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guile/module/language/scheme/translate.scm
Andy Wingo d51406fe87 lambda-lifting for (lambda () ...) as consumer of call-with-values
* libguile/vm-engine.c (vm_run): Add new error case,
  vm_error_not_enough_values.

* libguile/vm-i-system.c (goto/nargs, call/nargs): So, in these cases, if
  we get too many values, we don't truncate the values like we do in the
  single-value continuation case, or in the mvbind case. What to do? I
  guess we either truncate them here, or only allow the correct number of
  values. Dunno. Mark the code as a fixme.
  (truncate-values): New instruction, for mv-bind: checks that the number
  of values on the stack is compatible with the number of bindings we
  have arranged for them, truncating if necessary.

* module/language/scheme/translate.scm (custom-transformer-table):
  Compile receive as a primary form -- not so much because it is a
  primary form, but more to test the mv-bind machinery. Also it's more
  efficient, I think.

* module/system/il/compile.scm (lift-variables!): New helper, factored
  out of `optimize'.
  (optimize): Add a few more cases. Adapt `lambda' optimization, which
  isn't much. I'm not happy with ghil as a mungeable language.
  Add a case for call-with-values with the second argument is
  a lambda: lift the lambda. Untested.
  (codegen): Refactor the push-bindings! code. Compile mv-bind.

* module/system/il/ghil.scm (<ghil-mv-bind>): Add mv-bind construct,
  along with its procedures.

* module/system/il/glil.scm (<glil-mv-bind>): Add mv-bind construct,
  different from the high-level one. It makes sense in the source, I
  think.

* module/system/vm/assemble.scm (codegen): Assemble glil-mv-bind by
  pushing onto the bindings list, and actually push some code to truncate
  the values.
2008-09-18 22:49:55 +02:00

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;;; Guile Scheme specification
;; Copyright (C) 2001 Free Software Foundation, Inc.
;; This program is free software; you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation; either version 2, or (at your option)
;; any later version.
;;
;; This program is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
;; GNU General Public License for more details.
;;
;; You should have received a copy of the GNU General Public License
;; along with this program; see the file COPYING. If not, write to
;; the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
;; Boston, MA 02111-1307, USA.
;;; Code:
(define-module (language scheme translate)
#:use-module (system base pmatch)
#:use-module (system base language)
#:use-module (system il ghil)
#:use-module (system il inline)
#:use-module (ice-9 receive)
#:use-module ((system base compile) #:select (syntax-error))
#:export (translate))
(define (translate x e)
(call-with-ghil-environment (make-ghil-toplevel-env) '()
(lambda (env vars)
(make-ghil-lambda env #f vars #f '() (trans env (location x) x)))))
;;;
;;; Translator
;;;
(define *forbidden-primitives*
;; Guile's `procedure->macro' family is evil because it crosses the
;; compilation boundary. One solution might be to evaluate calls to
;; `procedure->memoizing-macro' at compilation time, but it may be more
;; compicated than that.
'(procedure->syntax procedure->macro))
;; Looks up transformers relative to the current module at
;; compilation-time. See also the discussion of ghil-lookup in ghil.scm.
(define (lookup-transformer head retrans)
(let* ((mod (current-module))
(val (and (symbol? head)
(and=> (module-variable mod head)
(lambda (var)
;; unbound vars can happen if the module
;; definition forward-declared them
(and (variable-bound? var) (variable-ref var)))))))
(cond
((assq-ref custom-transformer-table val))
((defmacro? val)
(lambda (env loc exp)
(retrans (apply (defmacro-transformer val) (cdr exp)))))
((and (macro? val) (eq? (macro-name val) 'sc-macro))
;; syncase!
(let* ((the-syncase-module (resolve-module '(ice-9 syncase)))
(eec (module-ref the-syncase-module 'expansion-eval-closure))
(sc-expand3 (module-ref the-syncase-module 'sc-expand3)))
(lambda (env loc exp)
(retrans
(with-fluids ((eec (module-eval-closure mod)))
(sc-expand3 exp 'c '(compile load eval)))))))
((primitive-macro? val)
(syntax-error #f "unhandled primitive macro" head))
((macro? val)
(syntax-error #f "unknown kind of macro" head))
(else #f))))
(define (trans e l x)
(define (retrans x) (trans e (location x) x))
(cond ((pair? x)
(let ((head (car x)) (tail (cdr x)))
(cond
((lookup-transformer head retrans)
=> (lambda (t) (t e l x)))
;; FIXME: lexical/module overrides of forbidden primitives
((memq head *forbidden-primitives*)
(syntax-error l (format #f "`~a' is forbidden" head)
(cons head tail)))
(else
(let ((tail (map retrans tail)))
(or (and (symbol? head)
(try-inline-with-env e l (cons head tail)))
(make-ghil-call e l (retrans head) tail)))))))
((symbol? x)
(make-ghil-ref e l (ghil-lookup e x)))
;; fixme: non-self-quoting objects like #<foo>
(else
(make-ghil-quote e l #:obj x))))
(define (valid-bindings? bindings . it-is-for-do)
(define (valid-binding? b)
(pmatch b
((,sym ,var) (guard (symbol? sym)) #t)
((,sym ,var ,update) (guard (pair? it-is-for-do) (symbol? sym)) #t)
(else #f)))
(and (list? bindings) (and-map valid-binding? bindings)))
(define-macro (make-pmatch-transformers env loc retranslate . body)
(define exp (gensym))
(define (make1 clause)
(let ((sym (car clause))
(clauses (cdr clause)))
`(cons ,sym
(lambda (,env ,loc ,exp)
(define (,retranslate x) (trans ,env (location x) x))
(pmatch (cdr ,exp)
,@clauses
(else (syntax-error ,loc (format #f "bad ~A" ',sym) ,exp)))))))
`(list ,@(map make1 body)))
(define *the-compile-toplevel-symbol* 'compile-toplevel)
(define custom-transformer-table
(make-pmatch-transformers
e l retrans
(quote
;; (quote OBJ)
((,obj) (make-ghil-quote e l obj)))
(quasiquote
;; (quasiquote OBJ)
((,obj) (make-ghil-quasiquote e l (trans-quasiquote e l obj 0))))
(define
;; (define NAME VAL)
((,name ,val) (guard (symbol? name)
(ghil-toplevel-env? (ghil-env-parent e)))
(make-ghil-define e l (ghil-define (ghil-env-parent e) name)
(maybe-name-value! (retrans val) name)))
;; (define (NAME FORMALS...) BODY...)
(((,name . ,formals) . ,body) (guard (symbol? name))
;; -> (define NAME (lambda FORMALS BODY...))
(retrans `(define ,name (lambda ,formals ,@body)))))
(set!
;; (set! NAME VAL)
((,name ,val) (guard (symbol? name))
(make-ghil-set e l (ghil-lookup e name) (retrans val)))
;; (set! (NAME ARGS...) VAL)
(((,name . ,args) ,val) (guard (symbol? name))
;; -> ((setter NAME) ARGS... VAL)
(retrans `((setter ,name) . (,@args ,val)))))
(if
;; (if TEST THEN [ELSE])
((,test ,then)
(make-ghil-if e l (retrans test) (retrans then) (retrans '(begin))))
((,test ,then ,else)
(make-ghil-if e l (retrans test) (retrans then) (retrans else))))
(and
;; (and EXPS...)
(,tail (make-ghil-and e l (map retrans tail))))
(or
;; (or EXPS...)
(,tail (make-ghil-or e l (map retrans tail))))
(begin
;; (begin EXPS...)
(,tail (make-ghil-begin e l (map retrans tail))))
(let
;; (let NAME ((SYM VAL) ...) BODY...)
((,name ,bindings . ,body) (guard (symbol? name)
(valid-bindings? bindings))
;; -> (letrec ((NAME (lambda (SYM...) BODY...))) (NAME VAL...))
(retrans `(letrec ((,name (lambda ,(map car bindings) ,@body)))
(,name ,@(map cadr bindings)))))
;; (let () BODY...)
((() . ,body)
;; Note: this differs from `begin'
(make-ghil-begin e l (list (trans-body e l body))))
;; (let ((SYM VAL) ...) BODY...)
((,bindings . ,body) (guard (valid-bindings? bindings))
(let ((vals (map retrans (map cadr bindings))))
(call-with-ghil-bindings e (map car bindings)
(lambda (vars)
(make-ghil-bind e l vars vals (trans-body e l body)))))))
(let*
;; (let* ((SYM VAL) ...) BODY...)
((() . ,body)
(retrans `(let () ,@body)))
((((,sym ,val) . ,rest) . ,body) (guard (symbol? sym))
(retrans `(let ((,sym ,val)) (let* ,rest ,@body)))))
(letrec
;; (letrec ((SYM VAL) ...) BODY...)
((,bindings . ,body) (guard (valid-bindings? bindings))
(call-with-ghil-bindings e (map car bindings)
(lambda (vars)
(let ((vals (map retrans (map cadr bindings))))
(make-ghil-bind e l vars vals (trans-body e l body)))))))
(cond
;; (cond (CLAUSE BODY...) ...)
(() (retrans '(begin)))
(((else . ,body)) (retrans `(begin ,@body)))
(((,test) . ,rest) (retrans `(or ,test (cond ,@rest))))
(((,test => ,proc) . ,rest)
;; FIXME hygiene!
(retrans `(let ((_t ,test)) (if _t (,proc _t) (cond ,@rest)))))
(((,test . ,body) . ,rest)
(retrans `(if ,test (begin ,@body) (cond ,@rest)))))
(case
;; (case EXP ((KEY...) BODY...) ...)
((,exp . ,clauses)
(retrans
;; FIXME hygiene!
`(let ((_t ,exp))
,(let loop ((ls clauses))
(cond ((null? ls) '(begin))
((eq? (caar ls) 'else) `(begin ,@(cdar ls)))
(else `(if (memv _t ',(caar ls))
(begin ,@(cdar ls))
,(loop (cdr ls))))))))))
(do
;; (do ((SYM VAL [UPDATE]) ...) (TEST RESULT...) BODY...)
((,bindings (,test . ,result) . ,body)
(let ((sym (map car bindings))
(val (map cadr bindings))
(update (map cddr bindings)))
(define (next s x) (if (pair? x) (car x) s))
(retrans
;; FIXME hygiene!
`(letrec ((_l (lambda ,sym
(if ,test
(begin ,@result)
(begin ,@body
(_l ,@(map next sym update)))))))
(_l ,@val))))))
(lambda
;; (lambda FORMALS BODY...)
((,formals . ,body)
(receive (syms rest) (parse-formals formals)
(call-with-ghil-environment e syms
(lambda (env vars)
(receive (meta body) (parse-lambda-meta body)
(make-ghil-lambda env l vars rest meta
(trans-body env l body))))))))
(eval-case
(,clauses
(retrans
`(begin
;; Compilation of toplevel units is always wrapped in a lambda
,@(let ((toplevel? (ghil-toplevel-env? (ghil-env-parent e))))
(let loop ((seen '()) (in clauses) (runtime '()))
(cond
((null? in) runtime)
(else
(pmatch (car in)
((else . ,body)
(if (and toplevel? (not (memq *the-compile-toplevel-symbol* seen)))
(primitive-eval `(begin ,@body)))
(if (memq (if toplevel? *the-compile-toplevel-symbol* 'evaluate) seen)
runtime
body))
((,keys . ,body) (guard (list? keys) (and-map symbol? keys))
(for-each (lambda (k)
(if (memq k seen)
(syntax-error l "eval-case condition seen twice" k)))
keys)
(if (and toplevel? (memq *the-compile-toplevel-symbol* keys))
(primitive-eval `(begin ,@body)))
(loop (append keys seen)
(cdr in)
(if (memq (if toplevel? 'load-toplevel 'evaluate) keys)
(append runtime body)
runtime)))
(else (syntax-error l "bad eval-case clause" (car in))))))))))))
;; FIXME: make this actually do something
(start-stack
((,tag ,expr) (retrans expr)))
;; FIXME: not hygienic, relies on @apply not being shadowed
(apply
(,args (retrans `(@apply ,@args))))
(@apply
((,proc ,arg1 . ,args)
(let ((args (cons (retrans arg1) (map retrans args))))
(cond ((and (symbol? proc)
(not (ghil-lookup e proc #f))
(and=> (module-variable (current-module) proc)
(lambda (var)
(and (variable-bound? var)
(lookup-apply-transformer (variable-ref var))))))
;; that is, a variable, not part of this compilation
;; unit, but defined in the toplevel environment, and has
;; an apply transformer registered
=> (lambda (t) (t e l args)))
(else (make-ghil-inline e l 'apply
(cons (retrans proc) args)))))))
;; FIXME: not hygienic, relies on @call-with-values not being shadowed
(call-with-values
((,producer ,consumer)
(retrans `(@call-with-values ,producer ,consumer)))
(else #f))
(@call-with-values
((,producer ,consumer)
(make-ghil-mv-call e l (retrans producer) (retrans consumer))))
(receive
((,formals ,producer-exp . ,body)
;; Lovely, self-referential usage. Not strictly necessary, the
;; macro would do the trick; but it's good to test the mv-bind
;; code.
(receive (syms rest) (parse-formals formals)
(call-with-ghil-bindings e syms
(lambda (vars)
(make-ghil-mv-bind e l (retrans `(lambda () ,producer-exp))
vars rest (trans-body e l body)))))))
(values
((,x) (retrans x))
(,args (make-ghil-values e l (map retrans args))))))
(define (lookup-apply-transformer proc)
(cond ((eq? proc values)
(lambda (e l args)
(make-ghil-values* e l args)))
(else #f)))
(define (trans-quasiquote e l x level)
(cond ((not (pair? x)) x)
((memq (car x) '(unquote unquote-splicing))
(let ((l (location x)))
(pmatch (cdr x)
((,obj)
(cond
((zero? level)
(if (eq? (car x) 'unquote)
(make-ghil-unquote e l (trans e l obj))
(make-ghil-unquote-splicing e l (trans e l obj))))
(else
(list (car x) (trans-quasiquote e l obj (1- level))))))
(else (syntax-error l (format #f "bad ~A" (car x)) x)))))
((eq? (car x) 'quasiquote)
(let ((l (location x)))
(pmatch (cdr x)
((,obj) (list 'quasiquote (trans-quasiquote e l obj (1+ level))))
(else (syntax-error l (format #f "bad ~A" (car x)) x)))))
(else (cons (trans-quasiquote e l (car x) level)
(trans-quasiquote e l (cdr x) level)))))
(define (trans-body e l body)
(define (define->binding df)
(pmatch (cdr df)
((,name ,val) (guard (symbol? name)) (list name val))
(((,name . ,formals) . ,body) (guard (symbol? name))
(list name `(lambda ,formals ,@body)))
(else (syntax-error (location df) "bad define" df))))
;; main
(let loop ((ls body) (ds '()))
(pmatch ls
(() (syntax-error l "bad body" body))
(((define . _) . _)
(loop (cdr ls) (cons (car ls) ds)))
(else
(if (null? ds)
(trans e l `(begin ,@ls))
(trans e l `(letrec ,(map define->binding ds) ,@ls)))))))
(define (parse-formals formals)
(cond
;; (lambda x ...)
((symbol? formals) (values (list formals) #t))
;; (lambda (x y z) ...)
((list? formals) (values formals #f))
;; (lambda (x y . z) ...)
((pair? formals)
(let loop ((l formals) (v '()))
(if (pair? l)
(loop (cdr l) (cons (car l) v))
(values (reverse! (cons l v)) #t))))
(else (syntax-error (location formals) "bad formals" formals))))
(define (parse-lambda-meta body)
(cond ((or (null? body) (null? (cdr body))) (values '() body))
((string? (car body))
(values `((documentation . ,(car body))) (cdr body)))
(else (values '() body))))
(define (maybe-name-value! val name)
(cond
((ghil-lambda? val)
(if (not (assq-ref (ghil-lambda-meta val) 'name))
(set! (ghil-lambda-meta val)
(acons 'name name (ghil-lambda-meta val))))))
val)
(define (location x)
(and (pair? x)
(let ((props (source-properties x)))
(and (not (null? props))
(vector (assq-ref props 'line)
(assq-ref props 'column)
(assq-ref props 'filename))))))