[stringtemplate-interest] Bug about map inheritance?

[Terence Parr]

thanks. adding to bug list. i'll check for v4.
Ter
On Jan 16, 2010, at 4:23 AM, Minglei.Lee wrote:

> Hi, everyone
>  
> I think I found a bug about map inheritance in StringTemplate.
>  
> The official page (http://www.antlr.org/wiki/display/ST/Template+inheritance) says that map can be inheritance and overrided:
>  
> “The descendant template group can then add more templates and maps, override inherited templates and maps or modify inherited templates in a finer-grained manner using the template regions feature.”
>  
> But when I defining a map in supergroup, and defining a map with the same name in subgroup, StringTemplate complains “redefinition of map” and reports an error. I found the following code in GroupParser.java:
>  
> if (g.getMap(name.getText())!=null) {
> g.error("redefinition of map: "+name.getText());
> }
>  
> Where g is an instance of StringTemplateGroup. The method ‘getMap’ is defined as following:
>  
> public Map getMap(String name) {
> if ( maps==null ) {
>               if ( superGroup==null ) {
>                         return null;
>               }
>               return superGroup.getMap(name);
>      }
>      Map m = (Map)maps.get(name);
>      if ( m==null && superGroup!=null ) {
>               m = superGroup.getMap(name);
>      }
>      return m;
> }
>  
> This method lookups map not only in subgroup, but also in supergroup. So when defining a map in subgroup with a same name in supergroup, an error occurs.
>  
> I added a new method in StringTemplateGroup:
>  
> public boolean isMapDefinedInThisGroup(String text) {
> return maps != null && maps.containsKey(text);
> }
>  
> And modified GroupParser as following:
>  
> if (g. isMapDefinedInThisGroup(name.getText())) {
> g.error("redefinition of map: "+name.getText());
> }
>  
> Then the error disappears, and the map inheritance functionality works as expected. J
>  
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