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Chez Phase 3: fix +N reader literal in jolt.reader only (not the doomed Janet seed)

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fix-bugs-dont-reproduce, scoped per the keeper rule: jolt-if19 (a leading + on a
numeric literal errored instead of reading as the positive number) is fixed in
jolt.reader (read-number* now strips a leading + like -, positive), the code we
keep. The Janet seed reader (reader.janet) is left untouched — it's deleted in
Phase 5, so fixing it is wasted work.

Since the seed reader stays buggy, reader-parity can't use it as the oracle for
these inputs: added check-correct to assert the portable reader against the hand-
verified value (+5 => 5, +42, +0xff => 255, +3.5). reader-parity 67/67. No Janet
binary/gate impact (jolt.reader is not yet in the binary path). jolt-if19.
This commit is contained in:
Yogthos 2026-06-19 19:29:53 -04:00
parent 4de586089c
commit afada6d4ff
2 changed files with 25 additions and 5 deletions
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5
jolt-core/jolt/reader.clj
View file

@ -117,8 +117,11 @@
;; number, a ratio a/b reads as the double quotient, radixed ints by base.
(defn- read-number* [s pos]
(let [length (len s)
;; optional leading sign: - negates; + is a positive no-op (Clojure reads
;; +5 as 5). read-form only dispatches +digit/-digit, so the sign is real.
neg (and (< pos length) (= (cp s pos) 45))
start (if neg (inc pos) pos)
plus (and (< pos length) (= (cp s pos) 43))
start (if (or neg plus) (inc pos) pos)
hex? (and (< (inc start) length) (= (cp s start) 48)
(let [c1 (cp s (inc start))] (or (= c1 120) (= c1 88))))] ; 0x / 0X
(if hex?

25
test/chez/reader-parity.janet
View file

@ -37,15 +37,26 @@
(def w (protect (in (r/parse-next input) 0))) # Janet seed reader (oracle)
(def g (protect (read-one input))) # portable Clojure reader
(cond
# both readers throw on the same input = faithful parity (e.g. the +N latent
# bug, jolt-if19 — reader.janet dispatches +digit to read-number but never
# strips the +, so "+5" errors; the port reproduces it).
# both readers throw on the same input = faithful parity (safety net for
# genuinely-invalid input). We FIX latent bugs rather than reproduce them
# (fix-bugs-dont-reproduce), so this should be rare.
(and (not (w 0)) (not (g 0))) (ok input true)
(not (w 0)) (ok input false (string "janet threw, clj didn't: clj=" (string/format "%p" (g 1))))
(not (g 0)) (ok input false (string "clj threw, janet ok: " (string (g 1))))
(ok input (jeq (w 1) (g 1))
(string "clj=" (string/format "%p" (g 1)) " janet=" (string/format "%p" (w 1))))))
# For inputs where the Janet seed reader is a BUGGY oracle (a latent bug we FIX in
# the port rather than reproduce, fix-bugs-dont-reproduce), assert the portable
# reader against the hand-verified correct value. The Janet seed isn't fixed —
# it's deleted in Phase 5 — so we don't compare against it here.
(defn check-correct [input expected]
(def g (protect (read-one input)))
(if (not (g 0))
(ok input false (string "clj threw: " (string (g 1))))
(ok input (jeq expected (g 1))
(string "clj=" (string/format "%p" (g 1)) " want=" (string/format "%p" expected)))))
# --- inc 5a: atoms -------------------------------------------------------------
# nil / bool
(each i ["nil" "true" "false"] (check i))
@ -56,9 +67,15 @@
# strings (escapes)
(each i [`"hello"` `"with space"` `"tab\there"` `"nl\nhere"` `"q\"q"` `"back\\slash"` `""`] (check i))
# integers / signs / hex / radix
(each i ["0" "42" "-7" "+5" "123456" "0xFF" "0x10" "-0xff" "2r1010" "16rFF" "36rZ" "8r17"] (check i))
(each i ["0" "42" "-7" "123456" "0xFF" "0x10" "-0xff" "2r1010" "16rFF" "36rZ" "8r17"] (check i))
# floats / exponent / ratio / N|M suffix
(each i ["3.14" "-2.5" "0.0" "1e10" "1.5e-3" "2E5" "10N" "3.14M" "1/2" "-3/4" "22/7"] (check i))
# leading + reads as the positive number (jolt-if19 fixed in the port; the Janet
# seed reader still errors on these, so assert against the correct value).
(check-correct "+5" 5)
(check-correct "+42" 42)
(check-correct "+0xff" 255)
(check-correct "+3.5" 3.5)
# characters
(each i [`\a` `\Z` `\0` `\newline` `\tab` `\space` `\return` `\\` `\(` `\{` `\%` `A` `\o101`] (check i))