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|
; Part of Scheme 48 1.9. See file COPYING for notices and license.
; Authors: Richard Kelsey, Jonathan Rees, Martin Gasbichler, Mike Sperber
; schemify
; This is only used for producing error and warning messages.
; Flush nodes and generated names in favor of something a little more
; readable. Eventually, (schemify node env) ought to produce an
; s-expression that has the same semantics as node, when node is fully
; expanded.
(define (schemify node . maybe-env)
(if (node? node)
(schemify-node node
(if (null? maybe-env)
#f
(car maybe-env)))
(schemify-sexp node)))
(define schemifiers
(make-operator-table (lambda (node env)
(let ((form (node-form node)))
(if (list? form)
(let ((op (car form)))
(cons (cond ((operator? op)
(operator-name op))
((node? op)
(schemify-node op env))
(else
(schemify-sexp op)))
(schemify-nodes (cdr form) env)))
form)))))
; We cache the no-env version because that's the one used to generate the
; sources in the debugging info (which takes up a lot of space).
(define (schemify-node node env)
(or (and (not env)
(node-ref node 'schemify))
(let ((form ((operator-table-ref schemifiers (node-operator-id node))
node
env)))
(if (not env)
(node-set! node 'schemify form))
form)))
(define (schemify-nodes nodes env)
(map (lambda (node)
(schemify-node node env))
nodes))
(define (define-schemifier name type proc)
(operator-define! schemifiers name type proc))
(define-schemifier 'name 'leaf
(lambda (node env)
(if env
(name->qualified (node-form node)
env)
(let ((form (node-form node)))
(if (or #f (node? form))
(schemify-node form env)
(desyntaxify form))))))
; Convert an alias (generated name) to S-expression form ("qualified name").
(define (name->qualified name env)
(cond ((not (generated? name))
name)
((let ((d0 (lookup env name))
(d1 (lookup env (generated-name name))))
(and d0 d1 (same-denotation? d0 d1)))
(generated-name name)) ;+++
(else
(make-qualified (qualify-parent (generated-parent-name name)
env)
(generated-name name)
(generated-uid name)))))
; As an optimization, we elide intermediate steps in the lookup path
; when possible. E.g.
; #(>> #(>> #(>> define-record-type define-accessors)
; define-accessor)
; record-ref)
; is replaced with
; #(>> define-record-type record-ref)
(define (qualify-parent name env)
(let recur ((name name) (env env))
(if (generated? name)
(let ((parent (generated-parent-name name)))
(if (and (environment-stable? env)
(let ((b1 (generic-lookup env name))
(b2 (generic-lookup env parent)))
(and b1
b2
(or (same-denotation? b1 b2)
(and (binding? b1)
(binding? b2)
(let ((s1 (binding-static b1))
(s2 (binding-static b2)))
(and (transform? s1)
(transform? s2)
(eq? (transform-env s1)
(transform-env s2)))))))))
(recur parent env) ;+++
(make-qualified (recur parent (generated-env name))
(generated-name name)
(generated-uid name))))
name)))
(define-schemifier 'quote syntax-type
(lambda (node env)
(let ((form (node-form node)))
`(quote ,(cadr form)))))
(define-schemifier 'call 'internal
(lambda (node env)
(map (lambda (node)
(schemify-node node env))
(node-form node))))
; We ignore the list of free variables in flat lambdas.
(define (schemify-lambda node env)
(let ((form (node-form node)))
`(lambda ,(schemify-formals (cadr form) env)
,(schemify-node (last form) env))))
(define-schemifier 'lambda syntax-type schemify-lambda)
(define-schemifier 'flat-lambda syntax-type schemify-lambda)
(define (schemify-formals formals env)
(cond ((node? formals)
(schemify-node formals env))
((pair? formals)
(cons (schemify-node (car formals) env)
(schemify-formals (cdr formals) env)))
(else
(schemify-sexp formals)))) ; anything besides '() ?
; let-syntax, letrec-syntax...
(define-schemifier 'letrec syntax-type
(lambda (node env)
(let ((form (node-form node)))
(schemify-letrec 'letrec (cadr form) (caddr form) env))))
(define-schemifier 'letrec* syntax-type
(lambda (node env)
(let ((form (node-form node)))
(schemify-letrec 'letrec* (cadr form) (caddr form) env))))
(define-schemifier 'pure-letrec syntax-type
(lambda (node env)
(let ((form (node-form node)))
(schemify-letrec 'letrec (cadr form) (cadddr form) env))))
(define (schemify-letrec op specs body env)
`(,op ,(map (lambda (spec)
(schemify-nodes spec env))
specs)
,(schemify-node body env)))
(define-schemifier 'loophole syntax-type
(lambda (node env)
(let ((form (node-form node)))
(list 'loophole
(type->sexp (cadr form) #t)
(schemify-node (caddr form) env)))))
(define-schemifier 'lap syntax-type
(lambda (node env)
(let ((form (node-form node)))
`(lap
,(cadr form)
,(schemify-nodes (caddr form) env)
. ,(cdddr form)))))
;----------------
(define (schemify-sexp thing)
(cond ((name? thing)
(desyntaxify thing))
((pair? thing)
(let ((x (schemify-sexp (car thing)))
(y (schemify-sexp (cdr thing))))
(if (and (eq? x (car thing))
(eq? y (cdr thing)))
thing ;+++
(cons x y))))
((vector? thing)
(let ((new (make-vector (vector-length thing) #f)))
(let loop ((i 0) (same? #t))
(if (>= i (vector-length thing))
(if same? thing new) ;+++
(let ((x (schemify-sexp (vector-ref thing i))))
(vector-set! new i x)
(loop (+ i 1)
(and same? (eq? x (vector-ref thing i)))))))))
(else thing)))
|
