Syntax10.Scn.Fnt
Syntax10i.Scn.Fnt
Syntax10b.Scn.Fnt
MODULE Terminals;	(*Copyright (c) Robert Griesemer and Wolfgang Weck, 1992-95 /gri, ww, mf 30.9.93*)
	IMPORT Texts;
	CONST
	(* geometry *)
		Height*=24; MaxWidth*=132;
	(* attributes *)
		none*=0; bold*=1; underline*=2; blinking*=4; reverse*=8;
	(* notifier id's *)
		update*=1; moveCursor*=2; scroll*=3;
	(* control characters *)
		ENQ=5X; BS=08X; HT=09X; LF=0AX; VT=0BX; FF=0CX; CR=0DX;
		CAN=18X; SUB=1AX; ESC=1BX; DEL=7FX; NSC=91X; BRK=0ACX;
	(* flags *)
		ansi*=0; applic*=1; lineFeed*=2; insert*=3; relative*=4; cursorKeys*=5; autowrap*=6;
	TYPE
		Char*=RECORD ch*: CHAR; attr*: SHORTINT END;
		Line*=POINTER TO RECORD
			len*: INTEGER;
			ch*: ARRAY MaxWidth+1 OF Char
		END;
		Location*=RECORD
			line*, col*: INTEGER
		END;
		Terminal*=POINTER TO TerminalDesc;
		Sender*=PROCEDURE (T: Terminal; ch: CHAR);
		Breaker*=PROCEDURE (T: Terminal);
		Notifier*=PROCEDURE (T: Terminal; op, fromLine, fromCol, toLine, toCol: INTEGER; oldCursor: Location);
		TerminalDesc*=RECORD
		(* text *)
			attr*: SHORTINT;
			width*: INTEGER;
			top, bottom: INTEGER;
			cursor*: Location;
			wrapBefore: BOOLEAN;
			notify*: Notifier;
			line*: ARRAY Height+1 OF Line;
		(* state machine *)
			flags*: SET;
			send: Sender;
			break: Breaker;
			state, parPos, strPos: INTEGER;
			parBuf: ARRAY 32 OF CHAR;
			strBuf: ARRAY 256 OF CHAR;
			tabs: ARRAY MaxWidth+1 OF BOOLEAN;
			answerback*: ARRAY 32 OF CHAR;
			oldAttr: SHORTINT;
			oldCursor: Location;
			oldRelative: BOOLEAN;
			cache*: Texts.Writer;
			text*: Texts.Text;
			pin*: LONGINT
		END;
(* text operations *)
	PROCEDURE MoveLines (t: Terminal; top, bot, dH: INTEGER);
		VAR i, j, d, s, from, to: INTEGER; line: Line; buf: ARRAY Height OF Line;
	BEGIN
		IF (dH # 0) & (top <= bot) THEN
			IF top < 1 THEN top:=1 END;
			IF bot > Height THEN bot:=Height END;
			IF dH < 0 THEN d:=1; from:=top-dH; to:=top; s:=bot ELSE d:=-1; from:=bot-dH; to:=bot; s:=top END;
			i:=to; j:=0;
			REPEAT line:=t.line[i]; line.len:=0; buf[j]:=line; i:=i+d; INC(j) UNTIL i=from;
			s:=s+d;
			WHILE from # s DO t.line[to]:=t.line[from]; to:=to+d; from:=from+d END;
			j:=0; s:=ABS(dH);
			REPEAT t.line[to]:=buf[j]; to:=to+d; INC(j) UNTIL j=s;
			t.notify(t, scroll, top, dH, bot, 0, t.cursor)
		END
	END MoveLines;
	PROCEDURE Erase (t: Terminal; fromLine, fromCol, toLine, toCol: INTEGER); (* [from, to] *)
		VAR line: Line; i, j, len: INTEGER; char: Char;
	BEGIN char.ch:=" "; char.attr:=none; line:=t.line[fromLine]; len:=line.len;
		IF fromLine=toLine THEN
			IF fromCol <= len THEN
				IF toCol > len THEN line.len:=fromCol-1
				ELSE j:=fromCol;
					WHILE j <= toCol DO line.ch[j]:=char; INC(j) END
				END
			END
		ELSE
			IF fromCol <= len THEN line.len:=fromCol-1 END;
			j:=fromLine+1;
			WHILE j < toLine DO t.line[j].len:=0; INC(j) END;
			line:=t.line[toLine]; len:=line.len;
			IF toCol >= len THEN line.len:=0
			ELSE i:=1;
				WHILE i <= toCol DO line.ch[i].ch:=" "; INC(i) END
			END
		END;
		t.notify(t, update, fromLine, fromCol, toLine, toCol, t.cursor)
	END Erase;
	PROCEDURE DeleteChars (t: Terminal; n: INTEGER); (* including cursor character *)
		VAR c, j, len: INTEGER; line: Line; cursor: Location;
	BEGIN cursor:=t.cursor; c:=cursor.col; line:=t.line[cursor.line]; j:=c+n; len:=line.len;
		IF j <= len THEN
			REPEAT line.ch[c]:=line.ch[j]; INC(c); INC(j) UNTIL j > len;
			line.len:=c-1;
			t.notify(t, update, cursor.line, cursor.col, cursor.line, len, cursor)
		END
	END DeleteChars;
	PROCEDURE DeleteLines (t: Terminal; n: INTEGER); (* including cursor line *)
		VAR top, bot: INTEGER;
	BEGIN top:=t.cursor.line; bot:=t.bottom;
		IF bot-top+1 < n THEN n:=bot-top+1 END;
		MoveLines(t, t.cursor.line, t.bottom, -n)
	END DeleteLines;
	PROCEDURE InsertChars (t: Terminal; n: INTEGER); (* move including cursor character, cursor not moved *)
		VAR i, j, len: INTEGER; line: Line; char: Char; cursor: Location;
	BEGIN cursor:=t.cursor; line:=t.line[cursor.line]; len:=line.len; j:=len+n;
		IF j >= t.width THEN j:=t.width END;
		i:=j-n;
		IF i < cursor.col THEN
			IF len >= cursor.col THEN line.len:=cursor.col-1 END
		ELSE line.len:=j;
			REPEAT line.ch[j]:=line.ch[i]; DEC(i); DEC(j) UNTIL i < cursor.col;
			char.ch:=" "; char.attr:=none;
			WHILE j >= cursor.col DO line.ch[j]:=char; DEC(j) END
		END;
		t.notify(t, update, cursor.line, cursor.col, cursor.line, line.len, cursor)
	END InsertChars;
	PROCEDURE InsertLines (t: Terminal; n: INTEGER); (* move including cursor line, cursor not moved *)
		VAR top, bot: INTEGER;
	BEGIN top:=t.cursor.line; bot:=t.bottom;
		IF bot-top+1 < n THEN n:=bot-top+1 END;
		MoveLines(t, top, bot, n)
	END InsertLines;
	PROCEDURE Scroll (t: Terminal; up: BOOLEAN); (* scroll one line within margins *)
	BEGIN
		IF up THEN MoveLines(t, t.top, t.bottom, -1) ELSE MoveLines(t, t.top, t.bottom, 1) END
	END Scroll;
	PROCEDURE SetCursor (t: Terminal; line, col: INTEGER; relative: BOOLEAN); (* (1, 1) means upper, left corner *)
		VAR newLoc: Location;
	BEGIN
		IF relative THEN
			IF line < t.top THEN line:=t.top ELSIF line > t.bottom THEN line:=t.bottom END
		ELSE
			IF line < 1 THEN line:=1 ELSIF line > Height THEN line:=Height END
		END;
		IF col < 1 THEN col:=1 ELSIF col > t.width THEN col:=t.width END;
		newLoc.line:=line; newLoc.col:=col;
		t.notify(t, moveCursor, t.cursor.line, t.cursor.col, line, col, newLoc);
		t.cursor:=newLoc; t.wrapBefore:=FALSE
	END SetCursor;
	PROCEDURE SetMargins (t: Terminal; top, bottom: INTEGER); (* [top, bottom] *)
	BEGIN t.top:=top; t.bottom:=bottom
	END SetMargins;
	PROCEDURE SetWidth (t: Terminal; width: INTEGER);
		VAR i: INTEGER;
	BEGIN t.width:=width; i:=1;
		WHILE i <= Height DO
			IF t.line[i].len > width THEN t.line[i].len:=width END;
			INC(i)
		END;
		IF t.cursor.col > width THEN t.cursor.col:=width END;
		t.notify(t, update, 1, 1, Height, t.width, t.cursor)
	END SetWidth;
	PROCEDURE SetAttribute (t: Terminal; attr: SHORTINT);
	BEGIN
		IF attr=none THEN t.attr:=attr ELSE t.attr:=t.attr+attr END
	END SetAttribute;
	PROCEDURE PutChar(t: Terminal; VAR cursor: Location; VAR wrapBefore: BOOLEAN; ch: Char; VAR dH: INTEGER);
		VAR len: INTEGER; line: Line; char: Char;
	BEGIN
		IF wrapBefore THEN
			IF cursor.col=t.width THEN INC(cursor.line); cursor.col:=1;
				IF cursor.line > t.bottom THEN Scroll(t, TRUE); DEC(cursor.line); DEC(dH) END
			ELSE INC(cursor.col)
			END
		END;
		line:=t.line[cursor.line]; len:=line.len;
		IF (ch.ch=" ") & (ch.attr=none) & (cursor.col=len) THEN DEC(line.len)
		ELSIF (ch.ch # " ") OR (ch.attr # none) OR (cursor.col < len) THEN
			IF len <= cursor.col THEN line.len:=cursor.col; char.ch:=" "; char.attr:=none; INC(len);
				WHILE len < cursor.col DO line.ch[len]:=char; INC(len) END
			END;
			line.ch[cursor.col]:=ch
		END;
		IF cursor.col=t.width THEN wrapBefore:=autowrap IN t.flags
		ELSE INC(cursor.col); wrapBefore:=FALSE
		END
	END PutChar;
	PROCEDURE WriteString (t: Terminal; s: ARRAY OF CHAR; n: INTEGER); (* writes n characters at curs. pos. *)
		VAR i, dH: INTEGER; cursor, oldCur: Location; char: Char;
	BEGIN cursor:=t.cursor;
		oldCur:=cursor; char.attr:=t.attr; dH:=0; i:=0;
		WHILE i < n DO char.ch:=s[i]; PutChar(t, cursor, t.wrapBefore, char, dH); INC(i) END;
		t.cursor:=cursor;
		IF oldCur.line+dH < 1 THEN t.notify(t, update, 1, oldCur.col, cursor.line, cursor.col, oldCur)
		ELSE t.notify(t, update, oldCur.line+dH, oldCur.col, cursor.line, cursor.col, oldCur)
		END
	END WriteString;
	PROCEDURE EFill (t: Terminal);
		VAR i, j, w: INTEGER; line: Line; char: Char;
	BEGIN i:=1; w:=t.width; char.ch:="E"; char.attr:=none;
		WHILE i <= Height DO j:=1; line:=t.line[i]; line.len:=w;
			WHILE j <= w DO line.ch[j]:=char; INC(j) END;
			INC(i)
		END;
		t.notify(t, update, 1, 1, Height, t.width, t.cursor)
	END EFill;
(* sequence interpretation *)
	PROCEDURE DelLast (T: Terminal);
	BEGIN
		IF T.cache.buf.len > 0 THEN Texts.Append(T.text, T.cache.buf) END;
		IF T.text.len > 0 THEN Texts.Delete(T.text, T.text.len-1, T.text.len) END
	END DelLast;
	PROCEDURE Reset* (T: Terminal);
		VAR i: INTEGER;
	BEGIN
		T.flags:={ansi, autowrap}; T.state:=0; T.strPos:=0; i:=1;
		WHILE i <= MaxWidth DO T.tabs[i]:=i MOD 8=1; INC(i) END;
		T.answerback:="*** Hello World ***";
		T.oldAttr:=none; T.oldCursor.line:=1; T.oldCursor.col:=1; T.oldRelative:=FALSE;
		Erase(T, 1, 1, Height, T.width);
		SetMargins(T, 1, Height);
		SetCursor(T, 1, 1, FALSE)
	END Reset;
	PROCEDURE SendStr (T: Terminal; s: ARRAY OF CHAR);
		VAR i: INTEGER;
	BEGIN i:=0;
		WHILE s[i] # 0X DO T.send(T, s[i]); INC(i) END
	END SendStr;
	PROCEDURE SendInt (T: Terminal; x: INTEGER);
		VAR i: INTEGER; d: ARRAY 3 OF CHAR;
	BEGIN i:=0;
		REPEAT d[i]:=CHR(x MOD 10+ORD("0")); x:=x DIV 10;  INC(i) UNTIL x=0;
		WHILE i > 0 DO DEC(i); T.send(T, d[i]) END
	END SendInt;
	PROCEDURE Update (T: Terminal);
	BEGIN IF T.strPos > 0 THEN WriteString(T, T.strBuf, T.strPos); T.strPos:=0 END
	END Update;
	PROCEDURE Flush* (T: Terminal);
	BEGIN Update(T);
		IF (T.text # NIL) & (T.cache.buf.len > 0) THEN Texts.Append(T.text, T.cache.buf) END
	END Flush;
	PROCEDURE Write (T: Terminal; ch: CHAR);
	BEGIN
		IF T.strPos >= LEN(T.strBuf) THEN Update(T) END;
		T.strBuf[T.strPos]:=ch; INC(T.strPos)
	END Write;
	PROCEDURE ESCSequence (T: Terminal; last: CHAR);
		VAR ch: CHAR;
	BEGIN ch:=T.parBuf[0];
		IF ansi IN T.flags THEN
			IF ("7" <= last) & (last <= "c") THEN
				CASE last OF
					| "7": T.oldAttr:=T.attr; T.oldCursor:=T.cursor; T.oldRelative:=relative IN T.flags
					| "8":
						IF ch="#" THEN EFill(T)
						ELSE SetAttribute(T, T.oldAttr);
							SetCursor(T, T.oldCursor.line, T.oldCursor.col, FALSE);
							IF T.oldRelative THEN INCL(T.flags, relative)
							ELSE EXCL(T.flags, relative)
							END
						END
					| "=": INCL(T.flags, applic)
					| ">": EXCL(T.flags, applic)
					| "D":
						IF T.cursor.line=T.bottom THEN Scroll(T, TRUE)
						ELSE SetCursor(T, T.cursor.line+1, T.cursor.col, FALSE)
						END
					| "E":
						IF T.cursor.line=T.bottom THEN Scroll(T, TRUE); SetCursor(T, T.cursor.line, 1, FALSE)
						ELSE SetCursor(T, T.cursor.line+1, 1, FALSE)
						END
					| "H": T.tabs[T.cursor.col]:=TRUE
					| "M":
						IF T.cursor.line=T.top THEN Scroll(T, FALSE)
						ELSE SetCursor(T, T.cursor.line-1, T.cursor.col, relative IN T.flags)
						END
					| "Z": T.send(T, ESC); SendStr(T, "[?1;2c") (* VT100 *)
					| "c": Reset(T)
					| "9" .. "<", "?" .. "C", "F", "G", "I" .. "L", "N" .. "Y", "[" .. "b": (* ignore *)
				END
			END
		ELSE (* VT52 mode *)
			IF ("<" <= last) & (last <= "Z") THEN
				CASE last OF
					| "<": INCL(T.flags, ansi)
					| "=": INCL(T.flags, applic)
					| ">": EXCL(T.flags, applic)
					| "A": SetCursor(T, T.cursor.line-1, T.cursor.col, FALSE)
					| "B": SetCursor(T, T.cursor.line+1, T.cursor.col, FALSE)
					| "C": SetCursor(T, T.cursor.line, T.cursor.col+1, FALSE)
					| "D": SetCursor(T, T.cursor.line, T.cursor.col-1, FALSE)
					| "H": SetCursor(T, 1, 1, FALSE)
					| "I":
						IF T.cursor.line=1 THEN Scroll(T, FALSE)
						ELSE SetCursor(T, T.cursor.line-1, T.cursor.col, FALSE)
						END
					| "J": Erase(T, T.cursor.line, T.cursor.col, Height, T.width)
					| "K": Erase(T, T.cursor.line, T.cursor.col, T.cursor.line, T.width)
					| "Z": T.send(T, ESC); SendStr(T, "/Z")
					| "?", "@", "E" .. "G", "L" .. "Y", "[", "\": (* ignore *)
				END
			END
		END
	END ESCSequence;
	PROCEDURE CSISequence (T: Terminal; last: CHAR);
		VAR ch: CHAR; pos, p1, p2: INTEGER;
		PROCEDURE Next;
		BEGIN ch:=T.parBuf[pos]; INC(pos)
		END Next;
		PROCEDURE Par (zeroVal: INTEGER): INTEGER;
			VAR x: INTEGER;
		BEGIN x:=0;
			IF ("0" <= ch) & (ch <= "9") THEN x:=ORD(ch)-ORD("0"); Next;
				WHILE ("0" <= ch) & (ch <= "9") & (x <= (MAX(INTEGER)-9) DIV 10) DO
					x:=10*x+ORD(ch)-ORD("0"); Next
				END;
				WHILE ("0" <= ch) & (ch <= "9") DO Next END;
				IF ch=";" THEN Next END
			ELSIF ch=";" THEN Next
			END;
			IF x=0 THEN x:=zeroVal END;
			RETURN x
		END Par;
	BEGIN T.parBuf[T.parPos]:=0FFX; pos:=0; Next;
		IF ( "@" <= last) & (last <= "y") THEN
			CASE last OF
				| "@": InsertChars(T, Par(1))
				| "A": SetCursor(T, T.cursor.line-Par(1), T.cursor.col, relative IN T.flags)
				| "B": SetCursor(T, T.cursor.line+Par(1), T.cursor.col, relative IN T.flags)
				| "C": SetCursor(T, T.cursor.line, T.cursor.col+Par(1), relative IN T.flags)
				| "D": SetCursor(T, T.cursor.line, T.cursor.col-Par(1), relative IN T.flags)
				| "H", "f":
					p1:=Par(1); p2:=Par(1);
					IF relative IN T.flags THEN SetCursor(T, T.top+p1-1, p2, TRUE)
					ELSE  SetCursor(T, p1, p2, FALSE)
					END
				| "J":
					p1:=Par(0);
					IF p1=0 THEN Erase(T, T.cursor.line, T.cursor.col, Height, T.width)
					ELSIF p1=1 THEN Erase(T, 1, 1, T.cursor.line, T.cursor.col)
					ELSIF p1=2 THEN Erase(T, 1, 1, Height, T.width)
					END
				| "K":
					p1:=Par(0);
					IF p1=0 THEN Erase(T, T.cursor.line, T.cursor.col, T.cursor.line, T.width)
					ELSIF p1=1 THEN Erase(T, T.cursor.line, 1, T.cursor.line, T.cursor.col)
					ELSIF p1=2 THEN Erase(T, T.cursor.line, 1, T.cursor.line, T.width)
					END
				| "L": InsertLines(T, Par(1))
				| "M": DeleteLines(T, Par(1))
				| "P": DeleteChars(T, Par(1))
				| "c": IF Par(0)=0 THEN T.send(T, ESC); SendStr(T, "[?1;2c") (* VT100 *) END
				| "g":
					REPEAT p1:=Par(0);
						IF p1=0 THEN T.tabs[T.cursor.col]:=FALSE
						ELSIF p1=3 THEN p1:=1;
							WHILE p1 <= MaxWidth DO T.tabs[p1]:=FALSE; INC(p1) END
						END
					UNTIL pos > T.parPos
				| "h":
					IF ch="?" THEN Next;
						REPEAT p1:=Par(0);
							IF p1=1 THEN INCL(T.flags, cursorKeys)
							ELSIF p1=3 THEN
								Erase(T, 1, 1, Height, T.width);
								SetWidth(T, MaxWidth);
								SetMargins(T, 1, Height);
								SetCursor(T, 1, 1, relative IN T.flags)
							ELSIF p1=6 THEN INCL(T.flags, relative); SetCursor(T, 1, 1, TRUE)
							ELSIF p1=7 THEN INCL(T.flags, autowrap)
							END
						UNTIL pos > T.parPos
					ELSE
						REPEAT p1:=Par(0);
							IF p1=4 THEN INCL(T.flags, insert)
							ELSIF p1=20 THEN INCL(T.flags, lineFeed)
							END
						UNTIL pos > T.parPos
					END
				| "l":
					IF ch="?" THEN Next;
						REPEAT p1:=Par(0);
							IF p1=1 THEN EXCL(T.flags, cursorKeys)
							ELSIF p1=2 THEN EXCL(T.flags, ansi)
							ELSIF p1=3 THEN
								Erase(T, 1, 1, Height, T.width);
								SetWidth(T, 80);
								SetMargins(T, 1, Height);
								SetCursor(T, 1, 1, relative IN T.flags)
							ELSIF p1=6 THEN EXCL(T.flags, relative); SetCursor(T, 1, 1, FALSE)
							ELSIF p1=7 THEN EXCL(T.flags, autowrap)
							END
						UNTIL pos > T.parPos
					ELSE
						REPEAT p1:=Par(0);
							IF p1=4 THEN EXCL(T.flags, insert)
							ELSIF p1=20 THEN EXCL(T.flags, lineFeed)
							END
						UNTIL pos > T.parPos
					END
				| "m":
					REPEAT p1:=Par(0);
						IF p1=0 THEN SetAttribute(T, none)
						ELSIF p1=1 THEN SetAttribute(T, bold)
						ELSIF p1=4 THEN SetAttribute(T, underline)
						ELSIF p1=5 THEN SetAttribute(T, blinking)
						ELSIF p1=7 THEN SetAttribute(T, reverse)
						END
					UNTIL pos > T.parPos
				| "n":
					IF ch="?" THEN Next;
						IF Par(0)=15 THEN (* printer status report *) T.send(T, ESC); SendStr(T, "[?13n") END
					ELSE p1:=Par(0);
						IF p1=5 THEN (* terminal status report *) T.send(T, ESC); SendStr(T, "[0n")
						ELSIF p1=6 THEN (* cursor position report *)
							T.send(T, ESC); T.send(T, "[");
							IF relative IN T.flags THEN SendInt(T, T.cursor.line-T.top+1)
							ELSE SendInt(T, T.cursor.line)
							END;
							T.send(T, ";"); SendInt(T, T.cursor.col); T.send(T, "R")
						END
					END
				| "r":
					p1:=Par(0); p2:=Par(0);
					IF (p1=0) & (p2=0) THEN p1:=1; p2:=Height END;
					SetMargins(T, p1, p2);
					SetCursor(T, 1, 1, TRUE)
				|"y":
					p1:=Par(0);
					IF p1=2 THEN p1:=Par(0);
						IF p1=1 THEN Reset(T)
						ELSE T.send(T, ESC); SendStr(T, "[0n")
						END
					END
				| "E" .. "G", "I", "N", "O", "Q" .. "b", "d", "e", "i" .. "k", "o" .. "q", "s" .. "x": (* ignore *)
			END
		END
	END CSISequence;
	PROCEDURE Receive* (T: Terminal; ch: CHAR);
		VAR p: INTEGER;
	BEGIN
		ch:=CHR(ORD(ch) MOD 128);
		IF ch < " " THEN (* interpret control characters immediately *)
			CASE ch OF
				| ENQ: SendStr(T, T.answerback)
				| BS:
					Update(T); SetCursor(T, T.cursor.line, T.cursor.col-1, FALSE);
					IF T.text # NIL THEN DelLast(T) END
				| HT:
					Update(T); p:=T.cursor.col+1;
					WHILE (p <= T.width) & ~T.tabs[p] DO INC(p) END;
					SetCursor(T, T.cursor.line, p, FALSE);
					IF T.text # NIL THEN Texts.Write(T.cache, HT) END
				| LF, VT, FF:
					Update(T);
					IF T.cursor.line=T.bottom THEN Scroll(T, TRUE);
						IF lineFeed IN T.flags THEN SetCursor(T, T.cursor.line, 1, FALSE) END
					ELSIF lineFeed IN T.flags THEN SetCursor(T, T.cursor.line+1, 1, FALSE)
					ELSE SetCursor(T, T.cursor.line+1, T.cursor.col, FALSE)
					END;
					IF T.text # NIL THEN Texts.Write(T.cache, CR) END
				| CR: Update(T); SetCursor(T, T.cursor.line, 1, FALSE)
				| CAN, SUB: (* cancel *) T.state:=0
				| ESC: T.state:=1
				| 0X .. 4X, 6X, 7X, 0EX .. 17X, 19X, 1CX .. 1FX: (* ignore *)
			END
		ELSE (* drive state machine *)
			CASE T.state OF
				| 0: (* normal characters *)
					IF ch=DEL THEN
						IF T.cursor.col > 1 THEN Update(T);
							SetCursor(T, T.cursor.line, T.cursor.col-1, FALSE);
							DeleteChars(T, 1)
						END;
						IF T.text # NIL THEN DelLast(T) END
					ELSE
						IF insert IN T.flags THEN Update(T); InsertChars(T, 1) END;
						Write(T, ch);
						IF T.text # NIL THEN Texts.Write(T.cache, ch) END
					END
				| 1: (* sequence introduction *)
					IF ch="[" THEN T.state:=3; T.parPos:=0
					ELSIF ~(ansi IN T.flags) & (ch="Y") THEN T.state:=4; T.parPos:=0
					ELSIF (" " <= ch) & (ch <= "/") THEN T.state:=2; T.parBuf[0]:=ch; T.parPos:=1
					ELSIF ("0" <= ch) & (ch <= "~") THEN T.state:=2; T.parPos:=0; Update(T); ESCSequence(T, ch); T.state:=0
					ELSE (* error *) T.state:=0
					END
				| 2: (* ESC sequence *)
					IF ("0" <= ch) & (ch <= "~") THEN Update(T); ESCSequence(T, ch); T.state:=0
					ELSIF T.parPos < LEN(T.parBuf) THEN T.parBuf[T.parPos]:=ch; INC(T.parPos)
					ELSE (* error *) T.state:=0
					END
				| 3: (* CSI sequence *)
					IF ("@" <= ch) & (ch <= "~") THEN Update(T); CSISequence(T, ch); T.state:=0
					ELSIF T.parPos < LEN(T.parBuf) THEN T.parBuf[T.parPos]:=ch; INC(T.parPos)
					ELSE (* error *) T.state:=0
					END
				| 4: (* VT52 ESC Y sequence *)
					IF T.parPos=0 THEN T.parBuf[0]:=ch; T.parPos:=1
					ELSE Update(T); SetCursor(T, ORD(T.parBuf[0])-31, ORD(ch)-31, FALSE); T.state:=0
					END
			END
		END
	END Receive;
	PROCEDURE Send* (T: Terminal; ch: CHAR);
	BEGIN
		IF T.text # NIL THEN T.pin:=T.text.len END;
		IF ch <= DEL THEN (* normal ASCII *) T.send(T, ch);
			IF (ch=CR) & (lineFeed IN T.flags) THEN T.send(T, LF) END
		ELSIF (ch=BRK) OR (ch=0ADX) THEN T.break(T)
		ELSIF (ch=0AEX) OR (ch=0AFX) THEN SendStr(T, T.answerback)
		ELSIF (0C1X <= ch) & (ch <= 0C4X) THEN (* cursor keys *) T.send(T, ESC);
			IF ansi IN T.flags THEN
				IF cursorKeys IN T.flags THEN T.send(T, "O") ELSE T.send(T, "[") END
			END;
			T.send(T, CHR(ORD(ch)-128))
		ELSIF ch=80X THEN T.send(T, "A")
		ELSIF ch=81X THEN T.send(T, "O")
		ELSIF ch=82X THEN T.send(T, "U")
		ELSIF ch=83X THEN T.send(T, "a")
		ELSIF ch=84X THEN T.send(T, "o")
		ELSIF ch=85X THEN T.send(T, "u")
		ELSIF ch=9FX THEN T.send(T, " ")
		END
	END Send;
	PROCEDURE SendString* (T: Terminal; VAR s: ARRAY OF CHAR);
		VAR i: INTEGER;
	BEGIN i:=0;
		WHILE s[i] # 0X DO Send(T, s[i]); INC(i) END
	END SendString;
	PROCEDURE SendText* (T: Terminal; text: Texts.Text; beg, end: LONGINT);
		VAR R: Texts.Reader; ch: CHAR;
	BEGIN Texts.OpenReader(R, text, beg);
		WHILE Texts.Pos(R) < end DO Texts.Read(R, ch); Send(T, ch) END
	END SendText;
	PROCEDURE Open* (T: Terminal; text: Texts.Text; send: Sender; break: Breaker; notify: Notifier);
		VAR l: Line; i: INTEGER;
	BEGIN
		T.width:=80; T.top:=1; T.bottom:=Height; T.cursor.line:=1; T.cursor.col:=1;
		T.attr:=none; T.wrapBefore:=FALSE; T.notify:=notify;
		i:=Height;
		REPEAT NEW(l); T.line[i]:=l ; DEC(i) UNTIL i=0;
		Reset(T); T.text:=text; Texts.OpenWriter(T.cache); T.pin:=0;
		T.send:=send; T.break:=break
	END Open;
END Terminals.