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speed up compare

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primo-ppcg 2023-08-11 22:40:02 +07:00
parent 7049f658ec
commit 9238b82cde
1 changed files with 19 additions and 13 deletions
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src/boot/boot.janet
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@ -739,6 +739,14 @@
## Polymorphic comparisons
(defmacro- do-compare
[x y]
~(if (def f (get ,x :compare))
(f ,x ,y)
(if (def f (get ,y :compare))
(- (f ,y ,x))
(cmp ,x ,y))))
(defn compare
``Polymorphic compare. Returns -1, 0, 1 for x < y, x = y, x > y respectively.
Differs from the primitive comparators in that it first checks to
@ -746,20 +754,18 @@
compare x and y. If so, it uses that method. If not, it
delegates to the primitive comparators.``
[x y]
(or
(when-let [f (get x :compare)] (f x y))
(when-let [f (get y :compare)] (- (f y x)))
(cmp x y)))
(do-compare x y))
(defn- compare-reduce [op xs]
(var r true)
(loop [i :range [0 (- (length xs) 1)]
:let [c (compare (xs i) (xs (+ i 1)))
ok (op c 0)]
:when (not ok)]
(set r false)
(break))
r)
(defmacro- compare-reduce [op xs]
~(do
(var res true)
(var x (get ,xs 0))
(forv i 1 (length ,xs)
(let [y (in ,xs i)]
(if (,op (do-compare x y) 0)
(set x y)
(do (set res false) (break)))))
res))
(defn compare=
``Equivalent of `=` but using polymorphic `compare` instead of primitive comparator.``