Joseph Ferano
a0f37e72a2
The !-means-mutates convention distinguished nothing — there is no immutable counterpart to contrast with — so every mutating name drops the mark: sort, sort-by, sort-bytes, swap, reverse, append, append-i64, append-f64, encode-rune, split-next, map-remove, map-next, and the test helpers beside them. Two could not simply shed it: map! is map-in-place, because map is the into transform's word and means the non-mutating thing; put! is put-at, because put is the Map builtin. The ?-means-asks convention stays. Dated records keep the old spellings; watch.clj's reset-spies! and the other Clojure names are not ours to rename.
121 lines
5.4 KiB
Plaintext
121 lines
5.4 KiB
Plaintext
;;;; The slice family at its second and third element types.
|
|
;;;;
|
|
;;;; sort was the only sort in the language. These are the other two, and
|
|
;;;; they are copies rather than an abstraction: map, filter, reduce and a sort
|
|
;;;; taking a comparator all need a *function value*, which check.ml refuses
|
|
;;;; with "a function type is not implemented yet -- milestone 5". So the
|
|
;;;; honest form is the concrete one, and the claim this file makes is only
|
|
;;;; that the concrete ones are right.
|
|
|
|
(defn show-f32 [s [f32]] ()
|
|
(dotimes [i (len s)]
|
|
(print (at s i))
|
|
(print " "))
|
|
(println ""))
|
|
|
|
(defn show-fields [s [[u8]]] ()
|
|
(dotimes [i (len s)]
|
|
(print (string (at s i)))
|
|
(print " "))
|
|
(println ""))
|
|
|
|
(defn main [] i32
|
|
;; Every float literal is cast. A literal defaults to f64 and an array
|
|
;; literal has no context to say otherwise -- a let has no type annotation --
|
|
;; so [3.5 -1.0] is an [f64] and (sort) refuses it by type. The cast is
|
|
;; the only spelling available today.
|
|
;;
|
|
;; sort: duplicates, negatives, a zero and an odd length, which is the
|
|
;; input shape the i32 sort is tested on for the same reasons.
|
|
(let [xs [(f32 3.5) (f32 -1.0) (f32 0.0) (f32 3.5) (f32 -2.25) (f32 10.0) (f32 0.5)]]
|
|
(sort (slice xs 0 7))
|
|
(show-f32 (slice xs 0 7))) ; -2.25 -1 0 0.5 3.5 3.5 10
|
|
|
|
;; In place and ptr+len: sorting a subslice leaves its neighbours alone. That
|
|
;; is the whole content of the in-place claim, and a version that copied
|
|
;; would pass every test above and fail this one.
|
|
(let [xs [(f32 9.0) (f32 4.0) (f32 3.0) (f32 2.0) (f32 1.0) (f32 9.0)]]
|
|
(sort (slice xs 1 5))
|
|
(show-f32 (slice xs 0 6))) ; 9 1 2 3 4 9
|
|
|
|
;; Already sorted, reverse sorted, and a single element -- the three inputs
|
|
;; where an insertion loop with the comparison the wrong way round still
|
|
;; looks plausible.
|
|
(let [xs [(f32 1.0) (f32 2.0) (f32 3.0)]]
|
|
(sort (slice xs 0 3))
|
|
(show-f32 (slice xs 0 3))) ; 1 2 3
|
|
(let [xs [(f32 3.0) (f32 2.0) (f32 1.0)]]
|
|
(sort (slice xs 0 3))
|
|
(show-f32 (slice xs 0 3))) ; 1 2 3
|
|
(let [xs [(f32 7.0)]]
|
|
(sort (slice xs 0 1))
|
|
(show-f32 (slice xs 0 1))) ; 7
|
|
;; The empty slice must not read (at s -1).
|
|
(let [xs [(f32 7.0)]]
|
|
(sort (slice xs 0 0))
|
|
(show-f32 (slice xs 0 0))) ;
|
|
|
|
(let [xs [(f32 1.0) (f32 2.0) (f32 3.0) (f32 4.0)]]
|
|
(reverse (slice xs 0 4))
|
|
(show-f32 (slice xs 0 4))) ; 4 3 2 1
|
|
|
|
;; min, max and sum. The empty slice is None for the first two -- there is no
|
|
;; least f32 that is also an honest answer -- and the sum accumulates in f64,
|
|
;; which is why 16777216 + 1 does not absorb here the way it would in f32.
|
|
(let [xs [(f32 3.5) (f32 -1.0) (f32 10.0)]]
|
|
(match (min-of (slice xs 0 3)) (Some m) (print m) None (print "none"))
|
|
(print " ")
|
|
(match (max-of (slice xs 0 3)) (Some m) (print m) None (print "none"))
|
|
(print " ")
|
|
(print (sum-f32 (slice xs 0 3)))
|
|
(println "")) ; -1 10 12.5
|
|
(let [xs [(f32 1.0)]]
|
|
(match (min-of (slice xs 0 0)) (Some m) (print m) None (print "none"))
|
|
(print " ")
|
|
(print (sum-f32 (slice xs 0 0)))
|
|
(println "")) ; none 0
|
|
;; The accumulator's width, made visible. 2^24 is where an f32 stops having
|
|
;; a bit for 1, so an f32 running total absorbs both of these and the
|
|
;; difference below is 0. In f64 they both land, and it is 2.
|
|
(let [xs [(f32 16777216.0) (f32 1.0) (f32 1.0)]]
|
|
(print (- (sum-f32 (slice xs 0 3)) 16777216.0))
|
|
(println "")) ; 2
|
|
|
|
;; bytes<? is bytewise and unsigned, and explicitly not alphabetical: "Zebra"
|
|
;; comes before "apple" because 'Z' is 90. A prefix comes before what extends
|
|
;; it, which is the case a loop running only to (len a) reads off the end
|
|
;; for, and 0x80 above 0x00 is the case a signed byte gets backwards.
|
|
(print (bytes<? (bytes "a") (bytes "b"))) (print " ") ; true
|
|
(print (bytes<? (bytes "b") (bytes "a"))) (print " ") ; false
|
|
(print (bytes<? (bytes "a") (bytes "a"))) (print " ") ; false
|
|
(print (bytes<? (bytes "ab") (bytes "abc"))) (print " ") ; true
|
|
(print (bytes<? (bytes "abc") (bytes "ab"))) (print " ") ; false
|
|
(print (bytes<? (bytes "") (bytes "a"))) (print " ") ; true
|
|
(print (bytes<? (bytes "Zebra") (bytes "apple"))) ; true
|
|
(println "")
|
|
;; 0x00 below 0x80, which is the pair a comparison over a *signed* byte gets
|
|
;; backwards -- and there is no \x escape in the reader, so these are built
|
|
;; as u8 arrays rather than written as string literals.
|
|
(let [lo [(u8 0)]
|
|
hi [(u8 128)]]
|
|
(print (bytes<? (slice lo 0 1) (slice hi 0 1))) (print " ") ; true
|
|
(print (bytes<? (slice hi 0 1) (slice lo 0 1))) ; false
|
|
(println ""))
|
|
|
|
;; sort-bytes over the fields split out of one buffer. The slices move and
|
|
;; the bytes never do, so this sorts a borrowed view of a string literal --
|
|
;; which an in-place byte sort could not, since a literal lives in .rodata.
|
|
(let [f (split (bytes "pear,apple,Fig,apple,banana") \,)]
|
|
(sort-bytes (as-slice f))
|
|
(show-fields (as-slice f)) ; Fig apple apple banana pear
|
|
(free f))
|
|
|
|
;; And the round trip the whole second tier is for: split, sort, join.
|
|
(let [f (split (bytes "delta,alpha,charlie,bravo") \,)]
|
|
(sort-bytes (as-slice f))
|
|
(let [j (join (as-slice f) (bytes " < "))]
|
|
(println (string (as-slice j))) ; alpha < bravo < charlie < delta
|
|
(free j))
|
|
(free f))
|
|
0)
|