Make hy-repr support dictionary views

hy/contrib/hy_repr.hy

@@ -7,6 +7,12 @@
   [hy._compat [PY3 str-type bytes-type long-type]]
   [hy.models [HyObject HyExpression HySymbol HyKeyword HyInteger HyFloat HyComplex HyList HyDict HySet HyString HyBytes]])
 
+(try
+  (import [_collections_abc [dict-keys dict-values dict-items]])
+  (except [ImportError]
+    (defclass C)
+    (setv [dict-keys dict-values dict-items] [C C C])))
+
 (setv -registry {})
 (defn hy-repr-register [types f &optional placeholder]
   (for [typ (if (instance? list types) types [types])]
@@ -39,8 +45,6 @@
       (when started-quoting
         (setv -quoting False)))))
 
-(hy-repr-register list :placeholder "[...]" (fn [x]
-  (+ "[" (-cat x) "]")))
 (hy-repr-register tuple (fn [x]
   (+ "(," (if x " " "") (-cat x) ")")))
 (hy-repr-register dict :placeholder "{...}" (fn [x]
@@ -55,10 +59,6 @@
   (if (% (len x) 2)
     (+= text (+ "  " (hy-repr (get x -1)))))
   (+ "{" text "}")))
-(hy-repr-register [set HySet] (fn [x]
-  (+ "#{" (-cat x) "}")))
-(hy-repr-register frozenset (fn [x]
-  (+ "(frozenset #{" (-cat x) "})")))
 (hy-repr-register HyExpression (fn [x]
   (setv syntax {
     'quote "'"
@@ -101,6 +101,17 @@
 (hy-repr-register fraction (fn [x]
   (.format "{}/{}" (hy-repr x.numerator) (hy-repr x.denominator))))
 
+(for [[types fmt] (partition [
+    list "[...]"
+    [set HySet] "#{...}"
+    frozenset "(frozenset #{...})"
+    dict-keys "(dict-keys [...])"
+    dict-values "(dict-values [...])"
+    dict-items "(dict-items [...])"])]
+  (defn mkrepr [fmt]
+    (fn [x] (.replace fmt "..." (-cat x) 1)))
+  (hy-repr-register types :placeholder fmt (mkrepr fmt)))
+
 (defn -cat [obj]
   (.join " " (map hy-repr obj)))
 

tests/native_tests/contrib/hy_repr.hy

@@ -87,6 +87,11 @@
   (assert (= (hy-repr (str ':mykeyword)) ":mykeyword"))
   (assert (= (hy-repr (.encode kw "UTF-8") #[[b"\xef\xb7\x90:hello"]])))))
 
+(when PY3 (defn test-dict-views []
+  (assert (= (hy-repr (.keys {1 2})) "(dict-keys [1])"))
+  (assert (= (hy-repr (.values {1 2})) "(dict-values [2])"))
+  (assert (= (hy-repr (.items {1 2})) "(dict-items [(, 1 2)])"))))
+
 (defn test-hy-model-constructors []
   (import hy)
   (assert (= (hy-repr (hy.HyInteger 7)) "'7"))