#| -*-Scheme-*-

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    2017, 2018, 2019, 2020 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.

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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.

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along with MIT/GNU Scheme; if not, write to the Free Software
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|#

;;;; Predicates
;;; package: (runtime predicate)

(declare (usual-integrations))

(add-boot-deps! '(runtime hash-table))

(define (predicate-name predicate)
  (dispatch-tag-name (predicate->dispatch-tag predicate)))

(define (predicate<= predicate1 predicate2)
  (dispatch-tag<= (predicate->dispatch-tag predicate1)
		  (predicate->dispatch-tag predicate2)))

(define (predicate>= predicate1 predicate2)
  (predicate<= predicate2 predicate1))

(define (dispatch-tag= tag1 tag2)
  (guarantee dispatch-tag? tag1 'dispatch-tag=)
  (guarantee dispatch-tag? tag2 'dispatch-tag=)
  (eq? tag1 tag2))

(define (dispatch-tag<= tag1 tag2)
  (guarantee dispatch-tag? tag1 'dispatch-tag<=)
  (guarantee dispatch-tag? tag2 'dispatch-tag<=)
  (cached-dispatch-tag<= tag1 tag2))

(define (dispatch-tag>= tag1 tag2)
  (dispatch-tag<= tag2 tag1))

(define (cached-dispatch-tag<= tag1 tag2)
  (hash-table-intern! dispatch-tag<=-cache
		      (weak-list tag1 tag2)
		      (lambda () (uncached-dispatch-tag<= tag1 tag2))))

(define (uncached-dispatch-tag<= tag1 tag2)
  (or (eq? tag1 tag2)
      (dispatch-tag-is-bottom? tag1)
      (dispatch-tag-is-top? tag2)
      (and (not (dispatch-tag-is-top? tag1))
	   (not (dispatch-tag-is-bottom? tag2))
	   (let ((v
		  (find (lambda (v)
			  (and ((vector-ref v 0) tag1)
			       ((vector-ref v 1) tag2)))
			dispatch-tag<=-overrides)))
	     (if v
		 ((vector-ref v 2) tag1 tag2)
		 (any-dispatch-tag-superset (lambda (tag)
					      (cached-dispatch-tag<= tag tag2))
					    tag1))))))

(define (define-dispatch-tag<= test1 test2 handler)
  (set! dispatch-tag<=-overrides
	(cons (vector test1 test2 handler)
	      dispatch-tag<=-overrides))
  unspecific)

(define-deferred dispatch-tag<=-cache (make-key-weak-list-eq-hash-table))
(define dispatch-tag<=-overrides '())

(define (any-object? object)
  (declare (ignore object))
  #t)

(define (no-object? object)
  (declare (ignore object))
  #f)

(define (top-dispatch-tag) the-top-dispatch-tag)
(define (bottom-dispatch-tag) the-bottom-dispatch-tag)

(define-integrable (dispatch-tag-is-top? tag)
  (eq? the-top-dispatch-tag tag))

(define-integrable (dispatch-tag-is-bottom? tag)
  (eq? the-bottom-dispatch-tag tag))

(define-deferred the-top-dispatch-tag
  (%make-compound-tag (list 'conjoin) any-object? #f '()))

(define-deferred the-bottom-dispatch-tag
  (%make-compound-tag (list 'disjoin) no-object? #f '()))

(define get-predicate-tag)
(add-boot-init!
 (lambda ()
   (let ((boot-predicate? predicate?))
     (let ((table (make-hashed-metadata-table)))
       (set! predicate? (bundle-ref table 'has?))
       (set! get-predicate-tag (bundle-ref table 'get))
       (set! set-predicate-tag! (bundle-ref table 'put!)))
     (set! predicate->dispatch-tag
	   (named-lambda (predicate->dispatch-tag predicate)
	     (let ((tag (get-predicate-tag predicate #f)))
	       (if (not tag)
		   (error:not-a predicate? predicate))
	       tag)))
     (seq:set-predicate-tag! 'trigger!)
     (set! register-predicate!
	   (let ((make-simple-tag
		  (dispatch-metatag-constructor
		   (make-dispatch-metatag 'simple-tag)
		   'register-predicate!)))
	     (named-lambda (register-predicate! predicate name . keylist)
	       (guarantee keyword-list? keylist 'register-predicate!)
	       (let ((tag
		      (let ((tag (get-predicate-tag predicate #f)))
			(if tag
			    (begin
			      (if (not (eq? name (dispatch-tag-name tag)))
				  (error "Can't re-register predicate:"
					 predicate name))
			      tag)
			    (make-simple-tag name predicate)))))
		 (for-each (lambda (superset)
			     (set-predicate<=! predicate superset))
			   (get-keyword-values keylist '<=))
		 tag))))
     (set! set-dispatch-tag<=!
	   (named-lambda (set-dispatch-tag<=! tag superset)
	     (if (dispatch-tag>= tag superset)
		 (error "Not allowed to create a superset loop:" tag superset))
	     (add-dispatch-tag-superset tag superset)
	     (hash-table-clear! dispatch-tag<=-cache)))
     (set! set-predicate<=!
	   (named-lambda (set-predicate<=! predicate superset)
	     (set-dispatch-tag<=! (predicate->dispatch-tag predicate)
				  (predicate->dispatch-tag
				   (if (eqv? boot-predicate? superset)
				       predicate?
				       superset)))))
     unspecific)))

(add-boot-init!
 (lambda ()
   (register-predicate! %record? '%record)
   (register-predicate! %tagged-object? 'tagged-object)
   (register-predicate! predicate? 'predicate)))

;;; Registration of standard predicates
(add-boot-init!
 (lambda ()
   ;; R7RS
   (register-predicate! boolean? 'boolean)
   (register-predicate! bytevector? 'bytevector)
   (register-predicate! char? 'char)
   (register-predicate! default-object? 'default-object)
   (register-predicate! eof-object? 'eof-object)
   (register-predicate! gc-reclaimed-object? 'gc-reclaimed-object)
   (register-predicate! list? 'list)
   (register-predicate! number? 'number)
   (register-predicate! pair? 'pair)
   (register-predicate! procedure? 'procedure)
   (register-predicate! string? 'string)
   (register-predicate! symbol? 'symbol)
   (register-predicate! vector? 'vector)

   (register-predicate! real? 'real-number '<= number?)
   (register-predicate! rational? 'rational-number '<= real?)
   (register-predicate! integer? 'integer '<= rational?)

   (register-predicate! null? 'empty-list '<= list?)

   ;; SRFI-1
   (register-predicate! circular-list? 'circular-list)
   (register-predicate! dotted-list? 'dotted-list)
   (register-predicate! not-pair? 'not-pair)))

;;; Registration of predicates defined earlier in the boot load, or
;;; needed before their packages are initialized.
(add-boot-init!
 (lambda ()
   ;; MIT/GNU Scheme: specialized arithmetic
   (register-predicate! exact-integer? 'exact-integer '<= integer?)
   (register-predicate! exact-nonnegative-integer? 'exact-nonnegative-integer
			'<= exact-integer?)
   (register-predicate! exact-positive-integer? 'exact-positive-integer
			'<= exact-integer?)
   (register-predicate! exact-rational? 'exact-rational '<= rational?)

   (register-predicate! fix:fixnum? 'fixnum '<= exact-integer?)
   (register-predicate! negative-fixnum? 'negative-fixnum '<= fix:fixnum?)
   (register-predicate! positive-fixnum? 'positive-fixnum
			'<= fix:fixnum?
			'<= exact-positive-integer?)
   (register-predicate! non-negative-fixnum? 'non-negative-fixnum
			'<= fix:fixnum?
			'<= exact-nonnegative-integer?)
   (register-predicate! non-positive-fixnum? 'non-positive-fixnum
			'<= fix:fixnum?)
   (register-predicate! radix? 'radix '<= non-negative-fixnum?)

   (register-predicate! flo:flonum? 'flonum '<= real?)

   ;; MIT/GNU Scheme: lists
   (register-predicate! alist? 'association-list '<= list?)
   (register-predicate! keyword-list? 'keyword-list '<= list?)
   (register-predicate! list-of-unique-symbols? 'list-of-unique-symbols
			'<= list?)
   (register-predicate! non-empty-list? 'non-empty-list
			'<= list?
			'<= pair?)
   (register-predicate! unique-keyword-list? 'unique-keyword-list
			'<= keyword-list?)

   ;; MIT/GNU Scheme: procedures
   (register-predicate! apply-hook? 'apply-hook '<= procedure?)
   (register-predicate! binary-procedure? 'binary-procedure '<= procedure?)
   (register-predicate! compiled-procedure? 'compiled-procedure '<= procedure?)
   (register-predicate! entity? 'entity '<= procedure?)
   (register-predicate! memoizer? 'memoizer '<= apply-hook?)
   (register-predicate! primitive-procedure? 'primitive-procedure
			'<= procedure?)
   (register-predicate! procedure-arity? 'procedure-arity)
   (register-predicate! thunk? 'thunk '<= procedure?)
   (register-predicate! unary-procedure? 'unary-procedure '<= procedure?)))

(add-boot-init!
 (lambda ()
   ;; MIT/GNU Scheme: misc
   (register-predicate! 8-bit-char? '8-bit-char '<= char?)
   (register-predicate! ascii-char? 'ascii-char '<= 8-bit-char?)
   (register-predicate! bit-string? 'bit-string)
   (register-predicate! bitless-char? 'bitless-char '<= char?)
   (register-predicate! code-point-list? 'code-point-list '<= list?)
   (register-predicate! compiled-code-address? 'compiled-code-address)
   (register-predicate! compiled-code-block? 'compiled-code-block)
   (register-predicate! compiled-expression? 'compiled-expression)
   (register-predicate! compiled-return-address? 'compiled-return-address)
   (register-predicate! control-point? 'control-point)
   (register-predicate! ephemeron? 'ephemeron)
   (register-predicate! interned-symbol? 'interned-symbol '<= symbol?)
   (register-predicate! keyword? 'keyword '<= symbol?)
   (register-predicate! lambda-tag? 'lambda-tag)
   (register-predicate! named-structure? 'named-structure)
   (register-predicate! named-list? 'named-list
			'<= non-empty-list?
			'<= named-structure?)
   (register-predicate! named-vector? 'named-vector
			'<= vector?
			'<= named-structure?)
   (register-predicate! record? 'record
			'<= %record?
			'<= named-structure?)
   (register-predicate! applicable-record? 'applicable-record '<= record?)
   (register-predicate! stack-address? 'stack-address)
   (register-predicate! thread-mutex? 'thread-mutex)
   (register-predicate! undefined-value? 'undefined-value)
   (register-predicate! unicode-code-point? 'unicode-code-point
			'<= non-negative-fixnum?)
   (register-predicate! unicode-scalar-value? 'unicode-scalar-value
			'<= unicode-code-point?)
   (register-predicate! uninterned-symbol? 'uninterned-symbol '<= symbol?)
   (register-predicate! weak-alist-table? 'weak-alist-table '<= %record?)
   (register-predicate! weak-alist? 'weak-association-list '<= list?)
   (register-predicate! weak-list-set? 'weak-list-set '<= %record?)
   (register-predicate! weak-list? 'weak-list)
   (register-predicate! weak-pair? 'weak-pair)))