COMMENT ⊗   VALID 00004 PAGES
C REC  PAGE   DESCRIPTION
C00001 00001
C00002 00002	{$NOMAIN	Editor: Expression editor and related routines }
C00024 00003	{ Externally defined routines from elsewhere: }
C00026 00004	(* expression/line editor: exprEditor *)
C00041 ENDMK
C⊗;
{$NOMAIN	Editor: Expression editor and related routines }

const

	(* Constants from EDIT *)
      	maxLines = 28;		(* smaller on the 11 than on the 10 *)
      	maxPPLines = 18;
      	maxBpts = 25;
      	maxTBpts = 20;	(* max could be exceeded by huge case stmnt *)
	listinglength = 2000;	(* Length of Listingarray *)

(* Random type declarations for OMSI/SAIL compatibility *)

type

  byte = 0..255;	(* doesn't really belong here, but... *)
  ascii = char; 
  atext = text;

{ Define all the pointer types here }

strngp = ↑strng;
statementp = ↑statement;
varidefp = ↑varidef;
nodep = ↑node;
identp = ↑ident;
tokenp = ↑token;
reswordp = ↑resword;
pdbp = ↑pdb;
envheaderp = ↑envheader;
enventryp = ↑enventry;
environp = ↑environment;
cmoncbp = ↑cmoncb;
linerecp = ↑linerec;
cursorpp = ↑cursorp;	{Ron's style, not mine}

(* This one is used whenever a pointer is needed for which the 	*)
(* definition is missing from this file; naturally, all 	*)
(* pointers use the same space 					*)

dump = ↑integer;

(* datatype definitions *)

datatypes = (pconstype, varitype, svaltype, vectype, rottype, transtype,
	     frametype, eventtype, strngtype, labeltype, proctype, arraytype,
	     reftype, valtype, cmontype, nulltype, undeftype,
	     dimensiontype, mactype, macargtype, freevartype);

scalar = real;

cstring = packed array [1..10] of ascii;
c4str = packed array [1..4] of ascii;
c5str = packed array [1..5] of ascii;
c20str = packed array [1..20] of ascii;
linestr = packed array [1..130] of ascii;

strng = record
	  next: strngp;
	  ch: cstring;
	end;


(* statement definitions *)

stmntypes = (progtype, blocktype, coblocktype, endtype, coendtype,
		fortype, iftype, whiletype, untiltype, casetype,
		calltype, returntype,
		printtype, prompttype, pausetype, aborttype, assigntype,
		signaltype, waittype, enabletype, disabletype, cmtype,
		affixtype, unfixtype,
		movetype, operatetype, opentype, closetype, centertype,
		stoptype, retrytype,
		requiretype, definetype, macrotype, commenttype, dimdeftype,
		setbasetype, wristtype, tovaltype, declaretype, emptytype);
		(* more??? *)

statement = packed record
		next, last: statementp; (* ↑ to lexical tokens? *)
		stlab: varidefp;
		exprs: nodep;	(* any expressions used by this statement *)
		nlines: integer;
		bpt: boolean;
		case stype: stmntypes of

    progtype:	    (pcode: statementp; errors: integer);
    blocktype,
    declaretype,
    endtype,
    coendtype:	    (bcode, bparent: statementp; blkid: identp;
			level, numvars: 0..255; variables: varidefp);
    coblocktype:    (threads: nodep; nthreads: integer; cblkid: identp);
    fortype:	    (forvar, initial, step, final: nodep; fbody: statementp);
    casetype:	    (index: nodep; range, ncases: integer; caselist: nodep);
    untiltype:	    (cond: nodep; body: statementp);
    iftype:	    (icond: nodep; thn, els: statementp);
    aborttype:	    (plist: nodep; debugLev: integer);
    cmtype:	    (oncond: nodep; conclusion: statementp;
			deferCm, exprCm: boolean; cdef: varidefp);
		end;

(* auxiliary definitions: variable, etc. *)

varidef = packed record
	    next,dnext: varidefp;
	    name: identp;
	    level: 0..255;	(* environment level *)
	    offset: 0..255;	(* environment offset *)
	    dtype: varidefp;	(* to hold the dimension info *)
	    tbits: 0..15;  (* special type bits: array = 1, proc = 2, ref = 4 & ? *)
	    dbits: 0..15;	(* for use by debugger/interpreter *)
	    case vtype: datatypes of
  arraytype:  (a: nodep);
  proctype:   (p: nodep);
  labeltype,
  cmontype:   (s: statementp);
  mactype:    (mdef: statementp);
  macargtype: (marg: tokenp);
  pconstype:  (c: nodep);
  dimensiontype: (dim: nodep);
	  end;

(* definition of the ubiquitous NODE record *)

nodetypes = (exprnode, leafnode, listnode, clistnode, colistnode, forvalnode,
		deprnode, viaptnode, apprnode, destnode, durnode,
		sfacnode, wobblenode, swtnode, nullingnode, wristnode, cwnode,
		arrivalnode, departingnode,
		ffnode, forcenode, stiffnode, gathernode, cmonnode, errornode,
		calcnode, arraydefnode, bnddefnode, bndvalnode,
		waitlistnode, procdefnode, tlistnode, dimnode, commentnode);

exprtypes =  (	svalop,					(* scalar operators *)
		sltop, sleop, seqop, sgeop, sgtop, sneop,	(* relations *)
		notop, orop, xorop, andop, eqvop,		(* logical *)
		saddop, ssubop, smulop, sdivop, snegop, sabsop, (* scalar ops *)
		sexpop, maxop, minop, intop, idivop, modop,
		sqrtop, logop, expop, timeop,			(* functions *)
		sinop, cosop, tanop, asinop, acosop, atan2op,	(* trig *)
		vdotop, vmagnop, tmagnop,
		vecop,					(* vector operators *)
		vmakeop, unitvop, vaddop, vsubop, crossvop, vnegop,
		svmulop, vsmulop, vsdivop, tvmulop, wrtop,
		tposop, taxisop,
		transop,				(* trans operators *)
		tmakeop, torientop, ttmulop, tvaddop, tvsubop, tinvrtop,
		vsaxwrop, constrop, ftofop, deproachop, fmakeop, vmkfrcop,
		ioop,					(* i/o operators *)
		queryop, inscalarop,
		specop,					(* special operators *)
		arefop, callop, grinchop, macroop, vmop, adcop, dacop,
		badop,
		addop, subop, negop, mulop, divop, absop); (* for parsing *)

leaftypes = pconstype..strngtype;

reltypes = sltop..sgtop;
forcetypes = (force,absforce,torque,abstorque,angvelocity);

node = record
	next: nodep;
	case ntype: nodetypes of
    exprnode:	(op: exprtypes; arg1, arg2, arg3: nodep; elength: integer);
    leafnode:	(case ltype: leaftypes of
	varitype:  (vari: varidefp; vid: identp);
	pconstype: (cname: varidefp; pcval: nodep);
	svaltype:  (s: scalar; wid: integer);
	vectype:   (v: dump);
	transtype: (t: dump);
	strngtype: (length: integer; str: strngp) ); (* also used by commentnodes *)
    listnode:	(lval: nodep);
    clistnode:	(cval: integer; stmnt: statementp; clast: nodep);
    colistnode:	(prev: nodep; cstmnt: statementp);
    errornode:	(eexpr: nodep);
    calcnode: 	(rigid, frame1: boolean; other: dump; case tvarp: boolean of 
		    false: (tval: dump); true: (tvar: enventryp) );
    arraydefnode: (numdims: 1..10; bounds: nodep; combnds: boolean);
    bnddefnode:	(lower, upper: nodep);
    bndvalnode:	(lb, ub, mult: integer);
    waitlistnode: (who: pdbp; when: integer);
    procdefnode:(ptype: datatypes; level: 0..255;
		    pname, paramlist: varidefp; body: statementp);
    tlistnode:	(tok: tokenp);
    dimnode:	(time, distance, angle, dforce: integer);
	end;

(* records for parser: ident, token, resword *)

ident = record
	    next: identp;
	    length: integer;
	    name: strngp;
	    predefined: varidefp;
	  end;


tokentypes = (reswdtype, identtype, constype, comnttype, delimtype, labeldeftype,
		macpartype);

constypes = svaltype..strngtype;

reswdtypes = (stmnttype, filtype, clsetype, decltype, optype, edittype);

filtypes = (abouttype,alongtype,attype,bytype,defertype,dotype,elsetype,
		errmodestype,fromtype,handtype,intype,nonrigidlytype,rigidlytype,
		sourcefiletype,steptype,thentype,totype,untltype,viatype,
		withtype,worldtype,zeroedtype,oftype,wheretype,nowaittype,
		ontype,offtype,ppsizetype,collecttype,alltype,lextype);

clsetypes = (approachtype,arrivaltype,departuretype,departingtype,durationtype,
		errortype,forcetype,forceframetype,forcewristtype,gathertype,
		nildeproachtype,nonullingtype,nullingtype,stiffnesstype,
		torquetype,velocitytype,wobbletype,
		cwtype,ccwtype,stopwaittimetype,angularvelocitytype,
		fxtype,fytype,fztype,mxtype,mytype,mztype,
		t1type,t2type,t3type,t4type,t5type,t6type,tbltype);

edittypes = (getcmd,savecmd,insertcmd,renamecmd,startcmd,gocmd,proceedcmd,
		stepcmd,sstepcmd,nstepcmd,gstepcmd,executecmd,setcmd,tracecmd,
		breakcmd,unbreakcmd,tbreakcmd,definecmd,markcmd,unmarkcmd,
		popcmd);

token = record
	  next: tokenp;
	  case ttype: tokentypes of
constype:   (cons: nodep);
comnttype:  (len: integer; str: strngp);
delimtype:  (ch: ascii);
reswdtype:  (case rtype: reswdtypes of
	stmnttype: (stmnt: stmntypes);
	filtype:   (filler: filtypes);
	clsetype:  (clause: clsetypes);
	decltype:  (decl: datatypes);
	optype:	   (op: exprtypes);
	edittype:  (ed: edittypes) );
identtype:  (id: identp);
labeldeftype: (lab: varidefp);
macpartype: (mpar: varidefp);
	end;


resword = record
	  next: reswordp;
	  length: integer;
	  name: strngp;
	  case rtype: reswdtypes of
	stmnttype:  (stmnt: stmntypes);
	filtype:    (filler: filtypes);
	clsetype:   (clause: clsetypes);
	decltype:   (decl: datatypes);
	optype:	    (op: exprtypes);
	edittype:  (ed: edittypes);
	  end;

(* process descriptor blocks & environment record definitions *)

queuetypes = (nullqueue,nowrunning,runqueue,inputqueue,eventqueue,sleepqueue,
		forcewait,devicewait,joinwait,proccall);

pdb = packed record
	nextpdb,next: pdbp;	(* for list of all/active pdb's *)
	level: 0..255;		(* lexical level *)
	mode: 0..255;		(* expression/statement/sub-statement *)
	priority: 0..255;
	status: queuetypes;	(* what are we doing *)
	env: envheaderp;
	spc: statementp;	(* current statement *)
	epc: nodep;		(* current expression (if any) *)
	sp: nodep;		(* intermediate value stack *)
	cm: cmoncbp;		(* if we're a cmon point to our definition *)
	mech: dump;		(* current device being used *)
	linenum: integer;	(* used by editor/debugger *)
	 case procp: boolean of	(* true if we're a procedure *)
true:  (opdb: pdbp;		(* pdb to restore when procedure exits *)
	pdef: nodep);		(* procedure definition node *)
false: (evt: dump;		(* event to signal when process goes away *)
	sdef: statementp);	(* first statement where process was defined *)
      end;


envheader = packed record
	      parent: envheaderp;
	      env: array [0..4] of environp;
	      varcnt: 0..255;		(* # of variables in use ??? *)
		case procp: boolean of  (* true if we're a procedure *)
	true: (proc: nodep);
	false:(block: statementp);
	    end;


enventry = record
	    case etype: datatypes of
  svaltype:  (s: scalar);
  vectype:   (v: dump);
  transtype: (t: dump);
  frametype: (f: dump);
  eventtype: (evt: dump);
  strngtype: (length: integer; str: strngp);
  cmontype:  (c: cmoncbp);
  proctype:  (p: nodep; penv: envheaderp);
  reftype:   (r: enventryp);
  arraytype: (a: envheaderp; bnds: nodep);
	   end;


environment = record
		next: environp;
		vals: array [0..9] of enventryp;
	      end;


cmoncb = record
	   running, enabled: boolean;		(* cmon's status *)
	   cmon: statementp;
	   pdb: pdbp;
	   evt: dump;
	   fbits: integer;			(* bits for force sensing *)
	   oldcmon: cmoncbp;			(* for debugger *)
	 end;

(* print related records: *)

cursorp = record
	  cline,ind: integer;
	  case stmntp: boolean of
  true:    (st: statementp);
  false:   (nd: nodep);
	 end;

linerec = record
	next: linerecp;
	start,length: integer
       end;

listingarray = packed array [0..listinglength] of ascii;


(* Global variables *)

var 
	(* From ALMAIN *)
    b:boolean;		
    ch:ascii;
    ltime: real;

	(* From PARSE *)
    reswords: array [0..26] of reswordp;
    idents: array [0..26] of identp;
    macrostack: array [1..10] of tokenp;
    curmacstack: array [1..10] of varidefp;
    macrodepth: integer;
    curchar, maxchar, curline: integer;
    curBlock,newDeclarations: statementp;
    curProc: varidefp;
    pnode: nodep;
    nodim, distancedim, timedim, angledim,
      forcedim, torquedim, veldim, angveldim: varidefp;
    fvstiffdim, mvstiffdim: nodep;
(*  filedepth: integer;
    curpage: integer;
    sysVars,unVars: varidefp;
    errcount: integer;
    outerBlock: statementp;
    curVariable: varidefp;
    curMotion: statementp;
    endOk,coendOk: integer;
    moveLevel: integer;
    curErrhandler, curCmon: statementp;	*)
    d1: array[1..13] of dump;
    endOfLine, backup, expandmacros, flushcomments, dimCheck: boolean;
(*  semiseen, shownline: boolean;
    eofError: boolean;
    inMove,inCoblock: boolean;	*)
    d2,d3,d4,d5,d6: boolean;
    curtoken: token;
    file1,file2,file3,file4,file5: atext;
    line: linestr;

	(* From INTERP *)
    curInt, activeInts, readQueue, allPdbs: pdbp;
(*  curEnv, sysEnv: envheaderp;
    clkQueue: nodep;
    allEvents: dump;
    STLevel: integer;		
    etime: integer;		
    curtime: integer; 		
    stime: integer;		
    msg: dump;			
    inputp: integer;		*)
    d10: array[1..10] of integer;
    debugLevel: integer;
    tSingleThreadMode: boolean;
    resched, running, escapeI, singleThreadMode: boolean;
    msgp: boolean;		(* flag set if any messages pending *)
    inputReady: boolean;
    inputLine: array [1..20] of ascii;

	(* From EDIT *)
    lines: array [1..maxLines] of linerecp; 
    ppLines: array [1..maxPPLines] of linerecp;	
    marks: array [1..20] of integer;
    cursorStack: array [1..15] of cursorp;
    bpts: array [1..maxBpts] of statementp;
    tbpts: array [1..maxTBpts] of statementp;
    debugPdbs: array [0..10] of pdbp;
    screenheight,dispHeight: integer;
    ppBufp,oppBufp,ppOffset,ppSize,nmarks: integer;
    lbufp,cursor,ocur,cursorLine,fieldnum,lineNum,findLine,pcLine: integer;
    firstDline,topDline,botDline,firstLine,lastLine: integer;
    freeLines,oldLines: linerecp;
    findStmnt: statementp;
    nbpts,ntbpts: integer;
    eCurInt: pdbp;
    dProg: statementp;	
    smartTerminal: boolean; 
    setUp,setExpr,setCursor,dontPrint,outFilep,newVarOk,collect: boolean;
    backUp: boolean;			
    eSingleThreadMode: boolean;	
    listing: listingarray;
    lbuf: array [1..160] of ascii;
    ppBuf: array [1..100] of ascii;
    outFile: atext;
    curToken: token;			

	(* Various device & variable pointers *)
    speedfactor: enventryp;
    barm: dump;

	(* Various constant pointers *)
    xhat,yhat,zhat,nilvect: dump;
    niltrans: dump;
    bpark, ypark, gpark, rpark: dump;		(* arm park positions *)

{ Externally defined routines from elsewhere: }

	(* From EAUX1A *)
function getAChar: ascii;					external;
procedure out1Line(line,start,length: integer); 		external;
procedure borderLines;						external;

	(* From PP *)
procedure ppLine; 						external;

	(* From DISP *)
procedure beep; 						external;
procedure showCursor(line,col: integer); 			external;
procedure outLine(line,col,start,length: integer); 		external;
function getChar: ascii; 					external;
procedure outChar(line,col: integer; ch: ascii; bold: boolean); external;
procedure insChar(line,col: integer; ch: ascii); 		external;
procedure delChar(line,col: integer); 				external;

(* expression/line editor: exprEditor *)

function exprEditor(line,lstart,llength,estart: integer;
		    var elength: integer; off: integer): ascii; external;
function exprEditor;
 var i,j,iCh,col,elenOld,arg: integer;
     ch,sch: ascii;
     b,done,insertmode,search,right,overflow: boolean;

  function seek(ch: ascii): integer;
   var i,j,colf: integer;
   begin
   seek := 0;			(* assume we don't find it *)
   if ch = chr(15B) then	(* need to treat <cr> specially *)
     if right then seek := estart + elength	(* end of expression *)
      else seek := estart-1			(* start of expression *)
    else if right then		(* see which way to seek *)
     begin			(* seeking for char to right *)
     i := col + 1;
     colf := estart + elength;
     for j := 1 to arg do
      begin
      while (listing[i] <> ch) and (i < colf) do i := i + 1;
      if i < colf then 
       if j < arg then i := i + 1	(* look for another *)
        else seek := i;			(* found it *)
      end
     end
    else
     begin			(* seeking for char to left *)
     i := col - 1;
     for j := 1 to arg do
      begin
      while (listing[i] <> ch) and (estart <= i) do i := i - 1;
      if estart <= i then
       if j < arg then i := i - 1	(* look for another *)
        else seek := i;			(* found it *)
      end
     end
   end;

  procedure dchar;
   var i,j: integer;
   begin
   for i := col + arg to llength do listing[i-arg] := listing[i];
   for i := llength - arg + 1 to llength do listing[i] := ' ';
   if not smartTerminal then
    outLine(line,col,col,llength-col+1)
   else
     begin
     for i := 1 to arg do delChar(line,col);
     if (llength > 80) and (col <= 80) then	(* deal with overflow line *)
       begin
       if col + arg > 81 then j := col else j := 81-arg;
       for i := j to 80 do		(* shift in chars from overflow line *)
	outChar(line,i,listing[i],i<(estart+elength-arg));
       if llength - arg >= 80 then
	 begin				(* shift overflow line to left *)
	 for i := 1 to arg do delChar(line+1,1);
	 end
	else outLine(line+1,1,81,1)	(* clear overflowed line *)
       end
     end;
   elength := elength - arg;		(* update lengths *)
   llength := llength - arg;
   end;

 begin
 search := true;
 right := true;
 sch := chr(0);		(* so ↑R does nothing til after a search/kill is done *)
 if llength < estart + elength - 1 then		(* consistency check *)
   elength := llength - estart + 1;
 elenOld := elength;		(* remember initial expr length *)
 for i := 1 to llength do listing[i] := listing[lstart+i-1]; (* load line *)
 if llength > 80 then
   begin
   outLine(line+1,1,81,llength-80);	(* show overflow *)
   overflow := true;
   end
  else overflow := false;
 if smartTerminal then
  for i := estart to estart+elength-1 do
   outChar(line,i,listing[i],true);	(* print expression in bold *)
 done := false;
 insertmode := (elength = 0) or (off <> 0);
 col := estart + off;
 repeat
  showCursor(line,col);
  repeat ch := getChar until ch <> chr(12B);	(* skip over any <lf>'s *)
  iCh := ord(ch);
  if (iCh = 34B) or (iCh = 33B) then	(* ↑\ or ALT *)
    begin				(* get repeat count *)
    arg := 0;
    ch := getChar;
    while ('0' <= ch) and (ch <= '9') do
     begin
     arg := 10*arg + (ord(ch) - ord('0'));	(* get next digit *)
     ch := getChar;
     end;
    iCh := ord(ch);
    end
   else arg := 1;
  if (iCh <> 30B) and ((iCh < 37B) or (177B = iCh)) then	(* control character *)
    begin
    if iCh = 177B then iCh := 10B;	(* convert rubout to backspace *)
    case iCh of
11B:	insertmode := true;		(* ↑I *)
10B:	begin				(* backspace *)
	if col - arg < estart then arg := col - estart;
	col := col - arg;
	if insertmode  and (arg > 0) then dchar;
	end;
4B:	begin				(* ↑D *)
	if col + arg > estart + elength then arg := estart + elength - col;
	if arg > 0 then dchar;
	end;
1B:	col := col + arg;		(* ↑A *)
5B:	col := estart + elength;	(* ↑E *)
6B:	col := estart;			(* ↑F *)
17B:	begin				(* ↑O *)
	j := llength + elenOld - elength;	(* restore initial line length *)
	if j < llength then			(* fix up end of line if needed *)
	 begin
	 for i := j to llength do listing[i] := ' ';
	 outLine(line,j,j,llength-j+1);		(* clean up the display *)
	 end;
	llength := j;
	elength := elenOld;		(* restore initial expr length *)
	for i := estart to llength do listing[i] := listing[lstart+i-1]; (* reload it *)
	if smartTerminal then		(* redisplay line *)
	  begin
	  for i := estart to estart+elength-1 do
	   outChar(line,i,listing[i],true);	(* print expression in bold *)
	  outLine(line,estart+elength,estart+elength,llength-estart-elength+1);
	  end
	 else outLine(line,estart,estart,llength-estart+1);
	insertmode := false;
	col := estart;
	end;
32B:	begin				(* 32B is ↑Z *)
	col := estart;			(* zero the expression *)
	arg := elength;
	dchar;
	elength := 0;
	end;
22B:	begin				(* ↑R *)
	i := seek(sch);			(* repeat last search/kill command *)
	if i > 0 then			(* if we found another of the char *)
	  if search then col := i	(* skip to it *)
	 else
	  if right then
	    begin
	    arg := i - col;
	    dchar;			(* kill right to char *)
	    end
	   else
	    begin
	    if col = estart + elength then col := col - 1;
	    arg := col - i - 1;
	    col := i+1;
	    dchar;			(* kill left to char *)
	    col := i;
	    end;
	end;
23B:	begin				(* ↑S *)
	search := true;			(* remember for ↑R command *)
	right := true;
	sch := getAChar;		(* skip right to char next typed *)
	i := seek(sch);
	if i > 0 then col := i;		(* skip ahead if we found one *)
	end;
2B:	begin				(* ↑B *)
	search := true;			(* remember for ↑R command *)
	right := false;
	sch := getAChar;		(* skip left to char next typed *)
	i := seek(sch);
	if i > 0 then col := i;		(* skip back if we found one *)
	end;
24B:	if col > estart + 1 then	(* ↑T *)
	 begin
	 ch := listing[col-1];		(* transpose last two chars *)
	 listing[col-1] := listing[col-2];
	 listing[col-2] := ch;
	 if smartTermingl then
	   begin
	   outChar(line,col-2,ch,true);	(* and update display *)
	   outChar(line,col-1,listing[col-1],true);
	   end
	  else outLine(line,col-2,col-2,llength-col+1);
	 end;
13B:	begin				(* ↑K <vt> *)
	search := false;		(* remember for ↑R command *)
	right := true;
	sch := getAChar;		(* try to find char *)
	i := seek(sch);
	if i > 0 then 
	 begin
	 arg := i - col;
	 dchar;				(* kill right to char *)
	 end
	end;
14B:	begin				(* ↑L <ff> *)
	search := false;		(* remember for ↑R command *)
	right := false;
	sch := getAChar;		(* try to find char *)
	i := seek(sch);
	if i > 0 then 
	 begin
(*	 if col = estart + elength then col := col - 1; *)
	 arg := col - i - 1;
	 col := i+1;
	 dchar;				(* kill left to char *)
	 col := i;
	 end
	end;
otherwise done := true;
     end;
    if (iCh <> 10B) and (iCh <> 11B) then insertmode := false;
    end
   else
    begin		(* ordinary character to insert *)
    if insertmode then
      begin
      for j := llength downto col do listing[j+1] := listing[j];
      listing[col] := ch;		(* now insert the new character *)
      elength := elength + 1;		(* update lengths *)
      llength := llength + 1;
      if llength > 80 then
	begin
	if smartTerminal and not overflow then	(* just overflowed *)
	  begin
	  listing[82] := ' ';
	  outLine(line+1,1,82,1);		(* zero line *)
	  end;
	overflow := true;			(* indicate we've overflowed *)
	end;
      if llength > 140 then
	begin			(* No more room in line buffer!!! *)
	beep;
	if llength > 149 then
	  begin
	  llength := llength - 1;
	  elength := elength - 1;
	  if col = 150 then col := 149;
	  end;
	end;
      if smartTerminal then
	begin
	insChar(line,col,ch);
	if (llength > 80) and (col <= 80) then
	  begin
	  insChar(line+1,1,listing[81]);
	  if estart+elength <= 81 then outChar(line+1,1,listing[81],false);
	  end;
	end
       else outLine(line,col,col,llength-col+1);
      end
     else
      begin
      listing[col] := ch;		(* overwrite whatever was there *)
      if smartTerminal then outChar(line,col,ch,true)
       else outLine(line,col,col,llength-col+1);
      end;
    col := col + 1;
    end;
  if col < estart then col := estart;		(* don't go before expression *)
  if col >= estart + elength then		(* at end of expression? *)
    begin
    col := estart + elength;		(* don't let it get past either end *)
    insertmode := true;
    end;
 until done;
 if overflow then
  begin					(* restore clobbered line *)
  if (line + 1 > dispHeight) or (line = dprog↑.nlines) then borderLines
   else
    with lines[firstDline+line]↑ do
     out1Line(line+1,start,length);
  end;
 if llength < 150 then listing[llength+1] := ' ';	(* for getToken *)
 i := estart;
 curChar := estart;		(* set up for parsing the expression *)
 maxChar := estart + elength - 1;
 endOfLine := false;
 backUp := false;
 expandMacros := true;
 iCh := ord(ch);
 if iCh < 40B then
   if iCh <> 15B then iCh := iCh + 100B;	(* convert back to ascii *)
 exprEditor := chr(iCh);			(* activating character *)
 end;