14547bd1d5
- take-last / drop-last return seqs, not vectors: take-last wraps in seq; drop-last is the JVM (map (fn [x _] x) coll (drop n coll)) form (lazy, () when empty). - cycle is lazy ((lazy-seq (concat coll (cycle coll)))) so it no longer counts its argument and terminates on a lazy/infinite input. - fold's foldable-call catch uses :default, matching the rest of jolt-core and also catching a raw host condition from a folding primitive. - alts! rejects non-channel ports with a clear error (put specs / :default are unsupported) instead of crashing inside ac-poll!. - Misc: drop the unreachable second getCause clause; jolt-nth on a string raises 'nth "index out of bounds" like the vector branch; name the inline fixpoint cap; bld-sh-capture rejoins lines with newlines; clarify a couple of comments.
343 lines
18 KiB
Scheme
343 lines
18 KiB
Scheme
;; persistent collections on the Chez RT.
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;;
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;; The vector / map / set the emitted programs construct from literals and
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;; operate on via the lowered leaf ops (conj/get/nth/count/assoc/...). Loaded by
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;; rt.ss after values.ss; jolt=2 / jolt-hash (values.ss) call into the
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;; jolt-coll? / jolt-coll=? / jolt-coll-hash hooks defined here (forward refs,
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;; resolved at run time — nothing is CALLED during load).
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;;
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;; The persistent vector is a copy-on-write Scheme vector and the map/set are a
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;; bitmap HAMT. They live in Scheme; correctness, not perf, is the gate.
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;; ============================================================================
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;; small immutable-vector helpers (manual; avoid stdlib arg-order ambiguity)
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;; ============================================================================
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(define (vec-copy-range v start end)
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(let ((out (make-vector (fx- end start))))
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(let loop ((i start))
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(when (fx<? i end) (vector-set! out (fx- i start) (vector-ref v i)) (loop (fx+ i 1))))
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out))
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(define (vec-insert v i x) ; copy of v with x spliced in at index i
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(let* ((n (vector-length v)) (out (make-vector (fx+ n 1))))
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(let loop ((j 0)) (when (fx<? j i) (vector-set! out j (vector-ref v j)) (loop (fx+ j 1))))
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(vector-set! out i x)
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(let loop ((j i)) (when (fx<? j n) (vector-set! out (fx+ j 1) (vector-ref v j)) (loop (fx+ j 1))))
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out))
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(define (vec-set v i x) ; functional update at index i
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(let ((out (vec-copy-range v 0 (vector-length v)))) (vector-set! out i x) out))
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(define (vec-remove v i) ; copy of v with index i dropped
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(let* ((n (vector-length v)) (out (make-vector (fx- n 1))))
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(let loop ((j 0)) (when (fx<? j i) (vector-set! out j (vector-ref v j)) (loop (fx+ j 1))))
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(let loop ((j (fx+ i 1))) (when (fx<? j n) (vector-set! out (fx- j 1) (vector-ref v j)) (loop (fx+ j 1))))
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out))
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;; ============================================================================
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;; persistent vector — copy-on-write over a Scheme vector
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;; ============================================================================
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;; A pvec carries an `ent` flag: #t marks a MAP ENTRY (the [k v] pair seq'd out
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;; of a map). A map entry equals its [k v] vector and walks like one (nth/count/
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;; seq/=/hash/print all read only `v`), but is NOT `vector?` and IS `map-entry?`
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;; — matching Clojure's MapEntry. The flag defaults #f, so every
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;; existing `(make-pvec v)` builds a plain vector; modifying an entry (conj/assoc)
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;; likewise yields a plain vector.
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(define-record-type pvec
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(fields v ent)
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(protocol (lambda (new) (case-lambda ((v) (new v #f)) ((v e) (new v e)))))
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(nongenerative chez-pvec-v1))
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(define empty-pvec (make-pvec (vector)))
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(define (jolt-vector . xs) (make-pvec (list->vector xs)))
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(define (make-map-entry k v) (make-pvec (vector k v) #t))
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(define (jolt-map-entry? x) (and (pvec? x) (pvec-ent x) #t))
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(define (pvec-count p) (vector-length (pvec-v p)))
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;; jolt models every number as a double, so vector indices arrive as flonums —
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;; coerce an integer-valued index to a Scheme fixnum before bounds math.
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(define (->idx i) (if (fixnum? i) i (if (flonum? i) (exact (floor i)) i)))
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(define (pvec-nth-d p i d)
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(let ((v (pvec-v p)) (i (->idx i)))
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(if (and (fixnum? i) (fx>=? i 0) (fx<? i (vector-length v))) (vector-ref v i) d)))
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(define (pvec-conj p x)
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(let* ((v (pvec-v p)) (n (vector-length v)) (out (make-vector (fx+ n 1))))
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(let loop ((i 0)) (when (fx<? i n) (vector-set! out i (vector-ref v i)) (loop (fx+ i 1))))
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(vector-set! out n x)
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(make-pvec out)))
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(define (pvec-assoc p i x) ; i in [0,count]; =count appends
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(let* ((v (pvec-v p)) (n (vector-length v)) (i (->idx i)))
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(cond ((and (fx>=? i 0) (fx<? i n)) (make-pvec (vec-set v i x)))
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((fx=? i n) (pvec-conj p x))
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(else (error 'assoc "vector index out of bounds")))))
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(define (pvec-peek p)
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(let ((n (pvec-count p))) (if (fx=? n 0) jolt-nil (vector-ref (pvec-v p) (fx- n 1)))))
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(define (pvec-pop p)
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(let ((n (pvec-count p)))
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(if (fx=? n 0) (error 'pop "can't pop empty vector")
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(make-pvec (vec-copy-range (pvec-v p) 0 (fx- n 1))))))
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;; ============================================================================
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;; bitmap HAMT — keys hashed by jolt-hash, leaves compared by jolt=
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;; arr slot is one of: leaf (cons k v) | hnode (branch) | hcoll (hash bucket)
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;; ============================================================================
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(define-record-type hnode (fields bm arr) (nongenerative chez-hnode-v1))
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(define-record-type hcoll (fields hash alist) (nongenerative chez-hcoll-v1))
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(define empty-hnode (make-hnode 0 (vector)))
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(define hmask #x3FFFFFFFFFFFFFF) ; 58-bit non-negative hash window
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(define max-shift 55)
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;; bitwise-and (not fxand): jolt-hash is set!-decorated per type (records/inst/
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;; sorted return their own hash) and Chez's equal-hash can yield a BIGNUM, so a
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;; key's hash isn't guaranteed to be a fixnum. Masking with the 58-bit window via
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;; the generic bitwise-and always lands in fixnum range for the HAMT's fx slicing.
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(define (key-hash k) (bitwise-and (jolt-hash k) hmask))
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(define (chunk h shift) (fxand (fxsra h shift) 31))
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(define (bitpos h shift) (fxsll 1 (chunk h shift)))
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(define (popcount n) (let loop ((n n) (c 0)) (if (fx=? n 0) c (loop (fxand n (fx- n 1)) (fx+ c 1)))))
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(define (arr-index bm bit) (popcount (fxand bm (fx- bit 1))))
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;; jolt= alist ops (for hash-collision buckets)
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(define (assoc-jolt k al) (cond ((null? al) #f) ((jolt= (caar al) k) (car al)) (else (assoc-jolt k (cdr al)))))
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(define (alist-replace k v al) (if (jolt= (caar al) k) (cons (cons k v) (cdr al)) (cons (car al) (alist-replace k v (cdr al)))))
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(define (alist-remove k al) (cond ((null? al) '()) ((jolt= (caar al) k) (cdr al)) (else (cons (car al) (alist-remove k (cdr al))))))
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;; split two leaves that collided at `shift` into a subtree (or hcoll if the
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;; full hashes are equal / the hash is exhausted).
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(define (split-leaf shift ek ev h k v)
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(let ((eh (key-hash ek)))
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(if (or (fx>? shift max-shift) (fx=? eh h))
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(make-hcoll h (list (cons ek ev) (cons k v)))
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(let ((ei (chunk eh shift)) (ni (chunk h shift)))
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(if (fx=? ei ni)
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(make-hnode (fxsll 1 ei) (vector (split-leaf (fx+ shift 5) ek ev h k v)))
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(let ((eb (fxsll 1 ei)) (nb (fxsll 1 ni)))
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(if (fx<? ei ni)
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(make-hnode (fxior eb nb) (vector (cons ek ev) (cons k v)))
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(make-hnode (fxior eb nb) (vector (cons k v) (cons ek ev))))))))))
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(define (node-assoc node shift h k v added)
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(let* ((bit (bitpos h shift)) (bm (hnode-bm node)) (arr (hnode-arr node)))
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(if (fx=? 0 (fxand bm bit))
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(begin (set-box! added #t)
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(make-hnode (fxior bm bit) (vec-insert arr (arr-index bm bit) (cons k v))))
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(let* ((i (arr-index bm bit)) (child (vector-ref arr i)))
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(cond
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((hnode? child) (make-hnode bm (vec-set arr i (node-assoc child (fx+ shift 5) h k v added))))
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((hcoll? child)
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(let ((al (hcoll-alist child)))
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(if (assoc-jolt k al)
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(make-hnode bm (vec-set arr i (make-hcoll (hcoll-hash child) (alist-replace k v al))))
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(begin (set-box! added #t)
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(make-hnode bm (vec-set arr i (make-hcoll (hcoll-hash child) (cons (cons k v) al))))))))
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((jolt= (car child) k) (make-hnode bm (vec-set arr i (cons k v)))) ; replace
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(else (set-box! added #t)
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(make-hnode bm (vec-set arr i (split-leaf (fx+ shift 5) (car child) (cdr child) h k v)))))))))
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(define (node-get node shift h k default)
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(let* ((bit (bitpos h shift)) (bm (hnode-bm node)))
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(if (fx=? 0 (fxand bm bit)) default
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(let ((child (vector-ref (hnode-arr node) (arr-index bm bit))))
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(cond ((hnode? child) (node-get child (fx+ shift 5) h k default))
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((hcoll? child) (let ((p (assoc-jolt k (hcoll-alist child)))) (if p (cdr p) default)))
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((jolt= (car child) k) (cdr child))
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(else default))))))
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(define (node-dissoc node shift h k removed)
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(let* ((bit (bitpos h shift)) (bm (hnode-bm node)) (arr (hnode-arr node)))
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(if (fx=? 0 (fxand bm bit)) node
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(let* ((i (arr-index bm bit)) (child (vector-ref arr i)))
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(cond
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((hnode? child) (make-hnode bm (vec-set arr i (node-dissoc child (fx+ shift 5) h k removed))))
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((hcoll? child)
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(if (assoc-jolt k (hcoll-alist child))
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(begin (set-box! removed #t)
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(let ((nal (alist-remove k (hcoll-alist child))))
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(cond ((null? nal) (make-hnode (fxand bm (fxnot bit)) (vec-remove arr i)))
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((null? (cdr nal)) (make-hnode bm (vec-set arr i (car nal)))) ; collapse to leaf
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(else (make-hnode bm (vec-set arr i (make-hcoll (hcoll-hash child) nal)))))))
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node))
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((jolt= (car child) k)
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(set-box! removed #t) (make-hnode (fxand bm (fxnot bit)) (vec-remove arr i)))
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(else node))))))
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(define (node-fold node proc acc) ; (proc k v acc) over every leaf
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(let ((arr (hnode-arr node)))
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(let loop ((i 0) (acc acc))
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(if (fx<? i (vector-length arr))
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(let ((child (vector-ref arr i)))
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(loop (fx+ i 1)
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(cond ((hnode? child) (node-fold child proc acc))
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((hcoll? child)
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(let cl ((al (hcoll-alist child)) (a acc))
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(if (null? al) a (cl (cdr al) (proc (caar al) (cdar al) a)))))
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(else (proc (car child) (cdr child) acc)))))
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acc))))
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;; ============================================================================
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;; persistent map / set over the HAMT
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;; ============================================================================
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(define-record-type pmap (fields root cnt) (nongenerative chez-pmap-v1))
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(define empty-pmap (make-pmap empty-hnode 0))
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(define pmap-absent (list 'absent)) ; unique missing-key sentinel
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(define (pmap-assoc m k v)
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(let* ((added (box #f)) (r (node-assoc (pmap-root m) 0 (key-hash k) k v added)))
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(make-pmap r (if (unbox added) (fx+ (pmap-cnt m) 1) (pmap-cnt m)))))
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(define (pmap-dissoc m k)
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(let* ((removed (box #f)) (r (node-dissoc (pmap-root m) 0 (key-hash k) k removed)))
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(make-pmap r (if (unbox removed) (fx- (pmap-cnt m) 1) (pmap-cnt m)))))
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(define (pmap-get m k default) (node-get (pmap-root m) 0 (key-hash k) k default))
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(define (pmap-contains? m k) (not (eq? pmap-absent (node-get (pmap-root m) 0 (key-hash k) k pmap-absent))))
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(define (pmap-fold m proc acc) (node-fold (pmap-root m) proc acc))
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(define (jolt-hash-map . kvs)
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(let loop ((m empty-pmap) (kvs kvs))
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(cond ((null? kvs) m)
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((null? (cdr kvs)) (error 'hash-map "odd number of map literal entries"))
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(else (loop (pmap-assoc m (car kvs) (cadr kvs)) (cddr kvs))))))
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(define-record-type pset (fields m) (nongenerative chez-pset-v1))
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(define empty-pset (make-pset empty-pmap))
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(define (pset-conj s e) (if (pmap-contains? (pset-m s) e) s (make-pset (pmap-assoc (pset-m s) e e))))
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(define (pset-disj s e) (make-pset (pmap-dissoc (pset-m s) e)))
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(define (pset-contains? s e) (pmap-contains? (pset-m s) e))
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(define (pset-count s) (pmap-cnt (pset-m s)))
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(define (pset-fold s proc acc) (pmap-fold (pset-m s) (lambda (k v a) (proc k a)) acc))
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(define (jolt-hash-set . xs) (let loop ((s empty-pset) (xs xs)) (if (null? xs) s (loop (pset-conj s (car xs)) (cdr xs)))))
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;; ============================================================================
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;; leaf ops the emitter lowers core/clojure fns to (mirrors native-ops)
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;; ============================================================================
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(define (jolt-conj1 coll x)
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(cond ((pvec? coll) (pvec-conj coll x)) ; nil is a valid vector/set element
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((pset? coll) (pset-conj coll x))
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;; a list/seq conjs by PREPENDING (seq.ss: cseq / empty-list). conj onto a
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;; list stays a list, conj onto a lazy/realized seq yields a seq cell (a
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;; Cons) — list?-preserving.
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((cseq? coll) (if (cseq-list? coll) (cseq-list x coll) (cseq-realized x coll)))
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((empty-list-t? coll) (cseq-list x jolt-nil))
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((pmap? coll)
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(cond ((jolt-nil? x) coll) ; (conj m nil) = m
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((pmap? x) (pmap-fold x (lambda (k v m) (pmap-assoc m k v)) coll)) ; merge
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((and (pvec? x) (fx=? 2 (pvec-count x)))
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(pmap-assoc coll (pvec-nth-d x 0 jolt-nil) (pvec-nth-d x 1 jolt-nil)))
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(else (error 'conj "conj on a map expects a [k v] pair or a map"))))
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(else (error 'conj "unsupported collection"))))
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;; (conj) -> []; (conj nil a b ...) builds a list (conj prepending -> (b a)).
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(define (jolt-conj . args)
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(if (null? args)
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(jolt-vector)
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(let ((coll (car args)) (xs (cdr args)))
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(if (jolt-nil? coll)
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(fold-left jolt-conj1 jolt-empty-list xs)
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(fold-left jolt-conj1 coll xs)))))
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(define jolt-get
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(case-lambda
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((coll k) (jolt-get coll k jolt-nil))
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((coll k d)
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(cond ((pmap? coll) (pmap-get coll k d))
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((pset? coll) (if (pset-contains? coll k) k d))
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((pvec? coll) (pvec-nth-d coll k d))
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((string? coll) (let ((i (->idx k)))
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(if (and (fixnum? i) (fx>=? i 0) (fx<? i (string-length coll))) (string-ref coll i) d)))
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(else d)))))
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(define jolt-nth
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(case-lambda
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((coll i)
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(let ((i (->idx i)))
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(cond ((pvec? coll) (let ((v (pvec-v coll)))
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(if (and (fx>=? i 0) (fx<? i (vector-length v))) (vector-ref v i)
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(error 'nth "index out of bounds"))))
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((string? coll) (if (and (fx>=? i 0) (fx<? i (string-length coll))) (string-ref coll i)
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(error 'nth "index out of bounds")))
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((or (cseq? coll) (empty-list-t? coll)) (seq-nth coll i #f jolt-nil))
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(else (error 'nth "unsupported collection")))))
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((coll i d)
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(let ((i (->idx i)))
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(cond ((pvec? coll) (pvec-nth-d coll i d))
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((string? coll) (if (and (fx>=? i 0) (fx<? i (string-length coll))) (string-ref coll i) d))
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((or (cseq? coll) (empty-list-t? coll)) (seq-nth coll i #t d))
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(else d))))))
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;; a count is an exact integer (JVM parity: count returns a long). jolt= is
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;; exactness-aware, so this must be exact to match an exact integer literal:
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;; (= 2 (count m)) -> 2 vs exact 2 -> true.
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(define (jolt-count coll)
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(begin
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(cond ((pvec? coll) (pvec-count coll))
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((pmap? coll) (pmap-cnt coll))
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((pset? coll) (pset-count coll))
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((string? coll) (string-length coll))
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((jolt-nil? coll) 0)
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((empty-list-t? coll) 0)
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((cseq? coll) (let loop ((s coll) (n 0)) ; walk (forces a finite seq)
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(if (jolt-nil? s) n (loop (jolt-seq (seq-more s)) (fx+ n 1)))))
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(else (error 'count "uncountable")))))
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(define (jolt-assoc1 coll k v)
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(cond ((pmap? coll) (pmap-assoc coll k v))
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((pvec? coll) (pvec-assoc coll k v))
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((jolt-nil? coll) (pmap-assoc empty-pmap k v))
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(else (error 'assoc "unsupported collection"))))
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(define (jolt-assoc coll . kvs)
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(let loop ((coll coll) (kvs kvs))
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(cond ((null? kvs) coll)
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((null? (cdr kvs)) (error 'assoc "assoc expects an even number of key/vals"))
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(else (loop (jolt-assoc1 coll (car kvs) (cadr kvs)) (cddr kvs))))))
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(define (jolt-dissoc coll . ks)
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(cond ((jolt-nil? coll) jolt-nil)
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((pmap? coll) (fold-left pmap-dissoc coll ks))
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(else (error 'dissoc "unsupported collection"))))
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(define (jolt-contains? coll k)
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(cond ((pmap? coll) (pmap-contains? coll k))
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((pset? coll) (pset-contains? coll k))
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((pvec? coll) (let ((k (->idx k))) (and (fixnum? k) (fx>=? k 0) (fx<? k (pvec-count coll)))))
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((jolt-nil? coll) #f)
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(else #f)))
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(define (jolt-empty? coll)
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(cond ((jolt-nil? coll) #t)
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((pvec? coll) (fx=? 0 (pvec-count coll)))
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((pmap? coll) (fx=? 0 (pmap-cnt coll)))
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((pset? coll) (fx=? 0 (pset-count coll)))
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((string? coll) (fx=? 0 (string-length coll)))
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((empty-list-t? coll) #t)
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((cseq? coll) #f) ; a cseq is non-empty by construction
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(else (error 'empty? "unsupported collection"))))
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(define (jolt-peek coll)
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(cond ((pvec? coll) (pvec-peek coll))
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((or (cseq? coll) (empty-list-t? coll)) (jolt-first coll)) ; list peek = first
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((jolt-nil? coll) jolt-nil) (else (error 'peek "unsupported collection"))))
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(define (jolt-pop coll)
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(cond ((pvec? coll) (pvec-pop coll))
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((cseq? coll) (jolt-rest coll)) ; list pop = rest
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((empty-list-t? coll) (error 'pop "can't pop empty list"))
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(else (error 'pop "unsupported collection"))))
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;; ============================================================================
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;; equality / hash hooks called from values.ss (jolt=2 / jolt-hash)
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;; ============================================================================
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(define (jolt-coll? x) (or (pvec? x) (pmap? x) (pset? x)))
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(define (jolt-coll=? a b)
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(cond
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((and (pvec? a) (pvec? b))
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(let ((va (pvec-v a)) (vb (pvec-v b)))
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(and (fx=? (vector-length va) (vector-length vb))
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(let loop ((i 0))
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(or (fx=? i (vector-length va))
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(and (jolt= (vector-ref va i) (vector-ref vb i)) (loop (fx+ i 1))))))))
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((and (pmap? a) (pmap? b))
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(and (fx=? (pmap-cnt a) (pmap-cnt b))
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(pmap-fold a (lambda (k v ok) (and ok (jolt= (pmap-get b k pmap-absent) v))) #t)))
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((and (pset? a) (pset? b))
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(and (fx=? (pset-count a) (pset-count b))
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(pset-fold a (lambda (e ok) (and ok (pset-contains? b e))) #t)))
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(else #f)))
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(define (jolt-coll-hash x)
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(cond
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((pvec? x)
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(let ((v (pvec-v x)))
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(let loop ((i 0) (h 1))
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(if (fx=? i (vector-length v)) (bitwise-and h hmask)
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(loop (fx+ i 1) (bitwise-and (+ (* 31 h) (key-hash (vector-ref v i))) hmask))))))
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;; maps/sets hash order-independently (sum), consistent with unordered =
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((pmap? x) (bitwise-and (pmap-fold x (lambda (k v a) (+ a (fxxor (key-hash k) (key-hash v)))) 0) hmask))
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((pset? x) (bitwise-and (pset-fold x (lambda (e a) (+ a (key-hash e))) 0) hmask))))
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