On Aug 28, 8:08 pm, Rich Hickey <[EMAIL PROTECTED]> wrote:
> On Aug 27, 10:37 pm, Parth Malwankar <[EMAIL PROTECTED]>
> wrote:
>
>
>
> > On Aug 28, 12:10 am, Rich Hickey <[EMAIL PROTECTED]> wrote:
>
> > > I posted a variant here:
>
> > >http://paste.lisp.org/display/65964
>
> > Rich,
>
> > It works very nicely. Thanks.
>
> > Just one thought in case the functions args are still being
> > decided on. Could we consider taking access path as a
> > vector rather than directly as function args.
>
> > Here is the use case I have in mind.
>
> > I think most access paths [:a :b :c] would be generated.
> > Nested structures would be something like
>
> > processor -> GPRs (general purpose regs) -> r0 r1 .. rN
> > -> FPRs (floating point regs) -> f0 f1 .. fN
>
> > fridge -> fruits -> apple mango ...
> > -> veggies -> eggplant ...
> > -> diary -> milk yoghurt ...
>
> > So the developer may set up something like a
> > (fridge-item-path (get-fruit)) => [:fruits :apple]
> > (processor-reg-path (get-reg-arg-from-instruction)) => [:gpr-set :r0]
>
> > With the current arg handling this is what we would need to do:
>
> > user=> (item-path :mango)
> > [:fruits :mango]
>
> > user=> (apply mk-get my-fridge (conj (item-path :mango) :quantity))
> > 30
>
> > user=> (apply mk-assoc my-fridge (conj (item-path :mango) :quantity
> > 40))
> > {:fruits {:mango {:quantity 40, :color :yellow},
> > :apple {:quantity 20, :color :red}},
> > :diary-products {:milk {:quantity 1, :color :white,
> > :type :low-fat},
> > :yoghurt {:quantity 10, :color :pink,
> > :type :strawberry}}}
>
> > [formatting added above for readability]
>
> > In case the access path were vectors the above could become:
>
> > (mk-get my-fridge (item-path :mango) :quantity)
> > (mk-assoc my-fridge (item-path :mango) :quantity new-quantity)
>
> > Much less noise.
>
> I don't see this (partial path + separate last key) as a general way
> of doing things. The only other way I would consider is the entire
> path as a sequence:
>
> (defn mk-get [m ks]
> (reduce get m ks))
>
> (defn mk-assoc [m [k & ks] v]
> (if ks
> (assoc m k (mk-assoc (get m k) ks v))
> (assoc m k v)))
>
> ;usage
> (def nx {:a {:b {:c {:content [1 10] :other 2}}}})
>
> (mk-get nx [:a :b :c :content])
> -> [1 10]
>
> (mk-assoc nx [:a :b :c :content 0] 42)
> -> {:a {:b {:c {:other 2, :content [42 10]}}}}
>
> (mk-assoc {} [:a :b :x] 42)
> -> {:a {:b {:x 42}}}
>
Thanks Rich.
Sounds like a good idea to me. Works beautifully.
user=> (load-file "fruits.clj")
#'user/my-fridge
user=> (mk-get my-fridge (item-quantity-path :mango))
30
user=> (mk-assoc my-fridge (item-quantity-path :mango) 50)
{:fruits {:mango {:quantity 50, :color :yellow}, :apple {:quantity
20, :color :red}}, :diary-products {:yoghurt {:quantity
10, :color :pink, :type :strawberry}, :milk {:quantity
1, :color :white, :type :low-fat}}}
user=>
Parth
> Rich
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