I would probably write the code like this:
(defrel permission role op state)
(defn add-permision [roles ops states]
(doseq [r roles o ops s states]
(fact permission r o s)))
(add-permision #{:admin :operator} #{:reject :accept} #{:applied})
(defn permissiono [role op state]
(run* [q]
(permission role op state)
(== q {:role role :op op :state state})))
(permissiono :admin (lvar) (lvar))
;; ({:role :admin, :op :reject, :state :applied}
;; {:role :admin, :op :accept, :state :applied})
We can use (lvar) for wildcards. If nothing can satisfy the query you'll
get back an empty sequences.
What in particular do you find unsatisfactory about this interface?
On Sat, Nov 5, 2011 at 2:46 PM, Michael Jaaka
<michael.ja...@googlemail.com>wrote:
>
> Thanks, it gave me insight into that framework.
> Unfortunately it doesn't look friendly in usage.
> Looks like there is a place for a clojure lib or wrapper around
> core.logic.
> It would be nice if it could answer to questions also in terms of
> truth.
>
> On 5 Lis, 18:24, Ambrose Bonnaire-Sergeant
> <abonnaireserge...@gmail.com> wrote:
> > I gave the wildcard requirement a bit of thought, no inspiration at the
> > moment.
> >
> > Maybe someone else can suggest a strategy.
> >
> > Ambrose
> >
> > On Sun, Nov 6, 2011 at 1:14 AM, Ambrose Bonnaire-Sergeant <
> >
> >
> >
> >
> >
> >
> >
> > abonnaireserge...@gmail.com> wrote:
> > > Hey Michael,
> >
> > > Here's a solution using core.logic.
> >
> > > ;; We can define a "permission" relation with "defrel".
> >
> > > (defrel permission roles ops state)
> >
> > > ;; and a helper function to add each combination of permissions
> >
> > > (defn add-permision [roles ops states]
> > > (for [r roles
> > > o ops
> > > s states]
> > > (fact permission r o s)))
> >
> > > ;; Here is your first example
> >
> > > (add-permision #{:admin :operator} #{:reject :accept} #{:applied})
> >
> > > ;; Now lets ask what are the permissions for the :admin role
> >
> > > logic-introduction.perm=> (run* [q]
> > > (fresh [ops states]
> > > (permission :admin ops states)
> > > (== q [ops states])))
> > > ([:reject :applied] [:accept :applied])
> >
> > > ;; Ask what permissions either a :admin or :operator role has
> >
> > > logic-introduction.perm=> (run* [q]
> > > (fresh [role ops states]
> > > (conde
> > > ((== role :admin))
> > > ((== role :operator)))
> > > (== q [ops states])
> > > (permission role ops states)))
> > > ([:reject :applied] [:accept :applied] [:reject :applied] [:accept
> > > :applied])
> >
> > > Thanks,
> > > Ambrose
> >
> > > On Sun, Nov 6, 2011 at 12:51 AM, Michael Jaaka <
> > > michael.ja...@googlemail.com> wrote:
> >
> > >> Hi,
> >
> > >> I would like to use logic programing to describe permissions. The
> > >> definition is
> >
> > >> We have set of triples which looks like:
> > >> Set of roles; set of operations; set of states
> >
> > >> Triples are defined in scope of some entity with states, wildcard is
> > >> defined with _
> >
> > >> All I need is to answer on some operation invocation if given user
> > >> with his role is able to execute that operation for particular entity
> > >> which is in one of its states
> >
> > >> Example:
> > >> Roles: admin, operator, auditor
> > >> Entity: data form with states dirty, applied, rejected, executed
> > >> Operations on data form: reject, acept, list, enter
> > >> Triples of permissions:
> > >> admin, operator; reject, accept; applied
> > >> auditor, operator; list; _
> > >> operator; enter; dirty
> >
> > >> The additional question beside checking permission is:
> > >> What are operations avaiable for given role and given state of entity
> >
> > >> Any thoughts? Maybe core.logic? It seems that I know its purpose but
> > >> don't know how to use it.
> > >> Thanks in advance.
> >
> > >> --
> > >> You received this message because you are subscribed to the Google
> > >> Groups "Clojure" group.
> > >> To post to this group, send email to clojure@googlegroups.com
> > >> Note that posts from new members are moderated - please be patient
> with
> > >> your first post.
> > >> To unsubscribe from this group, send email to
> > >> clojure+unsubscr...@googlegroups.com
> > >> For more options, visit this group at
> > >>http://groups.google.com/group/clojure?hl=en
>
> --
> You received this message because you are subscribed to the Google
> Groups "Clojure" group.
> To post to this group, send email to clojure@googlegroups.com
> Note that posts from new members are moderated - please be patient with
> your first post.
> To unsubscribe from this group, send email to
> clojure+unsubscr...@googlegroups.com
> For more options, visit this group at
> http://groups.google.com/group/clojure?hl=en
>
--
You received this message because you are subscribed to the Google
Groups "Clojure" group.
To post to this group, send email to clojure@googlegroups.com
Note that posts from new members are moderated - please be patient with your
first post.
To unsubscribe from this group, send email to
clojure+unsubscr...@googlegroups.com
For more options, visit this group at
http://groups.google.com/group/clojure?hl=en
