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Code Issues 1 Releases Wiki Activity

Update take/drop implementation.

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No more preserves input type.
This commit is contained in:
curist 2019-08-06 14:19:22 +08:00
parent 18da183ef7
commit 61bbeebfba
1 changed files with 8 additions and 18 deletions
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26
src/boot/boot.janet
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@ -705,15 +705,10 @@
(defn take
"Take first n elements in an indexed type. Returns new indexed instance."
[n xs]
(def [f empty] (case (type xs)
:array [array/slice @[]]
:buffer [buffer/slice @""]
:string [string/slice ""]
:tarray [tarray/slice @[]]
:tuple [tuple/slice (if (= :parens (tuple/type xs)) '() [])]
(error "should provide an indexed type")))
(def len (if (= :tarray (type xs)) (tarray/length xs) (length xs)))
(def end (if (pos? n) (min n len) 0))
(def use-str (bytes? xs))
(def f (if use-str string/slice tuple/slice))
# make sure end in [0, len]
(def end (max 0 (min n (length xs))))
(f xs 0 end))
(defn take-until
@ -733,15 +728,10 @@
(defn drop
"Drop first n elements in an indexed type. Returns new indexed instance."
[n xs]
(def [f empty] (case (type xs)
:array [array/slice @[]]
:buffer [buffer/slice @""]
:string [string/slice ""]
:tarray [tarray/slice @[]]
:tuple [tuple/slice (if (= :parens (tuple/type xs)) '() [])]
(error "should provide an indexed type")))
(def len (if (= :tarray (type xs)) (tarray/length xs) (length xs)))
(def start (if (pos? n) (min n len) 0))
(def use-str (bytes? xs))
(def f (if use-str string/slice tuple/slice))
# make sure start in [0, len]
(def start (max 0 (min n (length xs))))
(f xs start -1))
(defn drop-until