perm filename EEXPED.2[EAL,HE] blob
sn#708934 filedate 1983-05-01 generic text, type C, neo UTF8
COMMENT ⊗ VALID 00004 PAGES
C REC PAGE DESCRIPTION
C00001 00001
C00002 00002 {$NOMAIN Editor: Expression editor and related routines }
C00031 00003 { Externally defined routines from elsewhere: }
C00033 00004 (* expression/line editor: exprEditor *)
C00048 ENDMK
C⊗;
{$NOMAIN Editor: Expression editor and related routines }
(* definition of record types & global variables used by AL *)
const
maxLines = 28;
maxPPLines = 18;
maxBpts = 25;
maxTBpts = 20; (* max could be exceeded by huge case stmnt *)
listinglength = 2000; (* Length of Listingarray *)
type
(* random type declarations for OMSI/SAIL compatibility *)
ascii = char;
atext = text;
byte = 0..255;
(* Here are all the pointer-type definitions. Since the various *)
(* records reference each other so much, we have to put them all here. *)
vectorp = ↑vector;
transp = ↑trans;
strngp = ↑strng;
eventp = ↑event;
framep = ↑frame;
statementp = ↑statement;
varidefp = ↑varidef;
nodep = ↑node;
identp = ↑ident;
tokenp = ↑token;
reswordp = ↑resword;
pdbp = ↑pdb;
envheaderp = ↑envheader;
enventryp = ↑enventry;
environp = ↑environment;
cmoncbp = ↑cmoncb;
messagep = ↑message;
linerecp = ↑linerec;
(* 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;
vector = record refcnt: integer; val: array [1..3] of real end;
trans = record refcnt: integer; val: array [1..3,1..4] of real end;
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;
event = record
next: eventp; (* all events are on one big list *)
count: integer;
waitlist: pdbp;
end;
frame = record
vari: varidefp; (* back pointer to variable name & info *)
calcs: nodep; (* affixment info *)
case ftype: boolean of (* frame = true, device = false *)
true: (valid: integer; val, fdepr: transp; dcntr: integer; dev: framep);
false: (mech: integer; case sdev: boolean of
true: (sdest: real); false: (tdest,appr,depr: transp));
(* sdev = true for scalar devices, false for frames *)
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,jtmovetype,operatetype,opentype,closetype,centertype,
floattype, stoptype, retrytype,
requiretype, definetype, macrotype, commenttype, dimdeftype,
setbasetype, wristtype, saytype, declaretype, emptytype,
evaltype, armmagictype);
(* more??? *)
statement = packed record
next, last: statementp;
stlab: varidefp;
exprs: nodep; (* any expressions used by this statement *)
nlines: integer;
bpt,bad: 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);
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, byptnode, durnode,
sfacnode, wobblenode, swtnode, nullingnode, wristnode, cwnode,
arrivalnode, departingnode,
ffnode, forcenode, stiffnode, gathernode, cmonnode, errornode,
calcnode, arraydefnode, bnddefnode, bndvalnode,
waitlistnode, procdefnode, tlistnode, dimnode, commentnode,
linearnode, elbownode, shouldernode, flipnode, wrtnode,
loadnode,velocitynode);
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, jointop,
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: vectorp);
transtype: (t: transp);
strngtype: (length: integer; str: strngp) ); (* also used by commentnodes *)
listnode: (lval: nodep);
clistnode: (cval: integer; stmnt: statementp; clast: nodep);
colistnode: (prev: nodep; cstmnt: statementp);
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,
notype,righttype,lefttype,uptype,downtype,motiontype);
clsetypes = (approachtype,arrivaltype,departuretype,departingtype,durationtype,
errortype,forcetype,forceframetype,forcewristtype,gathertype,
nildeproachtype,nullingtype,stiffnesstype,
torquetype,velocitytype,wobbletype,
cwtype,ccwtype,stopwaittimetype,angularvelocitytype,
respecttype,elbowtype,shouldertype,fliptype,lineartype,
jointspacetype,loadtype);
edittypes = (getcmd,savecmd,insertcmd,renamecmd,startcmd,gocmd,proceedcmd,
stepcmd,sstepcmd,nstepcmd,gstepcmd,executecmd,setcmd,tracecmd,
breakcmd,unbreakcmd,tbreakcmd,definecmd,markcmd,unmarkcmd,
popcmd,atcmd,calibratecmd);
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; (* probably never greater than 3? *)
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: framep; (* 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: eventp; (* 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: vectorp);
transtype: (t: transp);
frametype: (f: framep);
eventtype: (evt: eventp);
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: eventp;
fbits: integer; (* bits for force sensing *)
oldcmon: cmoncbp; (* for debugger *)
end;
(* definition of AL-ARM messages *)
msgtypes = (initarmscmd,calibcmd,killarmscmd,wherecmd,
abortcmd,stopcmd,movehdrcmd,movesegcmd,
centercmd,operatecmd,movedonecmd,signalcmd,
setccmd,forcesigcmd,forceoffcmd,biasoncmd,biasoffcmd,setstiffcmd,
zerowristcmd,wristcmd,gathercmd,getgathercmd,readadccmd,writedaccmd,
errorcmd,floatcmd,setloadcmd,
armmagiccmd,realcmd,vectorcmd,transcmd);
errortypes = (noerror,noarmsol,timerr,durerr,toolong,featna,
unkmess,srvdead,adcdead,nozind,exjtfc,paslim,nopower,badpot,devbusy,
baddev,timout,panicb,nocart,cbound,badparm);
message = record
cmd: msgtypes;
ok: boolean;
case integer of
1: (dev, bits, n: integer;
(* (dev, bits, n, evt: integer; (* for arm code version *)
evt: eventp;
dur: real;
case integer of
1: (v1,v2,v3: real);
2: (sfac,wobble,pos: real);
3: (val,angle,mag: real);
4: (max,min: real);
5: (error: errortypes));
2: (fv1,fv2,fv3,mv1,mv2,mv3: real); (* may never use these... *)
3: (t: array [1..6] of real);
end;
interr = record
case integer of
0: (i: integer);
1: (err,foo: errortypes);
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 EDIT *)
listing: listingarray; (* first 150 chars are used by expression editor *)
(* next 40 by header & trailer lines *)
{*} cursorStack: array [1..15] of cursorp; {These are BIG records! }
lbuf: array [1..160] of ascii;
ppBuf: array [1..100] of ascii;
lines: array [1..maxLines] of linerecp; (* what's on the screen + some *)
ppLines: array [1..maxPPLines] of linerecp; (* for page printer *)
marks: array [1..20] of integer;
reswords: array [0..26] of reswordp;
idents: array [0..26] of identp;
macrostack: array [1..10] of tokenp;
curmacstack: array [1..10] of varidefp;
screenheight,dispHeight: integer;
ppBufp,oppBufp,ppOffset,ppSize,nmarks: integer;
lbufp,cursor,ocur,cursorLine,fieldnum,lineNum,findLine,pcLine: integer;
firstDline,topDline,botDline,firstLine,lastLine,curLine: integer;
freeLines,oldLines: linerecp;
sysVars: varidefp;
dProg: statementp;
curBlock, newDeclarations, findStmnt: statementp;
macrodepth: integer;
filedepth, errCount, sCursor: integer;
curChar, maxChar, curFLine, curPage: integer;
nodim, distancedim, timedim, angledim,
forcedim, torquedim, veldim, angveldim: varidefp;
fvstiffdim, mvstiffdim: nodep;
pnode: nodep;
smartTerminal: boolean; (* true = insert/delete, false = redraw line *)
setUp,setExpr,setCursor,dontPrint,outFilep,collect,fParse,sParse,
eofError,endOfLine,backup,expandmacros,flushcomments,checkDims,
shownLine: boolean;
curtoken: token;
file1,file2,file3,file4,file5,outFile: atext;
bpts: array [1..maxBpts] of statementp; (* debugging crap *)
tbpts: array [1..maxTBpts] of statementp;
debugPdbs: array [0..10] of pdbp;
nbpts,ntbpts,debugLevel: integer;
eCurInt: pdbp;
STLevel: integer; (* set by GO *)
singleThreadMode,tSingleThreadMode: boolean;
(* from INTERP *)
inputLine: array [1..20] of ascii;
talk: text; (* for using the speech synthesizer *)
curInt, activeInts, readQueue, allPdbs: pdbp;
sysEnv: envheaderp;
clkQueue: nodep;
allEvents: eventp;
etime: integer; (* used by eval *)
curtime: integer; (* who knows where this will get updated - an ast? *)
stime: integer; (* used for clock queue on 10 *)
msg: messagep; (* for AL-ARM interaction *)
inputp: integer; (* current offset into inputLine array above *)
resched, running, escapeI, iSingleThreadMode: boolean;
msgp: boolean; (* flag set if any messages pending *)
inputReady: boolean;
(* various constant pointers *)
xhat,yhat,zhat,nilvect: vectorp;
niltrans: transp;
gpark, rpark: transp; (* arm park positions *)
(* various device & variable pointers *)
speedfactor: enventryp;
garm: framep;
{ 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 smartTerminal 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;