[stringtemplate-interest] separator: a fix or breaking backward compatibility?

[Zenaan Harkness]

On Mon, Jul 06, 2009 at 07:18:59PM -0700, Terence Parr wrote:
> On Jul 6, 2009, at 6:44 PM, Sterling Clover wrote:
> > What I think you really want is something closer to standard list  
> > comprehension syntax, where a list is filtered on a condition. Since  
> > this provides the same power as what you've got below, I don't think  
> > it would hurt the logic/view split that stringtemplate enforces, and  
> > it would make templates more concise and readable. Now as to what  
> > the syntax is, that's a different issue. Something like the  
> > following, perhaps?
> >
> > <names:{n: n.cool | n}; separator=",">
> >
> > The problem here is of course the colon is somewhat unintuitive, but  
> > the standard set builder symbol for "such that" is the vertical bar,  
> > which is already taken. Other suggestions, all equally not ideal,  
> > follow:
> >
> > <names:{n st. n.cool | n}; separator=",">
> > <names:{n & n.cool | n}; separator=",">
> > <names:{n when n.cool | n}; separator=",">
> > <names:{n where n.cool | n}; separator=",">
> > <names:{n % n.cool | n}; separator=",">
> > <names:{n ^ n.cool | n}; separator=",">
> >
> > You get the idea.
> 
> Yep. it's a good idea.  The problem is that you might get multiple IF  
> in a row that are "nullable".  Or, you could ref an attribute that is  
> a list with no elements.
> 
> <foo : { f | <n>}; separator=", ">
> 
> if foo is List<List<string>> and one of the List<string> is length 0,  
> you'd want to avoid the extra separator, right?

Perhaps a good time to start looking at some standard lisp operators -
list concatenation, recursive function application/ conditional testing,
etc.

We're already seeing the fleshing out of first,last,rest,start functions
(or whatever they're called) - lisp is the original LISt Processor, of
course :)

Lisp is like the original pure state we all descended from, and are
slowly clamouring back to.

-- 
Homepage: www.SoulSound.net -- Free Australia: www.UPMART.org
Please respect the confidentiality of this email as sensibly warranted.