input = cluster is peek,		% peek a char
		   getc,		% read a char
		   pending,		% any input ready ?
		   pending_wait,	% wait a while for input
		   copy_wait,		% wait for raster_copy done
		   push,		% push back on input
		   in_macro,		% test if in macro
		   still_macro,		% test if still macro chars
		   push_macro,		% push macro back on input
		   flush_macro,		% flush any macro input
		   bpos,		% button position
		   set_highlight,	% control highlight
		   chan,		% input chan
		   reset

    rep = null          % own data is what is important

    inputs = KeyPressed + ButtonPressed + ButtonReleased
    exposures = ExposeRegion + ExposeWindow + ExposeCopy

    downs = sequence[string]$["\362\361\363\366\360\365\370\370",
			      "\355\351\352\356\350\353\357\357",
			      "\354\342\344\346\341\345\347\347"]
    ups = sequence[string]$["\322\321\323\326\320\325\330\330",
			    "\315\311\312\316\310\313\317\317",
			    "\314\302\304\306\301\305\307\307"]

    own peeks: act
    own rstart: int
    own copies: int
    own dones: int
    own xpos: int
    own ypos: int
    own highlight: bool
    own ev: event

    peek = proc () returns (char)
	return(act$top(peeks))
	   except when bounds: end
	c: char := getchar()
	act$addh(peeks, c)
	return(c)
	end peek

    getc = proc () returns (char)
	if act$empty(peeks)
	   then return(getchar())
	   else return(act$remh(peeks))
	   end
	end getc

    pending = proc () returns (bool)
	return(~act$empty(peeks)  cor  cpending())
	end pending

    pending_wait = proc () returns (bool)
	if ~act$empty(peeks)
	   then return(true)
	   else for i: int in int$from_to_by(1000, 1, -1) do
		    if cpending()
		       then return(true) end
		    end
		return(false)
	   end
	end pending_wait

    copy_wait = proc ()
	copies := copies + 1
	while copies > dones do
	    x_input$mdeq(exposures, ev)
	    if ev.kind = ExposeCopy
	       then dones := dones + 1
	       else screen$redisplay(ev.win, ev.x, ev.y, ev.x0, ev.y0)
	       end
	    end
	end copy_wait

    cpending = proc () returns (bool)
	while x_input$pending() do
	    x_input$deq(ev)
	    if ev.kind = KeyPressed
	       then act$addh(peeks, x_keymap$getc(ev.value, ev.mask))
		       except when none: continue
			      when multi (s: string):
				   for i: int in int$from_to_by(string$size(s), 1, -1) do
				       act$addh(peeks, s[i])
				       end
			      end
		    return(true)
	       end
	    if ev.kind = ButtonPressed
	       then act$addh(peeks, downs[ev.value + 1][ev.mask / 2**12 + 1])
		    xpos, ypos := screen$position(ev.x, ev.y)
		    act$addh(peeks, esc)
		    return(true)
	       end
	    if ev.kind = ButtonReleased
	       then act$addh(peeks, ups[ev.value + 1][ev.mask / 2**12 + 1])
		    xpos, ypos := screen$position(ev.x, ev.y)
		    act$addh(peeks, esc)
		    return(true)
	       end
	    if ev.kind = ExposeCopy
	       then dones := dones + 1
	     elseif ev.kind = UnmapWindow
	       then copies := copies - 1
		    copy_wait()
		    screen$unmapped(ev.win)
	     elseif ev.kind ~= MouseMoved
	       then screen$redisplay(ev.win, ev.x, ev.y, ev.x0, ev.y0) end
	    end
	return(false)
	end cpending

    getchar = proc () returns (char)
	rstart := -1
	high: bool := false
	while true do
	    if highlight  cand  ~high  cand  ~x_input$pending()
	       then high := true
		    screen$highlight(true)
	       end
	    x_input$deq(ev)
	    if ev.kind = MouseMoved
	       then if highlight
		       then high := true
			    screen$highlight(true)
		       end
		    continue
	       end
	    if high
	       then high := false
		    screen$highlight(false)
	       end
	    if ev.kind = KeyPressed
	       then return(x_keymap$getc(ev.value, ev.mask))
		       except when none: continue
			      when multi (s: string):
				   for i: int in int$from_to_by(string$size(s), 2, -1) do
				       act$addh(peeks, s[i])
				       end
				   return(s[1])
			      end
	       end
	    if ev.kind = ButtonPressed
	       then act$addh(peeks, downs[ev.value + 1][ev.mask / 2**12 + 1])
		    xpos, ypos := screen$position(ev.x, ev.y)
		    return(esc)
	       end
	    if ev.kind = ButtonReleased
	       then act$addh(peeks, ups[ev.value + 1][ev.mask / 2**12 + 1])
		    xpos, ypos := screen$position(ev.x, ev.y)
		    return(esc)
	       end
	    if ev.kind = ExposeCopy
	       then dones := dones + 1
	     elseif ev.kind = UnmapWindow
	       then copies := copies - 1
		    copy_wait()
		    screen$unmapped(ev.win)
	     else screen$redisplay(ev.win, ev.x, ev.y, ev.x0, ev.y0) end
	    end
	end getchar

    push = proc (c: char)
	if rstart > act$size(peeks)
	   then rstart := -1 end
	act$addh(peeks, c)
	end push

    in_macro = proc () returns (bool)
	return(rstart >= 0 cand rstart <= act$size(peeks))
	end in_macro

    still_macro = proc () returns (bool)
	return(rstart >= 0 cand rstart < act$size(peeks))
	end still_macro

    push_macro = proc (s: string)
	if ~string$empty(s)
	   then z: int := act$size(peeks)
		if rstart < 0 cor rstart > z then rstart := z end
		for i: int in int$from_to_by(string$size(s), 1, -1) do
		    act$addh(peeks, s[i])
		    end
	   end
	end push_macro

    flush_macro = proc () returns (string)
	s: string
	if rstart >= 0 cand rstart < act$size(peeks)
	   then s := _cvt[_bytevec, string](
				_bytevec$create(act$size(peeks) - rstart))
		for i: int in int$from_to(1, string$size(s)) do
		    _cvt[string, _bytevec](s)[i] := act$remh(peeks)
		    end
	   else s := ""
	   end
	rstart := -1
	return(s)
	end flush_macro

    bpos = proc () returns (int, int)
	return(xpos, ypos)
	end bpos

    set_highlight = proc (flag: bool)
	highlight := flag
	end set_highlight

    chan = proc () returns (_chan)
	return(_chan$nul())
	end chan

    reset = proc ()
	x_keymap$load("")
	peeks := act$new()
	rstart := -1
	copies := -1
	dones := 0
	xpos := 0
	ypos := 0
	highlight := false
	ev := x_input$empty_event()
	end reset

    end input