2022-02-23 datascript | Clojure Slack Archive

datascript

johanatan 2022-02-23T20:10:34.273659Z

hi, could someone please explain why the following predicate expression isn't filtering out the keyword mentioned:

core=> (cljs.pprint/pprint (d/q `[:find [?k ...] :where [?e :root/user ?r][?r ?k ?v][('not= ?k :user/feature-flags)]] @connection))
[:user/id
 :user/disable-global-role?
 :user/has-to-accept-license?
 :user/first-name
 :user/last-name
 :user/feature-flags
 :user/role
 :user/company-id 
 :user/avatar-url 
 :user/app-roles 
 :user/email]
nil

johanatan 2022-02-23T20:11:36.381549Z

I in fact get the same result if i toggle the not= to = (which violates boolean algebra). this indicates to me that the predicate isn't even running (and a println inside the predicate also confirms that [with a custom, user-defined predicate and the attending :in clause to bring it in]).

johanatan 2022-02-23T20:13:14.393619Z

this is the result with =:

core=> (cljs.pprint/pprint (d/q `[:find [?k ...] :where [?e :root/user ?r][?r ?k ?v][('= ?k :user/feature-flags)]] @connection))
[:user/id
 :user/disable-global-role?
 :user/has-to-accept-license?
 :user/first-name
 :user/last-name
 :user/feature-flags
 :user/role
 :user/company-id 
 :user/avatar-url 
 :user/app-roles 
 :user/email]
nil

2022-02-23T21:44:06.124889Z

I think your problem may be that you're quoting the '= and 'not= symbols.

👍 1

2022-02-23T21:45:04.992879Z

You're already inside an outer [:find ...] quote there, so this would not produce the desired result

2022-02-23T21:45:09.331549Z

user=> `[:find 'not]
[:find (quote clojure.core/not)]

2022-02-23T21:45:46.090709Z

Also, you probably want to use ' instead of `

👍 1

johanatan 2022-02-23T21:45:50.993389Z

Yes but strangely datascript does not throw the unknown predicate error

johanatan 2022-02-23T21:46:33.160409Z

I actually wanted backtick so I could use # to get unique variable syms

johanatan 2022-02-23T21:46:56.024619Z

But yea btw this conversation already occurred in #datomic

johanatan 2022-02-23T21:47:08.374909Z

Thanks for reaching out though

2022-02-23T21:47:52.844459Z

Sure thing

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