simon/jolt
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

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

Browse source 
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
Download patch file Download diff file Expand all files Collapse all files

5
host/chez/host-static.ss
View file

@ -108,7 +108,8 @@
(error #f (string-append "No constructor for class " class))))))))
;; ---- coercion helpers -------------------------------------------------------
(define (->num x) (exact->inexact x))
;; numeric tower (jolt-n6al): currentTimeMillis/nanoTime are exact longs (JVM).
(define (->num x) x)
(define (jnum->exact n) (exact (truncate n)))
;; parse an integer string in radix; #f on failure (matches the seed's scan-number)
(define (parse-int-str s radix)
@ -291,7 +292,7 @@
(register-host-methods! "string-reader"
(list (cons "read" (lambda (self)
(let ((s (sr-s self)) (p (sr-pos self)))
(if (>= p (string-length s)) -1.0
(if (>= p (string-length s)) -1 ; EOF -> exact int -1 (= JVM)
(begin (sr-pos! self (+ p 1)) (->num (char->integer (string-ref s p))))))))
(cons "mark" (lambda (self . _) (vector-set! (jhost-state self) 2 (sr-pos self)) jolt-nil))
(cons "reset" (lambda (self) (sr-pos! self (vector-ref (jhost-state self) 2)) jolt-nil))