#| -*-Scheme-*-

Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
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    2017, 2018, 2019, 2020, 2021, 2022 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.

|#

;;;; Command Tables

(declare (usual-integrations))

(define-structure (comtab (constructor make-comtab ()))
  (vector 0)
  (alist '()))

(define (comtab-get comtab key)
  (let ((vector (comtab-vector comtab)))
    (let ((try
	   (lambda (key)
	     (if (and (vector? vector)
		      (char? key)
		      (< (char->integer key) (vector-length vector)))
		 (vector-ref vector (char->integer key))
		 (let ((entry (assq key (comtab-alist comtab))))
		   (and entry
			(cdr entry)))))))
      (if (and (char? key) (char-upper-case? (char-base key)))
	  (or (try key) (try (char-downcase key)))
	  (try key)))))

(define (comtab-put! comtab key datum)
  (cond ((not datum)
	 (comtab-remove! comtab key))
	((and (char? key) (< (char->integer key) 256))
	 (let ((vector (comtab-vector comtab)))
	   (if (vector? vector)
	       (vector-set! vector (char->integer key) datum)
	       (let ((alist (comtab-alist comtab)))
		 (let ((entry (assq key alist)))
		   (if entry
		       (set-cdr! entry datum)
		       (let ((vector (+ vector 1))
			     (alist (cons (cons key datum) alist)))
			 (if (< vector 64)
			     (without-interrupts
			      (lambda ()
				(set-comtab-vector! comtab vector)
				(set-comtab-alist! comtab alist)))
			     (let* ((vector (make-vector 256 false))
				    (alist
				     (remove (lambda (entry)
					       (let ((key (car entry)))
						 (and (char? key)
						      (< (char->integer key)
							 256)
						      (begin
							(vector-set!
							 vector
							 (char->integer key)
							 (cdr entry))
							true))))
					     alist)))
			       (without-interrupts
				(lambda ()
				  (set-comtab-vector! comtab vector)
				  (set-comtab-alist! comtab alist))))))))))))
	(else
	 (let ((alist (comtab-alist comtab)))
	   (let ((entry (assq key alist)))
	     (if entry
		 (set-cdr! entry datum)
		 (set-comtab-alist! comtab
				    (cons (cons key datum) alist))))))))

(define (comtab-remove! comtab key)
  (if (and (char? key) (< (char->integer key) 256))
      (let ((vector (comtab-vector comtab)))
	(if (vector? vector)
	    (vector-set! vector (char->integer key) false)
	    (let ((alist (comtab-alist comtab)))
	      (let ((entry (assq key alist)))
		(if entry
		    (let ((vector (- vector 1))
			  (alist (delq entry alist)))
		      (without-interrupts
		       (lambda ()
			 (set-comtab-vector! comtab vector)
			 (set-comtab-alist! comtab alist)))))))))
      (set-comtab-alist! comtab (del-assq key (comtab-alist comtab)))))

(define (valid-comtabs? object)
  (or (mode? object)
      (symbol? object)
      (comtab? object)
      (list-of-comtabs? object)))

(define (guarantee-comtabs object procedure)
  (cond ((mode? object)
	 (mode-comtabs object))
	((symbol? object)
	 (mode-comtabs (->mode object)))
	((comtab? object)
	 (list object))
	((list-of-comtabs? object)
	 object)
	(else
	 (error:wrong-type-argument object "list of comtabs" procedure))))

(define (mode-name? object)
  (and (symbol? object)
       (string-table-get editor-modes (symbol->string object))))

(define (list-of-comtabs? object)
  (and (not (null? object))
       (list? object)
       (every comtab? object)))

(define (comtab-key? object)
  (or (key? object)
      (prefixed-key? object)
      (button? object)))

(define (prefixed-key? object)
  (let loop ((object object))
    (and (pair? object)
	 (key? (car object))
	 (or (null? (cdr object))
	     (loop (cdr object))))))

(define (valid-datum? object)
  (or (not object)
      (command? object)
      (comtab? object)
      (command&comtab? object)
      (comtab-alias? object)))

(define (command&comtab? object)
  (and (pair? object)
       (command? (car object))
       (comtab? (cdr object))))

(define (comtab-alias? object)
  (and (pair? object)
       (valid-comtabs? (car object))
       (comtab-key? (cdr object))))

(define (comtab-alias/dereference datum)
  (lookup-key (car datum) (cdr datum)))

(define (lookup-key comtabs key)
  (let ((comtabs (guarantee-comtabs comtabs 'LOOKUP-KEY)))
    (let ((simple-lookup
	   (lambda (key)
	     (let loop ((comtabs* comtabs))
	       (cond ((comtab-get (car comtabs*) key)
		      => handle-datum)
		     ((not (null? (cdr comtabs*)))
		      (loop (cdr comtabs*)))
		     (else
		      false))))))
      (cond ((key? key)
	     (simple-lookup (remap-alias-key key)))
	    ((button? key)
	     (simple-lookup key))
	    ((prefixed-key? key)
	     (let ((prefix (except-last-pair key))
		   (key (remap-alias-key (car (last-pair key)))))
	       (if (null? prefix)
		   (simple-lookup key)
		   (let loop ((comtabs* comtabs))
		     (let ((comtab
			    (lookup-prefix (car comtabs*) prefix false)))
		       (cond ((and comtab (comtab-get comtab key))
			      => handle-datum)
			     ((not (null? (cdr comtabs*)))
			      (loop (cdr comtabs*)))
			     (else
			      false)))))))
	    (else
	     (error:wrong-type-argument key "comtab key" 'LOOKUP-KEY))))))

(define (handle-datum datum)
  (cond ((or (command? datum)
	     (comtab? datum)
	     (command&comtab? datum))
	 datum)
	((comtab-alias? datum)
	 (comtab-alias/dereference datum))
	(else
	 (error "Illegal comtab datum:" datum))))

(define (lookup-prefix comtab prefix intern?)
  (let loop ((comtab comtab) (prefix* prefix))
    (if (null? prefix*)
	comtab
	(let ((key (remap-alias-key (car prefix*)))
	      (prefix* (cdr prefix*)))
	  (let datum-loop ((datum (comtab-get comtab key)))
	    (cond ((not datum)
		   (and intern?
			(let ((datum (make-comtab)))
			  ;; Note that this will clobber a comtab-alias
			  ;; that points to an undefined entry.
			  (comtab-put! comtab key datum)
			  (loop datum prefix*))))
		  ((comtab? datum)
		   (loop datum prefix*))
		  ((command&comtab? datum)
		   (loop (cdr datum) prefix*))
		  ((comtab-alias? datum)
		   (datum-loop (comtab-alias/dereference datum)))
		  ((command? datum)
		   (error "Key sequence too long:"
			  prefix
			  (- (length prefix) (length prefix*))))
		  (else
		   (error "Illegal comtab datum:" datum))))))))

(define (comtab-entry comtabs key)
  (or (%comtab-entry comtabs key)
      (and (not (button? key))
	   (ref-command-object undefined))))

(define (local-comtab-entry comtabs key mark)
  (or (and mark
	   (let ((local-comtabs (local-comtabs mark)))
	     (and local-comtabs
		  (%comtab-entry local-comtabs key))))
      (comtab-entry comtabs key)))

(define (%comtab-entry comtabs key)
  (let ((object (lookup-key comtabs key)))
    (cond ((not object)
	   #f)
	  ((command? object)
	   object)
	  ((command&comtab? object)
	   (car object))
	  ((comtab? object)
	   (ref-command-object prefix-key))
	  (else
	   (error "Illegal result from lookup-key:" object)))))

(define (prefix-key-list? comtabs key)
  (let ((object (lookup-key comtabs key)))
    (or (comtab? object)
	(command&comtab? object))))

(define (define-key mode key datum)
  (%define-key (guarantee-comtabs mode 'DEFINE-KEY)
	       key
	       (if (valid-datum? datum) datum (->command datum))
	       'DEFINE-KEY))

(define (define-prefix-key mode key #!optional command)
  (%define-key (guarantee-comtabs mode 'DEFINE-PREFIX-KEY)
	       (begin
		 (if (button? key)
		     (error:wrong-type-argument key
						"comtab prefix key"
						'DEFINE-PREFIX-KEY))
		 key)
	       (let ((comtab (make-comtab)))
		 (if (default-object? command)
		     comtab
		     (let ((command (->command command)))
		       (if (eq? command (ref-command-object prefix-key))
			   comtab
			   (cons command comtab)))))
	       'DEFINE-PREFIX-KEY))

(define (%define-key comtabs key datum procedure)
  (let* ((comtab (car comtabs))
	 (put!
	  (lambda (key)
	    (comtab-put! comtab (remap-alias-key key) datum))))
    (cond ((or (key? key) (button? key))
	   (put! key))
	  ((char-set? key)
	   (char-set-for-each put! (char-set-intersection key char-set:ascii)))
	  ((prefixed-key? key)
	   (let ((prefix (except-last-pair key)))
	     (comtab-put! (if (null? prefix)
			      comtab
			      (lookup-prefix comtab prefix true))
			  (remap-alias-key (car (last-pair key)))
			  datum)))
	  (else
	   (error:wrong-type-argument key "comtab key" procedure))))
  key)

(define (comtab-alist* comtab)
  (let ((vector (comtab-vector comtab))
	(alist (comtab-alist comtab)))
    (if (vector? vector)
	(let ((end (vector-length vector)))
	  (let loop ((index 0) (alist alist))
	    (if (fix:< index end)
		(loop (fix:+ index 1)
		      (let ((datum (vector-ref vector index)))
			(if datum
			    (cons (cons (integer->char index) datum)
				  alist)
			    alist)))
		alist)))
	alist)))

(define (comtab->alist comtab)
  (let loop ((prefix '()) (comtab comtab))
    (append-map!
     (lambda (entry)
       (if (and (button? (car entry))
		(not (null? prefix)))
	   '()
	   (let ((prefix (append prefix (list (car entry)))))
	     (let ((key (if (null? (cdr prefix)) (car prefix) prefix)))
	       (let datum-loop ((datum (cdr entry)))
		 (cond ((not datum)
			'())
		       ((command? datum)
			(list (cons key datum)))
		       ((comtab? datum)
			(loop prefix datum))
		       ((command&comtab? datum)
			(cons (cons key (car datum))
			      (loop prefix (cdr datum))))
		       ((comtab-alias? datum)
			(datum-loop (comtab-alias/dereference datum)))
		       (else
			(error "Illegal comtab datum:" datum))))))))
     (comtab-alist* comtab))))

(define (comtab-key-bindings comtabs command)
  (let ((comtabs (guarantee-comtabs comtabs 'COMTAB-KEY-BINDINGS))
	(command (->command command)))
    ;; In addition to having a binding of COMMAND, every key in the
    ;; result satisfies VALID-KEY?.  This eliminates bindings that are
    ;; shadowed by other bindings.
    (let ((valid-key?
	   (lambda (key)
	     (let ((datum (lookup-key comtabs key)))
	       (cond ((command? datum)
		      (eq? command datum))
		     ((comtab? datum)
		      (eq? command (ref-command-object prefix-key)))
		     ((command&comtab? datum)
		      (eq? command (car datum)))
		     (else
		      false))))))
      (sort (let loop ((comtabs comtabs))
	      (if (null? comtabs)
		  '()
		  (%comtab-bindings (car comtabs)
				    (loop (cdr comtabs))
				    command
				    valid-key?)))
	(let ((v
	       (lambda (k)
		 (cond ((char? k) 0)
		       ((list-of-type? k char?) 1)
		       ((special-key? k) 2)
		       ((button? k) 3)
		       (else 4)))))
	  (lambda (k1 k2)
	    (< (v k1) (v k2))))))))

(define (%comtab-bindings comtab keys command valid-key?)
  (let comtab-loop ((comtab comtab) (keys keys) (prefix '()))
    (let alist-loop ((entries (comtab-alist* comtab)))
      (if (null? entries)
	  keys
	  (let ((key
		 (if (pair? prefix)
		     (append prefix (list (caar entries)))
		     (caar entries))))
	    (let datum-loop
		((datum (cdar entries))
		 (keys (alist-loop (cdr entries))))
	      (cond ((not datum)
		     keys)
		    ((command? datum)
		     (if (and (eq? datum command)
			      (valid-key? key))
			 (cons key keys)
			 keys))
		    ((comtab? datum)
		     (let ((keys
			    (comtab-loop datum keys
					 (if (pair? prefix)
					     key
					     (list key)))))
		       (if (and (eq? command (ref-command-object prefix-key))
				(valid-key? key))
			   (cons key keys)
			   keys)))
		    ((command&comtab? datum)
		     (datum-loop (car datum)
				 (datum-loop (cdr datum) keys)))
		    ((comtab-alias? datum)
		     (datum-loop (comtab-alias/dereference datum) keys))
		    (else
		     (error "Illegal comtab datum:" datum)))))))))