Is this the common way to do it?
(def sister (assoc brother :name "Cindy"))
Reading up more on structs, it seems they have base keys that can't be
dissoc. Is that the main difference then between it and a hash?
On Mar 28, 2:48 pm, strattonbrazil <strattonbra...@gmail.com> wrote:
> I did a poor job explaining myself. Sorry. I understand that copying
> an immutable structure is worthless. I want a copy of a structure
> except one or two specific properties. For example,
>
> (defstruct person :name :address :mother :father)
> (def brother (struct person "Gary" ...))
>
> (def sister (struct person "Cindy" (:address brother) (:mother
> brother) (:father brother))) ; same attributes as brother except name
> is different
>
> Is there a shorter way to do this?
>
> While I'm on the subject, what is the difference between a structure
> and a hash? Are there performance implications? Why wouldn't I just
> use a hash if structs can hold new values anyway? When should I use
> one over the other?
>
> On Mar 28, 11:52 am, B Smith-Mannschott <bsmith.o...@gmail.com> wrote:
>
> > On Sun, Mar 28, 2010 at 18:29, strattonbrazil <strattonbra...@gmail.com>
> > wrote:
> > > This may be really basic. So much so that it's hard to find on the
> > > internet, but is there something like a copy constructor in clojure,
>
> > A copy-constructor is redundant in a language where values are
> > immutable. (Just refer to it since it can never change).
>
> > > where I can copy everything in a structure except one or two keys?
>
> > Something like this?
>
> > (select-keys map keyseq)
> > Returns a map containing only those entries in map whose key is in keys
>
> > > Maybe something like struct-map, but fills in the other variables not
> > > supplied by another data structure.
>
> > ?
>
> > (def another-datastructure {:a 1 :b 2})
> > (def my-datastructure (assoc another-datastructure :c 3 :d 4))
>
> > // Ben
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