racket/collects/redex/private/rg.ss
2010-01-27 20:03:57 +00:00

938 lines
38 KiB
Scheme

#lang scheme
(require "matcher.ss"
"reduction-semantics.ss"
"underscore-allowed.ss"
"term.ss"
"error.ss"
"struct.ss"
(for-syntax "rewrite-side-conditions.ss")
(for-syntax "term-fn.ss")
(for-syntax "reduction-semantics.ss")
(for-syntax "keyword-macros.ss")
mrlib/tex-table)
(define (exotic-choice? [random random]) (= 0 (random 5)))
(define (use-lang-literal? [random random]) (= 0 (random 20)))
(define default-check-attempts 1000)
(define ascii-chars-threshold 1000)
(define tex-chars-threshold 1500)
(define chinese-chars-threshold 2500)
(define (pick-var lang-lits attempt [random random])
(let ([length (add1 (random-natural 4/5 random))])
(string->symbol (random-string lang-lits length attempt random))))
(define (pick-char attempt [random random])
(cond [(or (< attempt ascii-chars-threshold) (not (exotic-choice? random)))
(let ([i (random (add1 (- (char->integer #\z) (char->integer #\a))))]
[cap? (zero? (random 2))])
(integer->char (+ i (char->integer (if cap? #\A #\a)))))]
[(or (< attempt tex-chars-threshold) (not (exotic-choice? random)))
(let ([i (random (- #x7E #x20 1))]
[_ (- (char->integer #\_) #x20)])
(integer->char (+ #x20 (if (= i _) (add1 i) i))))]
[(or (< attempt chinese-chars-threshold) (not (exotic-choice? random)))
(car (string->list (pick-from-list (map cadr tex-shortcut-table) random)))]
[else
(integer->char (+ #x4E00 (random (- #x9FCF #x4E00))))]))
(define (random-string lang-lits length attempt [random random])
(if (and (not (null? lang-lits)) (use-lang-literal? random))
(pick-from-list lang-lits random)
(list->string (build-list length (λ (_) (pick-char attempt random))))))
(define (pick-any lang sexp [random random])
(let ([c-lang (rg-lang-clang lang)]
[c-sexp (rg-lang-clang sexp)])
(if (and (not (null? (compiled-lang-lang c-lang))) (zero? (random 5)))
(values lang (pick-from-list (map nt-name (compiled-lang-lang c-lang)) random))
(values sexp (nt-name (car (compiled-lang-lang c-sexp)))))))
(define (pick-string lang-lits attempt [random random])
(random-string lang-lits (random-natural 1/5 random) attempt random))
(define (pick-nts name cross? lang attempt)
(nt-rhs (nt-by-name lang name cross?)))
(define (pick-from-list l [random random]) (list-ref l (random (length l))))
;; Chooses a random (exact) natural number from the "shifted" geometric distribution:
;; P(random-natural = k) = p(1-p)^k
;;
;; P(random-natural >= k) = (1-p)^(k+1)
;; E(random-natural) = (1-p)/p
;; Var(random-natural) = (1-p)/p^2
(define (random-natural p [random random])
(sub1 (inexact->exact (ceiling (real-part (/ (log (random)) (log (- 1 p))))))))
(define (negative? random)
(zero? (random 2)))
(define (random-integer p [random random])
(* (if (negative? random) -1 1) (random-natural p random)))
(define (random-rational p [random random])
(/ (random-integer p random) (add1 (random-natural p random))))
(define (random-real p [random random])
(* (random) 2 (random-integer p random)))
(define (random-complex p [random random])
(let ([randoms (list random-integer random-rational random-real)])
(make-rectangular ((pick-from-list randoms random) p random)
((pick-from-list randoms random) p random))))
(define integer-threshold 100)
(define rational-threshold 500)
(define real-threshold 1000)
(define complex-threshold 2000)
(define default-retries 100)
(define retry-threshold (max chinese-chars-threshold complex-threshold))
(define proportion-before-threshold 9/10)
(define proportion-at-size 1/10)
(define post-threshold-incr 50)
;; Determines the parameter p for which random-natural's expected value is E
(define (expected-value->p E)
;; E = 0 => p = 1, which breaks random-natural
(/ 1 (+ (max 1 E) 1)))
; Determines a size measure for numbers, sequences, etc., using the
; attempt count.
(define (attempt->size n)
(inexact->exact (floor (/ (log (add1 n)) (log 5)))))
(define (pick-number attempt #:top-threshold [top-threshold complex-threshold] [random random])
(let loop ([threshold 0]
[generator random-natural]
[levels `((,integer-threshold . ,random-integer)
(,rational-threshold . ,random-rational)
(,real-threshold . ,random-real)
(,complex-threshold . ,random-complex))])
(if (or (null? levels)
(< attempt (caar levels))
(< top-threshold (caar levels))
(not (exotic-choice? random)))
(generator (expected-value->p (attempt->size (- attempt threshold))) random)
(loop (caar levels) (cdar levels) (cdr levels)))))
(define (pick-natural attempt [random random])
(pick-number attempt #:top-threshold 0 random))
(define (pick-integer attempt [random random])
(pick-number attempt #:top-threshold integer-threshold random))
(define (pick-real attempt [random random])
(pick-number attempt #:top-threshold real-threshold random))
(define (pick-sequence-length attempt)
(random-natural (expected-value->p (attempt->size attempt))))
(define (zip . lists)
(apply (curry map list) lists))
(define (min-prods nt base-table)
(let* ([sizes (hash-ref base-table (nt-name nt))]
[min-size (apply min/f sizes)])
(map cadr (filter (λ (x) (equal? min-size (car x))) (zip sizes (nt-rhs nt))))))
(define-struct rg-lang (clang lits base-cases))
(define (prepare-lang lang)
(let ([lits (map symbol->string (compiled-lang-literals lang))]
[parsed (parse-language lang)])
(make-rg-lang parsed lits (find-base-cases parsed))))
(define-struct (exn:fail:redex:generation-failure exn:fail:redex) ())
(define (raise-gen-fail who what attempts)
(let ([str (format "~a: unable to generate ~a in ~a attempt~a"
who what attempts (if (= attempts 1) "" "s"))])
(raise (make-exn:fail:redex:generation-failure str (current-continuation-marks)))))
(define (generate lang decisions@ what)
(define-values/invoke-unit decisions@
(import) (export decisions^))
(define ((generate-nt lang base-cases generate retries)
name cross? size attempt in-hole env)
(let*-values
([(term _)
(generate/pred
name
(λ (size attempt)
(let ([rhs (pick-from-list
(if (zero? size)
(min-prods (nt-by-name lang name cross?)
((if cross? base-cases-cross base-cases-non-cross)
base-cases))
((next-non-terminal-decision) name cross? lang attempt)))])
(generate (max 0 (sub1 size)) attempt empty-env in-hole (rhs-pattern rhs))))
(λ (_ env) (mismatches-satisfied? env))
size attempt retries)])
term))
(define (generate-sequence ellipsis generate env length)
(define (split-environment env)
(foldl (λ (var seq-envs)
(let ([vals (hash-ref env var #f)])
(if vals
(map (λ (seq-env val) (hash-set seq-env var val)) seq-envs vals)
seq-envs)))
(build-list length (λ (_) #hash())) (ellipsis-vars ellipsis)))
(define (merge-environments seq-envs)
(foldl (λ (var env)
(hash-set env var (map (λ (seq-env) (hash-ref seq-env var)) seq-envs)))
env (ellipsis-vars ellipsis)))
(let-values
([(seq envs)
(let recur ([envs (split-environment env)])
(if (null? envs)
(values null null)
(let*-values
([(term env) (generate (car envs) the-hole (ellipsis-pattern ellipsis))]
[(terms envs) (recur (cdr envs))])
(values (cons term terms) (cons env envs)))))])
(values seq (merge-environments envs))))
(define (generate/pred name gen pred init-sz init-att retries)
(let ([pre-threshold-incr
(ceiling
(/ (- retry-threshold init-att)
(* proportion-before-threshold (add1 retries))))]
[incr-size?
(λ (remain)
(zero?
(modulo (sub1 remain)
(ceiling (* proportion-at-size
retries)))))])
(let retry ([remaining (add1 retries)]
[size init-sz]
[attempt init-att])
(if (zero? remaining)
(raise-gen-fail what (format "pattern ~a" name) retries)
(let-values ([(term env) (gen size attempt)])
(if (pred term env)
(values term env)
(retry (sub1 remaining)
(if (incr-size? remaining) (add1 size) size)
(+ attempt
(if (>= attempt retry-threshold)
post-threshold-incr
pre-threshold-incr)))))))))
(define (generate/prior name env generate)
(let* ([none (gensym)]
[prior (hash-ref env name none)])
(if (eq? prior none)
(let-values ([(term env) (generate)])
(values term (hash-set env name term)))
(values prior env))))
(define (mismatches-satisfied? env)
(let ([groups (make-hasheq)])
(define (get-group group)
(hash-ref groups group
(λ ()
(let ([vals (make-hash)])
(hash-set! groups group vals)
vals))))
(for/and ([(name val) env])
(or (not (mismatch? name))
(let ([prior (get-group (mismatch-group name))])
(and (not (hash-ref prior val #f))
(hash-set! prior val #t)))))))
(define empty-env #hash())
(define (bindings env)
(make-bindings
(for/fold ([bindings null]) ([(key val) env])
(if (binder? key)
(cons (make-bind (binder-name key) val) bindings)
bindings))))
(define (generate-pat lang sexp retries size attempt env in-hole pat)
(define recur (curry generate-pat lang sexp retries size attempt))
(define recur/pat (recur env in-hole))
(define ((recur/pat/size-attempt pat) size attempt)
(generate-pat lang sexp retries size attempt env in-hole pat))
(define clang (rg-lang-clang lang))
(define gen-nt
(generate-nt
clang
(rg-lang-base-cases lang)
(curry generate-pat lang sexp retries)
retries))
(match pat
[`number (values ((next-number-decision) attempt) env)]
[`natural (values ((next-natural-decision) attempt) env)]
[`integer (values ((next-integer-decision) attempt) env)]
[`real (values ((next-real-decision) attempt) env)]
[`(variable-except ,vars ...)
(generate/pred 'variable
(recur/pat/size-attempt 'variable)
(λ (var _) (not (memq var vars)))
size attempt retries)]
[`variable
(values ((next-variable-decision) (rg-lang-lits lang) attempt)
env)]
[`variable-not-otherwise-mentioned
(generate/pred 'variable
(recur/pat/size-attempt 'variable)
(λ (var _) (not (memq var (compiled-lang-literals clang))))
size attempt retries)]
[`(variable-prefix ,prefix)
(define (symbol-append prefix suffix)
(string->symbol (string-append (symbol->string prefix) (symbol->string suffix))))
(let-values ([(term env) (recur/pat 'variable)])
(values (symbol-append prefix term) env))]
[`string
(values ((next-string-decision) (rg-lang-lits lang) attempt)
env)]
[`(side-condition ,pat ,(? procedure? condition) ,guard-src-loc)
(generate/pred `(side-condition ,(unparse-pattern pat) ,guard-src-loc)
(recur/pat/size-attempt pat)
(λ (_ env) (condition (bindings env)))
size attempt retries)]
[`(name ,(? symbol? id) ,p)
(let-values ([(term env) (recur/pat p)])
(values term (hash-set env (make-binder id) term)))]
[`hole (values in-hole env)]
[`(in-hole ,context ,contractum)
(let-values ([(term env) (recur/pat contractum)])
(recur env term context))]
[`(hide-hole ,pattern) (recur env the-hole pattern)]
[`any
(let*-values ([(new-lang nt) ((next-any-decision) lang sexp)]
[(term _) (generate-pat new-lang
sexp
retries
size
attempt
empty-env
the-hole
nt)])
(values term env))]
[(? (is-nt? clang))
(values (gen-nt pat #f size attempt in-hole env) env)]
[(struct binder ((or (? (is-nt? clang) nt)
(app (symbol-match named-nt-rx) (? (is-nt? clang) nt)))))
(generate/prior pat env (λ () (recur/pat nt)))]
[(struct binder ((or (? built-in? b)
(app (symbol-match named-nt-rx) (? built-in? b)))))
(generate/prior pat env (λ () (recur/pat b)))]
[(struct mismatch (name (app (symbol-match mismatch-nt-rx)
(? symbol? (? (is-nt? clang) nt)))))
(let-values ([(term _) (recur/pat nt)])
(values term (hash-set env pat term)))]
[(struct mismatch (name (app (symbol-match mismatch-nt-rx)
(? symbol? (? built-in? b)))))
(let-values ([(term _) (recur/pat b)])
(values term (hash-set env pat term)))]
[`(cross ,(? symbol? cross-nt))
(values (gen-nt cross-nt #t size attempt in-hole env) env)]
[(or (? symbol?) (? number?) (? string?) (? boolean?) (? null?)) (values pat env)]
[(list-rest (and (struct ellipsis (name sub-pat class vars)) ellipsis) rest)
(let*-values ([(length) (let ([prior (hash-ref env class #f)])
(if prior prior ((next-sequence-decision) attempt)))]
[(seq env) (generate-sequence ellipsis recur env length)]
[(rest env) (recur (hash-set (hash-set env class length) name length)
in-hole rest)])
(values (append seq rest) env))]
[(list-rest pat rest)
(let*-values
([(pat-term env) (recur/pat pat)]
[(rest-term env) (recur env in-hole rest)])
(values (cons pat-term rest-term) env))]
[else
(error what "unknown pattern ~s\n" pat)]))
(let ([rg-lang (prepare-lang lang)]
[rg-sexp (prepare-lang sexp)])
(λ (pat)
(let ([parsed (reassign-classes (parse-pattern pat lang 'top-level))])
(λ (size attempt retries)
(let-values ([(term env)
(generate/pred
pat
(λ (size attempt)
(generate-pat
rg-lang
rg-sexp
retries
size
attempt
empty-env
the-hole
parsed))
(λ (_ env) (mismatches-satisfied? env))
size attempt retries)])
(values term (bindings env))))))))
(define-struct base-cases (cross non-cross))
;; find-base-cases : (list/c nt) -> base-cases
(define (find-base-cases lang)
(define nt-table (make-hash))
(define changed? #f)
(define (nt-get nt) (hash-ref nt-table nt 'inf))
(define (nt-set nt new)
(let ([old (nt-get nt)])
(unless (equal? new old)
(set! changed? #t)
(hash-set! nt-table nt new))))
(define ((process-nt cross?) nt)
(nt-set (cons cross? (nt-name nt)) (apply min/f (map process-rhs (nt-rhs nt)))))
(define (process-rhs rhs)
(let ([nts (rhs->nts (rhs-pattern rhs))])
(if (null? nts)
0
(add1/f (apply max/f (map nt-get nts))))))
;; rhs->path : pattern -> (listof (cons/c boolean symbol))
;; determines all of the non-terminals in a pattern
(define (rhs->nts pat)
(let ([nts '()])
(let loop ([pat pat])
(match pat
[(? symbol? pat)
(when ((is-nt? lang) (symbol->nt pat))
(set! nts (cons (cons #f (symbol->nt pat)) nts)))]
[`(cross ,(? symbol? x-nt))
(set! nts (cons (cons #t x-nt) nts))]
[`(variable-except ,s ...) (void)]
[`(variable-prefix ,p) (void)]
[`() (void)]
[(struct ellipsis (_ p _ _))
(loop p)]
[`(,a . ,b)
(loop a)
(loop b)]
[_ (void)]))
nts))
;; build-table : (listof nt) -> hash
(define (build-table nts)
(let ([tbl (make-hasheq)])
(for-each
(λ (nt) (hash-set! tbl (nt-name nt) (map process-rhs (nt-rhs nt))))
nts)
tbl))
(let loop ()
(set! changed? #f)
(for-each (process-nt #f) (compiled-lang-lang lang))
(for-each (process-nt #t) (compiled-lang-cclang lang))
(when changed?
(loop)))
(make-base-cases
(build-table (compiled-lang-cclang lang))
(build-table (compiled-lang-lang lang))))
(define min/f
(case-lambda
[(a) a]
[(a b)
(cond
[(eq? a 'inf) b]
[(eq? b 'inf) a]
[else (min a b)])]
[(a b . c) (min/f a (apply min/f b c))]))
(define max/f
(case-lambda
[(a) a]
[(a b)
(cond
[(eq? a 'inf) a]
[(eq? b 'inf) b]
[else (max a b)])]
[(a b . c) (max/f a (apply max/f b c))]))
(define (add1/f a) (if (eq? a 'inf) 'inf (+ a 1)))
;; is-nt? : compiled-lang any -> boolean
(define ((is-nt? lang) x)
(and (hash-ref (compiled-lang-ht lang) x #f) #t))
;; built-in? : any -> boolean
(define (built-in? x)
(and (memq x underscore-allowed) #t))
;; nt-by-name : lang symbol boolean -> nt
(define (nt-by-name lang name cross?)
(findf (λ (nt) (eq? name (nt-name nt)))
(if cross?
(compiled-lang-cclang lang)
(compiled-lang-lang lang))))
(define named-nt-rx #rx"^([^_]+)_[^_]*$")
(define mismatch-nt-rx #rx"([^_]+)_!_[^_]*$")
(define named-ellipsis-rx #rx"^\\.\\.\\._[^_]*$")
(define mismatch-ellipsis-rx #rx"^\\.\\.\\._!_[^_]*$")
;; symbol-match : regexp -> any -> (or/c false symbol)
;; Returns the sub-symbol matching the sub-pattern inside
;; the first capturing parens.
(define ((symbol-match rx) x)
(and (symbol? x)
(let ([match (regexp-match rx (symbol->string x))])
(and match (cadr match) (string->symbol (cadr match))))))
(define-struct class (id) #:inspector (make-inspector))
(define-struct mismatch (id group) #:inspector (make-inspector))
(define-struct binder (name) #:inspector (make-inspector))
;; name: (or/c symbol? mismatch?)
;; The generator records `name' in the environment when generating an ellipsis,
;; to enforce sequence length constraints.
;; class: class?
;; When one binding appears under two (non-nested) ellipses, the sequences generated
;; must have the same length; `class' groups ellipses to reflect this constraint.
;; var: (list/c (or/c symbol? class? mismatch? binder?))
;; the bindings within an ellipses, used to split and merge the environment before
;; and after generating an ellipsis
(define-struct ellipsis (name pattern class vars) #:inspector (make-inspector))
;; parse-pattern : pattern compiled-lang (or/c 'cross 'top-level 'grammar) -> parsed-pattern
;; Turns "pat ...", "pat ..._id", and "pat ..._!_id" into ellipsis structs,
;; "nt_!_id" into mismatch structs, "nt_id" into binder structs, and
;; "nt/underscore-allowed" in top-level patterns into binder structs.
(define (parse-pattern pattern lang mode)
(define (recur pat vars)
(match pat
[(or (app (symbol-match named-nt-rx) (or (? (is-nt? lang)) (? built-in?)))
(and (? (λ (_) (eq? mode 'top-level))) (or (? (is-nt? lang)) (? built-in?))))
(let ([b (make-binder pat)])
(values b (cons b vars)))]
[(app (symbol-match mismatch-nt-rx) (or (? (is-nt? lang)) (? built-in?)))
(let ([mismatch (make-mismatch (gensym) pat)])
(values mismatch (cons mismatch vars)))]
[`(name ,name ,sub-pat)
(let-values ([(parsed vars) (recur sub-pat vars)])
(values `(name ,name ,parsed) (cons (make-binder name) vars)))]
[(list-rest sub-pat (and (? symbol?) (app symbol->string (regexp named-ellipsis-rx)) name) rest)
(let*-values ([(sub-pat-parsed sub-pat-vars) (recur sub-pat null)]
[(seq) (make-ellipsis name sub-pat-parsed (make-class name) sub-pat-vars)]
[(vars) (append (list* name (make-class name) sub-pat-vars) vars)]
[(rest-parsed vars) (recur rest vars)])
(values (cons seq rest-parsed) vars))]
[(list-rest sub-pat '... rest)
(let*-values ([(sub-pat-parsed sub-pat-vars) (recur sub-pat null)]
[(class) (make-class (gensym))]
[(seq) (make-ellipsis '... sub-pat-parsed class sub-pat-vars)]
[(rest-parsed vars) (recur rest (cons class (append sub-pat-vars vars)))])
(values (cons seq rest-parsed) vars))]
[(list-rest sub-pat (and (? symbol?) (app symbol->string (regexp mismatch-ellipsis-rx)) name) rest)
(let*-values ([(sub-pat-parsed sub-pat-vars) (recur sub-pat null)]
[(mismatch) (make-mismatch (gensym) name)]
[(class) (make-class (gensym))]
[(seq) (make-ellipsis mismatch sub-pat-parsed class sub-pat-vars)]
[(vars) (append (list* class mismatch sub-pat-vars) vars)]
[(rest-parsed vars) (recur rest vars)])
(values (cons seq rest-parsed) vars))]
[(and (? (λ (_) (not (eq? mode 'cross)))) `(cross ,(and (? (is-nt? lang)) nt)))
(let ([nt-str (symbol->string nt)])
(values `(cross ,(string->symbol (string-append nt-str "-" nt-str))) vars))]
[`(side-condition ,pat ,guard ,guard-src-loc)
(let-values ([(parsed vars) (recur pat vars)])
(values `(side-condition ,parsed ,guard ,guard-src-loc) vars))]
[(cons first rest)
(let-values ([(first-parsed vars) (recur first vars)])
(let-values ([(rest-parsed vars) (recur rest vars)])
(values (cons first-parsed rest-parsed) vars)))]
[_ (values pat vars)]))
(let-values ([(parsed _) (recur pattern null)])
parsed))
;; parse-language: compiled-lang -> compiled-lang
(define (parse-language lang)
(define ((parse-nt mode) nt)
(make-nt (nt-name nt) (map (parse-rhs mode) (nt-rhs nt))))
(define ((parse-rhs mode) rhs)
(make-rhs (reassign-classes (parse-pattern (rhs-pattern rhs) lang mode))))
(struct-copy
compiled-lang lang
[lang (map (parse-nt 'grammar) (compiled-lang-lang lang))]
[cclang (map (parse-nt 'cross) (compiled-lang-cclang lang))]))
;; unparse-pattern: parsed-pattern -> pattern
(define unparse-pattern
(match-lambda
[(struct binder (name)) name]
[(struct mismatch (_ group)) group]
[(list-rest (struct ellipsis (name sub-pat _ _)) rest)
(let ([ellipsis (if (mismatch? name) (mismatch-group name) name)])
(list* (unparse-pattern sub-pat) ellipsis (unparse-pattern rest)))]
[(cons first rest)
(cons (unparse-pattern first) (unparse-pattern rest))]
[else else]))
;; class-reassignments : parsed-pattern -> hash[sym -o> sym]
(define (class-reassignments pattern)
; union-find w/o balancing or path compression (at least for now)
(define (union e f sets)
(hash-set sets (find f sets) (find e sets)))
(define (find e sets)
(let recur ([chd e] [par (hash-ref sets e #f)])
(if (and par (not (eq? chd par))) (recur par (hash-ref sets par #f)) chd)))
(let* ([last-contexts (make-hasheq)]
[record-binder
(λ (pat under assignments)
(if (null? under)
assignments
(let ([last (hash-ref last-contexts pat #f)])
(if last
(foldl (λ (cur last asgns) (union cur last asgns)) assignments under last)
(begin
(hash-set! last-contexts pat under)
assignments)))))]
[assignments
(let recur ([pat pattern] [under null] [assignments #hasheq()])
(match pat
;; `(name ,id ,sub-pat) not considered, since bindings introduced
;; by name must be unique.
[(struct binder (name))
(record-binder name under assignments)]
[(struct ellipsis (name sub-pat (struct class (cls)) _))
(recur sub-pat (cons cls under)
(if (and (symbol? name) (regexp-match named-ellipsis-rx (symbol->string name)))
(record-binder name under assignments)
assignments))]
[(? list?)
(foldl (λ (pat asgns) (recur pat under asgns)) assignments pat)]
[_ assignments]))])
(make-immutable-hasheq (hash-map assignments (λ (cls _) (cons cls (find cls assignments)))))))
(define (reassign-classes pattern)
(let* ([reassignments (class-reassignments pattern)]
[rewrite (λ (c) (make-class (hash-ref reassignments (class-id c) (class-id c))))])
(let recur ([pat pattern])
(match pat
[(struct ellipsis (name sub-pat class vars))
(make-ellipsis name (recur sub-pat) (rewrite class)
(map (λ (v) (if (class? v) (rewrite v) v)) vars))]
[(? list?) (map recur pat)]
[_ pat]))))
;; used in generating the `any' pattern
(define-language sexp (sexp variable string number hole (sexp ...)))
(define-for-syntax (metafunc name)
(let ([tf (syntax-local-value name (λ () #f))])
(and (term-fn? tf) (term-fn-get-id tf))))
(define-for-syntax (metafunc/err name stx)
(let ([m (metafunc name)])
(if m m (raise-syntax-error #f "not a metafunction" stx name))))
(define (assert-nat name x)
(if (and (integer? x) (>= x 0))
x
(raise-type-error name "natural number" x)))
(define (assert-rel name x)
(if (reduction-relation? x)
x
(raise-type-error 'redex-check "reduction-relation" x)))
(define-for-syntax (term-generator lang pat decisions@ what)
(with-syntax ([pattern
(rewrite-side-conditions/check-errs
(language-id-nts lang what)
what #t pat)])
#`((generate #,lang #,decisions@ '#,what) `pattern)))
(define-syntax (generate-term stx)
(syntax-case stx ()
[(name lang pat size . kw-args)
(with-syntax ([(attempt retries)
(parse-kw-args `((#:attempt-num . 1)
(#:retries . ,#'default-retries))
(syntax kw-args)
stx)])
(syntax/loc stx
((generate-term lang pat) size #:attempt-num attempt #:retries retries)))]
[(name lang pat)
(with-syntax ([make-gen (term-generator #'lang
#'pat
#'(generation-decisions)
(syntax-e #'name))])
(syntax/loc stx
(let ([generate make-gen])
(λ (size #:attempt-num [attempt-num 1] #:retries [retries default-retries])
(let ([att (assert-nat 'name attempt-num)]
[ret (assert-nat 'name retries)])
(let-values ([(term _) (generate size att ret)])
term))))))]))
(define-for-syntax (show-message stx)
(syntax-case stx ()
[(what . _)
(identifier? #'what)
(with-syntax ([loc (if (and (path? (syntax-source stx))
(syntax-line stx))
(format "~a:~a"
(path->string (syntax-source stx))
(syntax-line stx))
#f)])
#`(λ (msg)
(fprintf
(current-output-port)
"~a: ~a~a"
'what (if loc (string-append loc "\n") "") msg)))]))
(define-syntax (redex-check stx)
(syntax-case stx ()
[(_ lang pat property . kw-args)
(let-values ([(names names/ellipses)
(extract-names (language-id-nts #'lang 'redex-check)
'redex-check #t #'pat)]
[(attempts-stx source-stx retries-stx)
(apply values
(parse-kw-args `((#:attempts . ,#'default-check-attempts)
(#:source . #f)
(#:retries . ,#'default-retries))
(syntax kw-args)
stx))])
(with-syntax ([(name ...) names]
[(name/ellipses ...) names/ellipses]
[show (show-message stx)])
(with-syntax ([property (syntax
(λ (_ bindings)
(term-let ([name/ellipses (lookup-binding bindings 'name)] ...)
property)))])
(quasisyntax/loc stx
(let ([att (assert-nat 'redex-check #,attempts-stx)]
[ret (assert-nat 'redex-check #,retries-stx)])
(unsyntax
(if source-stx
#`(let-values ([(metafunc/red-rel num-cases)
#,(cond [(and (identifier? source-stx) (metafunc source-stx))
=> (λ (x) #`(values #,x (length (metafunc-proc-cases #,x))))]
[else
#`(let ([r (assert-rel 'redex-check #,source-stx)])
(values r (length (reduction-relation-make-procs r))))])])
(check-lhs-pats
lang
metafunc/red-rel
property
random-decisions@
(max 1 (floor (/ att num-cases)))
ret
'redex-check
show
(test-match lang pat)
(λ (generated) (redex-error 'redex-check "~s does not match ~s" generated 'pat))))
#`(check-prop
#,(term-generator #'lang #'pat #'random-decisions@ 'redex-check)
property att ret show)))
(void))))))]))
(define (format-attempts a)
(format "~a attempt~a" a (if (= 1 a) "" "s")))
(define (check-prop generator property attempts retries show)
(when (check generator property attempts retries show)
(show (format "no counterexamples in ~a\n"
(format-attempts attempts)))))
(define (check generator property attempts retries show
#:source [source #f]
#:match [match #f]
#:match-fail [match-fail #f])
(let loop ([remaining attempts])
(if (zero? remaining)
#t
(let ([attempt (add1 (- attempts remaining))])
(let-values ([(term bindings) (generator (attempt->size attempt) attempt retries)])
(if (andmap (λ (bindings)
(with-handlers
([exn:fail?
(λ (exn)
(show
(format "checking ~s raises an exception\n" term))
(raise exn))])
(property term bindings)))
(cond [(and match match-fail (match term))
=> (curry map (compose make-bindings match-bindings))]
[match (match-fail term)]
[else (list bindings)]))
(loop (sub1 remaining))
(begin
(show
(format "counterexample found after ~a~a:\n"
(format-attempts attempt)
(if source (format " with ~a" source) "")))
(pretty-print term (current-output-port))
#f)))))))
(define-syntax (check-metafunction-contract stx)
(syntax-case stx ()
[(_ name . kw-args)
(identifier? #'name)
(with-syntax ([m (metafunc/err #'name stx)]
[(attempts retries)
(parse-kw-args `((#:attempts . ,#'default-check-attempts)
(#:retries . ,#'default-retries))
(syntax kw-args)
stx)]
[show (show-message stx)])
(syntax/loc stx
(let ([lang (metafunc-proc-lang m)]
[dom (metafunc-proc-dom-pat m)]
[decisions@ (generation-decisions)]
[att (assert-nat 'check-metafunction-contract attempts)])
(check-prop
((generate lang decisions@ 'check-metafunction-contract)
(if dom dom '(any (... ...))))
(λ (t _)
(with-handlers ([exn:fail:redex? (λ (_) #f)])
(begin (term (name ,@t)) #t)))
att
retries
show))))]))
(define (check-lhs-pats lang mf/rr prop decisions@ attempts retries what show
[match #f]
[match-fail #f])
(let ([lang-gen (generate lang decisions@ what)])
(let-values ([(pats srcs)
(cond [(metafunc-proc? mf/rr)
(values (map metafunc-case-lhs-pat (metafunc-proc-cases mf/rr))
(metafunction-srcs mf/rr))]
[(reduction-relation? mf/rr)
(values (map (λ (rwp) ((rewrite-proc-lhs rwp) lang)) (reduction-relation-make-procs mf/rr))
(reduction-relation-srcs mf/rr))])])
(when (for/and ([pat pats] [src srcs])
(with-handlers ([exn:fail:redex:generation-failure?
; Produce an error message that blames the LHS as a whole.
(λ (_)
(raise-gen-fail what (format "LHS of ~a" src) retries))])
(check
(lang-gen pat)
prop
attempts
retries
show
#:source src
#:match match
#:match-fail match-fail)))
(show
(format "no counterexamples in ~a (with each clause)\n"
(format-attempts attempts)))))))
(define-syntax (check-metafunction stx)
(syntax-case stx ()
[(_ name property . kw-args)
(with-syntax ([m (metafunc/err #'name stx)]
[(attempts retries)
(parse-kw-args `((#:attempts . , #'default-check-attempts)
(#:retries . ,#'default-retries))
(syntax kw-args)
stx)]
[show (show-message stx)])
(syntax/loc stx
(let ([att (assert-nat 'check-metafunction attempts)]
[ret (assert-nat 'check-metafunction retries)])
(check-lhs-pats
(metafunc-proc-lang m)
m
(λ (term _) (property term))
(generation-decisions)
att
ret
'check-metafunction
show))))]))
(define (reduction-relation-srcs r)
(map (λ (proc) (or (rewrite-proc-name proc)
(format "clause at ~a" (rewrite-proc-lhs-src proc))))
(reduction-relation-make-procs r)))
(define (metafunction-srcs m)
(map (compose (curry format "clause at ~a") metafunc-case-src-loc)
(metafunc-proc-cases m)))
(define-syntax (check-reduction-relation stx)
(syntax-case stx ()
[(_ relation property . kw-args)
(with-syntax ([(attempts retries decisions@)
(parse-kw-args `((#:attempts . , #'default-check-attempts)
(#:retries . ,#'default-retries)
(#:decisions . ,#'random-decisions@))
(syntax kw-args)
stx)]
[show (show-message stx)])
(syntax/loc stx
(let ([att attempts]
[ret (assert-nat 'check-reduction-relation retries)]
[rel (assert-rel 'check-reduction-relation relation)])
(check-lhs-pats
(reduction-relation-lang rel)
rel
(λ (term _) (property term))
decisions@
attempts
retries
'check-reduction-relation
show))))]))
(define-signature decisions^
(next-variable-decision
next-number-decision
next-natural-decision
next-integer-decision
next-real-decision
next-non-terminal-decision
next-sequence-decision
next-any-decision
next-string-decision))
(define random-decisions@
(unit (import) (export decisions^)
(define (next-variable-decision) pick-var)
(define (next-number-decision) pick-number)
(define (next-natural-decision) pick-natural)
(define (next-integer-decision) pick-integer)
(define (next-real-decision) pick-real)
(define (next-non-terminal-decision) pick-nts)
(define (next-sequence-decision) pick-sequence-length)
(define (next-any-decision) pick-any)
(define (next-string-decision) pick-string)))
(define generation-decisions (make-parameter random-decisions@))
(provide redex-check
generate-term
check-metafunction-contract
check-reduction-relation
check-metafunction
exn:fail:redex:generation-failure?)
(provide (struct-out ellipsis)
(struct-out mismatch)
(struct-out class)
(struct-out binder)
(struct-out base-cases))
(provide pick-from-list pick-sequence-length pick-nts
pick-char pick-var pick-string pick-any
pick-number pick-natural pick-integer pick-real
parse-pattern unparse-pattern
parse-language prepare-lang
class-reassignments reassign-classes
default-retries proportion-at-size
retry-threshold proportion-before-threshold post-threshold-incr
is-nt? nt-by-name min-prods
generation-decisions decisions^
random-string
sexp find-base-cases)