racket/collects/macro-debugger/model/synth-derivs.ss
Ryan Culpepper 927c5b5b46 Macro stepper:
fixed bug in hiding + lifts in module
  explicit error on lift/let

svn: r6228
2007-05-17 17:56:08 +00:00

533 lines
24 KiB
Scheme

(module synth-derivs mzscheme
(require (lib "plt-match.ss")
(lib "list.ss")
"deriv.ss"
"deriv-util.ss"
"synth-engine.ss"
"stx-util.ss"
"context.ss")
(provide (all-defined))
;; machinery for reporting things that macro hiding can't handle
(define-struct nonlinearity (message paths))
(define-struct localactions ())
;; check-nonlinear-subterms : (list-of Subterm) -> void
;; FIXME: No checking on renamings... need to add
;; Note: Make sure subterm contexts are *disjoint*, not just *distinct*
(define (check-nonlinear-subterms subterm-derivs)
(check-nonlinear-paths
(map s:subterm-path
(filter s:subterm? subterm-derivs))))
;; check-nonlinear-paths : (list-of Path) -> void
;; FIXME: This is overly conservative for now, but probably
;; okay given the way I construct paths.
(define (check-nonlinear-paths paths)
;; If there is a self path (null), then it must be the only path.
;; If there are any tail paths, there can be only one (too restrictive?),
;; and the number must be at least as high as any ref paths.
;; Group ref paths by number and recur
(define (tail-path? x) (and (pair? x) (tail? (car x))))
(define (ref-path? x) (and (pair? x) (ref? (car x))))
(let ([null-paths (filter null? paths)]
[tail-paths (filter tail-path? paths)]
[ref-paths (filter ref-path? paths)])
(when (and (pair? null-paths)
(or (> (length null-paths) 1)
(pair? tail-paths)
(pair? ref-paths)))
(raise (make-nonlinearity "self path plus others" paths)))
(when (pair? tail-paths)
(when (> (length tail-paths) 1)
(raise (make-nonlinearity "multiple tail paths" paths)))
(let ([n (tail-n (car (car tail-paths)))])
(for-each (lambda (p)
(when (> (ref-n (car p)) n)
(raise (make-nonlinearity
"ref path after tail path"
paths))))
ref-paths)))
(let ([ref-path-partitions (partition&cdr-ref-paths ref-paths)])
(for-each check-nonlinear-paths ref-path-partitions))))
;; partition&cdr-ref-paths : (list-of Path) -> (list-of (list-of Path))
(define (partition&cdr-ref-paths paths)
(let ([t (make-hash-table 'equal)]
[/null (lambda () null)])
(for-each (lambda (p)
(hash-table-put! t (ref-n (car p))
(cons (cdr p)
(hash-table-get t (ref-n (car p)) /null))))
paths)
(hash-table-map t (lambda (k v) v))))
;; substitute-subterms : Syntax (list-of Subterm) -> Syntax
;; - s:subterm contexts guaranteed to be disjoint.
;; - s:renames replace syntax with syntax of same structure
;; FIXME: Could do this more efficiently using the structure of contexts...
(define (substitute-subterms stx subterm-derivs)
(cond [(null? subterm-derivs)
stx]
[(s:subterm? (car subterm-derivs))
(let* ([subterm0 (car subterm-derivs)]
[path0 (s:subterm-path subterm0)]
[deriv0 (s:subterm-deriv subterm0)])
(let ([e2 (lift/deriv-e2 deriv0)])
(and e2
(substitute-subterms
(if path0 (path-replace stx path0 (deriv-e2 deriv0)) stx)
(cdr subterm-derivs)))))]
[(s:rename? (car subterm-derivs))
(let ([subterm0 (car subterm-derivs)])
(substitute-subterms
(path-replace stx
(s:rename-path subterm0)
(s:rename-after subterm0))
(cdr subterm-derivs)))]
[else (error 'substitute-subterms "neither s:subterm nor s:rename")]))
;; combine-derivs : Derivation Derivation -> Derivation
;; Adds the second derivation to the end of the first derivation.
;; Inserts a p:rename rule when the final syntax of the first derivation
;; is not identical to the initial syntax of the second.
(define (combine-derivs head tail)
;; head-loop : Derivation -> (values Derivation syntax)
(define (head-loop head)
(match head
[(struct mrule (e1 e2 tx next))
(recv [(next e2) (head-loop next)]
(values (outer-rewrap tail (make-mrule e1 e2 tx next))
e2))]
[(IntW mrule (e1 e2 tx #f) 'macro)
(values head e2)]
;; FIXME!!!
[(struct p:stop (e1 e2 rs))
(adjust-tail e2 rs)]
;; FIXME: combine these?
[(struct p::STOP (e1 e2 rs))
(adjust-tail e2 rs)]
[(struct p:variable (e1 e2 rs))
(adjust-tail e2 rs)]))
;; adjust-tail : syntax (list-of syntax) -> (values Derivation syntax)
(define (adjust-tail head-e2 head-rs)
(match tail
[(AnyQ deriv (e1 e2))
(values (if (eq? head-e2 e1)
tail
(wrap/rename-from head-e2 tail))
e2)]
[#f (values (make-p:stop head-e2 head-e2 head-rs)
head-e2)]))
(recv [(d s) (head-loop head)]
d))
;; wrap-p:rename : syntax (cons syntax syntax) Derivation -> Derivation
(define (wrap-p:rename e1 rename deriv)
(make-p:rename e1 (lift/deriv-e2 deriv) null rename deriv))
;; wrap-rename : syntax (cons syntax syntax) Derivation -> Derivation
(define (wrap-rename e1 rename deriv)
(outer-rewrap deriv (wrap-p:rename e1 rename deriv)))
;; wrap/rename-from : syntax Derivation -> Derivation
;; Wrap with renaming: given syntax to initial term of given deriv
(define (wrap/rename-from e0 d)
(match d
[(AnyQ deriv (e1 e2))
(outer-rewrap d (wrap-p:rename e0 (cons e0 e1) d))]))
;; reconstruct-defval : syntax syntax Derivation -> Derivation
;; Reconstruct a define-values node from its rhs deriv
(define (reconstruct-defval head-e2 dvvars dvrhs)
(reconstruct-definition-form head-e2 dvvars dvrhs make-p:define-values))
;; reconstruct-defstx : syntax syntax Derivation -> Derivation
(define (reconstruct-defstx head-e2 dsvars dsrhs)
(reconstruct-definition-form head-e2 dsvars dsrhs make-p:define-syntaxes))
(define (reconstruct-definition-form head-e2 dvvars dvrhs make-Definition)
(match dvrhs
[(AnyQ deriv (rhs-e1 rhs-e2))
(with-syntax ([(?dv ?vars ?rhs) head-e2]
[?vars* dvvars]
[?rhs* rhs-e1])
;; Are there any other renames that
;; should be applied to the rhs?
(let* ([dv1 head-e2]
[dv1* (syntax/skeleton dv1 (?dv ?vars* ?rhs*))]
[dv2
(and rhs-e2
(with-syntax ([?rhs** rhs-e2])
(syntax/skeleton dv1 (?dv ?vars* ?rhs**))))])
(wrap-rename dv1
(cons (cons #'?vars #'?rhs)
(cons #'?vars* #'?rhs*))
(outer-rewrap dvrhs
(make-Definition dv1* dv2 null dvrhs)))))]))
;; bderiv->lderiv : BlockDerivation -> ListDerivation
;; Combines pass1 and pass2 into a single pass(2) list derivation
(define (bderiv->lderiv bd)
(match bd
[#f #f]
[(IntQ bderiv (es1 _es2 pass1 trans pass2))
(let-values ([(_dss dvs exprs)
(case trans
[(letrec)
(match pass2
[(IntQ lderiv (_ _ (list letrec-deriv)) _)
(decompose-letrec letrec-deriv)])]
[(list)
(match pass2
[(AnyQ lderiv (_ _ derivs))
(values null null derivs)]
[#f
(values null null null)])])]
[(brules) pass1]
[(suffix) es1]
[(interrupted?) (interrupted-wrap? bd)])
;; take-expr : -> Derivation/#f
(define (take-expr)
(if (pair? exprs)
(begin0 (car exprs)
(set! exprs (cdr exprs)))
#f))
;; take-defval : -> (cons syntax Derivation) | #f
(define (take-defval)
(if (pair? dvs)
(begin0 (car dvs)
(set! dvs (cdr dvs)))
#f))
;; loop : number -> (list-of BRule)
;; brules, dvs, exprs, suffix threaded through, so use set!
;; dss are all trivial; fully expanded in pass 1
(define (loop count)
(if (positive? count)
(match brules
[(cons (and first (struct error-wrap (exn tag #f))) next)
(set! suffix (stx-cdr suffix))
(set! brules next)
(cons first null)]
[(cons (struct b:defvals (renames head)) next)
(let ([dv (take-defval)])
(set! suffix (stx-cdr suffix))
(set! brules next)
(let ([finish (and dv (reconstruct-defval (deriv-e2 head) (car dv) (cdr dv)))])
(cons (make-b:expr renames (combine-derivs head finish))
(loop (sub1 count)))))]
[(cons (and first (ErrW b:defvals (renames head))) next)
;; Error is after head
(let ([dv (take-defval)])
(set! suffix (stx-cdr suffix))
(set! brules next)
(cons
(make-b:expr
renames
(combine-derivs head
(rewrap first
(make-p:define-values (deriv-e2 head)
#f
null
#f))))
null #;(loop (sub1 count))))]
[(cons (IntQ b:defstx (renames head rhs)) next)
(let ([stx (stx-car suffix)])
(set! _dss (cdr _dss))
(set! suffix (stx-cdr suffix))
(set! brules next)
(let* ([svars
(with-syntax ([(?ds ?svars . ?body) (cdr renames)])
#'?svars)]
[finish (reconstruct-defstx (deriv-e2 head) svars rhs)])
(cons (make-b:expr renames (combine-derivs head finish))
(loop (sub1 count)))))]
[(cons (struct b:splice (renames head tail)) next)
(let ([n (- (length (stx->list tail))
(length (stx->list (stx-cdr suffix))))])
(set! suffix tail)
(set! brules next)
(let* ([splice-derivs (loop n)]
[next (loop (sub1 count))])
(cons (make-b:begin renames head splice-derivs)
next)))]
[(cons (ErrW b:splice (renames head tail) exn) next)
;; Problem with tail
(set! suffix tail)
(set! brules next)
(cons (make-b:expr renames
(combine-derivs head
(make-error-wrap
exn
#f
(make-p:begin (deriv-e2 head)
#f
null
#f))))
null)]
[(cons (and first (IntQ b:expr (renames head))) next)
(let ([expr1 (take-expr)])
(set! suffix (stx-cdr suffix))
(set! brules next)
(cons (make-b:expr renames (combine-derivs head expr1))
(if (wrapped? first) null (loop (sub1 count)))))]
['()
;; We've reached the end of pass1 processing.
;; We need to pull in exprs to fill out the begin/block shape.
(let* ([expr1 (take-expr)]
[e1 (stx-car suffix)]
[expr1 (or expr1 (make-p:stop e1 e1 null))]
[expr1-e1 (match expr1 [(AnyQ deriv (e1 e2)) e1])])
(set! suffix (stx-cdr suffix))
(cons (make-b:expr (cons e1 expr1-e1) expr1)
(loop (sub1 count))))])
;; Otherwise, we've reached the end, either locally or globally
null))
;; to-deriv : BRule syntax -> Derivation
(define (to-deriv br stx)
(match br
[(struct b:expr (renames head))
(wrap-rename stx renames head)]
[(struct b:begin (renames head inners))
(with-syntax ([(?begin . ?inner-terms) (lift/deriv-e2 head)])
(let* ([inner-derivs (map to-deriv inners (syntax->list #'?inner-terms))]
[inner-es1 (map lift/deriv-e1 inner-derivs)]
[inner-es2 (map lift/deriv-e2 inner-derivs)]
[interrupted?
(or (wrapped? head)
(ormap wrapped? inner-derivs))]
[e2 (if interrupted?
#f
(with-syntax ([?inner-terms* inner-es2])
(syntax/skeleton (lift/deriv-e2 head) (?begin . ?inner-terms*))))]
[base
(wrap-p:rename stx renames
(combine-derivs
head
(make-p:begin (lift/deriv-e2 head) e2 null
(make-lderiv inner-es1 inner-es2
inner-derivs))))])
(if interrupted?
(make-interrupted-wrap #f base)
base)))]))
(define (map2stxs f as bs)
(if (pair? as)
(cons (f (car as) (stx-car bs)) (map2stxs f (cdr as) (stx-cdr bs)))
null))
(let* ([brules (loop (stx-improper-length es1))]
[derivs (map2stxs to-deriv brules es1)])
(rewrap/nt bd (make-lderiv es1 (if interrupted? #f (map deriv-e2 derivs)) derivs))))]))
;; module-begin->lderiv : PRule -> ListDerivation
(define (module-begin->lderiv pr)
(let-values ([(forms pass1 pass2)
(match pr
[(IntQ p:#%module-begin (e1 _ _ pass1 pass2))
(values (stx-cdr e1) pass1 pass2)])])
;; loop : number -> (list-of Derivation)
;; NOTE: Definitely returns a list of <number> elements;
;; fills the end of the list with #f if necessary.
(define (loop count)
;(printf "** MB->L (~s)~n" count)
;(printf " forms: ~s~n" forms)
;(printf " pass1: ~s~n" pass1)
(if (positive? count)
(match pass1
[(cons (struct mod:prim (head prim)) next)
(let ([form0 (stx-car forms)]
[pass1-part (car pass1)])
(set! forms (stx-cdr forms))
(set! pass1 next)
(let ([pass2-part (car (loop2 1))])
(cons (wrap/rename-from form0 (combine-prim pass1-part pass2-part))
(loop (sub1 count)))))]
[(cons (struct mod:splice (head tail)) next)
(let ([form0 (stx-car forms)]
[pass1-part (car pass1)]
[inner-n (- (length (stx->list tail))
(length (stx->list (stx-cdr forms))))])
(set! forms tail)
(set! pass1 next)
(let ([inners (loop inner-n)])
(cons (wrap/rename-from form0 (combine-begin head inners))
(loop (sub1 count)))))]
[(cons (struct mod:lift (head tail)) next)
(let ([form0 (stx-car forms)]
[inner-n (length (stx->list tail))])
(set! forms (stx-cdr forms))
(set! pass1 next)
(let ([inners (loop inner-n)])
(set! forms (cons (deriv-e2 head) forms))
(let ([finish (car (loop 1))])
(cons (wrap/rename-from form0 (combine-lifts head finish inners))
(loop (sub1 count))))))]
['()
#;(printf "module-begin->lderiv:loop: unexpected null~n")
(cons #f (loop (sub1 count)))])
null))
;; loop2 : number -> (list-of Derivation)
;; NOTE: Definitely returns a list of <number> elements;
;; fills the end of the list with #f if necessary.
(define (loop2 count)
;(printf "** loop2 (~s)~n" count)
;(printf " forms: ~s~n" forms)
;(printf " pass2: ~s~n" pass2)
(if (positive? count)
(match pass2
[(cons (struct mod:skip ()) next)
(set! pass2 next)
(cons #f (loop2 (sub1 count)))]
[(cons (struct mod:cons (deriv)) next)
(set! pass2 next)
(cons deriv (loop2 (sub1 count)))]
[(cons (struct mod:lift (deriv tail)) next)
(set! pass2 next)
(let* ([head-e1 (deriv-e1 deriv)]
[head-e2 (deriv-e2 deriv)]
[inner-n (length tail)]
[inners (loop2 inner-n)]
[inners-es1 (map deriv-e1 inners)]
[inners-es2 (map deriv-e2 inners)]
[begin-stx1 #`(begin #,@inners-es1 #,(deriv-e2 deriv))]
[begin-stx2 #`(begin #,@inners-es2 #,(deriv-e2 deriv))])
(eat-skip)
(cons
(make-lift-deriv
head-e1 begin-stx2
deriv
begin-stx1
(make-p:begin begin-stx1 begin-stx2 null
(make-lderiv (append inners-es1 (list head-e2))
(append inners-es2 (list head-e2))
(append inners
(list (make-p:stop head-e2 head-e2 null))))))
(loop2 (sub1 count))))]
['()
#;(printf "module-body->lderiv:loop2: unexpected null~n")
(cons #f (loop2 (sub1 count)))])
null))
;; eat-skip : -> void
(define (eat-skip)
(match pass2
[(cons (struct mod:skip ()) next)
(set! pass2 next)]
[else (error 'eat-skip "expected skip!")]))
(let* ([derivs (loop (stx-improper-length forms))]
[es1 (map lift/deriv-e1 derivs)]
[es2 (if (wrapped? pr) #f (map lift/deriv-e2 derivs))])
(rewrap pr (make-lderiv es1 es2 derivs)))))
;; combine-prim : MBRule Derivation -> Derivation
;; The MRule is always a mod:prim rule.
;; Need to insert a rename step in between...
(define (combine-prim mr deriv)
(let ([head (mod:prim-head mr)]
[pr (mod:prim-prim mr)])
(match pr
[(struct p:define-syntaxes (e1 e2 rs rhs))
;; deriv is #f or trivial
(combine-derivs head pr)]
[(struct p:define-values (e1 e2 '() #f))
;; deriv is a pderiv for the entire define-values form
(combine-derivs head deriv)]
[#f
;; deriv is a complete derivation of the rest of the form
(combine-derivs head deriv)]
[(struct p::STOP (e1 e2 rs))
;; deriv is #f
(combine-derivs head pr)])))
;; combine-begin : Derivation (list-of Derivation) -> Derivation
(define (combine-begin head inners)
(let* ([inners-es1 (map deriv-e1 inners)]
[inners-es2 (map deriv-e2 inners)]
[begin-e1 (deriv-e2 head)]
[begin-e2 (with-syntax ([(?begin . _) begin-e1]
[inners-es1 inners-es1])
(syntax/skeleton begin-e1 (?begin . inners-es1)))])
(combine-derivs head
(make-p:begin begin-e1 begin-e2 null
(make-lderiv inners-es1 inners-es2
inners)))))
;; combine-lifts : Derivation Derivation (list-of Derivation) -> Derivation
(define (combine-lifts head finish inners)
(let ([head-e1 (deriv-e1 head)]
[head-e2 (deriv-e2 head)]
[finish-e1 (deriv-e1 finish)]
[finish-e2 (deriv-e2 finish)]
[inners-es1 (map deriv-e1 inners)]
[inners-es2 (map deriv-e2 inners)])
(let ([begin-e1 #`(begin #,@inners-es1 #,finish-e2)]
[begin-e2 #`(begin #,@inners-es2 #,finish-e2)])
(make-lift-deriv
head-e1 begin-e2
(combine-derivs head finish)
(make-p:begin begin-e1 begin-e2 null
(make-lderiv (append inners-es1 (list finish-e2))
(append inners-es2 (list finish-e2))
(append inners
(list (make-p:stop finish-e2
finish-e2
null)))))))))
;; lderiv->module-begin : ListDerivation -> PRule
(define (lderiv->module-begin ld e1)
(match ld
[(IntQ lderiv (inners-es1 inners-es2 inners))
(with-syntax ([(?module-begin . _) e1]
[inners-es1* inners-es1]
[inners-es2* inners-es2])
(rewrap ld
(make-p:#%module-begin
(syntax/skeleton e1 (?module-begin . inners-es1*))
(syntax/skeleton e1 (?module-begin . inners-es2*))
null ;; FIXME
(map (lambda (d) (make-mod:cons d)) inners)
(map (lambda (x) (make-mod:skip)) inners))))]))
;; decompose-letrec : Derivation -> (values DerivList
;; (list-of (cons Syntax Derivation))
;; (list-of (cons Syntax Derivation))
;; Extract the syntax RHS, value RHSs, and expression derivs
;; from a block-generated letrec-values or letrec-syntaxes form.
(define (decompose-letrec deriv)
(match deriv
[(IntQ p:letrec-syntaxes+values (_ _ _ srenames srhss vrenames vrhss body))
;; Assertion: pass1 of the body is always trivial
(with-syntax ([(([?svars ?srhs] ...) ([?vvars ?vrhs] ...) . ?body) srenames])
(with-syntax ([(([?vvars* ?vrhs*] ...) . ?body*)
(or vrenames #'(([?vvars ?vrhs] ...) . ?body))])
(values (map cons
(syntax->list #'(?svars ...))
srhss)
(map cons (syntax->list #'(?vvars* ...)) vrhss)
(lderiv-derivs (bderiv-pass2 body)))))]
[(IntQ p:letrec-values (_ _ _ vrenames vrhss body))
;; Assertion: pass1 of the body is always trivial
(with-syntax ([(([?vars ?rhs] ...) . ?body) vrenames])
(values null
(map cons (syntax->list #'(?vars ...)) vrhss)
(match body
[(IntQ bderiv (_ _ _pass1 _ (IntQ lderiv (_ _ derivs))))
derivs]
[#f
null])))]))
)