racket/collects/mzlib/private/plt-match/coupling-and-binding-new.scm
2005-05-27 18:56:37 +00:00

301 lines
15 KiB
Scheme

;; This library is used by match.ss
(define-values (couple-tests meta-couple subst-bindings)
(letrec
(
;;!(function couple-tests
;; (form (couple-tests test-list ks-func kf-func let-bound)
;; ->
;; ((list list) -> syntax))
;; (contract (list
;; ((((list list) -> syntax) list) ->
;; ((list list) -> syntax))
;; (list -> ((list list) -> syntax))
;; list)
;; ->
;; ((list list) -> syntax)))
;; This is a major function of the compiler. This function
;; couples a list of tests together. Here is where state is
;; passed around to the various partially compiled tests so that
;; compilation can be completed. This returns a function that takes a
;; list of tests so far and a list of bound pattern variables.
(couple-tests
(lambda (test-list ks-func kf-func let-bound)
(if (null? test-list)
(ks-func (kf-func let-bound) let-bound)
(let ((cur-test (car test-list)))
(if (and (>= (test-bind-count cur-test) 2)
(not (exp-already-bound?
(test-bind-exp cur-test)
let-bound))) ;; if it is member of
;;let-bound skip it
(let* ((new-exp (get-exp-var))
(binding (list (test-bind-exp cur-test)
(test-bind-exp-stx cur-test)
new-exp))
(let-bound (cons binding
let-bound))
(kf (kf-func let-bound)))
(lambda (sf bv)
(let ((coup-res
(((test-comp (car test-list))
(couple-tests (cdr test-list)
ks-func
(if (negate-test? cur-test)
(lambda (let-bound)
(lambda (sf bv)
(quasisyntax/loc
(test-bind-exp-stx cur-test)
(match-failure))))
kf-func)
;kf-func
let-bound)
kf let-bound) sf bv)))
(if (equal? (syntax-object->datum coup-res)
'(match-failure))
coup-res
(quasisyntax/loc
(test-bind-exp-stx cur-test)
(let ((#,new-exp
#,(sub-expr-subst (bind-get-exp-stx binding)
let-bound)))
#,coup-res))))))
(let* ((kf (kf-func let-bound)))
((test-comp (car test-list))
(couple-tests (cdr test-list)
ks-func
(if (negate-test? cur-test)
(lambda (let-bound)
(lambda (sf bv)
(quasisyntax/loc
(test-bind-exp-stx cur-test)
(match-failure))))
kf-func)
;kf-func
let-bound)
kf
let-bound)))))))
;;!(function bind-get-exp
;; (form (bind-get-exp binding) -> exp)
;; (contract binding -> exp))
;; This is just an accessor function for a binding. This function
;; returns the expression that is bound in s-exp form.
(bind-get-exp
(lambda (binding)
(car binding)))
;;!(function bind-get-exp-stx
;; (form (bind-get-exp-stx binding) -> exp)
;; (contract binding -> exp))
;; This is just an accessor function for a binding. This function
;; returns the expression that is bound in syntax form.
(bind-get-exp-stx
(lambda (binding)
(cadr binding)))
;;!(function bind-get-new-exp
;; (form (bind-get-new-exp binding) -> exp)
;; (contract binding -> exp))
;; This is just an accessor function for a binding. This function
;; returns the new symbol that will represent the expression.
(bind-get-new-exp
(lambda (binding)
(caddr binding)))
;;!(function subst-bindings
;; (form (subst-bindings exp-stx let-bound) -> syntax)
;; (contract (syntax list) -> syntax)
;; (example (subst-bindings (syntax (car (cdr x)))
;; (list (list '(cdr x)
;; (syntax (cdr x))
;; 'exp5)))
;; -> (syntax (car 'exp5))))
;; This function substitutes let bound variables names for the
;; expressions that they represent.
(subst-bindings
(lambda (exp-stx let-bound)
(let* ((exp (syntax-object->datum exp-stx))
(binding (get-bind exp let-bound)))
(if binding
(bind-get-new-exp binding)
(sub-expr-subst exp-stx let-bound)))))
;;!(function sub-exp-subst
;; (form (sub-exp-subst exp-stx let-bound) -> syntax)
;; (contract (syntax list) -> syntax)
;; (example (subst-bindings (syntax (car (cdr x)))
;; (list (list '(cdr x)
;; (syntax (cdr x))
;; 'exp5)))
;; -> (syntax (car 'exp5))))
;; This function substitutes let bound variables names for the
;; expressions that they represent. This only works if a
;; subexpression of exp-stx is bound in the let-bound list.
(sub-expr-subst
(lambda (exp-stx let-bound)
(syntax-case exp-stx ()
((access sub-exp rest ...)
(let ((binding (get-bind
(syntax-object->datum (syntax sub-exp))
let-bound)))
(if binding
(quasisyntax/loc
exp-stx (access #,(bind-get-new-exp binding) rest ...))
(quasisyntax/loc
exp-stx (access #,(sub-expr-subst (syntax sub-exp)
let-bound)
rest ...)))))
(other (syntax other)))))
;;!(function get-bind
;; (form (get-bind exp let-bound) -> binding)
;; (contract (any list) -> list))
;; This function looks up the binding for a given expression exp
;; in the binding list let-bound. If the binding is found then the
;; binding is returned if not then #f is returned.
(get-bind
(lambda (exp let-bound)
(cond ((null? let-bound) #f)
((equal? exp (bind-get-exp (car let-bound))) (car let-bound))
(else (get-bind exp (cdr let-bound))))))
;;!(function exp-already-bound?
;; (form (exp-already-bound? exp let-bound) -> binding)
;; (contract (any list) -> list))
;; This function looks up the binding for a given expression exp
;; in the binding list let-bound. If the binding is found then #t
;; binding is returned if not then #f is returned.
(exp-already-bound?
(lambda (exp let-bound)
(cond ((null? let-bound) #f)
((equal? exp (bind-get-exp (car let-bound))) #t)
(else (exp-already-bound? exp (cdr let-bound))))))
;;!(function meta-couple
;; (form (meta-couple rendered-list failure-func
;; let-bound bvsf)
;; ->
;; ((list list) -> syntax))
;; (contract (list ((list list) -> syntax) list list)
;; ->
;; ((list list) -> syntax)))
;; This function takes a list of rendered clauses which also have
;; success functions attached and couples the whole lot together
;; yeilding one function that when invoked will compile the whole
;; original match expression.
(meta-couple
(lambda (rendered-list failure-func let-bound bvsf)
;; here we are going to tag the rendered-list before moving on
(let* ((count 0)
(rendered-list
(map (lambda (x)
(begin
(set! count (add1 count))
(cons count x)))
rendered-list)))
(meta-couple-help rendered-list failure-func let-bound bvsf))))
;; so the shape of the data is ((index test-list . success-func) ...)
(tests-index (lambda (x) (car x)))
(tests-list (lambda (x) (cadr x)))
(tests-succ-func (lambda (x) (cddr x)))
(no-group? (lambda (x) (<= (length (test-used-set x)) 1)))
(meta-couple-help
(lambda (rendered-list failure-func let-bound bvsf)
(cond ((null? rendered-list) failure-func)
;; if the top list is null
;; or the first item of the top list
;; has no group associated with it
;; or is a negate test
;; handle list normally
((let ((tlist (tests-list (car rendered-list))))
(or (null? tlist)
(or (negate-test? (car tlist))
(no-group? (car tlist)))))
;; here we erase the previously bound (bv) variables
(let* ((failed
(lambda (let-bound)
(lambda (sf bv)
((meta-couple-help (cdr rendered-list)
failure-func
let-bound
bvsf) sf bvsf)))))
(couple-tests (tests-list (car rendered-list))
(tests-succ-func (car rendered-list)) ;; successfunc needs
;; failure method
failed ;; needs let-bound
let-bound ;; initial-let bindings
)))
(else
(let ((upper-left-test
(car (tests-list (car rendered-list)))))
(let-values (((top-group remainder-of-list)
(lift-out-group (test-used-set
upper-left-test)
rendered-list)))
(let* ((failed
(lambda (let-bound)
(lambda (sf bv)
((meta-couple-help remainder-of-list
failure-func
let-bound
bvsf) sf bvsf)))))
(couple-tests (list upper-left-test)
(lambda (fail let-bound)
(lambda (sf bv)
((meta-couple-help
(cons
(cons (tests-index (car top-group))
(cons
(cdr (tests-list (car top-group)))
(tests-succ-func (car top-group))))
(map
(lambda (tests)
(cons
(tests-index tests)
(cons
(eliminate-test-from-list
upper-left-test
(tests-list tests)
)
(tests-succ-func tests))))
(cdr top-group)))
fail
let-bound
bv)
sf bv)))
failed
let-bound))))))))
;; returns a list containing the separated group and the
;; the rest of the rendered list
(lift-out-group
(lambda (group-list rendered-list)
(let loop ((rl rendered-list)
(k (lambda (grp rest)
(values grp rest))))
(when (null? group-list) (error 'null-group-list))
(if (null? rl)
(k '() '())
(if (member (caar rl) group-list)
(loop (cdr rl)
(lambda (g r)
(k (cons (car rl) g)
r)))
(loop (cdr rl)
(lambda (g r)
(k g
(cons (car rl) r)))))))))
(eliminate-test-from-list
(lambda (test tl)
(filter
(lambda (t)
(or (action-test? t)
(not (in (test-tst t) (list (test-tst test))))))
tl)))
)
(values couple-tests meta-couple subst-bindings)))