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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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7
test/chez/_reader.janet
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@ -14,9 +14,12 @@
[# --- scalars + collections (value equality, order-independent) ---
["(= 42 (read-string \"42\"))" "true"]
["(= 42 (read-string \"0x2A\"))" "true"]
["(= 0.5 (read-string \"1/2\"))" "true"]
# numeric tower (jolt-n6al): "1/2" reads as an exact Ratio (= JVM), so a
# category-aware = against the double 0.5 is false; assert numeric value (==),
# which holds in both the all-flonum and tower models.
["(== 0.5 (read-string \"1/2\"))" "true"]
["(= -3.5 (read-string \"-3.5\"))" "true"]
["(= 1000.0 (read-string \"1e3\"))" "true"]
["(== 1000.0 (read-string \"1e3\"))" "true"]
["(= 1 (read-string \"1N\"))" "true"]
["(integer? (read-string \"7\"))" "true"]
["(= :foo (read-string \":foo\"))" "true"]