"Display operations"

"Get/set x/y position, width, height"
<DEFINE TTY-PARM (CHANNEL OPER "OPTIONAL" NEW
		  "AUX" (DATA <CHANNEL-DATA .CHANNEL>))
  #DECL ((CHANNEL) CHANNEL (NEW) FIX (DATA) TTY-CHANNEL)
  <COND (<TC-TTY .DATA>
	 <COND (<==? .OPER PAGE-WIDTH>
		<COND (<NOT <ASSIGNED? NEW>>
		       <DO-TTY-PARM .DATA PAGE-WIDTH>)
		      (T
		       <DO-TTY-PARM .DATA PAGE-WIDTH .NEW>)>)
	       (<==? .OPER PAGE-HEIGHT>
		<COND (<NOT <ASSIGNED? NEW>>
		       <DO-TTY-PARM .DATA PAGE-HEIGHT>)
		      (T
		       <DO-TTY-PARM .DATA PAGE-HEIGHT .NEW>)>)
	       (<==? .OPER PAGE-X>
		<COND (<NOT <ASSIGNED? NEW>>
		       <DO-TTY-PARM .DATA PAGE-X>)
		      (T
		       <DO-TTY-PARM .DATA PAGE-X .NEW>
		       <UPDATE-MC .CHANNEL <DO-TTY-PARM .DATA PAGE-X>>)>)
	       (<==? .OPER PAGE-Y>
		<COND (<NOT <ASSIGNED? NEW>>
		       <DO-TTY-PARM .DATA PAGE-Y>)
		      (T
		       <DO-TTY-PARM .DATA PAGE-Y .NEW>
		       <UPDATE-MC .CHANNEL <> <DO-TTY-PARM .DATA PAGE-Y>>)>)>)
	(0)>>

; "Anything that is simple (perhaps change cursor position, and output
   some string) is handled by DO-TTY-OP."
<DEFINE CLEAR-SCREEN (CHANNEL OPER)
  #DECL ((CHANNEL) CHANNEL)
  <DO-TTY-OP ,TTY-CLR .CHANNEL 0 0>>

<DEFINE CLEAR-EOL (CHANNEL OPER)
  #DECL ((CHANNEL) CHANNEL)
  <DO-TTY-OP ,TTY-CEL .CHANNEL>>

<DEFINE CLEAR-EOS (CHANNEL OPER)
  #DECL ((CHANNEL) CHANNEL)
  <DO-TTY-OP ,TTY-CEW .CHANNEL>>

<DEFINE FRESH-LINE (CHANNEL OPER "OPTIONAL" (N 1)
		    "AUX" (DATA <CHANNEL-DATA .CHANNEL>) (TTY <TC-TTY .DATA>))
  #DECL ((N) FIX (CHANNEL) CHANNEL (DATA) TTY-CHANNEL (TTY) TTY)
  <COND (<0? <TT-X .TTY>>
	 <SET N <- .N 1>>)>
  <COND (<G? .N 0>
	 <REPEAT ()
	   <TTY-NORMAL-OUT .CHANNEL .OPER ,CRLF-STRING>
	   <COND (<L=? <SET N <- .N 1>> 0> <RETURN>)>>)>>

<DEFINE HOME-CURSOR (CHANNEL OPER)
  #DECL ((CHANNEL) CHANNEL)
  <DO-TTY-OP ,TTY-HOM .CHANNEL 0 0>>

<DEFINE BOTTOM-CURSOR (CHANNEL OPER "AUX" (DATA <CHANNEL-DATA .CHANNEL>)
		       H)
  #DECL ((CHANNEL) CHANNEL (DATA) TTY-CHANNEL)
  <COND (<DO-TTY-OP ,TTY-HMD .CHANNEL 0
		    <SET H <- <TD-HEIGHT <TT-DESC <TC-TTY .DATA>>> 1>>>)
	(T
	 <DO-TTY-OP ,TTY-MOV .CHANNEL 0 .H>)>>

<DEFINE HOR-POS-CURSOR (CHANNEL OPER NEW)
  #DECL ((CHANNEL) CHANNEL (NEW) FIX)
  <DO-TTY-OP ,TTY-HRZ .CHANNEL .NEW>>

<DEFINE VER-POS-CURSOR (CHANNEL OPER NEW)
  #DECL ((CHANNEL) CHANNEL (NEW) FIX)
  <DO-TTY-OP ,TTY-VRT .CHANNEL <> .NEW>>

<DEFINE MOVE-CURSOR (CHANNEL OPER X Y)
  #DECL ((CHANNEL) CHANNEL (X Y) FIX)
  <DO-TTY-OP ,TTY-MOV .CHANNEL .X .Y>>

<DEFINE SAVE-CURSOR (CHANNEL OPER "AUX" (DATA <CHANNEL-DATA .CHANNEL>)
		     (TTY <TC-TTY .DATA>))
  #DECL ((CHANNEL) CHANNEL (DATA) TTY-CHANNEL (TTY) TTY)
  <TT-SAV-X .TTY <TT-X .TTY>>
  <TT-SAV-Y .TTY <TT-Y .TTY>>>

<DEFINE RESTORE-CURSOR (CHANNEL OPER "AUX" (DATA <CHANNEL-DATA .CHANNEL>)
			(TTY <TC-TTY .DATA>))
  #DECL ((CHANNEL) CHANNEL (DATA) TTY-CHANNEL (TTY) TTY)
  <COND (<TT-SAV-X .TTY>
	 <DO-TTY-OP ,TTY-MOV .CHANNEL <TT-SAV-X .TTY> <TT-SAV-Y .TTY>>)>>

<DEFINE BACK-CURSOR (CHANNEL OPER "OPTIONAL" (N 1)
		     "AUX" (TC <CHANNEL-DATA .CHANNEL>) (TTY <TC-TTY .TC>)
		     (CURX <TT-X .TTY>) TD WIDTH HEIGHT CURY NEWX NEWY)
  #DECL ((CHANNEL) CHANNEL (N CURX WIDTH HEIGHT CURY NEWX NEWY) FIX
	 (TC) TTY-CHANNEL (TTY) TTY)
  <COND (<L? .N 0>
	 <FORWARD-CURSOR .CHANNEL .OPER <- .N>>)
	(<L=? .N .CURX>
	 <COND (<NOT <AND <1? .N>
			  <DO-TTY-OP ,TTY-BCK .CHANNEL <- .CURX 1>>>>
		<DO-TTY-OP ,TTY-HRZ .CHANNEL <- .CURX .N>>)>)
	(T
	 <SET CURY <TT-Y .TTY>>
	 <SET TD <TT-DESC .TTY>>
	 <SET WIDTH <TD-WIDTH .TD>>
	 <SET HEIGHT <TD-HEIGHT .TD>>
	 <SET NEWX <- .CURX .N>>
	 <SET NEWY .CURY>
	 <REPEAT ()
	   <SET NEWX <+ .NEWX .WIDTH>>
	   <SET NEWY <- .NEWY 1>>
	   <COND (<G=? .NEWX 0> <RETURN>)>>
	 <COND (<L? .NEWY 0>
		<SET NEWY <+ .HEIGHT .NEWY>>)>
	 <COND (<==? .NEWY .CURY>
		<DO-TTY-OP ,TTY-HRZ .CHANNEL .NEWX>)
	       (T
		<DO-TTY-OP ,TTY-MOV .CHANNEL .NEWX .NEWY>)>)>>

<DEFINE FORWARD-CURSOR (CHANNEL OPER "OPTIONAL" (N 1)
			"AUX" (TC <CHANNEL-DATA .CHANNEL>) (TTY <TC-TTY .TC>)
			(CURX <TT-X .TTY>) (TD <TT-DESC .TTY>)
			(WIDTH <TD-WIDTH .TD>) HEIGHT CURY NEWX NEWY)
  #DECL ((CHANNEL) CHANNEL (N CURX WIDTH HEIGHT CURY NEWX NEWY) FIX
	 (TC) TTY-CHANNEL (TTY) TTY (TD) TTY-DESC)
  <COND (<L? .N 0>
	 <BACK-CURSOR .CHANNEL .OPER <- .N>>)
	(<L? <SET NEWX <+ .CURX .N>> .WIDTH>
	 <COND (<NOT <AND <1? .N>
			  <DO-TTY-OP ,TTY-FWD .CHANNEL <+ .CURX 1>>>>
		<DO-TTY-OP ,TTY-HRZ .CHANNEL .NEWX>)>)
	(T
	 <SET CURY <TT-Y .TTY>>
	 <SET CURX <MOD .NEWX .WIDTH>>
	 <SET NEWY <+ .CURY </ .NEWX .WIDTH>>>
	 <COND (<G=? .NEWY <SET HEIGHT <TD-HEIGHT .TD>>>
		<SET NEWY <MOD .NEWY .HEIGHT>>)>
	 <DO-TTY-OP ,TTY-MOV .CHANNEL .CURX .NEWY>)>>

<DEFINE UP-CURSOR (CHANNEL OPER "OPTIONAL" (N 1)
		   "AUX" (TC <CHANNEL-DATA .CHANNEL>) (TTY <TC-TTY .TC>)
		   (TD <TT-DESC .TTY>) (CURY <TT-Y .TTY>)
		   (HEIGHT <TD-HEIGHT .TD>))
  #DECL ((CHANNEL) CHANNEL (TC) TTY-CHANNEL (TTY) TTY (TD) TTY-DESC
	 (CURY HEIGHT N) FIX)
  <COND (<L? .N 0> <DOWN-CURSOR .CHANNEL .OPER <- .N>>)
	(<G=? <SET CURY <- .CURY .N>> 0>
	 <COND (<NOT <AND <1? .N>
			  <DO-TTY-OP ,TTY-UP .CHANNEL <> .CURY>>>
		<DO-TTY-OP ,TTY-VRT .CHANNEL <> .CURY>)>)
	(T
	 <SET CURY <MOD .CURY .HEIGHT>>
	 <DO-TTY-OP ,TTY-VRT .CHANNEL <> .CURY>)>>

<DEFINE DOWN-CURSOR (CHANNEL OPER "OPTIONAL" (N 1)
		     "AUX" (TC <CHANNEL-DATA .CHANNEL>) (TTY <TC-TTY .TC>)
		     (TD <TT-DESC .TTY>) (CURY <TT-Y .TTY>)
		     (HEIGHT <TD-HEIGHT .TD>))
  #DECL ((CHANNEL) CHANNEL (TC) TTY-CHANNEL (TTY) TTY (TD) TTY-DESC
	 (CURY HEIGHT N) FIX)
  <COND (<L? .N 0> <UP-CURSOR .CHANNEL .OPER <- .N>>)
	(<L? <SET CURY <+ .CURY .N>> .HEIGHT>
	 <COND (<AND <1? .N>
		     <0? <TT-X .TTY>>>
		; "Output a linefeed where possible."
		<TT-Y .TTY .CURY>
		<OUTPUT-RAW-STRING .CHANNEL <ASCII 10>>)
	       (<NOT <AND <1? .N>
			  <DO-TTY-OP ,TTY-DWN .CHANNEL <> .CURY>>>
		<DO-TTY-OP ,TTY-VRT .CHANNEL <> .CURY>)>)
	(T
	 <SET CURY <MOD .CURY .HEIGHT>>
	 <DO-TTY-OP ,TTY-VRT .CHANNEL <> .CURY>)>>

<DEFINE KILL-CHAR (CHANNEL OPER)
  #DECL ((CHANNEL) CHANNEL)
  <BACK-CURSOR .CHANNEL .OPER>
  <OUTPUT-RAW-STRING .CHANNEL " ">>

<DEFINE ERASE-CHAR (CHANNEL OPER "OPTIONAL" (N 1)
		    "AUX" (TC <CHANNEL-DATA .CHANNEL>) (TTY <TC-TTY .TC>)
			  (X <TT-X .TTY>))
  #DECL ((CHANNEL) CHANNEL (N X) FIX (TC) TTY-CHANNEL (TTY) TTY)
  <COND
   (<G? .N 0>
    <REPEAT (NX (NY <TT-Y .TTY>))
      #DECL ((NX) FIX)
      <COND
       (<G? .X 0>
	<COND (<G? .N .X>
	       <SET NX 0>
	       <SET N <- .N .X>>)
	      (T
	       <SET NX <- .X .N>>
	       <SET N 0>)>
	; "Avoid absolute cursor position where possible on rubouts"
	<COND (<N==? .NY <TT-Y .TTY>>
	       <MOVE-CURSOR .CHANNEL .OPER .NX .NY>)
	      (<1? <- .X .NX>>
	       <BACK-CURSOR .CHANNEL .OPER>)
	      (T
	       <HOR-POS-CURSOR .CHANNEL .OPER .NX>)>
	<CLEAR-EOL .CHANNEL .OPER>)>
      <COND (<G? .N 0>
	     <COND (<L? <SET NY <- .NY 1>> 0>
		    <SET NY <- <TD-HEIGHT <TT-DESC .TTY>> 1>>)>
	     <SET X <- <TD-WIDTH <TT-DESC .TTY>> 1>>)
	    (<RETURN>)>>)>>


"More operations--line and char i&d"
<DEFINE INSERT-LINE (CHANNEL OPER "OPTIONAL" (N 1) (TOP <>) (BOT <>)
		     "AUX" (TC <CHANNEL-DATA .CHANNEL>) (TTY <TC-TTY .TC>)
			   (TD <TT-DESC .TTY>) (RBOT <- <TD-HEIGHT .TD> 1>)
			   TEMP (SAVX <TT-X .TTY>) (SAVY <TT-Y .TTY>))
  #DECL ((CHANNEL) CHANNEL (N) FIX (TOP BOT) <OR FALSE FIX>
	 (TC) TTY-CHANNEL (TTY) TTY (TD) TTY-DESC (TEMP RBOT) FIX)
  <COND (<NOT .TOP>
	 <SET TOP .SAVY>)>
  <COND (<NOT .BOT>
	 <SET BOT .RBOT>)>
  <COND (<G? .TOP .BOT>
	 <SET TEMP .BOT>
	 <SET BOT .TOP>
	 <SET TOP .TEMP>)>
  <COND (<AND <L=? .TOP .RBOT>
	      <NOT <0? .N>>>
	 <SET BOT <MIN .BOT .RBOT>>
	 <COND (<DO-TTY-OP ,TTY-DS .CHANNEL .BOT .TOP <>>
		; "Try defining a scrolling region, making things much simpler"
		<COND (<L? .N 0>	; "Deleting lines"
		       <MOVE-CURSOR .CHANNEL .OPER 0 .BOT>
		       <REPEAT ()
		         <DO-TTY-OP ,TTY-SU .CHANNEL>
			 <COND (<0? <SET N <+ .N 1>>> <RETURN>)>>)
		      (T
		       <MOVE-CURSOR .CHANNEL .OPER 0 .TOP>
		       <REPEAT ()
		         <DO-TTY-OP ,TTY-SD .CHANNEL>
			 <COND (<0? <SET N <- .N 1>>> <RETURN>)>>)>
		<DO-TTY-OP ,TTY-DS .CHANNEL .RBOT 0 <>>)
	       (<==? .BOT .RBOT>
		; "Straight line insert/delete"
		<MOVE-CURSOR .CHANNEL .OPER 0 .TOP>
		<PROG (OP)
		  <COND (<L? .N 0> <SET OP ,TTY-DL>)
			(<SET OP ,TTY-IL>)>
		  <SET N <ABS .N>>
		  <REPEAT ()
		    <DO-TTY-OP .OP .CHANNEL>
		    <COND (<0? <SET N <- .N 1>>> <RETURN>)>>>)
	       (T
		; "Simulated scrolling region"
		<COND (<G? .N 0>
		       <SET N <MIN .N <- .BOT .TOP>>>
		       <MOVE-CURSOR .CHANNEL .OPER 0 <- .BOT <- .N 1>>>
		       <INSERT-LINE .CHANNEL .OPER <- .N>>
		       <MOVE-CURSOR .CHANNEL .OPER 0 .TOP>
		       <INSERT-LINE .CHANNEL .OPER .N>)
		      (T
		       <SET N <MAX .N <- .TOP .BOT>>>
		       <MOVE-CURSOR .CHANNEL .OPER 0 .TOP>
		       <INSERT-LINE .CHANNEL .OPER .N>
		       <MOVE-CURSOR .CHANNEL .OPER 0 <+ .BOT .N 1>>
		       <INSERT-LINE .CHANNEL .OPER <- .N>>)>)>
	 <MOVE-CURSOR .CHANNEL .OPER .SAVX .SAVY>)>>

<DEFINE INSERT-CHAR (CHANNEL OPER "OPTIONAL" (N 1) (LEFT <>) (RIGHT <>)
		     "AUX" (TC <CHANNEL-DATA .CHANNEL>) (TTY <TC-TTY .TC>)
		     (TD <TT-DESC .TTY>) (RRIGHT <- <TD-WIDTH .TD> 1>)
		     (SAVX <TT-X .TTY>) TEMP)
  #DECL ((CHANNEL) CHANNEL (N RRIGHT SAVX) FIX (LEFT RIGHT) <OR FALSE FIX>
	 (TC) TTY-CHANNEL (TTY) TTY (TD) TTY-DESC)
  <COND (<NOT .LEFT>
	 <SET LEFT .SAVX>)>
  <COND (<NOT .RIGHT>
	 <SET RIGHT .RRIGHT>)>
  <COND (<G? .LEFT .RIGHT>
	 <SET TEMP .LEFT>
	 <SET LEFT .RIGHT>
	 <SET RIGHT .TEMP>)>
  <COND (<AND <L=? .LEFT .RRIGHT>
	      <NOT <0? .N>>>
	 <SET LEFT <MIN .LEFT .RRIGHT>>)>>