;;; $letk binds a set of mutually recursive continuations, each one an
;;; instance of $cont. A $cont declares the name of a continuation, and
;;; then contains as a subterm the particular continuation instance:
-;;; $kif for test continuations, $kargs for continuations that bind
-;;; values, etc.
+;;; $kargs for continuations that bind values, $ktail for the tail
+;;; continuation, etc.
;;;
;;; $continue nodes call continuations. The expression contained in the
;;; $continue node determines the value or values that are passed to the
;;; - $letk, $letrec, and $continue are terms.
;;;
;;; - $cont is a continuation, containing a continuation body ($kargs,
-;;; $kif, etc).
+;;; $ktail, etc).
;;;
;;; - $continue terms contain an expression ($call, $const, $fun,
;;; etc).
$cont
;; Continuation bodies.
- $kif $kreceive $kargs $kfun $ktail $kclause
+ $kreceive $kargs $kfun $ktail $kclause
;; Expressions.
- $void $const $prim $fun $call $callk $primcall $values $prompt
+ $void $const $prim $fun $closure $branch
+ $call $callk $primcall $values $prompt
+
+ ;; First-order CPS root.
+ $program
;; Fresh names.
label-counter var-counter
;; Misc.
parse-cps unparse-cps
- make-cont-folder fold-conts fold-local-conts
+ make-global-cont-folder make-local-cont-folder
+ fold-conts fold-local-conts
visit-cont-successors))
;; FIXME: Use SRFI-99, when Guile adds it.
;; Terms.
(define-cps-type $letk conts body)
(define-cps-type $continue k src exp)
-(define-cps-type $letrec names syms funs body)
+(define-cps-type $letrec names syms funs body) ; Higher-order.
;; Continuations
(define-cps-type $cont k cont)
-(define-cps-type $kif kt kf)
(define-cps-type $kreceive arity k)
(define-cps-type $kargs names syms body)
(define-cps-type $kfun src meta self tail clause)
(define-cps-type $void)
(define-cps-type $const val)
(define-cps-type $prim name)
-(define-cps-type $fun free body)
+(define-cps-type $fun free body) ; Higher-order.
+(define-cps-type $closure label nfree) ; First-order.
+(define-cps-type $branch k exp)
(define-cps-type $call proc args)
-(define-cps-type $callk k proc args)
+(define-cps-type $callk k proc args) ; First-order.
(define-cps-type $primcall name args)
(define-cps-type $values args)
(define-cps-type $prompt escape? tag handler)
+;; The root of a higher-order CPS term is $cont containing a $kfun. The
+;; root of a first-order CPS term is a $program.
+(define-cps-type $program funs)
+
(define label-counter (make-parameter #f))
(define var-counter (make-parameter #f))
(make-$arity req opt rest kw allow-other-keys?))))
(define-syntax build-cont-body
- (syntax-rules (unquote $kif $kreceive $kargs $kfun $ktail $kclause)
+ (syntax-rules (unquote $kreceive $kargs $kfun $ktail $kclause)
((_ (unquote exp))
exp)
- ((_ ($kif kt kf))
- (make-$kif kt kf))
((_ ($kreceive req rest kargs))
(make-$kreceive (make-$arity req '() rest '() #f) kargs))
((_ ($kargs (name ...) (unquote syms) body))
(define-syntax build-cps-exp
(syntax-rules (unquote
- $void $const $prim $fun $call $callk $primcall $values $prompt)
+ $void $const $prim $fun $closure $branch
+ $call $callk $primcall $values $prompt)
((_ (unquote exp)) exp)
((_ ($void)) (make-$void))
((_ ($const val)) (make-$const val))
((_ ($prim name)) (make-$prim name))
- ((_ ($fun free body))
- (make-$fun free (build-cps-cont body)))
+ ((_ ($fun free body)) (make-$fun free (build-cps-cont body)))
+ ((_ ($closure k nfree)) (make-$closure k nfree))
((_ ($call proc (unquote args))) (make-$call proc args))
((_ ($call proc (arg ...))) (make-$call proc (list arg ...)))
((_ ($call proc args)) (make-$call proc args))
((_ ($values (unquote args))) (make-$values args))
((_ ($values (arg ...))) (make-$values (list arg ...)))
((_ ($values args)) (make-$values args))
+ ((_ ($branch k exp)) (make-$branch k (build-cps-exp exp)))
((_ ($prompt escape? tag handler))
(make-$prompt escape? tag handler))))
(define-syntax build-cps-term
- (syntax-rules (unquote $letk $letk* $letconst $letrec $continue)
+ (syntax-rules (unquote $letk $letk* $letconst $letrec $program $continue)
((_ (unquote exp))
exp)
((_ ($letk (unquote conts) body))
($const val))))))
((_ ($letrec names gensyms funs body))
(make-$letrec names gensyms funs (build-cps-term body)))
+ ((_ ($program (unquote conts)))
+ (make-$program conts))
+ ((_ ($program (cont ...)))
+ (make-$program (list (build-cps-cont cont) ...)))
+ ((_ ($program conts))
+ (make-$program conts))
((_ ($continue k src exp))
(make-$continue k src (build-cps-exp exp)))))
(('k sym body)
(build-cps-cont
(sym ,(parse-cps body))))
- (('kif kt kf)
- (build-cont-body ($kif kt kf)))
(('kreceive req rest k)
(build-cont-body ($kreceive req rest k)))
(('kargs names syms body)
(build-cps-exp ($prim name)))
(('fun free body)
(build-cps-exp ($fun free ,(parse-cps body))))
+ (('closure k nfree)
+ (build-cps-exp ($closure k nfree)))
(('letrec ((name sym fun) ...) body)
(build-cps-term
($letrec name sym (map parse-cps fun) ,(parse-cps body))))
+ (('program (cont ...))
+ (build-cps-term ($program ,(map parse-cps cont))))
(('call proc arg ...)
(build-cps-exp ($call proc arg)))
(('callk k proc arg ...)
(build-cps-exp ($callk k proc arg)))
(('primcall name arg ...)
(build-cps-exp ($primcall name arg)))
+ (('branch k exp)
+ (build-cps-exp ($branch k ,(parse-cps exp))))
(('values arg ...)
(build-cps-exp ($values arg)))
(('prompt escape? tag handler)
`(letk ,(map unparse-cps conts) ,(unparse-cps body)))
(($ $cont sym body)
`(k ,sym ,(unparse-cps body)))
- (($ $kif kt kf)
- `(kif ,kt ,kf))
(($ $kreceive ($ $arity req () rest '() #f) k)
`(kreceive ,req ,rest ,k))
(($ $kargs () () body)
`(prim ,name))
(($ $fun free body)
`(fun ,free ,(unparse-cps body)))
+ (($ $closure k nfree)
+ `(closure ,k ,nfree))
(($ $letrec names syms funs body)
`(letrec ,(map (lambda (name sym fun)
(list name sym (unparse-cps fun)))
names syms funs)
,(unparse-cps body)))
+ (($ $program conts)
+ `(program ,(map unparse-cps conts)))
(($ $call proc args)
`(call ,proc ,@args))
(($ $callk k proc args)
`(callk ,k ,proc ,@args))
(($ $primcall name args)
`(primcall ,name ,@args))
+ (($ $branch k exp)
+ `(branch ,k ,(unparse-cps exp)))
(($ $values args)
`(values ,@args))
(($ $prompt escape? tag handler)
(_
(error "unexpected cps" exp))))
-(define-syntax-rule (make-cont-folder global? seed ...)
+(define-syntax-rule (make-global-cont-folder seed ...)
(lambda (proc cont seed ...)
- (define (fold-values proc in seed ...)
- (if (null? in)
- (values seed ...)
- (let-values (((seed ...) (proc (car in) seed ...)))
- (fold-values proc (cdr in) seed ...))))
-
(define (cont-folder cont seed ...)
(match cont
(($ $cont k cont)
(match term
(($ $letk conts body)
(let-values (((seed ...) (term-folder body seed ...)))
- (fold-values cont-folder conts seed ...)))
+ (let lp ((conts conts) (seed seed) ...)
+ (if (null? conts)
+ (values seed ...)
+ (let-values (((seed ...) (cont-folder (car conts) seed ...)))
+ (lp (cdr conts) seed ...))))))
(($ $continue k src exp)
(match exp
- (($ $fun)
- (if global?
- (fun-folder exp seed ...)
- (values seed ...)))
+ (($ $fun) (fun-folder exp seed ...))
(_ (values seed ...))))
(($ $letrec names syms funs body)
(let-values (((seed ...) (term-folder body seed ...)))
- (if global?
- (fold-values fun-folder funs seed ...)
- (values seed ...))))))
+ (let lp ((funs funs) (seed seed) ...)
+ (if (null? funs)
+ (values seed ...)
+ (let-values (((seed ...) (fun-folder (car funs) seed ...)))
+ (lp (cdr funs) seed ...))))))))
(cont-folder cont seed ...)))
+(define-syntax-rule (make-local-cont-folder seed ...)
+ (lambda (proc cont seed ...)
+ (define (cont-folder cont seed ...)
+ (match cont
+ (($ $cont k (and cont ($ $kargs names syms body)))
+ (let-values (((seed ...) (proc k cont seed ...)))
+ (term-folder body seed ...)))
+ (($ $cont k cont)
+ (proc k cont seed ...))))
+ (define (term-folder term seed ...)
+ (match term
+ (($ $letk conts body)
+ (let-values (((seed ...) (term-folder body seed ...)))
+ (let lp ((conts conts) (seed seed) ...)
+ (match conts
+ (() (values seed ...))
+ ((cont) (cont-folder cont seed ...))
+ ((cont . conts)
+ (let-values (((seed ...) (cont-folder cont seed ...)))
+ (lp conts seed ...)))))))
+ (($ $letrec names syms funs body) (term-folder body seed ...))
+ (_ (values seed ...))))
+ (define (clause-folder clause seed ...)
+ (match clause
+ (($ $cont k (and cont ($ $kclause arity body alternate)))
+ (let-values (((seed ...) (proc k cont seed ...)))
+ (if alternate
+ (let-values (((seed ...) (cont-folder body seed ...)))
+ (clause-folder alternate seed ...))
+ (cont-folder body seed ...))))))
+ (match cont
+ (($ $cont k (and cont ($ $kfun src meta self tail clause)))
+ (let*-values (((seed ...) (proc k cont seed ...))
+ ((seed ...) (if clause
+ (clause-folder clause seed ...)
+ (values seed ...))))
+ (cont-folder tail seed ...))))))
+
(define (compute-max-label-and-var fun)
- ((make-cont-folder #t max-label max-var)
- (lambda (label cont max-label max-var)
- (values (max label max-label)
- (match cont
- (($ $kargs names vars body)
- (let lp ((body body) (max-var (fold max max-var vars)))
- (match body
- (($ $letk conts body) (lp body max-var))
- (($ $letrec names vars funs body)
- (lp body (fold max max-var vars)))
- (_ max-var))))
- (($ $kfun src meta self)
- (max self max-var))
- (_ max-var))))
- fun
- -1
- -1))
+ (match fun
+ (($ $cont)
+ ((make-global-cont-folder max-label max-var)
+ (lambda (label cont max-label max-var)
+ (values (max label max-label)
+ (match cont
+ (($ $kargs names vars body)
+ (let lp ((body body) (max-var (fold max max-var vars)))
+ (match body
+ (($ $letk conts body) (lp body max-var))
+ (($ $letrec names vars funs body)
+ (lp body (fold max max-var vars)))
+ (_ max-var))))
+ (($ $kfun src meta self)
+ (max self max-var))
+ (_ max-var))))
+ fun -1 -1))
+ (($ $program conts)
+ (define (fold/2 proc in s0 s1)
+ (if (null? in)
+ (values s0 s1)
+ (let-values (((s0 s1) (proc (car in) s0 s1)))
+ (fold/2 proc (cdr in) s0 s1))))
+ (let lp ((conts conts) (max-label -1) (max-var -1))
+ (if (null? conts)
+ (values max-label max-var)
+ (call-with-values (lambda ()
+ ((make-local-cont-folder max-label max-var)
+ (lambda (label cont max-label max-var)
+ (values (max label max-label)
+ (match cont
+ (($ $kargs names vars body)
+ (fold max max-var vars))
+ (($ $kfun src meta self)
+ (max self max-var))
+ (_ max-var))))
+ (car conts) max-label max-var))
+ (lambda (max-label max-var)
+ (lp (cdr conts) max-label max-var))))))))
(define (fold-conts proc seed fun)
- ((make-cont-folder #t seed) proc fun seed))
+ ((make-global-cont-folder seed) proc fun seed))
(define (fold-local-conts proc seed fun)
- ((make-cont-folder #f seed) proc fun seed))
+ ((make-local-cont-folder seed) proc fun seed))
(define (visit-cont-successors proc cont)
(match cont
(($ $continue k src exp)
(match exp
(($ $prompt escape? tag handler) (proc k handler))
+ (($ $branch kt) (proc k kt))
(_ (proc k)))))))
- (($ $kif kt kf) (proc kt kf))
-
(($ $kreceive arity k) (proc k))
(($ $kclause arity ($ $cont kbody) #f) (proc kbody))
HCoop / bpt / guile.git / blobdiff