The way I see things, it is: ant provides a different interface to call the jython interpreter.On the other hand, having jython depend on (or recommend or suggest) ant is quite nonsensical as well, since ant is not really a tool for script writers - in fact jython is not enhanced by ant at all.
Look at it this way: if I need to use jython (I have jython source i'd like to compile or execute), I might find ant a useful tool, as a way to specify the compilation options.
On the other hand, if I need to use ant (say, to write a build script for a complex Java project), how would jython be a tool to help me in that?
It's the same relationship as between a compiler and an editor: the editor helps me use the compiler, the compiler does not help me use the editor.
Is the point that you can write python code inside your build.xml? If so, then I agree. From what I saw, the task is more like glue to call the jython compiler, and then I disagree.The relationship works the other way around: jython enhances the functionality of ant.
(for antlr, it's even more obscure how it could enhance ant) Daniel