cyclone/find-named-lets.scm
2018-05-21 18:12:16 -04:00

140 lines
4.4 KiB
Scheme

(import
(scheme base)
(scheme cyclone ast)
(scheme cyclone util)
(scheme cyclone pretty-print)
(scheme write)
(srfi 2)
)
;; TODO: can we scan the ast to find loops created by named lets?
;;
;; This is the typical structure of such a loop:
;;
;; ((lambda (loop$14$171)
;; (set! loop$14$171
;; (lambda (zr$17$174 zi$16$173 c$15$172)
;; (...)))
;; (loop$14$171 zr$13$170 zi$12$169 c$11$168))
;; #f)
(define (scan exp)
(cond
((ast:lambda? exp)
(let* ((id (ast:lambda-id exp))
(has-cont (ast:lambda-has-cont exp))
(sym (string->symbol
(string-append
"lambda-"
(number->string id)
(if has-cont "-cont" ""))))
)
`(,sym ,(ast:lambda-args exp)
,@(map scan (ast:lambda-body exp))))
)
((quote? exp) exp)
((const? exp) exp)
((ref? exp) exp)
((define? exp)
`(define ,(define->var exp)
,@(scan (define->exp exp))))
((set!? exp)
`(set! ,(set!->var exp)
,(scan (set!->exp exp))))
((if? exp)
`(if ,(scan (if->condition exp))
,(scan (if->then exp))
,(scan (if->else exp))))
((app? exp)
(cond
((and-let* (
;; Find lambda with initial #f assignment
((lambda? (car exp)))
((pair? (cdr exp)))
((not (cadr exp)))
(= 1 (length (lambda->formals (car exp))))
;; Get information for continuation
(loop-sym (car (lambda->formals (car exp))))
(inner-exp (car (lambda->exp (car exp))))
((app? inner-exp))
((lambda? (car inner-exp)))
;; Find the set (assumes CPS conversion)
((pair? (cdr inner-exp)))
((set!? (cadr inner-exp)))
((equal? (set!->var (cadr inner-exp)) loop-sym))
;; Check the set's continuation
((app? (car (lambda->exp (car inner-exp)))))
((equal? (caar (lambda->exp (car inner-exp))) loop-sym))
)
(write `(found named lambda loop ,loop-sym))
;; Continue scanning
(map scan exp)
))
(else
(map scan exp))))
(else exp)))
;; Test code follows:
(define sexp
'(define count
(lambda
(k$296 r$5$163
i$4$162
step$3$161
x$2$160
y$1$159)
((lambda
(loop$14$171)
((lambda
(r$299)
(loop$14$171
k$296
(Cyc-fast-plus
r$5$163
(Cyc-fast-mul
(inexact__inline__ x$2$160)
step$3$161))
(Cyc-fast-plus
i$4$162
(Cyc-fast-mul
(inexact__inline__ y$1$159)
step$3$161))
0))
(set! loop$14$171
(lambda
(k$301 zr$17$174 zi$16$173 c$15$172)
(if (Cyc-fast-eq c$15$172 64)
(k$301 c$15$172)
(if (Cyc-fast-gt
(Cyc-fast-plus
(Cyc-fast-mul zr$17$174 zr$17$174)
(Cyc-fast-mul zi$16$173 zi$16$173))
16.0)
(k$301 c$15$172)
(loop$14$171
k$301
(Cyc-fast-plus
(Cyc-fast-sub
(Cyc-fast-mul zr$17$174 zr$17$174)
(Cyc-fast-mul zi$16$173 zi$16$173))
(Cyc-fast-plus
r$5$163
(Cyc-fast-mul
(inexact__inline__ x$2$160)
step$3$161)))
(Cyc-fast-plus
(Cyc-fast-mul
2.0
(Cyc-fast-mul zr$17$174 zi$16$173))
(Cyc-fast-plus
i$4$162
(Cyc-fast-mul
(inexact__inline__ y$1$159)
step$3$161)))
(Cyc-fast-plus c$15$172 1))))))))
#f))))
(scan
;(ast:sexp->ast
sexp);)