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Chez numeric tower: exact ints / Ratio / double for JVM parity (jolt-n6al)

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jolt was all-flonum (one :number type, inherited from Janet whose only number
type is a double). The Chez runtime has a full numeric tower, so the zero-Janet
path now carries it = JVM Clojure semantics:

  (/ 1 2)      => 1/2      (exact Ratio, was 0.5)
  (integer? 3) => true   (integer? 3.0) => false   (float? 3.0) => true
  (ratio? (/ 1 2)) => true   (= 3 3.0) => false   (== 3 3.0) => true
  (+ 1 2) => 3 (exact)   (/ 1.0 2) => 0.5 (double)

jolt= was already exactness-aware (values.ss) and == is value-equality, so
=/== match the JVM split. The reader preserves exactness (integer literals exact,
a/b ratios exact rationals, decimals/exponents flonums); backend_scheme emit-const
renders exact ints/ratios and flonums faithfully; the value-position arithmetic,
count, int, compare, bit ops, parseLong, string .length/.indexOf, range,
timestamps, and array bytes return exact integers (= JVM int/long) instead of
coercing to flonum. double/parseDouble/clojure.math floor|ceil|signum stay double.

Only the zero-Janet path carries the tower (the Janet reader loses exactness into
a double before emit). The prelude/all-flonum path is unaffected for compiled code;
the runtime reader is shared, so a couple of all-flonum reader assertions become
value (==) assertions. ~16 numeric corpus cases now give the JVM tower value vs the
Janet-era :expected and are allowlisted as tower divergences (Chez == reference
JVM) pending the corpus flip to JVM (jolt-ecz0). No BigDecimal type (1M).

Re-minted. zero-janet 2682 (floor 2698->2682, the reclassified tower cases), 0 new
divergences; fixpoint 10/10, bootstrap 6/6, spine 35/35, cli 49/49; Janet gate 155
files 0 failed.
This commit is contained in:
Yogthos 2026-06-20 23:09:27 -04:00
parent eb1c3298a4
commit 467ad75ff7
20 changed files with 291 additions and 210 deletions
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12
host/chez/natives-array.ss
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@ -17,9 +17,9 @@
(make-jolt-array (make-vector (exact (na-idx a)) (if (pair? rest) (car rest) init)) kind)
(na-from-seq a kind)))
;; jolt numbers are flonums — array element defaults / masked bytes / count must be
;; INEXACT or jolt's exactness-aware = fails (= 3.0 (exact 3) -> false).
(define (na-byte-of v) (exact->inexact (bitwise-and (exact (floor v)) #xff)))
;; numeric tower (jolt-n6al): array element defaults / masked bytes / count are
;; EXACT integers (= JVM byte/short/int), matching exact integer literals.
(define (na-byte-of v) (bitwise-and (exact (floor v)) #xff))
;; --- constructors -----------------------------------------------------------
(define (na-object-array a . rest) (na-num-array a rest jolt-nil 'object))
@ -60,9 +60,9 @@
(define (na-bytes? x) (and (jolt-array? x) (eq? (jolt-array-kind x) 'byte)))
(define (na-identity x) x)
(define (na-byte x)
(let ((b (bitwise-and (exact (floor x)) #xff))) (exact->inexact (if (>= b 128) (- b 256) b))))
(let ((b (bitwise-and (exact (floor x)) #xff))) (if (>= b 128) (- b 256) b)))
(define (na-short x)
(let ((s (bitwise-and (exact (floor x)) #xffff))) (exact->inexact (if (>= s #x8000) (- s #x10000) s))))
(let ((s (bitwise-and (exact (floor x)) #xffff))) (if (>= s #x8000) (- s #x10000) s)))
;; --- chunked seqs (Jolt does not chunk; eager equivalents over a buffer) -----
(define-record-type jolt-chunkbuf (fields (mutable items)) (nongenerative jolt-chunkbuf-v1))
@ -76,7 +76,7 @@
;; --- extend the collection dispatchers to see a jolt-array ------------------
(define %na-count jolt-count)
(set! jolt-count (lambda (c) (if (jolt-array? c) (exact->inexact (vector-length (jolt-array-vec c))) (%na-count c))))
(set! jolt-count (lambda (c) (if (jolt-array? c) (vector-length (jolt-array-vec c)) (%na-count c))))
(define %na-seq jolt-seq)
(set! jolt-seq (lambda (c) (if (jolt-array? c) (list->cseq (vector->list (jolt-array-vec c))) (%na-seq c))))
(define %na-nth jolt-nth)