;;; nrepl.scm -- notcurses-based repl

(set! (*s7* 'history-enabled) #f)
(provide 'nrepl.scm)

(define libc-let (if (defined? '*nlibc*) ; nrepl.c has the parts of *libc* we need under the name *nlibc*
		     *nlibc*
		     (begin
		       (require libc.scm)
		       *libc*)))

(unless (defined? '*notcurses*)          ; nrepl.c has notcurses_s7.c (thus *notcurses*) built-in
  (load "notcurses_s7.so" (inlet 'init_func 'notcurses_s7_init)))
(unless (defined? 'notcurses_getc) (define (notcurses_getc a b c d) (notcurses_get a b d)))

(define (drop-into-repl call e)
  ((*nrepl* 'run) "break>" (object->string call) e))

(define (display-debug-info cint) #f) ; replaced later
(define (remove-watcher var) #f)
(define (nrepl-lookup symbol) (((*nrepl* 'top-level-let) 'run-let) symbol))

(define (debug.scm-init)
  (set! (debug-repl)
	drop-into-repl)
  (set! (debug-port)
	(open-output-function display-debug-info))
  (set! (hook-functions ((funclet trace-in) '*debug-unwatch-hook*))
	(list (lambda (h)
		(remove-watcher (h 'var))))))

(define old-debug (*s7* 'debug))
(set! (*s7* 'debug) 0)

(define startup-symbols (copy (symbol-table)))
;(autoload 'lint "lint.scm")
(require lint.scm)
(define with-lint (defined? '*lint*)) ; maybe require should return #f if no luck? (or a list since it takes any number of args), or an error??

(autoload 'pretty-print "write.scm")
(autoload 'pp "write.scm")
(autoload '*libc* "libc.scm")
(autoload '*libm* "libm.scm")
(autoload '*libgsl* "libgsl.scm")
(autoload 'trace "debug.scm")
(autoload 'untrace "debug.scm")
(autoload 'break "debug.scm")
(autoload 'unbreak "debug.scm")
(autoload 'watch "debug.scm")
(autoload 'unwatch "debug.scm")
(autoload 'ow! "stuff.scm")
(autoload 'show-profile "profile.scm")
(autoload 'profile-port "profile.scm")

(when (file-exists? ".nrepl")         ; local (scheme) initialization file for nrepl
  (load ".nrepl"))

;(define dbstr "")

(unless (defined? '*nrepl*)
  (define *nrepl*
    (let* ((nc #f)
	   (nc-cols 0)
	   (nc-rows 0)
	   (status-rows 3)
	   (status-cells (vector (nccell_make) (nccell_make) (nccell_make) (nccell_make) (nccell_make) (nccell_make)))
	   (statp #f)
	   (statp-row 0)
	   (recursor #f)

	   (top-level-let
	    (sublet (rootlet) ; environment in which evaluation takes place
	      :history #f        ; set below
	      :ncp-let #f
	      :display-status #f
	      :status-text ""
	      :run-let #f

	      :s7-version (lambda () (*s7* 'version))

	      :exit (let ((+documentation+ "(exit) stops notcurses and then calls #_exit"))
		      (let-temporarily (((*s7* 'debug) 0))
			(lambda ()
			  (notcurses_stop (*nrepl* 'nc))
			  (#_exit))))

	      :time (macro (expr)
		      `(let ((start (*s7* 'cpu-time)))
			 ,expr
			 (- (*s7* 'cpu-time) start)))

	      :with-profile (macro body
	                      `(let-temporarily (((*s7* 'profile) 1)
						 ((profile-port) (open-output-string)))
				 ,@body
				 (show-profile)
				 (clear-profile)
                                 (get-output-string (profile-port))))
	      ;; the profiler has to be on when the to-be-profiled functions are loaded

	      :apropos
	      (let ((levenshtein
		     (lambda (s1 s2)
		       (let ((L1 (length s1))
			     (L2 (length s2)))
			 (cond ((zero? L1) L2)
			       ((zero? L2) L1)
			       (else (let ((distance (make-vector (list (+ L2 1) (+ L1 1)) 0)))
				       (do ((i 0 (+ i 1)))
					   ((> i L1))
					 (set! (distance 0 i) i))
				       (do ((i 0 (+ i 1)))
					   ((> i L2))
					 (set! (distance i 0) i))
				       (do ((i 1 (+ i 1)))
					   ((> i L2))
					 (do ((j 1 (+ j 1)))
					     ((> j L1))
					   (let ((c1 (+ (distance i (- j 1)) 1))
						 (c2 (+ (distance (- i 1) j) 1))
						 (c3 (if (char=? (s2 (- i 1)) (s1 (- j 1)))
							 (distance (- i 1) (- j 1))
							 (+ (distance (- i 1) (- j 1)) 1))))
					     (set! (distance i j) (min c1 c2 c3)))))
				       (distance L2 L1)))))))

		    (make-full-let-iterator             ; walk the entire let chain
		     (lambda* (lt (stop (rootlet)))
		       (if (eq? stop lt)
			   (make-iterator lt)
			   (letrec ((iterloop
				     (let ((iter (make-iterator lt))
					   (+iterator+ #t))
				       (lambda ()
					 (let ((result (iter)))
					   (if (and (eof-object? result)
						    (iterator-at-end? iter)
						    (not (eq? stop (iterator-sequence iter))))
					       (begin
						 (set! iter (make-iterator (outlet (iterator-sequence iter))))
						 (iterloop))
					       result))))))
			     (make-iterator iterloop))))))

		(lambda* (name (e (sublet (*nrepl* 'top-level-let) *notcurses*)))
		  (let ((ap-name (if (string? name) name
				     (if (symbol? name)
					 (symbol->string name)
					 (error 'wrong-type-arg "apropos argument 1 should be a string or a symbol"))))
			(ap-env (if (let? e) e
				    (error 'wrong-type-arg "apropos argument 2 should be an environment"))))
		    (let ((strs ())
			  (min2 (floor (log (length ap-name) 2))))
		      (for-each
		       (lambda (binding)
			 (if (pair? binding)
			     (let ((symbol-name (symbol->string (car binding))))
			       (if (string-position ap-name symbol-name)
				   (set! strs (cons (cons binding 0) strs))
				   (let ((distance (levenshtein ap-name symbol-name)))
				     (if (< distance min2)
					 (set! strs (cons (cons binding distance) strs))))))))
		       (make-full-let-iterator ap-env))

		      (if (not (pair? strs))
			  'no-match
			  (let ((data "")
				(name-len (length name)))
			    (for-each (lambda (b)
					(set! data (string-append data
								  (if (> (length data) 0) (string #\newline) "")
								  (if (procedure? (cdar b))
								      (let ((doc (documentation (cdar b)))) ; returns "" if no doc
									(if (positive? (length doc))
									    doc
									    (object->string (caar b))))
								      (object->string (caar b))))))
				      (sort! strs (lambda (a b)
						    (or (< (cdr a) (cdr b))
							(and (= (cdr a) (cdr b))
							     (< (abs (- (length (symbol->string (caar a))) name-len))
								(abs (- (length (symbol->string (caar b))) name-len))))))))
			    data))))))
	      )))


      ;; to call notcurses functions in the repl, use *nrepl* or ncp-let:
      ;;   (notcurses_refresh (ncp-let 'nc))
      ;; to call run within run:
      ;;   ((*nrepl* 'run) "new-prompt>" "header info")

      ;; -------- completion --------
      (define (symbol-completion text)
	(let ((text-len (length text))
	      (match #f))
	  (call-with-exit
	   (lambda (return)
	     (for-each
	      (lambda (lst)
		(for-each
		 (lambda (par)
		   (let* ((sym (symbol->string par))
			  (sym-len (length sym)))
		     (when (and (>= sym-len text-len)
				(string=? text (substring sym 0 text-len)))
		       (if match
			   ;; more than one match, save the longest text that all syms match
			   (do ((min-len (min (string-length match) sym-len))
				(i text-len (+ i 1)))
			       ((or (= i min-len)
				    (not (char=? (match i) (sym i))))
				(if (= min-len text-len)
				    (return text)
				    (set! match (substring match 0 i)))))
			   (set! match sym)))))
		 lst))
	      (list startup-symbols (map car top-level-let))) ; (using startup-symbols to avoid all the lint junk), any others?
	     match))))

      (define (filename-completion text)
	(and (> (length text) 0)
	     (with-let (sublet libc-let :text text)
	       (let ((g (glob.make)))
		 (glob (string-append text "*")
		       (logior (if (and (defined? 'GLOB_TILDE)
					(char=? (text 0) #\~))
				   GLOB_TILDE
				   0)
			       GLOB_MARK)
		       g)
		 (let ((files (map (lambda (f) ; get rid of emacs' *~ files
				     (if (and (> (length f) 1)
					      (char=? #\~ (f (- (length f) 1))))
					 (values)
					 f))
				   (glob.gl_pathv g))))
		   (globfree g)
		   (and (not (null? files))
			(null? (cdr files))
			(car files)))))))


      ;; -------- status area --------

      (define (display-status-area)
	(ncplane_cursor_move_yx statp 0 0)
	(ncplane_box statp
		     (status-cells 0) (status-cells 1) (status-cells 2)
		     (status-cells 3) (status-cells 4) (status-cells 5)
		     2 (- nc-cols 1) 0)
	(ncplane_move_yx statp statp-row 0)
	(notcurses_render nc))

      (define (statp-set-bg-color r g b)
	;; (statp-bg-set-color 0.85 0.85 0.85): light gray background
	(let ((c1 (nccell_make)))
	  (let ((color (logior (ash (floor (* r 256)) 16)
			       (ash (floor (* g 256)) 8)
			       (floor (* b 256)))))
	    (set! (nccell_gcluster c1) (char->integer #\space))
	    (set! (nccell_channels c1) (logior (ash NC_BGDEFAULT_MASK 32) NC_BGDEFAULT_MASK color)))
	  (set! (nccell_stylemask c1) 0)
	  (ncplane_set_base_cell statp c1)
	  (notcurses_render nc)
	  c1))

      (define (clear-status)
	(ncplane_putstr_yx statp 1 1 (make-string (- nc-cols 2) #\space)))

      (define (display-status str)
	(clear-status)
	(ncplane_putstr_yx statp 1 2 (substring str 0 (min (length str) (- nc-cols 3))))
	(notcurses_render nc))

      (set! (top-level-let 'display-status) display-status)

      (define (first-line text)
	(let ((pos (char-position #\newline text)))
	  (if (not pos)
	      text
	      (substring text 0 pos))))


      ;; -------- red text --------
      (define (red c)
	(let ((c1 (nccell_make)))
	  (set! (nccell_gcluster c1) (char->integer c))
	  (set! (nccell_channels c1)  (logior (ash NC_BGDEFAULT_MASK 32) #xff000000000000))
	  (set! (nccell_stylemask c1) 0)
	  c1))

      (define (normal c)
	(let ((c1 (nccell_make)))
	  (set! (nccell_gcluster c1) (char->integer c))
	  (set! (nccell_channels c1)  0)
	  (set! (nccell_stylemask c1) 0)
	  c1))

      (define red-error (let ((v (make-vector 5)))
			  (set! (v 0) (red #\e))
			  (set! (v 1) (red #\r))
			  (set! (v 2) (v 1))
			  (set! (v 3) (red #\o))
			  (set! (v 4) (v 1))
			  v))

      (define red-paren (red #\())
      (define normal-paren (normal #\())


      ;; -------- run --------
      (define* (run (prompt ">") header (envir (*nrepl* 'top-level-let)))

	(let ((ncp-col 0)                  ; top-left in ncp
	      (ncp-row 0)
	      (ncp-cols (max 100 nc-cols))
	      (ncp-rows (max 100 nc-rows))
	      (ncp-max-row 0)
	      (ncp #f)
	      (col 0)                      ; ncplane-relative row/column
	      (row 0)
	      (header-row 0)
	      (prev-pars #f)
	      (keymap (make-hash-table 512))
	      (old-history (top-level-let 'history)) ; see below, old restored upon exit from this ncplane
	      (hc #f)
	      (hc-cells #f)
	      (header-cols 0)
	      (header-strings #f)
	      (watch-row 0)
	      (watch-rows 3)
	      (watch-col 0)
	      (watch-cols 0)
	      (watchers (make-hash-table 8 eq?))
	      (wc #f)
	      (wc-cells #f))

	  (define (move-cursor y x)   ; this was (format *stderr* "~C[~D;~DH" #\escape y x) in repl.scm
	    (notcurses_refresh nc)    ; needed in 1.7.1, not in 1.6.11
	    (notcurses_cursor_enable nc 
				     (max header-row (+ y ncp-row))
				     (if (and wc (= y (+ watch-row 1)))
					 (min (- watch-col 1) (+ x ncp-col))
					 (+ x ncp-col))))
	  (set! (top-level-let :run-let) (curlet))
	  (when header
	    (set! hc-cells (vector (nccell_make) (nccell_make) (nccell_make) (nccell_make) (nccell_make) (nccell_make)))
	    (let ((newline-pos (char-position #\newline header)))
	      (if newline-pos
		  (let loop ((str (substring header (+ newline-pos 1)))
			     (newlines (list (+ newline-pos 1) 0)))
		    (let ((pos (char-position #\newline str)))
		      (if pos
			  (loop (substring str (+ pos 1))
				(cons (+ (car newlines) pos 1) newlines))
			  (let ((npos (reverse newlines))
				(nlen (length newlines)))
			    (set! hc (ncplane_new nc (+ 3 nlen) ncp-cols 0 0 (c-pointer 0)))
			    (ncplane_cursor_move_yx hc 0 0)
			    (nccells_double_box hc 0 0 (hc-cells 0) (hc-cells 1) (hc-cells 2) (hc-cells 3) (hc-cells 4) (hc-cells 5))
			    (ncplane_box hc (hc-cells 0) (hc-cells 1) (hc-cells 2) (hc-cells 3) (hc-cells 4) (hc-cells 5) (+ 1 nlen) (- nc-cols 1) 0)
			    (set! header-strings (make-vector nlen))
			    (do ((i 0 (+ i 1))
				 (hrow 1 (+ hrow 1))
				 (posl npos (cdr posl)))
				((= hrow nlen)
				 (ncplane_putstr_yx hc hrow 1 (make-string (- nc-cols 5) #\space))
				 (set! (header-strings i) (substring header (car posl)))
				 (ncplane_putstr_yx hc hrow 2 (substring (header-strings i) 0 (min (length (header-strings i)) (- nc-cols 3))))
				 (set! header-row (+ 3 nlen))
				 (set! row header-row))
			      (ncplane_putstr_yx hc hrow 1 (make-string (- nc-cols 5) #\space))
			      (set! (header-strings i) (substring header (car posl) (cadr posl)))
			      (ncplane_putstr_yx hc hrow 2 (substring (header-strings i) 0 (min (length (header-strings i)) (- nc-cols 3)))))))))
		  (begin
		    (set! hc (ncplane_new nc 3 ncp-cols 0 0 (c-pointer 0)))
		    (ncplane_cursor_move_yx hc 0 0)
		    (nccells_double_box hc 0 0 (hc-cells 0) (hc-cells 1) (hc-cells 2) (hc-cells 3) (hc-cells 4) (hc-cells 5))
		    (ncplane_box hc (hc-cells 0) (hc-cells 1) (hc-cells 2) (hc-cells 3) (hc-cells 4) (hc-cells 5) 2 (- nc-cols 1) 0)
		    (ncplane_putstr_yx hc 1 1 (make-string (- nc-cols 5) #\space))
		    (set! header-strings (vector header))
		    (ncplane_putstr_yx hc 1 2 (substring (header-strings 0) 0 (min (length header) (- nc-cols 3))))
		    (set! header-row 3)
		    (set! row header-row))))
	    (set! header-cols nc-cols))

	  (set! ncp (ncplane_new nc ncp-rows ncp-cols 0 0 (c-pointer 0)))
	  (let ((eols (make-int-vector ncp-rows 0))
		(bols (make-int-vector ncp-rows 0)))

	    (ncplane_move_below ncp statp) ; statp always displayed with ncplanes sliding underneath conceptually

	    ;; opaque plane
	    (let ((c1 (nccell_make)))
	      (set! (nccell_gcluster c1) (char->integer #\space))
	      (set! (nccell_channels c1) 0)
	      (set! (nccell_stylemask c1) 0)
	      (ncplane_set_base_cell ncp c1)

	      (unless header
		(set! header-row 1) ; avoid first row -- output is messed up by notcurses
		(set! row 1)
		(set! header-cols nc-cols))

	      (notcurses_render nc))

	    (let ((last-name ""))
	      (set! (hook-functions *load-hook*)
		    (cons (lambda (h)
			    (unless (string=? (h 'name) last-name)
			      (set! last-name (h 'name))
			      (display-status (format #f "loading ~S" (h 'name)))))
			  (hook-functions *load-hook*)))

	      (set! (hook-functions *autoload-hook*)
		    (cons (lambda (h)
			    (set! last-name (h 'file))
			    (display-status (format #f "autoloading ~S from ~S" (h 'name) (h 'file))))
			  (hook-functions *autoload-hook*))))


	    ;; -------- scrolling and resizing --------
	    ;;
	    ;; row and col are ncp-relative, its ncp-row|col are the location of its top left corner (0,0)
	    ;;   in the terminal window.  ncp-rows|cols are its size.  nc-rows|cols is the terminal size.
	    ;;   ncp-col = -5 means ncp is shifted left (to display the rightward portion),
	    ;;   ncp-col = 5 means ncp is shifted right (moving its top-left corner to (5,0) in the terminal
	    ;;   (using (row,col) throughout).  This won't happen in normal editing, but the user
	    ;;   can easily move ncp: (ncplane_move_yx (ncp-let 'ncp) 5 0).
	    ;; Here the assumption is we want val to be visible and the current row is already visible.
	    ;;   The currently visible portion of ncp is from ((max 0 -ncp-row), (max 0 -ncp-col)) to (bottom right)
	    ;;   ((nc-rows - ncp-row), (nc-cols - ncp-col)) (assuming we're not completely off screen).

	    (define (set-ncp-row val)
	      (when prev-pars
		(set! prev-pars #f)
		(notcurses_refresh nc))
	      (set! ncp-row val))

	    (define (set-ncp-col val)
	      (when prev-pars
		(set! prev-pars #f)
		(notcurses_refresh nc))
	      (set! ncp-col val))

	    (define (resize-watcher)
	      (when wc
		(let ((old-watch-cols watch-cols)
		      (old-watch-rows watch-rows))
		  (set! watch-rows (+ (hash-table-entries watchers) 2))
		  (set! watch-col (floor (* 0.618 nc-cols)))
		  (set! watch-cols (- nc-cols watch-col))
		  (ncplane_resize wc 0 0
				  (min old-watch-rows watch-rows)
				  (min old-watch-cols watch-cols)
				  0 0
				  watch-rows watch-cols)
		  (ncplane_move_yx wc header-row watch-col)
		  (ncplane_cursor_move_yx wc 0 0)
		  (ncplane_box wc (wc-cells 0) (wc-cells 1) (wc-cells 2) (wc-cells 3) (wc-cells 4) (wc-cells 5) (- watch-rows 1) (- watch-cols 1) 0)
		  (for-each (lambda (key-row&str)
			      (ncplane_putstr_yx wc (cadr key-row&str) 1 (make-string (- watch-cols 2) #\space))
			      (ncplane_putstr_yx wc (cadr key-row&str) 2 (cddr key-row&str)))
			    watchers))))

	    (define (nc-resize new-rows new-cols)
	      (let ((old-nc-cols nc-cols))
		(set! nc-cols new-cols)
		(set! nc-rows new-rows)

		;; resize status area
		(set! statp-row (- nc-rows status-rows))
		(ncplane_putstr_yx statp 1 (- old-nc-cols 1) " ")
		(ncplane_resize statp 0 0 status-rows (min old-nc-cols nc-cols) 0 0 status-rows nc-cols)

		;; resize header
		(when hc
		  (ncplane_resize hc 0 0 header-row (min old-nc-cols nc-cols) 0 0 header-row nc-cols)
		  (ncplane_cursor_move_yx hc 0 0)
		  (ncplane_box hc (hc-cells 0) (hc-cells 1) (hc-cells 2) (hc-cells 3) (hc-cells 4) (hc-cells 5) (+ (length header-strings) 1) (- nc-cols 1) 0)
		  (do ((i 0 (+ i 1))
		       (hrow 1 (+ hrow 1)))
		      ((= i (length header-strings)))
		    (ncplane_putstr_yx hc hrow (- old-nc-cols 1) " "))
		  (set! header-cols nc-cols)
		  ;; redisplay the header from the original strings

		  (do ((i 0 (+ i 1))
		       (hrow 1 (+ hrow 1)))
		      ((= i (length header-strings)))
		    (ncplane_putstr_yx hc hrow 1 (make-string (- nc-cols 5) #\space))
		    (ncplane_putstr_yx hc hrow 2 (substring (header-strings i) 0 (min (length (header-strings i)) (- nc-cols 3))))))

		(resize-watcher)

		;; resize current pane (ncp)
		(when (or (< ncp-rows nc-rows)
			  (< ncp-cols nc-cols))
		  (ncplane_resize ncp 0 0 ncp-rows ncp-cols 0 0 (max ncp-rows nc-rows) (max ncp-cols nc-cols))
		  (when (> nc-rows ncp-rows)
		    (set! bols (copy bols (make-int-vector nc-rows)))
		    (set! eols (copy eols (make-int-vector nc-rows)))
		    (set! ncp-rows nc-rows))
		  (set! ncp-cols (max ncp-cols nc-cols)))))

	    (define (visible? r c)
	      (and (< r (- statp-row ncp-row))
		   (>= r (- header-row ncp-row))
		   (< c (- nc-cols ncp-col))
		   (>= c (- ncp-col))))

	    (define (set-row val)
	      (set! row (max header-row val))
	      (when (>= row ncp-rows)
		(ncplane_resize ncp 0 0 ncp-rows ncp-cols 0 0 (+ row 40) ncp-cols)
		(set! ncp-rows (+ row 40))
		(set! bols (copy bols (make-int-vector ncp-rows)))
		(set! eols (copy eols (make-int-vector ncp-rows))))
	      (cond ((>= row (- statp-row ncp-row))             ; current row is outside (below) the terminal window
		     (set-ncp-row (min 0 (- statp-row row 2)))
		     (ncplane_move_yx ncp ncp-row ncp-col)
		     (move-cursor row col))
		    ((< row (- header-row ncp-row))             ; current row is outside (above) the terminal window
		     (set-ncp-row (- header-row row))
		     (ncplane_move_yx ncp ncp-row ncp-col))))

	    (define (set-col val)
	      (set! col val)
	      (when (>= col ncp-cols)
		(ncplane_resize ncp 0 0 ncp-rows ncp-cols 0 0 ncp-rows (+ col 10))
		(set! ncp-cols (+ col 10)))
	      (cond ((>= col (- nc-cols ncp-col))  ; current column is outside (to the right of) the terminal window
		     (set-ncp-col (min 0 (- nc-cols col 2)))
		     (ncplane_move_yx ncp ncp-row ncp-col))
		    ((< col (- ncp-col))           ; current column is outside (to the left of) the terminal window, ncp-col < 0 means the ncp plane is shifted left
		     (set-ncp-col (- col))
		     (ncplane_move_yx ncp ncp-row ncp-col))
		    ((and (= col (bols row))       ; special case: we're stuck against the prompt, but want move it into view
			  (< ncp-col 0))
		     (set-ncp-col 0)
		     (ncplane_move_yx ncp ncp-row ncp-col))))


	    (define (increment-row incr)
	      (set! row (+ row incr))
	      ;; (display-status (format #f "increment -> ~D~%" row))
	      (when (>= row ncp-rows)
		(ncplane_resize ncp 0 0 ncp-rows ncp-cols 0 0 (+ row 40) ncp-cols)
		(set! ncp-rows (+ row 40))
		(set! bols (copy bols (make-int-vector ncp-rows)))
		(set! eols (copy eols (make-int-vector ncp-rows))))
	      (when (>= row (- statp-row ncp-row))
		(set-ncp-row (min 0 (- statp-row row 1))) ; this moves to bottom, (- row) to top??
		(ncplane_move_yx ncp ncp-row ncp-col)
		(move-cursor row col)))

	    (define (increment-col incr)
	      (set! col (+ col incr))
	      (when (>= col ncp-cols)
		(ncplane_resize ncp 0 0 ncp-rows ncp-cols 0 0 ncp-rows (+ col 10))
		(set! ncp-cols (+ col 10)))
	      (when (>= col (+ ncp-col nc-cols))
		(set-ncp-col (min 0 (- nc-cols col 2)))
		(ncplane_move_yx ncp ncp-row ncp-col)))


	    (define (decrement-row incr)
	      (set! row (max header-row (- row incr)))
	      (when (<= row (- header-row ncp-row)) ; current row is outside (above) the terminal window
		(set-ncp-row (- header-row row))
		(ncplane_move_yx ncp ncp-row ncp-col)))

	    (define (decrement-col incr)
	      (set! col (- col incr))
	      (when (<= col (- ncp-col)) ; current column is outside (to the left of) the terminal window
		(set-ncp-col (- col))
		(ncplane_move_yx ncp ncp-row ncp-col)))


	    (define (nc-multiline-display str) ; increment-row below will make space if needed
	      (let ((len (length str)))
		(if (not (char-position #\newline str))
		    (begin
		      (nc-display row 0 str)
		      (set! (eols row) len))
		    (do ((start 0)
			 (i 0 (+ i 1)))
			((= i len)
			 (nc-display row 0 (substring str start len))
			 (set! (eols row) (- len start)))
		      (if (char=? #\newline (str i))
			  (begin
			    (nc-display row 0 (substring str start i))
			    (set! (eols row) (- i start))
			    (increment-row 1)
			    (set! ncp-max-row (max ncp-max-row row))
			    (set! start (+ i 1))))))))


	    ;; -------- lint (redirect output) --------
	    ;; 
	    ;; we load lint above, at which time it sets its *output-port* to *stderr* (the global built-in port), but
	    ;;   when called in the repl, we have over-ridden *stderr* to place that output in the notcurses display,
	    ;;   so we need to redirect lint's output by hand.
	    (when with-lint
	      (set! lint ; force top-level change
		    (let ((old-lint lint))
		      (lambda* (file (outp :unset) (report-input :unset))
			(if (and (eq? outp :unset)
				 (eq? report-input :unset))
			    (nc-multiline-display
			     (call-with-output-string
			      (lambda (p)
				(old-lint file p))))
			    (old-lint file outp report-input))))))


	    ;; -------- top-level-let --------
	    (set! (top-level-let 'history)
		  (lambda (filename)
		    (call-with-output-file filename
		      (lambda (p)
			(let ((timestamp (with-let (sublet libc-let)
					   (let ((timestr (make-string 128)))
					     (strftime timestr 128 "%a %d-%b-%Y %H:%M:%S %Z"
						       (localtime
							(time.make (time (c-pointer 0 'time_t*)))))
					     timestr))))
			  (format p ";;; nrepl: ~A~%~%" timestamp))
			(do ((i 0 (+ i 1)))
			    ((= i ncp-max-row))
			  (if (> (bols i) 0)
			      (format p "~A ~A~%" (ncplane_contents ncp i 0 1 (bols i)) (ncplane_contents ncp i (bols i) 1 (eols i)))
			      (format p "~A~%" (ncplane_contents ncp i 0 1 (eols i)))))))))


	    ;; --------display --------
	    (define (clear-line row)
	      (ncplane_putstr_yx ncp row (bols row) (make-string (max 80 (- (eols row) (bols row))) #\space)))

	    (define (nc-display r c str)
	      (let ((len (length str)))
		(when (>= (+ c len) ncp-cols)
		  (ncplane_resize ncp 0 0 ncp-rows ncp-cols 0 0 ncp-rows (+ c len 10))
		  (set! ncp-cols (+ c len 10)))
		(ncplane_putstr_yx ncp r c str)
		(if (= c 0) (set! (bols r) 0))))

	    (define (reprompt y)
	      (ncplane_cursor_move_yx ncp y 0)
	      ;(clear-line y)
	      (ncplane_putstr_yx ncp y 0 prompt)
	      (notcurses_render nc)
	      (let ((prompt-len (+ (length prompt) 1)))
		(when (zero? (bols row)) ; might be in pre-existing section where we're just re-establishing an existing prompt
		  (set! (bols row) prompt-len)
		  (set! (eols row) prompt-len))
		(set! col prompt-len)
		(set-row y)
		(notcurses_refresh nc)
		(move-cursor y prompt-len)))

	    (define (display-error ncp row info)
	      (do ((i 0 (+ i 1)))
		  ((= i 5))
		(ncplane_putc_yx ncp row i (red-error i)))
	      (notcurses_render nc) ; else cursor jumps back!
	      (ncplane_putstr_yx ncp row 5 ": ")
	      (set! (eols row) 7)
	      (if (and (pair? info)
		       (string? (car info)))
		  (let ((err (apply format #f info)))
		    (nc-display row 7 err)
		    (set! (eols row) (+ (length err) 7)))
		  (if (not (null? info))
		      (let ((err (object->string info)))
			(nc-display row 1 err)
			(set! (eols row) (+ (length err) 7)))))
	      row)

	    ;; -------- watchers --------
	    (define local-debug-info
	      (let ((str ""))
		(lambda (int)
		  (if (= int (char->integer #\newline))
		      (begin ; watch
			(display-status str)

			(if (string-position "set! to " str) ; it's a watcher
			    (let* ((pos (char-position #\space str))
				   (var (string->symbol (substring str 0 pos)))
				   (var-data (watchers var))
				   (var-row (and (pair? var-data) (car var-data)))
				   (var-str (format #f "~A: ~A" var (substring str (+ pos 9)))))

			      (unless wc
				(set! wc-cells (vector (nccell_make) (nccell_make) (nccell_make) (nccell_make) (nccell_make) (nccell_make)))
				(set! watch-row header-row)
				(set! watch-col (floor (* 0.618 nc-cols))) ; ah the good old days
				(set! watch-cols (- nc-cols watch-col))
				(set! wc (ncplane_new nc watch-rows watch-cols watch-row watch-col (c-pointer 0)))
				(nccells_double_box wc 0 0 (wc-cells 0) (wc-cells 1) (wc-cells 2) (wc-cells 3) (wc-cells 4) (wc-cells 5))
				(ncplane_box wc (wc-cells 0) (wc-cells 1) (wc-cells 2) (wc-cells 3) (wc-cells 4) (wc-cells 5) (- watch-rows 1) (- watch-cols 1) 0)
				(let ((c1 (nccell_make)))
				  (set! (nccell_gcluster c1) (char->integer #\space))
				  (set! (nccell_channels c1) 0)   ; opaque apparently
				  (set! (nccell_stylemask c1) 0)
				  (ncplane_set_base_cell wc c1)
				  (notcurses_render nc)))

			      (if var-row
				  (set-cdr! var-data var-str)
				  (begin
				    (set! var-row (+ 1 (hash-table-entries watchers)))
				    (set! var-data (cons var-row var-str))
				    (hash-table-set! watchers var var-data)
				    (resize-watcher)))

			      (ncplane_putstr_yx wc var-row 1 (make-string (- watch-cols 2) #\space))
			      (ncplane_putstr_yx wc var-row 2 (cdr var-data))
			      (notcurses_render nc))

			    (begin ; trace etc
			      ;(nc-display row 0 str) ; this is break in debug.scm reporting the result "  -> 1" but we have already done that
			      (set! (eols row) (length str))
			      (increment-row 1)))
			(set! str ""))
		      (set! str (append str (string (integer->char int))))))))

	    (define (local-remove-watcher var)
	      (hash-table-set! watchers var #f)
	      (if (and wc (zero? (hash-table-entries watchers)))
		  (begin
		    (ncplane_destroy wc)
		    (set! wc #f))
		  (let ((r 1))
		    (resize-watcher)

		    (for-each (lambda (var&row)
				(hash-table-set! watchers (car var&row) (cons r (cddr var&row)))
				(ncplane_putstr_yx wc r 1 (make-string (max 0 (- nc-cols watch-col 3)) #\space))
				(ncplane_putstr_yx wc r 2 (cddr var&row))
				(set! r (+ r 1)))
			      watchers)

		    ;(ncplane_putstr_yx wc r 2 (make-string (max 0 (max 0 (- nc-cols watch-col 3)) #\space)))
		    )))


	    ;; -------- match close paren --------
	    (define (match-close-paren ncp row col indenting)
	      ;; if row/col is just after #|), get start of current expr, scan until row/col
	      ;;   return either matching row/col or #f if none
	      (call-with-exit
	       (lambda (return)
		 (do ((r row (- r 1)))
		     ((> (bols r) 0)

		      (do ((cur-row r (+ cur-row 1))
			   (oparens ()))
			  ((> cur-row row)
			   ;; ((top-level-let 'display-status) (format #f "~S ~S ~S" row cur-row oparens))
			   (and (pair? oparens)
				oparens))

			(let* ((cur-line (ncplane_contents ncp cur-row (bols cur-row) 1 (- (eols cur-row) (bols cur-row))))
			       (len (if (and (= cur-row row)
					     (not indenting))
					(min (- col (bols row) 1) (length cur-line))
					(length cur-line))))

			  (do ((i 0 (+ i 1)))
			      ((>= i len))
			    (case (cur-line i)
			      ((#\()
			       (set! oparens (cons (list cur-row (+ i (bols cur-row)) 0 #f) oparens)))

			      ((#\))
			       (when (pair? oparens)
				 (set! oparens (cdr oparens))
				 (when (and indenting
					    (pair? oparens))
				   (let ((top (cddar oparens)))
				     (set-car! top (+ (car top) 1))))))

			      ((#\;)
			       (set! i (+ len 1)))

			      ((#\")
			       (do ((found-close-quote #f))
				   (found-close-quote) ; need to look possibly across several rows
				 (do ((k (+ i 1) (+ k 1)))
				     ((or (>= k len)
					  (and (char=? (cur-line k) #\")
					       (not (char=? (cur-line (- k 1)) #\\))))
				      ;; ((top-level-let 'display-status) (format #f "~S ~S ~S ~S" cur-row row k len))
				      (if (>= k len)  ; no close quotes by eol
					  (if (= cur-row row)
					      (return #f)
					      (begin
						(set! cur-row (+ cur-row 1))
						(set! i 0)
						(set! cur-line (ncplane_contents ncp cur-row (bols cur-row) 1 (- (eols cur-row) (bols cur-row))))
						(set! len (if (and (= cur-row row)
								   (not indenting))
							      (min (- col (bols row) 1) (length cur-line))
							      (length cur-line)))))
					  (begin
					    (set! found-close-quote #t)
					    (set! i k)))))))

			      ((#\#)
			       (when (and (< i (- len 1))
					  (char=? (cur-line (+ i 1)) #\|))
				 (do ((found-close-comment #f))
				     (found-close-comment)
				   (do ((k (+ i 1) (+ k 1)))
				       ((or (>= k (- len 1))
					    (and (char=? (cur-line k) #\|)
						 (char=? (cur-line (+ k 1)) #\#)))
					(if (>= k len)
					    (if (= cur-row row)
						(return #f)
						(begin
						  (set! cur-row (+ cur-row 1))
						  (set! i -1)
						  (set! cur-line (ncplane_contents ncp cur-row (bols cur-row) 1 (- (eols cur-row) (bols cur-row))))
						  (set! len (if (and (= cur-row row)
								     (not indenting))
								(min (- col (bols row) 1) (length cur-line))
								(length cur-line)))))
					    (begin
					      (set! found-close-comment #t)
					      (set! i (+ k 1)))))))))

			      ((#\space #\newline #\tab #\return))

			      (else
			       (when (and indenting
					  (pair? oparens))
				 (let ((top (cdddar oparens))
				       (c (+ i (bols cur-row))))
				   (if (pair? (car top))
				       (set-car! (cdar top) c)
				       (set! (car top) (list c c)))))))))))))))


	    ;; -------- indentation --------
	    (define indent
	      (let ((white-space (string #\newline #\space #\return #\tab #\linefeed)))
		(lambda (ncp row col)
		  (if (not (zero? (bols row)))
		      col
		      (let ((pars (match-close-paren ncp (- row 1) (eols (- row 1)) #t)))
			(if (not pars)
			    (set! (eols row) 0)
			    (let ((unmatched-par (car pars)))
			      ;;     -> (row col-of-( visits #f-or-(name-start name-end)
			      ;;  row/col args = cursor pos
			      (let ((open-row (car unmatched-par))
				    (open-col (cadr unmatched-par))
				    (visits (caddr unmatched-par))       ; how many complete lists follow this (
				    (name-bounds (cadddr unmatched-par)) ; bounds of non-white-space after (
				    (trailer (ncplane_contents ncp row 0 1 (eols row)))
				    (slice 0))

				(let ((tlen (length trailer)))
				  (when (positive? tlen)
				    (do ((i 0 (+ i 1)))
					((or (= i tlen)
					     (not (char-whitespace? (trailer i))))
					 (set! slice i)
					 (set! trailer (substring trailer i))))))

				(if (not (pair? name-bounds))
				    (let ((incr 2))
				      (let ((uname (and (pair? (cdr pars))
							(let* ((upar (cadr pars))
							       (uopen-row (car upar))
							       (uname-bounds (cadddr upar))
							       (uname+args (ncplane_contents ncp
											     uopen-row (car uname-bounds)
											     1 (+ (- (cadr uname-bounds) (car uname-bounds)) 1)))
							       (uwpos (char-position white-space uname+args)))
							  (if (integer? uwpos)
							      (substring uname+args 0 uwpos)
							      uname+args)))))
					(if (member uname '("do" "let" "let*" "letrec" "letrec*" "let-temporarily") string=?)
					    (set! incr 1)))

				      ;; nothing after the ( on its row, might be moving back, so we need to erase the current line
				      (clear-line row)
				      (nc-display row 0 (format #f "~NC~A" (+ open-col incr) #\space trailer))
				      (set! (eols row) (+ open-col incr (length trailer)))
				      (min (+ open-col incr (- col slice)) (eols row))) ; keep cursor in its relative-to-trailer position if possible

				    (let* ((name+args (ncplane_contents ncp open-row (car name-bounds) 1 (+ (- (cadr name-bounds) (car name-bounds)) 1)))
					   (wpos (char-position white-space name+args))
					   (name (if (integer? wpos)
						     (substring name+args 0 wpos)
						     name+args))
					   (increment
					    (cond ((member name '("cond" "when" "unless" "lambda" "lambda*" "begin" "case" "with-let"
								  "let" "let*" "letrec" "letrec*" "let-temporarily"
								  "call-with-exit" "call/cc" "call-with-current-continuation"
								  "define" "define*" "define-macro" "catch" "sublet")
							   string=?)
						   2)

						  ((string=? name "do")
						   (if (= visits 1) 4 2))

						  ((member name '("call-with-input-string" "call-with-input-file") string=?)
						   (if (= open-row (- row 1)) 4 2))

						  (else (+ (length name) 2)))))

				      ;; might be moving back, so we need to erase the current line
				      (clear-line row)
				      (nc-display row 0 (format #f "~NC~A" (+ increment open-col) #\space trailer))
				      (set! (eols row) (+ open-col increment (length trailer)))
				      (max 0 (min (+ open-col increment (- col slice)) (eols row))))
				    ;; keep cursor in its relative-to-trailer position if possible, but squeeze slice (space) if not enough room
				    )))))))))

	    ;;-------- tab --------
	    (define (tab c)
	      (if (< col (eols row))
		  (set-col (indent ncp row col))

		  (let ((start (bols row))
			(end (eols row)))
		    (if (= end start)
			(begin
			  (nc-display row end "    ")
			  (set! (eols row) (+ end 4))
			  (increment-col 4))

			(let ((cur-line (ncplane_contents ncp row (bols row) 1 (- (eols row) (bols row)))))

			  (if (not (let loop ((i 0) (len (length cur-line)))
				     (and (< i len)
					  (or (not (char-whitespace? (cur-line i)))
					      (loop (+ i 1) len)))))
			      (set-col (indent ncp row col))
			      (let ((loc (do ((i (- (length cur-line) 1) (- i 1)))
					     ((or (< i 0)
						  (char-whitespace? (cur-line i))
						  (memv (cur-line i) '(#\( #\' #\" #\))))
					      i))))

				(if (= (+ loc 1) (eols row))
				    (set-col (indent ncp row col))
				    (let ((completion (if (< loc 0) ; match whole cur-line
							  (symbol-completion cur-line)
							  ((if (char=? (cur-line loc) #\") filename-completion symbol-completion)
							   (substring cur-line (+ loc 1))))))
				      (if (not completion)
					  (set-col (min (indent ncp row col) (eols row)))
					  (unless (string=? completion cur-line)

					    (when (>= loc 0)
					      (set! completion (string-append (substring cur-line 0 (+ loc 1)) completion))
					      (if (char=? (cur-line loc) #\")
						  (set! completion (string-append completion "\""))))

					    (nc-display row (bols row) completion)
					    (set-col (+ (bols row) (length completion)))
					    (set! (eols row) col))))))))))))


	    ;; -------- run ---------
	    (reprompt header-row)

	    (catch #t
	      (lambda ()
		(let ((ni (ncinput_make))
		      (mouse-col #f)
		      (mouse-row #f)
		      (repl-done #f)
		      (selection "")
                      (previously-selected #f)
                      (just-selected #f)
		      (control-key (ash 1 33))
                      (meta-key (ash 1 34)))    ; notcurses get returns 32 bits

		  (set! (top-level-let 'ncp-let) (curlet))
		  (set! display-debug-info local-debug-info)
		  (set! remove-watcher local-remove-watcher)

		  ;; -------- enter --------
		  (define enter                      ; either eval/print or insert newline
		    (let ()
		      (define stdin-wrapper (open-input-function ; current-input-port for scheme input in repl
					     (lambda (choice)
					       (case choice
						 ((read char-ready? peek-char) "?")
						 ((read-char) (integer->char (notcurses_getc nc (c-pointer 0) (c-pointer 0) ni)))
						 ((read-line)
						  (let loop ((str ""))
						    (let ((c (notcurses_getc nc (c-pointer 0) (c-pointer 0) ni)))
						      (if (or (= c (char->integer #\newline))
							      (> c 255))
							  str
							  (loop (append str (string (integer->char c))))))))))))

		      ;; -------- evaluation ---------
		      (define (badexpr h)            ; *missing-close-paren-hook* function for Enter command
			(let ((ow (owlet)))
			  (if (and (ow 'error-file)
				   (not (equal? (ow 'error-file) "nrepl.scm")))
			      (error 'syntax-error "missing close paren in ~S" (ow 'error-file))
			      (set! (h 'result) 'string-read-error))))

		      (define (shell? h)             ; *unbound-variable-hook* function, also for Enter
			;; examine cur-line -- only call system if the unbound variable matches the first non-whitespace chars
			;;   of cur-line, and command -v name returns 0 (indicating the shell thinks it is an executable command)
			(let ((cur-line (ncplane_contents ncp (- row 1) (bols (- row 1)) 1 col)))
			  ;; at this point (eols row) has not been set, so use col?
			  (do ((i 0 (+ i 1)))
			      ((or (= i (length cur-line))
				   (not (char-whitespace? (cur-line i))))
			       (let ((var-name (symbol->string (h 'variable))))
				 (when (and (>= (- (length cur-line) i) (length var-name)) ; var-name might be unrelated to cur-line
					    (string=? var-name (substring cur-line i (+ i (length var-name))))
					    (zero? (system (string-append "command -v " var-name " >/dev/null"))))
				   (set! (h 'result)
					 (and (procedure? ((rootlet) 'system))
					      (((rootlet) 'system) cur-line #t)))))))))

		      (define new-eval
			(let ((+documentation+ "this is the repl's eval replacement; its default is to use the repl's top-level-let.")
			      (+signature+ '(values #t let?)))
			  (lambda (form . rest) ; use lambda (not lambda*) so we can handle forms like :key
			    (let ((e (if (pair? rest)
					 (car rest)
					 (*nrepl* 'top-level-let))))
			      (let-temporarily (((hook-functions *unbound-variable-hook*) (list shell?)) ; so pwd et al will work
						((*s7* 'history-enabled) #t))
				(eval form e))))))

		      (define (current-expression ncp row)
			(if (> (bols row) 0)
			    (ncplane_contents ncp row (bols row) 1 (- (eols row) (bols row)))
			    (do ((i (- row 1) (- i 1)))
				((not (zero? (bols i)))
				 (let ((expr (ncplane_contents ncp i (bols i) 1 (- (eols i) (bols i)))))
				   (do ((nrow (+ i 1) (+ nrow 1)))
				       ((> nrow row)
					expr)
				     (set! expr (append expr "\n" ; need newline to terminate comments
							(ncplane_contents ncp nrow (bols nrow) 1 (- (eols nrow) (bols nrow)))))))))))
		      (lambda (c)
			(let ((cur-line (current-expression ncp row)))
			  (increment-row 1)
			  (set! ncp-max-row (max ncp-max-row row))

			  (if (> (eols row) 0)
			      (clear-line row))

			  (call-with-exit
			   (lambda (return)
			     (do ((len (length cur-line))
				  (i 0 (+ i 1)))               ; check for just whitespace
				 ((or (= i len)
				      (not (char-whitespace? (cur-line i))))
				  (when (= i len)
				    (set! (eols row) col)
				    (return))))

			     (catch #t
			       (lambda ()

				 (catch 'string-read-error ; this matches (throw #t 5) -- is this correct? *missing-close-paren-hook* returns 'string-read-error
				   (lambda ()

				     (let-temporarily (((hook-functions *missing-close-paren-hook*) (list badexpr))
						       ((hook-functions *read-error-hook*) ()))    ; lint sets this and messes up our error reporting

				       ;; catch and report reader errors as well as eval troubles
				       (let-temporarily ((*stderr* (open-output-string))           ; capture *stderr* output
							 (*stdout* (open-output-string))
							 ((current-output-port) (open-output-string))
							 ((current-error-port) (open-output-string))
							 ((*s7* 'undefined-constant-warnings) #t)) ; ??? what about case*?

					 (let ((form (with-input-from-string cur-line #_read))
					       (val #f))
					   (let-temporarily (((current-input-port) stdin-wrapper)  ; for scheme side input (read-char etc)
							     ((hook-functions *ncp-move-hook*)     ; scheme code calls ncplane_move_yx??
							      (list (lambda (h)
								      (when (eq? (h 'plane) ncp)
									(set! ncp-row (h 'y))
									(set! ncp-col (h 'x)))))))
					     ;(set-sigint-handler)                                 ; catch C-C to interrupt computation -- this no longer works in notcurses
					     (let ((str (with-output-to-string                     ; for scheme side output
							  (lambda ()
							    (set! val (list (new-eval form envir))))))) ; list, not lambda -- confuses trace!
					       ;(unset-sigint-handler nc)                           ; catch C-C to exit cleanly

					       (for-each
						(lambda (s)
						  (when (> (length s) 0)
						    (set-col 0)
						    (nc-multiline-display s)
						    (increment-row 1)))
						(list str
						      (get-output-string *stderr*)
						      (get-output-string *stdout*)
						      (get-output-string (current-error-port))
						      (get-output-string (current-output-port))))))

					   (set! val (if (or (null? val)   ; try to trap (values) -> #<unspecified>
							     (and (unspecified? (car val))
								  (null? (cdr val))))
							 #<unspecified>
							 (if (pair? (cdr val))  ; val is a list, it must have caught multiple values if cdr is a pair
							     (cons 'values val)
							     (car val))))

					   (nc-multiline-display (object->string val))))))

				   (lambda (type info)
				     ;(unset-sigint-handler nc)
				     (if (eq? type 'string-read-error)
					 (begin
					   ;; missing close paren, newline already added, spaces here are not optional!
					   (nc-display row 0 (make-string col #\space))
					   (set! (eols row) col)
					   (return))
					 (apply throw type info)))))   ; re-raise error

			       (lambda (type info)
				 ;(unset-sigint-handler nc)
				 (if (and (eq? type 'read-error)       ; maybe we hit <enter> in a block comment
					  (equal? info '("unexpected end of input while reading #|")))
				     (begin
				       (nc-display row 0 (make-string col #\space))
				       (set! (eols row) col)
				       (return)))
				 (display-error ncp row info)))

			     (increment-row 1)
			     (set! ncp-max-row (max ncp-max-row row))
			     (reprompt row)))))))


		  ;; -------- keymap --------
		  (define (normal-char c)
		    (let ((trailing (and (> (eols row) col)
					 (ncplane_contents ncp row col 1 (- (eols row) col -1)))))
		      (nc-display row col (string (integer->char c)))
		      (if (and trailing (> (length trailing) 0))
			  (nc-display row (+ col 1) trailing)))

		    (if (or (char=? (integer->char c) #\space)
			    (= col (bols row)))         ; maybe (memv (integer->char c) '(#\space #\())
			(notcurses_refresh nc))
		    (increment-col 1) ; might be midline
		    (set! (eols row) (+ (eols row) 1))) ; in any case we've added a character

		  (do ((i 0 (+ i 1)))
		      ((= i 256))
		    (set! (keymap i) normal-char))

                  (define (prepend-to-selection new-text)
                    (unless (zero? (length new-text))
                      (set! selection (if previously-selected (append new-text selection)
					  new-text))
                      (set! just-selected #t)))
                  (define (append-to-selection new-text)
                    (unless (zero? (length new-text))
                      (set! selection (if previously-selected (append selection new-text)
					  new-text))
                      (set! just-selected #t)))
                  (define (char-separator? c)
                    (char-position c " ()`',\"#"))
                  (define (word-back-x) ;; some of these are courtesy of Elijah Stone
                    (let loop ((col (max (bols row) (- col 1))))
                      (if (= col (bols row))
			  col
			  (if (char-separator? (ncplane_contents ncp row col 1 1))
			      (loop (- col 1))
			      (let loop ((col col))
				(if (or (= col (bols row))
					(char-separator? (ncplane_contents ncp row (- col 1) 1 1)))
				    col
				    (loop (- col 1))))))))
                  (define (word-forward-x)
                    (let loop ((col (min (eols row) (+ col 1))))
                      (if (= col (eols row))
			  col
			  (if (char-separator? (ncplane_contents ncp row col 1 1))
			      (loop (+ col 1))
			      (let loop ((col col))
				(if (or (= col (eols row))
					(char-separator? (ncplane_contents ncp row col 1 1)))
				    col
				    (loop (+ col 1))))))))
		  
                  (set! (keymap (+ meta-key (char->integer #\B)))
			(set! (keymap (+ meta-key (char->integer #\b)))
			      (lambda (c)
				(set! col (word-back-x)))))
		  
                  (set! (keymap (+ meta-key (char->integer #\C)))
			(set! (keymap (+ meta-key (char->integer #\c)))
			      (lambda (c)
				(do ((len (- (eols row) col))
				     (cur-line (ncplane_contents ncp row col 1 (- (eols row) col)))
				     (i 0 (+ i 1)))
				    ((or (= i len)
					 (char-alphabetic? (cur-line i)))
				     (when (< i len)
				       (set! (cur-line i) (char-upcase (cur-line i)))
				       (nc-display row col cur-line)
				       (notcurses_refresh nc)
				       (do ((k (+ i 1) (+ k 1)))
					   ((or (>= k len)
						(not (or (char-alphabetic? (cur-line k))
							 (char-numeric? (cur-line k)))))
					    (set! col (min (eols row) (+ col k)))))))))))
		  
                  (set! (keymap (+ meta-key (char->integer #\D)))
			(set! (keymap (+ meta-key (char->integer #\d)))
			      (lambda (c)
				(let ((newcol (word-forward-x)))
				  (append-to-selection (ncplane_contents ncp row col 1 (- newcol col)))
				  (nc-display row col (ncplane_contents ncp row newcol 1 (- (eols row) newcol)))
				  (nc-display row (- (eols row) (- newcol col)) (make-string (- newcol col) #\space))
				  (set! (eols row) (- (eols row) (- newcol col)))))))
		  
                  (set! (keymap (+ meta-key (char->integer #\F)))
			(set! (keymap (+ meta-key (char->integer #\f)))
			      (lambda (c)
				(set! col (word-forward-x)))))
		  
                  (set! (keymap (+ meta-key (char->integer #\L)))
			(set! (keymap (+ meta-key (char->integer #\l)))
			      (lambda (c)
				(do ((len (- (eols row) col))
				     (cur-line (ncplane_contents ncp row col 1 (- (eols row) col)))
				     (i 0 (+ i 1)))
				    ((or (= i len)
					 (char-alphabetic? (cur-line i)))
				     (when (< i len)
				       (do ((k i (+ k 1)))
					   ((or (= k len)
						(not (char-alphabetic? (cur-line k))))
					    (nc-display row col cur-line)
					    (notcurses_refresh nc)
					    (set! col (+ col k)))
					 (set! (cur-line k) (char-downcase (cur-line k))))))))))
		  
                  (set! (keymap (+ meta-key (char->integer #\U)))
			(set! (keymap (+ meta-key (char->integer #\u)))
			      (lambda (c)
				(do ((len (- (eols row) col))
				     (cur-line (ncplane_contents ncp row col 1 (- (eols row) col)))
				     (i 0 (+ i 1)))
				    ((or (= i len)
					 (char-alphabetic? (cur-line i)))
				     (when (< i len)
				       (do ((k i (+ k 1)))
					   ((or (= k len)
						(not (char-alphabetic? (cur-line k))))
					    (nc-display row col cur-line)
					    (notcurses_refresh nc)
					    (set! col (+ col k)))
					 (set! (cur-line k) (char-upcase (cur-line k))))))))))
		  
                  (set! (keymap (+ meta-key (char->integer #\<)))
			(lambda (c)
			  (set-row 0)
			  (set-col (bols 0))))
		  
                  (set! (keymap (+ meta-key (char->integer #\>)))
			(lambda (c)
			  (set-row ncp-max-row)
			  (set-col (bols ncp-max-row))))

		  (set! (keymap (char->integer #\tab)) tab)

		  (set! (keymap (+ control-key (char->integer #\A)))
			(lambda (c)
			  (unless (>= ncp-col 0)
			    (set-ncp-col 0)
			    (ncplane_move_yx ncp ncp-row ncp-col))
			  (set-col (bols row))))

		  (set! (keymap (+ control-key (char->integer #\B)))
			(lambda (c)
			  (if (and (= col (bols row))
				   (> row 0))
			      (let ((old-row row))
				(decrement-row 1)
				(if (< row old-row)
				    (set-col (eols row))))
			      (set-col (max (bols row) (- col 1))))))

		  (set! (keymap (+ control-key (char->integer #\C)))
			(lambda (c)
			  (set! repl-done #t)))

		  (set! (keymap (+ control-key (char->integer #\D)))
			(lambda (c)
			  (when (and (< col (eols row)) ; should this delete the newline?
				     (> (eols row) (bols row)))
			    (let ((trailing (ncplane_contents ncp row (+ col 1) 1 (- (eols row) col -1))))
			      (nc-display row col trailing)
			      (nc-display row (+ col (length trailing)) " "))
			    (set! (eols row) (- (eols row) 1)))))

		  (set! (keymap (+ control-key (char->integer #\E)))
			(lambda (c)
			  (set-col (eols row))))

		  (set! (keymap (+ control-key (char->integer #\F)))
			(lambda (c)
			  (if (and (= col (eols row))
				   (< row ncp-max-row))
			      (begin
				(increment-row 1)
				(set! ncp-max-row (max ncp-max-row row))
				(set-col (bols row)))
			      (set-col (min (eols row) (+ col 1))))))

		  (set! (keymap (+ control-key (char->integer #\G))) ; get a prompt
			(lambda (c)
			  (increment-row 1)
			  (set-ncp-col 0)
			  (ncplane_move_yx ncp ncp-row ncp-col)
			  (reprompt row)))

                  (set! (keymap (+ control-key (char->integer #\K)))
			(lambda (c)
			  (append-to-selection (ncplane_contents ncp row col 1 (- (eols row) col)))
			  (nc-display row col (make-string (- (eols row) col) #\space))
			  (set! (eols row) col)))

		  (set! (keymap (+ control-key (char->integer #\L))) ; not the same as emacs's C-l (moves current row to top)
			(lambda (c)
			  (unless (= row (- ncp-row))
			    (set-ncp-row (- row))
			    (ncplane_move_yx ncp ncp-row ncp-col))))

		  (set! (keymap (+ control-key (char->integer #\N)))
			(lambda (c)
			  (when (< row ncp-max-row)
			    (increment-row 1)
			    (set-col (min (max col (bols row)) (eols row))))))

		  (set! (keymap (+ control-key (char->integer #\O)))
			(lambda (c)
			  (let ((trailer (ncplane_contents ncp row col 1 (- (eols row) col)))
				(old-row row))
			    (when (> ncp-max-row row)

			      (when (>= (+ ncp-max-row 1) ncp-rows)
				(ncplane_resize ncp 0 0 ncp-rows ncp-cols 0 0 (+ ncp-rows 40) ncp-cols)
				(set! ncp-rows (+ ncp-rows 40))
				(set! bols (copy bols (make-int-vector ncp-rows)))
				(set! eols (copy eols (make-int-vector ncp-rows))))

			      (do ((i (+ ncp-max-row 1) (- i 1)))
				  ((= i (+ row 1))
				   (set! ncp-max-row (+ ncp-max-row 1)))
				(let ((contents (ncplane_contents ncp (- i 1) 0 1 (eols (- i 1)))))
				  (clear-line i)
				  (nc-display i 0 contents)) ; should this be indented?
				(set! (eols i) (eols (- i 1)))
				(set! (bols i) (bols (- i 1)))))

			    (nc-display row col (make-string (- (eols row) col) #\space))
			    (set! (eols row) col)
			    (increment-row 1)
			    (set! ncp-max-row (max ncp-max-row row))
			    (clear-line row)
			    (nc-display row 0 trailer)
			    (set! (bols row) 0)
			    (set! (eols row) (length trailer))
			    (set-row old-row))))

		  (set! (keymap (+ control-key (char->integer #\P)))
			(lambda (c)
			  (set-row (- row 1))
			  (set-col (min (max col (bols row)) (eols row)))))

		  (set! (keymap (+ control-key (char->integer #\Q)))
			(lambda (c)
			  (set! repl-done #t)
			  (set! (top-level-let 'history) old-history))) ; fix up the ncp pointer I think

		  (set! (keymap (+ control-key (char->integer #\T)))
			(lambda (c)
			  (when (> col (bols row))
			    (let ((cur (if (>= col (eols row))
					   (- col 1)
					   col))
				  (cur-line (ncplane_contents ncp row 0 1 (eols row))))
			      (let ((tmp-c (cur-line (- cur 1))))
				(set! (cur-line (- cur 1)) (cur-line cur))
				(set! (cur-line cur) tmp-c))
			      (nc-display row (bols row) (substring cur-line (bols row))) ; if c=0 nc-display sets (bols row) to 0
			      (if (< cur (eols row))
				  (set-col (+ cur 1)))))))

                  (set! (keymap (+ control-key (char->integer #\U)))
			(lambda (c)
			  (prepend-to-selection (ncplane_contents ncp row (bols row) 1 (- col (bols row))))
			  (nc-display row (bols row) (ncplane_contents ncp row col 1 (- (eols row) col)))
			  (nc-display row (- (eols row) (- col (bols row))) (make-string (- col (bols row)) #\space))
			  (set! (eols row) (- (eols row) (- col (bols row))))
			  (set! col (bols row))))
		  
                  (set! (keymap (+ control-key (char->integer #\W)))
			(lambda (c)
			  (let ((newcol (word-back-x)))
			    (prepend-to-selection (ncplane_contents ncp row newcol 1 (- col newcol)))
			    (nc-display row newcol (ncplane_contents ncp row col 1 (- (eols row) col)))
			    (nc-display row (- (eols row) (- col newcol)) (make-string (- col newcol) #\space))
			    (set! (eols row) (- (eols row) (- col newcol)))
			    (set! col newcol))))
		  
		  (set! (keymap (+ control-key (char->integer #\Y)))
			(lambda (c)
			  (when (string? selection)
			    (let ((trailing (and (> (eols row) col)
						 (ncplane_contents ncp row col 1 (- (eols row) col -1)))))
			      (nc-display row col selection)
			      (if (char=? #\space (selection (- (length selection) 1)))
				  (notcurses_refresh nc))
			      (if (and trailing
				       (> (length trailing) 0))
				  (nc-display row (+ col (length selection)) trailing)))
			    (set! (eols row) (+ (eols row) (length selection)))
			    (set-col (+ col (length selection))))))

		  (set! (keymap NCKEY_LEFT)       ; arrow keys
			(lambda (c)
			  (set-col (max (bols row) (- col 1)))))

		  (set! (keymap NCKEY_RIGHT)
			(lambda (c)
			  (set-col (min (eols row) (+ col 1)))))

		  (set! (keymap NCKEY_UP)
			(lambda (c)
			  (set-row (- row 1))
			  (set-col (min (max col (bols row)) (eols row)))))

		  (set! (keymap NCKEY_DOWN)
			(lambda (c)
			  (when (< row ncp-max-row)
			    (increment-row 1)
			    (set-col (min (max col (bols row)) (eols row))))))

		  (set! (keymap NCKEY_HOME)
			(lambda (c)
			  (set-row 0)
			  (set-col (bols 0))))

		  (set! (keymap NCKEY_END)
			(lambda (c)
			  (set-row ncp-max-row)
			  (set-col (bols ncp-max-row))))

		  (set! (keymap NCKEY_PGUP)
			(lambda (c)
			  (set-row (max 0 (- row (- nc-rows status-rows))))))

		  (set! (keymap NCKEY_PGDOWN)
			(lambda (c)
			  (set-row (max 0 (min ncp-max-row (+ row (- nc-rows status-rows)))))))

		  (set! (keymap NCKEY_RESIZE)      ; terminal window resized (not a key event)
			(lambda (c)
			  (apply nc-resize (ncplane_dim_yx (notcurses_stdplane nc)))))

		  (set! (keymap NCKEY_BACKSPACE)   ; backspace
			(lambda (c)
			  (when (> col (bols row))
			    (let ((trailing (and (> (eols row) col)
						 (ncplane_contents ncp row col 1 (- (eols row) col -1)))))
			      (if trailing
				  (begin
				    (nc-display row (- col 1) trailing)
				    (nc-display row (+ col (- (length trailing) 1)) " "))
				  (nc-display row (- col 1) " "))

			      (set! (eols row) (- (eols row) 1))
			      (decrement-col 1)))))
		  ;; check this: if we backspaced past ncp-col, scroll-left

		  (set! (keymap NCKEY_BUTTON1) ; mouse click, doesn't work in rxvt apparently, right button = button2? click scroll??
			(lambda (c)
			  ;; ncinput gives row|col in current view, so we need to map that to the ncplane row|col
			  ;(display-status (format #f "nc-rows: ~S, ncp-row: ~S, input: ~S" nc-rows ncp-row (ncinput_y ni)))
			  (if (= (ncinput_evtype ni) NCTYPE_RELEASE)
			      (begin
				(when (and (number? mouse-col)
					   (not (= col mouse-col)))
				  (set! selection (ncplane_contents ncp mouse-row (min col mouse-col) 1 (abs (- col mouse-col)))))
				(set! mouse-col #f))
			      (begin
				(set-row (min ncp-max-row (- (ncinput_y ni) ncp-row)))
				(set-col (max (min (eols row) (ncinput_x ni)) (bols row)))
				(unless mouse-col
				  (set! mouse-col col)
				  (set! mouse-row row))))))

		  (set! (keymap NCKEY_ENTER) enter)


		  ;; -------- read/eval/print loop --------

		  (define (recover-previous-layout)
		    (set! display-debug-info local-debug-info)
		    (set! recursor #f)
		    (notcurses_render nc)
		    (move-cursor row col)

		    ;; perhaps a resize happened while we were away
		    (when (and hc
			       (not (= header-cols nc-cols)))
		      (ncplane_resize hc 0 0 header-row (min old-nc-cols nc-cols) 0 0 header-row nc-cols)
		      (ncplane_cursor_move_yx hc 0 0)
		      (ncplane_box hc (hc-cells 0) (hc-cells 1) (hc-cells 2) (hc-cells 3) (hc-cells 4) (hc-cells 5) (- header-row 1) (- nc-cols 1) 0)
		      (do ((i 1 (+ i 1)))
			  ((= i (- header-row 1)))
			(ncplane_putstr_yx hc i (- old-nc-cols 1) " "))
		      (set! header-cols nc-cols))

		    (when (or (< ncp-rows nc-rows)
			      (< ncp-cols nc-cols))
		      (ncplane_resize ncp 0 0 ncp-rows ncp-cols 0 0 (max ncp-rows nc-rows) (max ncp-cols nc-cols))
		      (when (> nc-rows ncp-rows)
			(set! bols (copy bols (make-int-vector nc-rows)))
			(set! eols (copy eols (make-int-vector nc-rows)))
			(set! ncp-rows nc-rows))
		      (set! ncp-cols (max ncp-cols nc-cols))))

		  (let repl-loop ()
		    (display-status-area)

		    (if repl-done
			(begin
			  (ncplane_destroy ncp) ; does this free ncp?
			  (if hc (ncplane_destroy hc)) ; free cells?
			  (if wc (ncplane_destroy wc))
			  (set! ncp #f) ; unnecessary?
			  (set! hc #f) ; old header if nested??
			  (set! wc #f)
			  (set! recursor #t))
			(begin
			  (when recursor
			    (recover-previous-layout))

                          (set! previously-selected just-selected)
                          (set! just-selected #f)
			  
			  (let* ((c (notcurses_getc nc (c-pointer 0) (c-pointer 0) ni))
                                 (c (if (= c (char->integer #\escape))
					(logior meta-key (notcurses_getc nc (c-pointer 0) (c-pointer 0) ni))
					c))
				 (func (hash-table-ref keymap (logior c (if (ncinput_ctrl ni) control-key 0)
								      (if (ncinput_alt ni) meta-key 0)))))

			    (if (procedure? func)
				(catch #t
				  (lambda ()
				    (func c))
				  (lambda (type info) ; this is usually an internal (nrepl) error, or sometimes a read error
				    (display-error ncp row info)
				    (increment-row 1)
				    (reprompt row)))
				;(display-status (format #f "unhandled ~D" c))
				))

			  (notcurses_render nc)

			  ;; if cursor is after ), look for matching open, highlight if found
			  (when (and (pair? prev-pars)
				     (visible? (car prev-pars) (cadr prev-pars)))
			    (ncplane_putc_yx ncp (car prev-pars) (cadr prev-pars) normal-paren)
			    (notcurses_render nc)
			    (set! prev-pars #f))

			  ;; if we have "(name" and name is a function/macro, and it has either
			  ;;   a signature or documentation, post it in the status area
			  (let ((name (ncplane_contents ncp row (bols row) 1 (- col (bols row)))))
			    (do ((i (- (length name) 1) (- i 1)))
				((or (< i 0)
				     (char-whitespace? (name i))
				     (memv (name i) '(#\( #\) #\# #\; #\" #\' #\`)))
				 (when (and (>= i 0)
					    (char=? (name i) #\())
				   (set! name (substring name 1))
				   (when (positive? (length name))
				     (let ((value (symbol->value (string->symbol name) top-level-let)))
				       (when (or (procedure? value)
						 (macro? value))   ; syntax here is just noise -- everyone knows about "if"!
					 (let ((sig (signature value))
					       (args (let ((source (procedure-source value)))
						       (and (pair? source)
							    (pair? (cdr source))
							    (cadr source))))
					       (doc (documentation value)))
					   (let ((str (format #f "~A~A~A"
							      (if (pair? sig)
								  (format #f "sig: ~S" sig)
								  "")
							      (if args
								  (format #f "~Aargs: ~S" (if sig ", " "") args)
								  "")
							      (if (and (string? doc)
								       (> (length doc) 0))
								  (format #f "~Adoc: ~S" (if (or args sig) ", " "") doc)
								  ""))))
					     (set! (top-level-let 'status-text) str)
					     (display-status (first-line str)))))))))))

			  ;; show matching open paren, if it's a complete expression, ask lint about it
			  (unless (or (<= col (+ (bols row) 1))              ; got to be room for #\(
				      (not (string=? ")" (ncplane_contents ncp row (- col 1) 1 1)))
				      (and (>= col (+ (bols row) 3))
					   (string=? (ncplane_contents ncp row (- col 3) 1 3) "#\\)")))
			    (let ((pars (match-close-paren ncp row col #f)))
			      (when (and (pair? pars)
					 (visible? (caar pars) (cadar pars)))
				(ncplane_putc_yx ncp (caar pars) (cadar pars) red-paren)
				(set! prev-pars (car pars))
				(notcurses_render nc)
				(when (and with-lint (= row (caar pars)))
				  (let ((expr (ncplane_contents ncp row (cadar pars) 1 (- col (cadar pars)))))
				    (catch #t
				      (lambda ()
					(let ((result (call-with-output-string
						       (lambda (op)
							 (call-with-input-string expr
							   (lambda (ip)
							     (let-temporarily ((*report-laconically* #t)
									       (*report-combinable-lets* #f)
									       (*report-boolean-functions-misbehaving* #f)
									       (*report-quasiquote-rewrites* #f))
							       (lint ip op #f))))))))
					  (unless (string=? result expr)
					    (set! (top-level-let 'status-text) result)
					    (display-status (first-line result)))))
				      (lambda (type info)
					#f)))))))
			  (move-cursor row col)
			  (repl-loop))))))

	      (lambda (type info)
		(display-error ncp row info)
		(notcurses_stop nc)
		(apply format *stderr* info)
		(format *stderr* "~%line ~A: ~A~%" ((owlet) 'error-line) ((owlet) 'error-code))
		(#_exit)
		)
	    )))) ; run


      (define (stop)
	(notcurses_stop nc)
	(#_exit))


      ;; -------- emacs --------
      (define (emacs-repl)
	;; also this does not resend the entire expression after editing
	;;   and does not notice in-place edits
	;;   can <cr> get entire expr?
	(with-let (sublet libc-let)
	  (let ((buf (c-pointer->string (calloc 512 1) 512)))
	    (format *stderr* "> ")
	    (do ((b (fgets buf 512 stdin) (fgets buf 512 stdin)))
		((zero? (length b))
		 (#_exit))
	      (let ((len (strlen buf)))
		(when (positive? len)
		  (do ((i 0 (+ i 1)))
		      ((or (not (char-whitespace? (buf i)))
			   (= i len))
		       (when (< i len)
			 (let ((str (substring buf 0 (- (strlen buf) 1))))
			   (catch #t
			     (lambda ()
			       (do ()
				   ((= (string-length str) 0))
				 (catch 'string-read-error
				   (lambda ()
				     (format *stderr* "~S~%> " (eval-string str (*nrepl* 'top-level-let)))
				     (set! str ""))
				   (lambda (type info)
				     (fgets buf 512 stdin)
				     (set! str (string-append str " " (substring buf 0 (- (strlen buf) 1))))))))
			     (lambda (type info)
			       (set! str "")
			       (apply format *stderr* info)
			       (format *stderr* "~%> ")))))))))))))

      (define (start)
	(if (with-let libc-let
	      (or (zero? (isatty (fileno stdin)))      ; not a terminal -- input from pipe probably
		  (string=? (getenv "TERM") "dumb")))  ; no vt100 codes -- emacs subjob for example
	    (emacs-repl)
	    (begin
	      (let ((noptions (notcurses_options_make)))
		(set! (notcurses_options_flags noptions) NCOPTION_SUPPRESS_BANNERS)
		(set! nc (notcurses_core_init noptions)))
	      (notcurses_cursor_enable nc 0 2)
	      (unless (string-position "rxvt" ((libc-let 'getenv) "TERM"))
		(notcurses_mice_enable nc NCMICE_ALL_EVENTS)) ; 0 if ok, -1 if failure
	      (let ((size (ncplane_dim_yx (notcurses_stdplane nc))))
		(set! nc-cols (cadr size))
		(set! nc-rows (car size))
		(set! statp-row (- nc-rows status-rows)))
	      (set! statp (ncplane_new nc nc-rows nc-cols 0 0 (c-pointer 0)))
	      (nccells_double_box statp 0 0 (status-cells 0) (status-cells 1) (status-cells 2) (status-cells 3) (status-cells 4) (status-cells 5))
	      (ncplane_putstr_yx statp 1 1 (make-string (- nc-cols 5) #\space))
	      (when (string-position "rxvt" (getenv "TERM"))
		(ncplane_putstr_yx statp 1 2 (substring "rxvt doesn't support the mouse" 0 (min 30 (- nc-cols 3))))
		(notcurses_render nc)))))
      (curlet)))

  (with-let *nrepl*
    (start)
    (run)
    (stop)))

;; selection (both ways):
;;   (currently works by dragging mouse and using C-y, but text is not highlighted)
;;   xclip to access the clipboard?? (system "xclip -o")=current contents, (system "echo ... | xclip")=set contents
;;   so if mouse(2)=get from xclip if it exists etc, or maybe add example function, or can we do this in nrepl.c?
;;     right button is nckey_button2, scroll=nckey_button3 (lxterminal -- not rxvt)
;;   C_<space>+move cursor -- need highlighting too
;;
;; some terminals have "zoom" -- can we tell this has happened? apparently not
;;     (ncplane_dim_yx (notcurses_stdplane (*nrepl* 'nc))) doesn't change, but cursor movement is confused and status area gets lost
;; add signatures and help for notcurses
;; C-s|r? [need positions as adding chars, backspace=remove and backup etc, display current search string in status]
;;   start at row/col, get contents, go to current match else increment, save row/col of match
;; begin_hook for stepper: at each call, drop back into the debugger with curlet -- how to keep our place? (step=continue+break -- ambiguous)
;; colorize, perhaps make a vector for each color indexed by char; for colorized name, for each char get cell from vector (or make it if needed)

(set! (*s7* 'debug) old-debug)
*nrepl*