[stringtemplate-interest] support for set

[John Snyders]

In a previous thread
(http://www.antlr.org:8080/pipermail/stringtemplate-interest/2006-December/0
00836.html) Nate
had asked for support for the Java Set
"$if (someSet.moo)$ would be >> equivalent to the Java: if
(someSet.contains("moo"))"

I see no reason why Set should not be more fully supported. I agree that the
syntax get(string) should not be supported because it acts as a method call.

Because set is a collection it is already supported in that you can do this
$myset$ and it will enumerate all the keys.

$myset.key1$ should be replaced with "key1" if key1 is in the set and ""
otherwise.
Or should $myset.key1$ be replaced with "true" if it is present?

The change is very localized. Add this code to ASTExpr.java
rawGetObjectProperty just before the  // try getXXX and isXXX properties
comment.

  // Special case: if it's a Set then use the set value
  // not the property method.
  if ( o instanceof Set ) {
      Set set = (Set)o;
      if ( set.contains(propertyName) ) {
          value = propertyName;
      }
      return value;
  }

I tested the above with
        StringTemplate test = new StringTemplate("$set : { [$it$] }$,
$set$\n"
                + "access: $set.key1$\n"
                + "$if(set.key2)$found key2$endif$\n"
                + "$if(set.key3)$found key3$else$no key 3$endif$");
        HashSet s = new HashSet();
        s.add("key1");
        s.add("key2");
        test.setAttribute("set", s);
        System.out.println(test.toString());
Which produced:
 [key1]  [key2] , key1key2
access: key1
found key2
no key 3

Nate, As for maintaining your own ST source, that is a matter of choice. For
me, I soon found that there were bugs I needed to fix so I checked in the ST
source to my own repository and started making changes.(I think most of my
changes I posted back to this list) Also it looks like you may be using Java
1.5 and there are some things you can do to better support Iterable objects.

-John
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