Joseph Ferano
a0278378ab
rand-int, rand, rand-bool, rand-int-range and rand-float-range, at the widths the author ruled: a u64 draw and an f64 in [0, 1). rand-seed and rand-state keep their names. The four old names are not names, and each is refused by the one that is, with a call that compiles — in both the call and the bare-name position, because a Lisp-1 makes the second a real thing to write. The generator's step is untouched, so a seed means what it meant. Its output function is not: PCG-XSH-RR folded the state to 32 bits, and no honest u64 or 53-bit f64 comes out of 32 bits without a second step. PCG-RXS-M-XS 64 answers 64 from the same one, so all five still cost exactly one draw and a seeded run is reproducible. The price, written where it lives: the permutation is a bijection of the state, which is what 64 output bits from 64 state bits costs. The sequence is therefore a different one, and programs/rand.flan pins it — reproducibility across the five, the single-draw cost of each, the half-open boundaries, and rand-bool's count over a thousand flips. sand.flan is not touched. It calls rand-f32, so the cases that compile or re-evaluate it skip themselves on the fixture rather than on a comment: fix its two calls and every one of them runs again. Its hash is the old generator's grid and gets re-taken then.
84 lines
3.7 KiB
Plaintext
84 lines
3.7 KiB
Plaintext
;;;; The prelude's byte predicates, parse-i64, and the two number helpers.
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;;;;
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;;;; The cases are chosen so a wrong implementation fails one: a prefix longer
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;;;; than the string (which must answer false, not trap), the empty prefix and
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;;;; the whole string as its own prefix, a prefix that matches at the wrong
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;;;; end, and for parse-i64 every shape strtoll answers 0 for — "", "abc",
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;;;; "12x", "-" — each of which a caller could not tell from a real 0.
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(defn show-bool [b bool] ()
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(print (if b "t" "f")))
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(defn main [] i32
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(show-bool (bytes=? (bytes-view "abc") (bytes-view "abc"))) ; t
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(show-bool (bytes=? (bytes-view "abc") (bytes-view "abd"))) ; f same length
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(show-bool (bytes=? (bytes-view "abc") (bytes-view "ab"))) ; f prefix, not equal
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(show-bool (bytes=? (bytes-view "") (bytes-view ""))) ; t
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(println "")
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(show-bool (starts-with? (bytes-view "hello") (bytes-view "hel"))) ; t
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(show-bool (starts-with? (bytes-view "hello") (bytes-view "llo"))) ; f matches the end
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(show-bool (starts-with? (bytes-view "hi") (bytes-view "hiya"))) ; f longer, no trap
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(show-bool (starts-with? (bytes-view "hello") (bytes-view ""))) ; t
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(show-bool (starts-with? (bytes-view "hello") (bytes-view "hello"))) ; t
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(println "")
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(show-bool (ends-with? (bytes-view "hello") (bytes-view "llo"))) ; t
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(show-bool (ends-with? (bytes-view "hello") (bytes-view "hel"))) ; f matches the start
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(show-bool (ends-with? (bytes-view "hi") (bytes-view "hiya"))) ; f longer, no trap
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(show-bool (ends-with? (bytes-view "hello") (bytes-view ""))) ; t
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(show-bool (ends-with? (bytes-view "hello") (bytes-view "hello"))) ; t
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(println "")
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;; First occurrence, and None for a byte that is not there.
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(print (match (index-of (bytes-view "banana") \a) (Some i) i None -1))
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(print " ")
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(print (match (index-of (bytes-view "banana") \z) (Some i) i None -1))
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(print " ")
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(print (match (index-of (bytes-view "") \a) (Some i) i None -1))
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(println "")
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;; Accepted.
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(print (match (parse-i64 (bytes-view "0")) (Some v) v None -999)) (print " ")
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(print (match (parse-i64 (bytes-view "42")) (Some v) v None -999)) (print " ")
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(print (match (parse-i64 (bytes-view "-42")) (Some v) v None -999)) (print " ")
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(print (match (parse-i64 (bytes-view "+7")) (Some v) v None -999)) (print " ")
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(print (match (parse-i64 (bytes-view "9007199254740993")) (Some v) v None -999))
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(println "")
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;; Refused. Each of these is a 0 out of strtoll, which is the point.
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(print (match (parse-i64 (bytes-view "")) (Some v) v None -999)) (print " ")
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(print (match (parse-i64 (bytes-view "abc")) (Some v) v None -999)) (print " ")
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(print (match (parse-i64 (bytes-view "12x")) (Some v) v None -999)) (print " ")
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(print (match (parse-i64 (bytes-view "-")) (Some v) v None -999)) (print " ")
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(print (match (parse-i64 (bytes-view " 1")) (Some v) v None -999))
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(println "")
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(print (sign-f32 3.5)) (print " ")
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(print (sign-f32 -3.5)) (print " ")
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(print (sign-f32 0.0))
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(println "")
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;; t = 1.0 must return b exactly, which a + t*(b - a) does not always do.
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(print (lerp 0.0 10.0 0.0)) (print " ")
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(print (lerp 0.0 10.0 0.25)) (print " ")
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(print (lerp 0.0 10.0 1.0)) (print " ")
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(print (lerp 2.0 -2.0 0.5))
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(println "")
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;; The RNG ranges, off a fixed seed, so the numbers are the sequence and not
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;; just "something in range". An empty range answers lo and must not divide.
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(rand-seed 7)
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(dotimes [i 5]
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(when (> i 0) (print " "))
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(print (rand-int-range 10 20)))
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(println "")
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(print (rand-int-range 5 5)) (print " ")
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(print (rand-int-range 5 -5))
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(println "")
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(rand-seed 7)
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(dotimes [i 3]
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(when (> i 0) (print " "))
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(print (rand-float-range 0.0 1.0)))
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(println "")
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0)
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