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Code Issues 1 Releases Wiki Activity

Make take/take-while/take-until fiber-aware

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Zach Smith
2021-08-06 15:40:29 -04:00
parent 61769c8f16
commit 34019222c2
2 changed files with 50 additions and 12 deletions
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54
src/boot/boot.janet
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@@ -1031,30 +1031,60 @@
(set k (next ind k)))
ret)
(defn take
"Take the first n elements of an indexed or bytes type. Returns a new tuple or string, respectively."
[n ind]
(def use-str (bytes? ind))
(def f (if use-str string/slice tuple/slice))
(defn- resume-n
[n fib]
(def res @[])
(var taken 0)
(while (and (< taken n) (fiber/can-resume? fib))
(let [elem (resume fib)]
(+= taken 1)
(array/push res elem)))
res)
(defn- slice-n
[f n ind]
(def len (length ind))
# make sure end is in [0, len]
(def m (if (> n 0) n 0))
(def end (if (> m len) len m))
(f ind 0 end))
(defn take-until
"Same as `(take-while (complement pred) ind)`."
[pred ind]
(def use-str (bytes? ind))
(def f (if use-str string/slice tuple/slice))
(defn take
"Take the first n elements of a fiber, indexed or bytes type. Returns a new array, tuple or string, respectively."
[n ind]
(cond
(fiber? ind) (resume-n n ind)
(bytes? ind) (slice-n string/slice n ind)
(slice-n tuple/slice n ind)))
(defn- resume-until
[pred fib]
(def res @[])
(while (fiber/can-resume? fib)
(let [elem (resume fib)]
(if (pred elem)
(break)
(array/push res elem))))
res)
(defn- slice-until
[f pred ind]
(def len (length ind))
(def i (find-index pred ind))
(def end (if (nil? i) len i))
(f ind 0 end))
(defn take-until
"Same as `(take-while (complement pred) ind)`."
[pred ind]
(cond
(fiber? ind) (resume-until pred ind)
(bytes? ind) (slice-until string/slice pred ind)
(slice-until tuple/slice pred ind)))
(defn take-while
`Given a predicate, take only elements from an indexed or bytes type that satisfy
the predicate, and abort on first failure. Returns a new tuple or string, respectively.`
`Given a predicate, take only elements from a fiber, indexed or bytes type that satisfy
the predicate, and abort on first failure. Returns a new array, tuple or string, respectively.`
[pred ind]
(take-until (complement pred) ind))