[Bese-devel] Re: Proposal (was: [Lispweb] [ANN] UnCommon Web 0.2 - learning to walk)

[Marco Baringer]

get yaclml--dev--0.4--patch-7 and you'll find the tal enviroment based 
on three methods:

(defgeneric lookup-tal-variable (name enviroment)
   (:documentation "Return the value assciated with NAME in the
   enviroment ENVIROMENT."))

(defgeneric fetch-value (name binding)
   (:documentation "Return the value associated with NAME in the
   binding set BINDING."))

(defgeneric push-binding (binding enviroment)
   (:documentation "Create a new enviroment with all the bindings
   in BINDING. Any bindings in BINDING must shadow (on successive
   calls to LOOKUP-TAL-VARIABLE) other bindings currently present
   in ENVIROMENT."))

(defun make-standard-enviroment (&rest binding-sets)
   "Given a list of binding-sets (BINDING-SETS) creates a new
   standard TAL enviroment. The enviroment is created by,
   conceptually, taking the elements of binding-sets in reverse
   order and push-binding them onto an initially empty
   enviroment.")

I removed add-binding since that's binding-set specific (for example 
the binding-set based on objects doesn't even have it). I've included 
an implementation of fetch-value for standard-objects, hash tables and 
alists, which should cover most common uses.

Binding-sets in an enviroment can, and, in ucw at least, often are, be 
of different types.

--
Marco
Ring the bells that still can ring.
Forget the perfect offering.
There is a crack in everything.
That's how the light gets in.
	-Leonard Cohen