[wip] support generators in seq processing fns

Author: ikappaki

src/basilisp/core.lpy

@@ -2187,7 +2187,7 @@
   [coll]
   (let [do-reverse (fn do-reverse
                      [in out]
-                     (if (seq in)
+                     (if-let [in (seq in)]
                        (recur (rest in) (cons (first in) out))
                        out))]
     (do-reverse coll '())))
@@ -2668,10 +2668,11 @@
 (defn every?
   "Return ``true`` if every element in ``coll`` satisfies ``pred``\\."
   [pred coll]
-  (cond
-    (nil? (seq coll))   true
-    (pred (first coll)) (recur pred (rest coll))
-    :else               false))
+  (let [coll (seq coll)]
+    (cond
+      (nil? coll)   true
+      (pred (first coll)) (recur pred (rest coll))
+      :else               false)))
 
 (defn every-pred
   "Return a predicate composed of all of the input predicates, which returns ``true``
@@ -2700,7 +2701,7 @@
 (defn some
   "Return ``true`` if at least one element in ``coll`` satisfies ``pred``\\."
   [pred coll]
-  (when (seq coll)
+  (when-let [coll (seq coll)]
     (or (pred (first coll))
         (recur pred (rest coll)))))
 
@@ -2745,13 +2746,15 @@
         (rf result (apply f input inputs))))))
   ([f coll]
    (lazy-seq
-    (when (seq coll)
+    (when-let [coll (seq coll)]
       (cons (f (first coll)) (map f (rest coll))))))
   ([f coll & colls]
    (lazy-seq
-    (when (and (seq coll) (every? seq colls))
-      (cons (apply f (first coll) (map first colls))
-            (apply map f (rest coll) (map rest colls)))))))
+    (when-let [coll (seq coll)]
+      (let [colls (map seq colls)]
+        (when (every? some? colls)
+          (cons (apply f (first coll) (map first colls))
+                (apply map f (rest coll) (map rest colls)))))))))
 
 (def ^{:doc "Return a vector of ``(f elem)`` for elements in ``coll``\\. More than one
              collection may be supplied. If more than one collection is supplied, the
@@ -2806,7 +2809,7 @@
           result)))))
   ([pred coll]
    (lazy-seq
-    (when (seq coll)
+    (when-let [coll (seq coll)]
       (if (pred (first coll))
         (cons (first coll) (filter pred (rest coll)))
         (filter pred (rest coll)))))))
@@ -2841,7 +2844,7 @@
             (rf result v)))))))
   ([f coll]
    (lazy-seq
-    (when (seq coll)
+    (when-let [coll (seq coll)]
       (let [elem (f (first coll))]
         (if (nil? elem)
           (keep f (rest coll))
@@ -2867,7 +2870,7 @@
    (let [keep-idx (fn keep-idx
                     [rng coll]
                     (lazy-seq
-                     (when (seq coll)
+                     (when-let [coll (seq coll)]
                        (let [elem (f (first rng) (first coll))]
                          (if (nil? elem)
                            (keep-idx (rest rng) (rest coll))
@@ -2889,7 +2892,7 @@
   ([n coll]
    (lazy-seq
     (when (> n 0)
-      (when (seq coll)
+      (when-let [coll (seq coll)]
         (cons (first coll) (take (dec n) (rest coll))))))))
 
 (defn take-while
@@ -2907,7 +2910,7 @@
           (ensure-reduced result))))))
   ([pred coll]
    (lazy-seq
-    (when (seq coll)
+    (when-let [coll (seq coll)]
       (when (pred (first coll))
         (cons (first coll) (take-while pred (rest coll))))))))
 
@@ -2927,7 +2930,7 @@
             (rf result input)))))))
   ([n coll]
    (lazy-seq
-    (when (seq coll)
+    (when-let [coll (seq coll)]
       (if (> n 0)
         (drop (dec n) (rest coll))
         (seq coll))))))
@@ -2949,7 +2952,7 @@
             :else              result))))))
   ([pred coll]
    (lazy-seq
-    (when (seq coll)
+    (when-let [coll (seq coll)]
       (if (pred (first coll))
         (drop-while pred (rest coll))
         (seq coll))))))
@@ -3019,7 +3022,7 @@
             (rf (rf result sep) input)))))))
   ([sep coll]
    (lazy-seq
-    (when (seq coll)
+    (when-let [coll (seq coll)]
       (if (seq (rest coll))
         (cons (first coll)
               (cons sep (interpose sep (rest coll))))
@@ -3038,14 +3041,17 @@
                         (when (seq colls)
                           (cons (ffirst colls) (apply coll-firsts (rest colls))))))]
      (lazy-seq
-      (when (and (seq coll) (every? seq colls))
-        (concat (apply coll-firsts coll colls)
-                (apply interleave (rest coll) (map rest colls))))))))
+      (when-let [coll (seq coll)]
+        (let [colls (map seq colls)]
+          (when (every? some? colls)
+            (concat (apply coll-firsts coll colls)
+                    (apply interleave (rest coll) (map rest colls))))))))))
 
 (defn cycle
   "Cycle the items in ``coll`` infinitely."
   [coll]
-  (let [coll-cycle (fn coll-cycle
+  (let [coll (seq coll)
+        coll-cycle (fn coll-cycle
                      [curr]
                      (lazy-seq
                       (if (seq curr)
@@ -3091,7 +3097,7 @@
               result)))))))
   ([n coll]
    (lazy-seq
-    (when (seq coll)
+    (when-let [coll (seq coll)]
       (if (<= n 0)
         (repeat (first coll))
         (cons (first coll)
@@ -3108,13 +3114,13 @@
    (partition n n coll))
   ([n step coll]
    (lazy-seq
-    (when (seq coll)
+    (when-let [coll (seq coll)]
       (let [s (take n coll)]
         (when (= n (count s))
           (cons s (partition n step (drop step coll))))))))
   ([n step pad coll]
    (lazy-seq
-    (when (seq coll)
+    (when-let [coll (seq coll)]
       (let [s  (take n coll)
             ns (count s)
             s  (if (< ns n)
@@ -3151,7 +3157,7 @@
    (partition-all n n coll))
   ([n step coll]
    (lazy-seq
-    (when (seq coll)
+    (when-let [coll (seq coll)]
       (cons (take n coll) (partition-all n step (drop step coll)))))))
 
 (defn partition-by
@@ -3191,7 +3197,7 @@
                 (rf result elem)))))))))
   ([f coll]
    (lazy-seq
-    (when (seq coll)
+    (when-let [coll (seq coll)]
       (let [elem  (first coll)
             felem (f elem)
             run   (cons elem (take-while #(= felem (f %)) (next coll)))]
@@ -3216,7 +3222,7 @@
    (let [coll-distinct (fn coll-distinct
                          [coll found]
                          (lazy-seq
-                          (when (seq coll)
+                          (when-let [coll (seq coll)]
                             (let [e (first coll)]
                               (if-not (contains? found e)
                                 (cons e (coll-distinct (rest coll) (conj found e)))
@@ -3250,8 +3256,9 @@
                               (cons e (coll-dedupe (rest coll) e))
                               (coll-dedupe (rest coll) prev))))))]
      (lazy-seq
-      (when-let [e (first coll)]
-        (cons e (coll-dedupe (rest coll) e)))))))
+      (let [coll (seq coll)]
+        (when-let [e (first coll)]
+          (cons e (coll-dedupe (rest coll) e))))))))
 
 (defn flatten
   "Flatten any combination of nested sequences (such as lists or vectors) into a single
@@ -3269,11 +3276,12 @@
 (defn take-last
   "Return the last ``n`` items in ``coll`` in linear time."
   [n coll]
-  (loop [c   (seq coll)
-         rem (seq (drop n coll))]
-    (if rem
-      (recur (next c) (next rem))
-      c)))
+  (let [coll (seq coll)]
+    (loop [c   coll
+           rem (seq (drop n coll))]
+      (if rem
+        (recur (next c) (next rem))
+        c))))
 
 (defn min-key
   "Return the arg for which ``(k arg)`` is the smallest number. If multiple values

tests/basilisp/test_core_fns.lpy

@@ -2453,6 +2453,92 @@
             cat
             (iteration range-chunk :somef (partial some #(< % 7)) :kf (comp inc last) :initk 0))))))
 
+(def test-generator-vals [0 1 2 "three" nil 5])
+
+(defn test-generator []
+  (dotimes [i (count test-generator-vals)]
+    (yield (nth test-generator-vals i))))
+
+(deftest python-iterators-seq-fns-test
+  ;; The plan here is to consume with each function the test generator
+  ;; in its entirety, and check for missing values.
+
+  (testing "every?"
+    (let [nums* (atom [])]
+      (is (every? #(do (swap! nums* conj %)
+                       (or (number? %) (string? %) (nil? %)))
+                  (test-generator)))
+      (is (= test-generator-vals @nums*))))
+
+  (testing "some"
+    (let [nums* (atom [])]
+      (is (some #(do (swap! nums* conj %)
+                     (= % 5))
+                (test-generator)))
+      (is (= test-generator-vals @nums*))))
+
+  (testing "map"
+    (is (= test-generator-vals (map identity (test-generator))))
+    (is (= ["00" "11" "22" "threethree" "" "55"] (map str (test-generator) (test-generator)))))
+
+  (testing "filter"
+    (is (= [0 1 2 5] (filter #(and (number? %) (> % -1)) (test-generator)))))
+
+  (testing "keep"
+    (is (= [0 1 2 "three" 5] (keep identity (test-generator)))))
+
+  (testing "keep-indexed"
+    (is (= [[0 0] [1 1] [2 2] [3 "three"] [4 nil] [5 5]] (keep-indexed vector (test-generator)))))
+
+  (testing "take"
+    (is (= test-generator-vals (take 6 (test-generator)))))
+
+  (testing "take-while"
+    (is (= test-generator-vals (take-while #(not= % 7) (test-generator)))))
+
+  (testing "take-while"
+    (is (= test-generator-vals (drop 0 (test-generator)))))
+
+  (testing "take-while"
+    (is (= [1 2 "three" nil 5] (drop-while #(not= % 1) (test-generator)))))
+
+  (testing "interpose"
+    (is (= [0 "-" 1 "-" 2 "-" "three" "-" nil "-" 5] (interpose "-" (test-generator)))))
+
+  (testing "interleave"
+    (is (= [0 0 1 1 2 2 "three" "three" nil nil 5 5] (interleave (test-generator) (test-generator)))))  
+
+  (testing "cycle"
+    (is (= [0 1 2 "three" nil 5 0 1 2 "three"] (take 10 (cycle (test-generator))))))
+
+  (testing "take-nth"
+    (is (= [0 2 nil] (take-nth 2 (test-generator)))))
+
+  (testing "partition"
+    (is (= [[0 1] [2 "three"] [nil 5]] (partition 2 (test-generator))))
+    (is (= [[0 1] [1 2] [2 "three"] ["three" nil] [nil 5]] (partition 2 1 (test-generator))))
+    (is (= [[0 1 2 "three"] [nil 5 :pad :pad]] (partition 4 4 (repeat :pad) (test-generator)))))
+
+  (testing "partition-all"
+    (is (= [[0 1 2 "three"] [nil 5]] (partition-all 4 (test-generator))))
+    (is (= [[0 1 2 "three"] [nil 5]] (partition-all 4 4 (test-generator)))))  
+
+  (testing "distinct"
+    (is (= test-generator-vals (dedupe (test-generator)))))  
+
+  ;; TODO
+  ;; (testing "flatten"
+  ;;   (is (= nil (flatten [[:a :b :c] (test-generator)]))))
+
+
+  (testing "take-last"
+    (is (= [2 "three" nil 5] (take-last 4 (test-generator)))))  
+
+  (testing "sort-by"
+    (is (= [5 nil "three" 2 1 0] (reverse (test-generator)))))
+  
+  )
+
 ;;;;;;;;;;
 ;; Taps ;;
 ;;;;;;;;;;
@@ -2470,7 +2556,7 @@
         a2-fn    #(swap! a2-atom conj [:a2 %])
         b-fn     #(swap! b-atom conj %)]
     (add-tap def-fn)
-    (remove-tap b-fn)  ;; not an error
+    (remove-tap b-fn) ;; not an error
     (tap> "this is a test")
 
     ;; Wait for the tap thread to drain