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[CTYP-222] if-let on an hmap with an optional entry always expected to succeed Created: 30/May/15  Updated: 03/Dec/17

Status: Open
Project: core.typed
Component/s: None
Affects Version/s: None
Fix Version/s: Backlog

Type: Defect Priority: Major
Reporter: Vince Broz Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: hmap, occurrence-typing


How to reproduce:

(t/cf (t/fn [m :- (t/HMap :optional {:a String} :complete? true)] (if-let [b (get m :a)] true)))

Observed result:

[[(t/HMap :optional {:a String} :complete? true) -> true :filters {:then tt, :else ff}] {:then tt, :else ff}]

Expected result (pseudeocode):

[(t/HMap :optional {:a String} :complete? true) -> (t/U nil true)]

This is what you get if you replace the if-let above with if.

Return type should be (t/Option true), as the if-let will result in a nil return if the :a key is not set on the map.


broz@macmicro:~$ grep try ~/.lein/profiles.clj
   [lein-try "0.4.3"]
broz@macmicro:~$ lein try org.clojure/core.typed
nREPL server started on port 52406 on host - nrepl://
REPL-y 0.3.5, nREPL 0.2.6
Clojure 1.6.0
Java HotSpot(TM) 64-Bit Server VM 1.8.0_40-b26
    Docs: (doc function-name-here)
          (find-doc "part-of-name-here")
  Source: (source function-name-here)
 Javadoc: (javadoc java-object-or-class-here)
    Exit: Control+D or (exit) or (quit)
 Results: Stored in vars *1, *2, *3, an exception in *e

user=> (require ['clojure.core.typed :as 't])
user=> (t/cf (t/fn [m :- (t/HMap :optional {:a String} :complete? true)] (if-let [b (get m :a)] true)))
Initializing core.typed ...
Building core.typed base environments ...
Finished building base environments
"Elapsed time: 14055.732654 msecs"
core.typed initialized.
[[(t/HMap :optional {:a String} :complete? true) -> true :filters {:then tt, :else ff}] {:then tt, :else ff}]

[CTYP-194] HMap merged type Created: 14/Jan/15  Updated: 03/Dec/17  Resolved: 03/Dec/17

Status: Closed
Project: core.typed
Component/s: None
Affects Version/s: None
Fix Version/s: None

Type: Enhancement Priority: Major
Reporter: Bryan Hoyle Assignee: Unassigned
Resolution: Declined Votes: 0
Labels: enhancement, hmap, merge



It would be nice to be able to merge several HMaps in order to simulate a parent-child relationship.
For example

(defalias Parent (t/HMap :mandatory {:type t/Keyword}))
(defalias Child1 (t/HMap :mandatory {:type (t/Value :child1)
                                     :value t/Int})

(defalias Child2 (t/HMap :mandatory {:type (t/Value :child2)
                                     :size t/Int})

(ann is-child1?
    Parent -> t/Bool])
(defn is-child1? [child]
    (= (:type child) :child1))

And have that typecheck appropriately.
As of right now, one would have to do something like

(defalias Parent (t/U Child1 Child2))

which means you have to keep track of the definition in two places to make it work as expected.

Comment by Ambrose Bonnaire-Sergeant [ 03/Dec/17 6:24 PM ]

Unclear how to proceed.

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