#| -*-Scheme-*-

$Id: pardec.scm,v 4.19 2008/01/30 20:02:38 cph Exp $

Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
    1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
    2006, 2007, 2008 Massachusetts Institute of Technology

This file is part of MIT/GNU Scheme.

MIT/GNU Scheme 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 of the License, or (at
your option) any later version.

MIT/GNU Scheme 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 MIT/GNU Scheme; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301,
USA.

|#

;;;; SCode Optimizer: Parse Declarations
;;; package: (scode-optimizer declarations)

(declare (usual-integrations)
	 (integrate-external "object"))

;;;; Main Entry Points

(define (declarations/parse block declarations)
  (let ((declarations (merge-usual-integrations declarations)))
    (make-declaration-set declarations
			  (append-map (lambda (declaration)
					(parse-declaration block declaration))
				      declarations))))

(define (merge-usual-integrations declarations)
  (let loop ((declarations declarations) (exclusions 'NONE) (other '()))
    (if (pair? declarations)
	(if (eq? (caar declarations) 'USUAL-INTEGRATIONS)
	    (loop (cdr declarations)
		  (if (eq? exclusions 'NONE)
		      (cdar declarations)
		      (append exclusions (cdar declarations)))
		  other)
	    (loop (cdr declarations)
		  exclusions
		  (cons (car declarations) other)))
	(if (eq? exclusions 'NONE)
	    (reverse! other)
	    (cons `(USUAL-INTEGRATIONS ,@exclusions)
		  (reverse! other))))))

(define (declarations/make-null)
  (make-declaration-set '() '()))

(define (declarations/original declaration-set)
  (declaration-set/original declaration-set))

(define (declarations/bind operations declaration-set)
  (let loop
      ((operations operations)
       (declarations (declaration-set/declarations declaration-set)))
    (if (null? declarations)
	operations
	(loop (let ((declaration (car declarations)))
		((if (declaration/overridable? declaration)
		     operations/bind-global
		     operations/bind)
		 operations
		 (declaration/operation declaration)
		 (declaration/variable declaration)
		 (declaration/value declaration)))
	      (cdr declarations)))))

(define (declarations/map declaration-set per-variable per-value)
  (make-declaration-set
   (declaration-set/original declaration-set)
   (map (lambda (declaration)
	  (make-declaration (declaration/operation declaration)
			    (per-variable (declaration/variable declaration))
			    (let ((value (declaration/value declaration)))
			      (and value
				   (per-value value)))
			    (declaration/overridable? declaration)))
	(declaration-set/declarations declaration-set))))

(define (declarations/known? declaration)
  (assq (car declaration) known-declarations))

;;;; Data Structures

(define-structure (declaration-set
		   (type vector)
		   (named
		    (string->symbol
		     "#[(scode-optimizer declarations)declaration-set]"))
		   (constructor make-declaration-set)
		   (conc-name declaration-set/))
  (original #f read-only #t)
  (declarations #f read-only #t))

(define-structure (declaration
		   (type vector)
		   (named
		    (string->symbol
		     "#[(scode-optimizer declarations)declaration]"))
		   (constructor make-declaration)
		   (conc-name declaration/))
  ;; OPERATION is the name of the operation that is to be performed by
  ;; this declaration.
  (operation #f read-only #t)

  ;; The variable that this declaration affects.
  (variable #f read-only #t)

  ;; The value associated with this declaration.  The meaning of this
  ;; field depends on OPERATION.
  (value #f read-only #t)

  ;; OVERRIDABLE? means that a user-defined variable of the same name
  ;; will override this declaration.  It also means that this
  ;; declaration should not be written out to the ".ext" file.
  (overridable? #f read-only #t))

(define (make-declarations operation variables values overridable?)
  (if (eq? values 'NO-VALUES)
      (map (lambda (variable)
	     (make-declaration operation variable #f overridable?))
	   variables)
      (map (lambda (variable value)
	     (make-declaration operation variable value overridable?))
	   variables
	   values)))

(define (parse-declaration block declaration)
  (let ((association (assq (car declaration) known-declarations)))
    (if (not association)
	'()
	((cdr association) block (cdr declaration)))))

(define (define-declaration operation parser)
  (let ((entry (assq operation known-declarations)))
    (if entry
	(set-cdr! entry parser)
	(set! known-declarations
	      (cons (cons operation parser)
		    known-declarations))))
  operation)

(define known-declarations
  '())

;;;; Integration Declarations

(define-declaration 'USUAL-INTEGRATIONS
  ;; This is written in a strange way because the obvious way to write
  ;; it is quadratic in the number of names being declared.  Since
  ;; there are typically over 300 names, this matters some.  I believe
  ;; this algorithm is linear in the number of names.
  (lambda (block deletions)
    (let ((deletions
	   (append sf/usual-integrations-default-deletions deletions))
	  (declarations '())
	  (remaining '()))
      (let ((do-deletions
	     (lambda (names vals)
	       (if (null? deletions)
		   (values names vals)
		   (let deletion-loop
		       ((names names)
			(vals vals)
			(names* '())
			(vals* '()))
		     (cond ((null? names)
			    (values names* vals*))
			   ((memq (car names) deletions)
			    (deletion-loop (cdr names)
					   (cdr vals)
					   names*
					   vals*))
			   (else
			    (deletion-loop (cdr names)
					   (cdr vals)
					   (cons (car names) names*)
					   (cons (car vals) vals*))))))))
	    (constructor
	     (lambda (operation)
	       (lambda (name value)
		 (let ((variable (block/lookup-name block name #f)))
		   (if variable
		       (set! declarations
			     (cons (make-declaration operation
						     variable
						     value
						     #t)
				   declarations))
		       (set! remaining
			     (cons (vector operation name value)
				   remaining))))
		 unspecific))))
	(call-with-values
	    (lambda ()
	      (do-deletions usual-integrations/expansion-names
			    usual-integrations/expansion-values))
	  (lambda (expansion-names expansion-values)
	    (for-each (constructor 'EXPAND)
		      expansion-names
		      expansion-values)))
	(call-with-values
	    (lambda ()
	      (do-deletions usual-integrations/constant-names
			    usual-integrations/constant-values))
	  (lambda (constant-names constant-values)
	    (for-each (constructor 'INTEGRATE)
		      constant-names
		      constant-values))))
      (map* declarations
	    (let ((top-level-block
		   (let loop ((block block))
		     (if (block/parent block)
			 (loop (block/parent block))
			 block))))
	      (lambda (remaining)
		(make-declaration
		 (vector-ref remaining 0)
		 (variable/make&bind! top-level-block (vector-ref remaining 1))
		 (vector-ref remaining 2)
		 #t)))
	    remaining))))

(define (define-integration-declaration operation)
  (define-declaration operation
    (lambda (block names)
      (make-declarations operation
			 (block/lookup-names block names #t)
			 'NO-VALUES
			 #f))))

(define-integration-declaration 'INTEGRATE)
(define-integration-declaration 'INTEGRATE-OPERATOR)
(define-integration-declaration 'INTEGRATE-SAFELY)

(define-declaration 'INTEGRATE-EXTERNAL
  (lambda (block specifications)
    (append-map
     (lambda (pathname)
       (call-with-values (lambda () (read-externs-file pathname))
	 (lambda (externs-block externs)
	   (if externs-block
	       (change-type/block externs-block))
	   (append-map
	    (lambda (extern)
	      (let ((operation (vector-ref extern 0))
		    (name (vector-ref extern 1))
		    (value (vector-ref extern 2)))
		(if (and (eq? 'EXPAND operation)
			 (dumped-expander? value))
		    (parse-declaration block
				       (dumped-expander/declaration value))
		    (begin
		      (change-type/expression value)
		      (list
		       (make-declaration operation
					 (if (symbol? name)
					     (block/lookup-name block name #t)
					     name)
					 (make-integration-info
					  (copy/expression/extern block value))
					 #t))))))
	    externs))))
     (append-map (lambda (specification)
		   (let ((value
			  (eval specification system-global-environment)))
		     (if (pair? value)
			 (map ->pathname value)
			 (list (->pathname value)))))
		 specifications))))

(define (operations->external operations environment)
  (let ((block (block/make #f #f '())))
    (values
     block
     (delq! #f
	    (operations/map-external operations
	      (lambda (operation variable value)
		(let ((finish
		       (lambda (value)
			 (vector operation
				 (variable/name variable)
				 (copy/expression/extern block value)))))
		  (cond ((not value)
			 (variable/final-value variable
					       environment
					       finish
					       (lambda () #f)))
			((integration-info? value)
			 (finish (integration-info/expression value)))
			((dumpable-expander? value)
			 (vector operation
				 (if (variable? variable)
				     (variable/name variable)
				     variable)
				 (dumpable-expander->dumped-expander value)))
			(else
			 (error "Unrecognized extern value:" value))))))))))

;;;; Flag Declarations

(for-each (lambda (flag)
	    (define-declaration flag
	      (lambda (block tail)
		(if (not (null? tail))
		    (error "This declaration does not take arguments:"
			   (cons flag tail)))
		(if (not (memq flag (block/flags block)))
		    (set-block/flags! block (cons flag (block/flags block))))
		'())))
	  '(AUTOMAGIC-INTEGRATIONS
	    ETA-SUBSTITUTION
	    OPEN-BLOCK-OPTIMIZATIONS
	    NO-AUTOMAGIC-INTEGRATIONS
	    NO-ETA-SUBSTITUTION
	    NO-OPEN-BLOCK-OPTIMIZATIONS))

(define-declaration 'IGNORE
  (lambda (block names)
    (for-each (lambda (variable)
		(if variable
		    (variable/can-ignore! variable)))
	      (block/lookup-names block names #f))
    '()))

;;;; Reductions and Expansions
;;; See "reduct.scm" for description of REDUCE-OPERATOR and REPLACE-OPERATOR.

(define-declaration 'REDUCE-OPERATOR
  (lambda (block reduction-rules)
    (check-declaration-syntax 'REDUCE-OPERATOR reduction-rules)
    (map (lambda (rule)
	   (make-declaration 'EXPAND
			     (block/lookup-name block (car rule) #t)
			     (make-dumpable-expander (reducer/make rule block)
						     `(REDUCE-OPERATOR ,rule))
			     #f))
	 reduction-rules)))

(define (check-declaration-syntax kind declarations)
  (if (not (and (list? declarations)
		(for-all? declarations
		  (lambda (declaration)
		    (and (pair? declaration)
			 (symbol? (car declaration))
			 (list? (cdr declaration)))))))
      (error "Bad declaration:" kind declarations)))

(define-declaration 'REPLACE-OPERATOR
  (lambda (block replacements)
    (if (not (and (list? replacements)
		  (for-all? replacements
		    (lambda (replacement)
		      (and (pair? replacement)
			   (or (symbol? (car replacement))
			       (and (pair? (car replacement))
				    (eq? 'PRIMITIVE (caar replacement))
				    (pair? (cdar replacement))
				    (symbol? (cadar replacement))
				    (or (null? (cddar replacement))
					(and (pair? (cddar replacement))
					     (null? (cdddar replacement))))))
			   (list? (cdr replacement)))))))
	(error "Bad declaration:" 'REPLACE-OPERATOR replacements))
    (map (lambda (replacement)
	   (make-declaration
	    'EXPAND
	    (let ((name (car replacement)))
	      (cond ((symbol? name)
		     (block/lookup-name block name #t))
		    ((and (pair? name)
			  (eq? (car name) 'PRIMITIVE))
		     (make-primitive-procedure (cadr name)
					       (and (not (null? (cddr name)))
						    (caddr name))))
		    (else
		     (error "Illegal name in replacement:" name))))
	    (make-dumpable-expander
	     (replacement/make replacement block)
	     `(REPLACE-OPERATOR ,replacement))
	    #f))
	 replacements)))

(define (make-dumpable-expander expander declaration)
  (make-entity (lambda (self expr operands if-expanded if-not-expanded block)
		 self			; ignored
		 (expander expr operands if-expanded if-not-expanded block))
	       (cons '*DUMPABLE-EXPANDER* declaration)))

(define (dumpable-expander? object)
  (and (entity? object)
       (let ((extra (entity-extra object)))
	 (and (pair? extra)
	      (eq? '*DUMPABLE-EXPANDER* (car extra))))))

(define (dumpable-expander->dumped-expander expander)
  (cons dumped-expander-tag (cdr (entity-extra expander))))

(define (dumped-expander? object)
  (and (pair? object)
       (eq? dumped-expander-tag (car object))))

(define (dumped-expander/declaration expander)
  (cdr expander))

(define dumped-expander-tag
  (string->symbol "#[(scode-optimizer declarations)dumped-expander]"))

;;; Expansions.  These should be used with great care, and require
;;; knowing a fair amount about the internals of sf.  This declaration
;;; is purely a hook, with no convenience.

(define-declaration 'EXPAND-OPERATOR
  (lambda (block expanders)
    block				;ignored
    (map (lambda (expander)
	   (make-declaration 'EXPAND
			     (block/lookup-name block (car expander) #t)
			     (eval (cadr expander)
				   expander-evaluation-environment)
			     #f))
	 expanders)))