Accessing fact slot values

[slander]

I can see from the CLIPS parser and manual that this does not work because T is not a <regular-parameter> nor a <wildcard-parameter>.

CLIPS> ( deftemplate T (slot x)  (slot y)  ) 
CLIPS> ( deffunction Ttot (?a)  (return (+ ?a:x ?a:y))  )

[PRCCODE3] Undefined variable ?a:x referenced in deffunction.

My question is:
I have a template, and I want to define a function that is something-like a method (?) for it.
How should I express this idea in the most CLIPS-native way?
for now, I am doing something like this, and it feels very cack-handed.

CLIPS> (deftemplate T (slot name) (slot x) (slot y))
CLIPS> (deffunction Ttot (?n)
   (do-for-fact ((?t T)) (eq ?t:name ?n) (bind ?x ?t:x) (bind ?y ?t:y))
   (return (+ ?x ?y ))
   )

Is this where I step away from my safe place and type (defclass ... into that scary box?

[Gary Riley]

I'm planning on supporting the short hand syntax for retrieving fact slots at the very least within the actions of a rule. Currently you can use the fact-slot-value function to retrieve the slot values. I'd suggesting wrapping the function with a deffunction so it's not so verbose.

CLIPS (6.4.1 4/8/23)
CLIPS> (deftemplate T (slot x) (slot y))
CLIPS> (deffunction fsv (?f ?s) (fact-slot-value ?f ?s))
CLIPS> (deffunction Ttot (?a) (+ (fsv ?a x) (fsv ?a y)))
CLIPS> (assert (T (x 1) (y 2)))
<Fact-1>
CLIPS> (Ttot 1)
3
CLIPS> 

[slander]

Thanks Gary! I did not mean to make your life more difficult.
fact-slot-value looks definitely nice-enough to me.
A thought. Might you (ab)use the template notation a bit in deffunctions, perhaps like this?

(deffunction Ttot ((?a T)) ... )

ugh, no that's a lot of parens. Oh well,
THANKS!

[Gary Riley]

That's the syntax for generic functions. You can specify class names, but not current deftemplate names.

         CLIPS (6.4.1 4/8/23)
CLIPS> (+ "a" "b")
[ARGACCES2] Function '+' expected argument #1 to be of type integer or float.
CLIPS> (defmethod + ((?s1 STRING) (?s2 STRING)) (str-cat ?s1 ?s2))
CLIPS> (+ "a" "b")
"ab"
CLIPS> (+ 2 3)
5
CLIPS>