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Merged
heyLu merged 1 commit into from
Jun 15, 2015
Merged

add select-keys, rand-int, some? #333

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19 changes: 19 additions & 0 deletions pixie/stdlib.pxi
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Original file line number Diff line number Diff line change
Expand Up @@ -552,6 +552,11 @@ returns true"
(defn rem [num div]
(-rem num div))

(defn rand-int
{:doc "random integer between 0 (inclusive) and n (exclusive)"}
[n]
(rem (rand) n))

(defn =
{:doc "Returns true if all the arguments are equivalent. Otherwise, returns false. Uses
-eq to perform equality checks."
Expand Down Expand Up @@ -946,6 +951,16 @@ If further arguments are passed, invokes the method named by symbol, passing the
(fn [v]
(transduce ordered-hash-reducing-fn v)))

(defn select-keys
{:doc "Produces a map with only the values in m contained in key-seq"}
[m key-seq]
(with-meta
(transduce
(comp (filter (fn [k] (contains? m k)))
(map (fn [k] [k (get m k)])))
conj {} key-seq)
(meta m)))

(defn keys
{:doc "If called with no arguments returns a transducer that will extract the key from each map entry. If passed
a collection, will assume that it is a hashmap and return a vector of all keys from the collection."
Expand Down Expand Up @@ -1411,6 +1426,10 @@ The new value is thus `(apply f current-value-of-atom args)`."
(defn nil? [x]
(identical? x nil))

(defn some? [x]
{:doc "true if x is not nil"}
(not (nil? x)))

(defn fnil [f else]
(fn [x & args]
(apply f (if (nil? x) else x) args)))
Expand Down
14 changes: 14 additions & 0 deletions tests/pixie/tests/test-stdlib.pxi
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Original file line number Diff line number Diff line change
Expand Up @@ -189,6 +189,16 @@
(t/assert= (set (vals v)) #{1 2 3})
(t/assert= (transduce (vals) conj! v) (vals v))))

(t/deftest test-select-keys
(let [m ^{:k :v} {:a 1 :b 2}]
(t/assert= (select-keys m [:a :b]) m)
(t/assert= :v
(-> (select-keys m [:a])
meta
:k))
(t/assert= (select-keys m [:a :not-found]) {:a 1})
(t/assert= (select-keys m nil) {})
(t/assert= (select-keys {} [:a]) {})))

(t/deftest test-empty
(t/assert= (empty '(1 2 3)) '())
Expand Down Expand Up @@ -273,6 +283,10 @@
(t/assert= (every? even? []) true)
(t/assert= (every? odd? []) true))

(t/deftest test-rand-int
(let [vs (repeatedly 10 #(rand-int 4))]
(t/assert (every? #(and (>= % 0) (< % 4)) vs))))

(t/deftest test-some
(t/assert= (some even? [2 4 6 8]) true)
(t/assert= (some odd? [2 4 6 8]) false)
Expand Down