Arithmetic and comparisons lowered to raw Chez ops, so an operand outside
Chez's tower (BigDecimal) crashed with a raw condition, and Chez contagion
leaked: (* 1.0 0) gave exact 0 where the JVM gives 0.0, (* ##Inf 0) gave 0
instead of ##NaN, (/ 1 0) raised an untyped error.
One seam now (host/chez/seq.ss): call position emits jolt-n* macros with the
both-Chez-numbers fast path open-coded; value position folds through the same
binary ops. Anything outside the tower falls to per-op slow hooks that
java/bigdec.ss extends, so bigdec arithmetic works in every position (the old
static-only :bigdec typing limitation is gone). JVM rules patched into the
fast path: a double operand wins, an exact zero divisor throws
ArithmeticException while a double zero divisor yields Inf/NaN, quot/rem/mod
cover ratios and doubles, min/max return the original operand with NaN
winning, a nil operand is NPE and a non-number CCE, zero-arg -// throw
ArityException at runtime instead of failing expansion.
Also: with-precision now binds *math-context* and bigdec results round with
real RoundingMode semantics (UNNECESSARY throws; division rounds to precision
instead of throwing); rationalize goes through the shortest decimal print
like BigDecimal.valueOf (the identity stub is gone); ratios coerce to bigdec
like Numbers.toBigDecimal; min/max int-literal operands no longer coerce to
flonum in the numeric pass.
Perf neutral: fib and seq benches unchanged (the fast path is two type checks
the optimizer folds); hinted fl/fx paths untouched. 19 JVM-certified corpus
rows; cts baseline 5614->5730 pass, 192->88 errors, 84->79 baselined
namespaces.
Review found (< 1M 2M) worked but (min 1M 2M) threw — incoherent. Wire min/max
the same way as the other ops: value-position jolt-min/jolt-max shims (new in
seq.ss, added to core-value-procs) and call-position via bd-spec/bd-ops ->
jbd-min/jbd-max.
min/max return the original operand by value, not a coerced copy, matching
Clojure: (min 1M 2.0) -> 1M, (max 1M 2.0) -> 2.0, (min 1.50M 2M) -> 1.50M; a tie
keeps the second operand ((max 1.5M 1.50M) -> 1.50M). bigdec mixed with a flonum
in call position stays in the documented :any/contagion gap (value position
handles it). Re-mint; 6 more JVM-certified rows.
A direct (+ 1.5M 2.5M) emits a raw Chez + that rejects the bigdec record. Rather
than guard every arithmetic call site (measured 2-4x on unhinted fixnum loops),
let the analyzer dispatch where it can prove the type.
jolt.passes.numeric seeds a :bigdec kind from the M-literal and flows it through
let/loop/if like the existing :double/:long kinds; an arithmetic/comparison invoke
whose operands are all bigdec (integer literals allowed) gets :num-kind :bigdec.
The back end (bd-ops + emit-numeric) lowers those to the bigdec.ss engine
(jbd-add/-sub/-mul/-div, jbd-lt?/…, jbd-zero?/-pos?/-neg?, jbd-quot/-rem).
Zero cost on non-bigdec code: with no bigdec literals present the kind never
arises, so emission is byte-identical — the re-mint leaves prelude.ss unchanged,
only image.ss (the compiler) moves. Gaps (filed): a bigdec mixed with a flonum in
call position, and a bigdec the analyzer types :any, still hit the raw op and
throw; use value position or a literal-typed let.
Re-mint (numeric/backend are seed sources). 16 JVM-certified corpus rows.
bigdec values existed but +,-,*,/ and compare threw — the header even said
"arithmetic contagion is not modelled". Add the scale-aware engine on the
{unscaled, scale} pair (jbd-add/-sub/-mul/-div + comparison helpers) following
java.math.BigDecimal's rules: add/sub align to the larger scale, multiply adds
scales, divide gives the exact quotient at minimal scale or throws
ArithmeticException on a non-terminating expansion. Clojure contagion: a bigdec
mixed with an integer stays bigdec, a flonum operand wins (result is a double).
Wire it into the value-position shims only — jolt-add/-sub/-mul/-div (what
(reduce + bigs)/(apply * bigs) lower to) and compare — so the inlined native hot
path is untouched. A call-position (+ 1.5M 2.5M) still reaches the raw Chez op;
that needs the analyzer's :bigdec type (next).
Runtime .ss only, no re-mint. 13 JVM-certified corpus rows.
The host/chez directory mixed jolt's own runtime (value model, seq, reader,
vars, ns, multimethods) with the shims that emulate the JVM: java.* / javax.*
classes, clojure.lang interfaces, and the host-class registry they hang off.
Move that JVM-emulation layer into host/chez/java/ so it reads as a distinct
unit instead of being interleaved with the platform runtime.
Moved (content unchanged): host-static, host-static-methods,
host-static-classes, host-class, dot-forms, records-interop, byte-buffer,
io, io-streams, inst-time, java-time, bigdec, natives-queue, natives-str,
natives-array, math, concurrency, async, ffi.
The load paths in rt.ss/cli.ss and the build.ss runtime manifest are updated
to point at java/; the build inliner follows the (load ...) strings, so the
AOT path needs no other change. All runtime shims, no seed source touched
(the three .clj edits are doc comments), so no re-mint.
Gate green: make test (selfhost fixpoint, certify 0-new, sci 211, infer),
shakesmoke (4 apps byte-identical).
