; //here's the problematic code
> 
> Hi. You need to set the token object to be TokenWithIndex as 
well :)
> 
> Terence



 
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