[stringtemplate-interest] StringTemplate rules

[Jose San Leandro]

Hi,

I have some questions regarding template groups and rules.
I'm trying to define a template to generate some kind of Java source files.

type1.st :

//;-*- mode: antlr-*-
group javaSourceType1Group;

source(year, name, package) ::= <<
<header_declaration()>
<package_declaration(package)>
>>

header_declaration() ::= <<
/*
  (GPL License) Copyright <year>
  Description: <name> does whatever.
 */
>>

package_declaration(package) ::= <<
package <package>;
>>

I test it through a beanshell script.
type1.bsh:

import org.antlr.stringtemplate.*;
import org.antlr.stringtemplate.language.*;
import java.util.*;
import java.io.*;
StringTemplateGroup group =
  new StringTemplateGroup(
      new FileReader("path-to/type1.st"), AngleBracketTemplateLexer.class);
StringTemplate template = group.getInstanceOf("source");
template.setAttribute("year", "2005");
template.setAttribute("name", "Euler");
template.setAttribute("package", "com.foo.bar");
print(template.toString());

The template below works. However, I'd rather use something like:

type1.st :

//;-*- mode: antlr-*-
group javaSourceType1Group;

source(year, name, package) ::= <<
<header_declaration(year,name)>
<package_declaration(package)>
>>

header_declaration(year,name) ::= <<
/*
  (GPL License) Copyright <year>
  Description: <name> does whatever.
 */
>>

package_declaration(package) ::= <<
package <package>;
>>


My questions are:
1) I cannot define "header_declaration" rule parameters, since, if I use
header_declaration(year,name) ::= <<
...
>>
the parameters are not being passed by the "source" rule (which is the one I 
want to use to trigger the whole generation process), and they're not 
printed. If "source" rule passes them explicitly

source(year, name, package) ::= <<
<header_declaration(year,name)>
<package_declaration(package)>
>>

I get an ANTLR saying

StringTemplate: error: template parse error: line 1:1: unexpected token: 
header_declaration
StringTemplate: error: template parse error: line 1:24: unexpected token: ,
StringTemplate: error: problem parsing template 'source': 
java.lang.NullPointerException

Also, if I pass only "year" parameter to "header_declaration", I get

StringTemplate: error: template header_declaration must have exactly one 
formal arg in template context [source <invoke header_declaration arg 
context>]

I wonder if I can define more than one parameter on nested rules, without 
taking it from the context. That would allow me to use "header_declaration" 
directly or not without having to define two identical rules. If I use
<header_declaration()> inside "source" rule, and define
header_declaration(year,name) ::= << ..., the rule cannot see the parameters.

2) My "source" rule will act as the entry point in the generation process for 
each type. I don't know in advance the parameters its nested rules will 
require. Do I have to declare them all in its declaration?

Thank you for you time!
Jose.