[antlr-interest] tree grammars that output templates

[Michael LeBlanc]

Hello, everyone.  I'm trying to get up to speed with ANTLR.  At this  
time my big interest is multi-pass rigs that (re)write trees and  
finally output templates.  I'm having some trouble with my own  
efforts and similar problems with the v3 examples.  This leads me to  
suspect that I don't have in place some crucial piece of the puzzle.

I'm following the book (A Definitive ANTLR Reference) from page 222,  
the section Generating Bytecode Templates with a Tree Grammar.  I  
downloaded the files and ...

> $ java -Xmx200M org.antlr.Tool *.g
> ANTLR Parser Generator  Version 3.0.1 (August 13, 2007)  1989-2007
> Expr.g
> Gen.g
>
> $ javac Test.java
> Test.java:43: incompatible types
> found   : java.lang.Object
> required: org.antlr.stringtemplate.StringTemplate
>         StringTemplate output = r2.getTemplate();
>                                               ^
> Note: Some input files use unchecked or unsafe operations.
> Note: Recompile with -Xlint:unchecked for details.
> 1 error

Why does this happen?  Anyhow, I changed the offending line to read

	StringTemplate output = (StringTemplate)r2.getTemplate();

> $ javac Test.java
> Note: Some input files use unchecked or unsafe operations.
> Note: Recompile with -Xlint:unchecked for details.
>
> $ java Test
> 3+4*5
> ^D
> BR.recoverFromMismatchedToken
> line 0:-1 mismatched input '<EOF>' expecting NEWLINE
> Gen.g: node from line 0:0 required (...)+ loop did not match  
> anything at input 'EOF'
> Exception in thread "main" java.lang.NullPointerException
>         at Test.main(Test.java:44)

I am running on MacOSX 10.4.10 with

> java -version
> java version "1.5.0_07"
> Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_07-164)
> Java HotSpot(TM) Client VM (build 1.5.0_07-87, mixed mode)

Any ideas?

Mike

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