[antlr-interest] Problem runnign ANTLR

[Terence Parr]

space in path?
Ter
On Feb 7, 2009, at 2:14 PM, Ed Keith wrote:

> I am at a machine running Windows XP.
>
> I downloaded antlrworks-1.2.2.jar and ran it.
>
> Then I tried to work through the tutorial at http://www.antlr.org/works/help/tutorial/calculator.html 
> .
>
> I pasted the Expr grammar into the editor window, selected the  
> interpreter tab, entered "2+3*4", selected "prog", clicked on the  
> indicated button. . .
>
> A message in red appeared at the bottom of the window. It Read  
> "Errors reported in console", So I clicked on the console tab and  
> found the following message:
>
> [16:56:01] java.lang.NullPointerException
> 	at org.antlr.xjlib.foundation.XJUtils.concatPath(Unknown Source)
> 	at org.antlr.xjlib.foundation.XJUtils.concatPath(Unknown Source)
> 	at  
> org 
> .antlr 
> .works 
> .components.editor.ComponentEditorGrammar.getOutputPath(Unknown  
> Source)
> 	at  
> org 
> .antlr 
> .works.components.editor.ComponentEditorGrammar.getANTLRTool(Unknown  
> Source)
> 	at  
> org 
> .antlr.works.grammar.engine.GrammarEngineImpl.getANTLRTool(Unknown  
> Source)
> 	at  
> org 
> .antlr 
> .works.grammar.antlr.ANTLRGrammarEngineImpl.createNewGrammar(Unknown  
> Source)
> 	at  
> org 
> .antlr 
> .works 
> .grammar.antlr.ANTLRGrammarEngineImpl.createParserGrammar(Unknown  
> Source)
> 	at  
> org 
> .antlr 
> .works 
> .grammar.antlr.ANTLRGrammarEngineImpl.createCombinedGrammar(Unknown  
> Source)
> 	at  
> org 
> .antlr 
> .works.grammar.antlr.ANTLRGrammarEngineImpl.createGrammars(Unknown  
> Source)
> 	at  
> org.antlr.works.grammar.antlr.ANTLRGrammarEngineImpl.analyze(Unknown  
> Source)
> 	at org.antlr.works.grammar.engine.GrammarEngineImpl.analyze(Unknown  
> Source)
> 	at org.antlr.works.interpreter.EditorInterpreter.run(Unknown Source)
> 	at java.lang.Thread.run(Unknown Source)
>
>
> A friend who is trying to convince to to give up C++ and move to  
> Java tells me the main reason I should change is that you do not  
> need to worry about NULL pointers in Java, looks like he is wrong.
>
> Can anyone point me to a solution for this problem?
>
> Thanks in advance,
>
>   -EdK
>
>
>
> Ed Keith
> e_d_k at yahoo.com
>
> Blog: edkeith.blogspot.com
>
>
>
>
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