10 REM SCREEN EDITOR BY M W BENNETT UPDATED 26.04.81 VERSION 04.39
   20 DEG : NOESC : IMODE : X=1.1 : IF X<>1 THEN RUN
   30 DIM A$(1918),B$(0),B1$(1),C$(0),D$(0),E$(1),E5$(2),F$(13),F1$(13)
   40 DIM G$(77),H$(2),I$(1918),J$(0),K$(0),M$(0),N$(0),R$(0),S$(0),T$(0),U$(17),Z$(77)
   50 INTEGER A1,A,B,B1,E,E1,F,F(9),H,I,L,L1,N,O,P,R,S,S1,V,V1,X,X1,Y,Y1,Z,Z1
   60 SHORT G,G1,G2,G3,G4,G5,D,M1,M2,M(9,2)
   70 MAT M=1
   80 MAT F=0
   90 H=1
  100 V=24
  110 SET 0,-1
  120 OPEN\1\"$SY"
  130 B$=CHR$(8)
  140 D$=CHR$(30)
  150 E$=CHR$(13)+CHR$(10)
  160 E5$=CHR$(27)+"="
  170 H$=CHR$(11)+CHR$(7)+CHR$(11)
  180 J$=" "
  190 K$=CHR$(10)
  200 M$=CHR$(11)
  210 N$=CHR$(12)
  220 R$=CHR$(13)
  230 S$=" "
  240 T$=CHR$(26)
  250 U$=" Computer working "
  260 REM.
  270 @\1\T$;
  280 @"BENNETT Screen Editor version 04.39"
  290 @"Screen allows you to create and alter upto 10 pages of text."
  300 @
  310 INPUT"What is the filename to be edited (including extension TXT) ? ",F$
  320 L=LEN(F$)
  330 IF F$(L-3)<>"TXT"THEN@H$; : GOTO 300
  340 REM.
  350 ON ERROR GOTO 380
  360 CREATE F$
  370 F=1
  380 OPEN\2,1920\F$ : ON ERROR GOTO 420
  390 GET\2,0\A$(-1)
  400 F(0)=1
  410 GOTO 470
  420 @"File ";F$;" not found. Create anyway (Y/N) ? ";
  430 GOSUB 8430
  440 IF A<>89 AND A<>121 THEN ERASE F$ : GOTO 300
  450 @E$;"Creating file ";F$;" on drive ";IOSTAT(0,0)
  460 A$(-1)=S$+A$(-1)
  470 P=0
  480 F1$=F$
  490 F1$(L-3)="BAK"
  500 ON ERROR GOTO 530
  510 CLOSE\2\
  520 ERASE F1$
  530 RENAME F$,F1$
  540 CREATE F$
  550 OPEN\2,1920\F1$
  560 OPEN\3,1920\F$
  570 ON ERROR GOTO 8490
  580 GOTO 8450
  590 REM.
  600 @\1\T$;
  610 @A$;
  620 @E5$;CHR$(56-V);CHR$(H+31);
  630 GOSUB 8430
  640 REM.
  650 IF A<>95 THEN 680
  660 H=H-1 : IF H<1 THEN H=1
  670 Z=(24-V)*80+H-1 : A$(Z,Z)=S$ : @B$;S$;B$; : GOTO 630
  680 IF H<1 THEN H=1
  690 IF V>24 THEN V=24
  700 IF H<>79 THEN 720
  710 IF A>31 OR A=12 OR A=21 OR A=22 OR A=23 OR A=29 THEN 630
  720 IF V<>1 THEN 740
  730 IF A=10 OR A=13 OR A=15 OR A=22 THEN 630
  740 IF A=23 OR A=16 THEN 780
  750 IF A>31 THEN@C$; : Z=(24-V)*80+H-1 : A$(Z,Z)=C$ : H=H+1 : GOTO 630
  760 REM.
  770 ON A+1 GOTO 800,600,1020,1950,2110,4940,5240,5420,5540,5560,7090,7100,7110,7120,630,7140
  780 ON A-15 GOTO 7190,7270,7290,7390,7460,7690,7760,7770,7800,7840,7970,8070,7940,8110,8140
  790 REM.
  800 @\1\T$;
  810 @"List of all Editor commands :" : @ : @
  820 @"@   Print list of Editor commands      P   Output Page to printer"
  830 @"A   Retype current page                Q   Cursor to Horizontal centre"
  840 @"B   Supplementary text commands        R   Renter character"
  850 @"C   Change one string to another       S   Specify character"
  860 @"D   Delete / Insert / Move Screen      T   Set markers (0-9)"
  870 @"E   Exit Screen to Basic               U   Draw Upwards"
  880 @"F   File input / output                V   Draw Verically downwards"
  890 @"G   Grid screen                        W   Draw left"
  900 @"H   Move cursor left                   X   Up tab cursor"
  910 @"I   Invert parts of screen             Y   Yank page from file"
  920 @"J   Move cursor down                   Z   Zap character"
  930 @"K   Move cursor up                     [   Back tab cursor"
  940 @"L   Move cursor right                  \   Cursor to Vertical centre"
  950 @"M   Return and line feed               ]   Forward tab cursor"
  960 @"N   ***  H  E  L  P  ***               ^   Home cursor"
  970 @"O   Down tab cursor";D$;
  980 GOSUB 8430
  990 IF A>31 THEN 600
 1000 GOTO 650
 1010 REM.
 1020 @\1\T$;
 1030 @"Auxiliary text commands"
 1040 @TAB(4);"Press :"
 1050 @TAB(11);"C";SPC(4);"Centre text on current line"
 1060 @TAB(11);"D";SPC(4);"Display marker positions"
 1070 @TAB(11);"G";SPC(4);"Goto marker"
 1080 @TAB(11);"L";SPC(4);"Line between two markers"
 1090 @TAB(11);"M";SPC(4);"Marker positions on screen"
 1100 @TAB(11);"P";SPC(4);"Position of cursor"
 1110 GOSUB 8390
 1120 IF A<1 OR A>26 THEN 600
 1130 ON A GOTO 600,600,1150,1330,600,600,1430,600,600,600,600,1530
 1140 ON A-12 GOTO 1810,600,600,1890,600,600,600,600,600,600,600,600,600,600
 1150 S=(24-V)*80
 1160 E=S+77
 1170 G$(-1)=S$+G$(-1)
 1180  FOR X=S TO E
 1190  A=ASC(A$(X,X))
 1200  IF A<>32 THEN S1=X : GOTO 1230
 1210  NEXT X
 1220 REM.
 1230  FOR X=E TO S STEP-1
 1240  A=ASC(A$(X,X))
 1250  IF A<>32 THEN E1=X : GOTO 1270
 1260  NEXT X
 1270 X=E1-S1
 1280 B=38-(X+1)/2
 1290 G$(B,B+X)=A$(S1,E1)
 1300 A$(S,E)=G$
 1310 GOTO 600
 1320 REM.
 1330 @\1\T$;
 1340 @"Marker positions :"
 1350 @ : @ : @"Marker Number","X coord","Y coord"
 1360  FOR L=0 TO 9
 1370  @L,M(L,1),M(L,2)
 1380  NEXT L
 1390 @ : @ : @"Press any key to return to screen ";
 1400 GET\1\C$
 1410 GOTO 600
 1420 REM.
 1430 @\1\T$;
 1440 @"Goto marker"
 1450 @ : @ : @"Enter marker number [0] (0-9) ? ";
 1460 GOSUB 8430
 1470 A=ASC(C$)-48
 1480 IF A<0 OR A>9 THEN@R$;H$;H$ : GOTO 1450
 1490 @\1\T$;
 1500 @A$;E5$;CHR$(56-M(A,2));CHR$(M(A,1)+31);
 1510 GOTO 630
 1520 REM.
 1530 @\1\T$;
 1540 @"Draw a line between markers"
 1550 @ : @ : INPUT"Enter marker1 , marker2 (0-9),(0-9) ",M1,M2
 1560 IF M1=M2 OR M1<1 OR M2<1 OR M1>9 OR M2>9 THEN@H$;H$ : GOTO 1550
 1570 IF M(M2,1)=M(M1,1)THEN G=999 : GOTO 1590
 1580 G=(M(M2,2)-M(M1,2))/(M(M2,1)-M(M1,1))
 1590 G1=MIN(M(M1,1),M(M2,1))
 1600 G2=MAX(M(M1,1),M(M2,1))
 1610 Y1=MIN(M(M1,2),M(M2,2))
 1620 Y2=MAX(M(M1,2),M(M2,2))
 1630 @ : @ : @"Enter character that is to be used for drawing ";
 1640 GOSUB 8430
 1650 IF A<32 THEN@R$;H$;H$ : GOTO 1630
 1660 IF G=999 THEN 1740
 1670  FOR G3=G1 TO G2
 1680  Y=INT(G*(G3-M(M1,1))+M(M1,2)+0.1)
 1690  Z=(24-Y)*80+G3-1
 1700  A$(Z,Z)=C$
 1710  NEXT G3
 1720 GOTO 600
 1730 REM.
 1740  FOR G3=Y1 TO Y2
 1750  X=M(M1,1)
 1760  Z=(24-G3)*80+X-1
 1770  A$(Z,Z)=C$
 1780  NEXT G3
 1790 GOTO 600
 1800 REM.
 1810 @\1\T$;
 1820 @"Press any key to return to Screen"
 1830  FOR L=0 TO 9
 1840  @E5$;CHR$(56-M(L,2));CHR$(M(L,1)+31);L;
 1850  NEXT L
 1860 GET\1\C$
 1870 GOTO 600
 1880 REM.
 1890 @\1\T$;
 1900 @"Cursor position at (";H;" , ";V;")"
 1910  FOR L=1 TO 5000
 1920  NEXT L
 1930 GOTO 600
 1940 REM.
 1950 @\1\T$;
 1960 @"Change one string for another." : @ : G$="" : Z$=""
 1970 INPUT"Enter string to be changed (length upto 78 characters) ? ",G$
 1980 INPUT"Enter new string (length upto 78 characters) ? ",Z$
 1990 @
 2000 @"Changing all references of ";G$ : @TAB(24);"to ";Z$
 2010 L=LEN(G$)
 2020 L1=LEN(Z$)
 2030 IF L<L1 THEN Z$(L)="" : GOTO 2050
 2040 IF L>L1 THEN Z$(L1,L)=S$+Z$(L1,L)
 2050  FOR X=1 TO 1872
 2060  P1=POS(A$,G$,P1) : IF P1=-1 THEN 600
 2070  A$(P1,P1+L-1)=Z$
 2080  NEXT X
 2090 GOTO 600
 2100 REM.
 2110 @\1\T$;
 2120 @"Delete / Move / Insert selective parts of screen. Press :"
 2130 @TAB(11);"A";SPC(4);"Deletes from top of page to cursor"
 2140 @TAB(11);"B";SPC(4);"Deletes from cursor to end of page"
 2150 @TAB(11);"C";SPC(4);"Deletes current line"
 2160 @TAB(11);"D";SPC(4);"Deletes current line and moves up text"
 2170 @TAB(11);"E";SPC(4);"Deletes above cursor and moves up text"
 2180 @TAB(11);"F";SPC(4);"Deletes from cursor to end of line"
 2190 @TAB(11);"G";SPC(4);"Deletes from margin to cursor"
 2200 @TAB(11);"I";SPC(4);"Insert line and move down text"
 2210 @TAB(11);"J";SPC(4);"Rotate screen about Centre"
 2220 @TAB(11);"K";SPC(4);"Reflect screen about Horizontal axis"
 2230 @TAB(11);"L";SPC(4);"Reflect screen in Vertical axis"
 2240 @TAB(11);"M";SPC(4);"Move whole screen"
 2250 @TAB(11);"N";SPC(4);"Reverse whole screen"
 2260 @TAB(11);"O";SPC(4);"Obliterate page"
 2270 @TAB(11);"P";SPC(4);"Rotate whole screen about any point"
 2280 @TAB(11);"R";SPC(4);"Renter whole column"
 2290 @TAB(11);"S";SPC(4);"Wraparound right column to left     >  []"
 2300 @TAB(11);"T";SPC(4);"Wraparound left  column to right    <  []"
 2310 @TAB(11);"U";SPC(4);"Wraparound bottom row to top        V  []"
 2320 @TAB(11);"V";SPC(4);"Wraparound top row to bottom        ^  []"
 2330 @TAB(11);"W";SPC(4);"Write whole column"
 2340 @TAB(11);"Y";SPC(4);"Write whole row"
 2350 @TAB(11);"Z";SPC(4);"Zap whole column";D$;
 2360 GOSUB 8390
 2370 @\1\T$;
 2380 @U$;
 2390 REM.
 2400 Z=(24-V)*80+H-1
 2410 S=Z-H+1
 2420 E=S+77
 2430 ON A GOTO 2450,2460,2470,2490,2540,2600,2610,600,2620,2670,2680,2780,2880
 2440 ON A-13 GOTO 3690,3800,3850,600,4130,4220,4360,4500,4610,4720,600,4790,4830
 2450 A$(0,Z)=S$+A$(0,Z) : GOTO 8450
 2460 A$(Z,1917)=S$+A$(Z,1917) : GOTO 8450
 2470 A$(S,E)=S$+A$(S,E) : GOTO 600
 2480 REM.
 2490 I$=A$(E+3,1917)
 2500 A$(1840,1917)=S$+A$(1840,1917)
 2510 A$(S,1837)=I$
 2520 GOTO 600
 2530 REM.
 2540 A$(S,Z)=S$+A$(S,Z)
 2550 I$=A$(S,1917)
 2560 A$(-1)=S$+A$(-1)
 2570 A$(0,1917-S)=I$
 2580 GOTO 8450
 2590 REM.
 2600 A$(Z,E)=S$+A$(Z,E) : GOTO 600
 2610 A$(S,Z)=S$+A$(S,Z) : GOTO 600
 2620 I$=A$(S,1837)
 2630 A$(S,E)=S$+A$(S,E)
 2640 A$(E+3,1917)=I$
 2650 GOTO 600
 2660 REM.
 2670 G1=38 : G2=12 : GOTO 3930
 2680 I$=A$
 2690 A$(-1)=S$+A$(-1)
 2700  FOR Y=1 TO 24
 2710   FOR X=1 TO 78
 2720   Z1=(24-Y)*80+X-1
 2730   Z2=(Y-1)*80+X-1
 2740   A$(Z2,Z2)=I$(Z1,Z1)
 2750   NEXT X
 2760  NEXT Y
 2770 GOTO 8450
 2780 I$=A$
 2790 A$(-1)=S$+A$(-1)
 2800  FOR Y=1 TO 24
 2810   FOR X=1 TO 78
 2820   Z1=(24-Y)*80+X-1
 2830   Z2=(24-Y)*80+78-X
 2840   A$(Z2,Z2)=I$(Z1,Z1)
 2850   NEXT X
 2860  NEXT Y
 2870 GOTO 8450
 2880 @\1\T$;
 2890 @"Move Whole screen"
 2900 @"This command will destroy part of the screen." : @"Press :"
 2910 @TAB(11);"D";SPC(4);"Move screen Down by one row                   V"
 2920 @TAB(11);"E";SPC(4);"Move screen Diagonally upwards and left       \"
 2930 @TAB(11);"F";SPC(4);"Move screen Diagonally upwards and right      /"
 2940 @TAB(11);"G";SPC(4);"Move screen Diagonally downwards and left     /"
 2950 @TAB(11);"H";SPC(4);"Move screen Diagonally downwards and right    \"
 2960 @TAB(11);"L";SPC(4);"Move screen left one column                   <"
 2970 @TAB(11);"R";SPC(4);"Move screen right one column                  >"
 2980 @TAB(11);"U";SPC(4);"Move screen up one row                        ^"
 2990 GOSUB 8310
 3000 IF R<1 OR R>78 THEN@H$ : GOTO 2990
 3010 @ : @"Select option from the above list (any other key to abort) ";
 3020 GOSUB 8430
 3030 @C$;
 3040 IF A>90 THEN A=A-32
 3050 IF A<>68 THEN 3120
 3060  FOR L=1 TO R
 3070  I$=A$
 3080  A$(80,1917)=I$(0,1837)
 3090  A$(0,77)=S$+A$(0,77)
 3100  NEXT L
 3110 GOTO 600
 3120 IF A<>69 THEN 3210
 3130  FOR L=1 TO R
 3140  I$=A$
 3150  A$(0,1836)=I$(81,1917)
 3160  A$(1837,1917)=S$+A$(1837,1917)
 3170  GOSUB 8160
 3180  NEXT L
 3190 GOTO 8450
 3200 REM.
 3210 IF A<>70 THEN 3290
 3220  FOR L=1 TO R
 3230  I$=A$
 3240  A$(0,1838)=I$(79,1917)
 3250  A$(1840,1917)=S$+A$(1840,1917)
 3260  GOSUB 8200
 3270  NEXT L
 3280 GOTO 8450
 3290 IF A<>71 THEN 3370
 3300  FOR L=1 TO R
 3310  I$=A$
 3320  A$(80,1917)=I$(1,1838)
 3330  A$(0,77)=S$+A$(0,77)
 3340  GOSUB 8160
 3350  NEXT L
 3360 GOTO 8450
 3370 IF A<>72 THEN 3450
 3380  FOR L=1 TO R
 3390  I$=A$
 3400  A$(81,1917)=I$(0,1836)
 3410  A$(0,77)=S$+A$(0,77)
 3420  GOSUB 8200
 3430  NEXT L
 3440 GOTO 8450
 3450 IF A<>76 THEN 3530
 3460  FOR L=1 TO R
 3470  I$=A$
 3480  A$(0,1916)=I$(1,1917)
 3490  GOSUB 8160
 3500  NEXT L
 3510 GOTO 8450
 3520 RETURN
 3530 IF A<>82 THEN 3610
 3540  FOR L=1 TO R
 3550  I$=A$
 3560  A$(1,1917)=I$(0,1916)
 3570  GOSUB 8200
 3580  NEXT L
 3590 GOTO 8450
 3600 RETURN
 3610 IF A<>85 THEN 600
 3620  FOR L=1 TO R
 3630  I$=A$
 3640  A$(0,1837)=I$(80,1917)
 3650  A$(1840,1917)=S$+A$(1840,1917)
 3660  NEXT L
 3670 GOTO 600
 3680 REM.
 3690 I$=A$
 3700 A$(-1)=S$+A$(-1)
 3710  FOR Y=1 TO 24
 3720   FOR X=1 TO 78
 3730   Z=(24-Y)*80+X-1
 3740   Z1=(Y-1)*80+78-X
 3750   A$(Z1,Z1)=I$(Z,Z)
 3760   NEXT X
 3770  NEXT Y
 3780 GOTO 600
 3790 REM.
 3800 A$(-1)=S$+A$(-1)
 3810 H=1
 3820 V=24
 3830 GOTO 8450
 3840 REM.
 3850 @\1\T$;
 3860 @"Rotate screen about any point"
 3870 ON ERROR GOTO 3880
 3880 @ : @"Please specify axis of roation [39,12] (X:1-78 , Y:1-24)  ";
 3890 INPUT G1,G2
 3900 ON ERROR GOTO 8490
 3910 IF G1=0 OR G2=0 THEN G1=38 : G2=24
 3920 IF G1<1 OR G2<1 OR G1>78 OR G2>24 THEN@H$; : GOTO 3880
 3930 @
 3940 INPUT"Rotate by how many degrees [180] (1-360) ? ",B1$
 3950 D=VAL(B1$)
 3960 IF D=0 THEN D=180
 3970 IF D<1 OR D>360 THEN@H$ : GOTO 3930
 3980 I$=A$
 3990 A$(-1)=S$+A$(-1)
 4000  FOR Y=1 TO 24
 4010   FOR X=1 TO 78
 4020   Z1=(X-G1)*COS(D)-(Y-G2)*SIN(D)+G1
 4030   Z2=(X-G1)*SIN(D)+(Y-G2)*COS(D)+G2
 4040   IF Z1<1 OR Z2<1 OR Z1>78 OR Z2>24 THEN 4080
 4050   Z3=(24-Y)*80+X-1
 4060   Z4=(24-Z2)*80+Z1-1
 4070   A$(Z4,Z4)=I$(Z3,Z3)
 4080   NEXT X
 4090  NEXT Y
 4100 H=1
 4110 V=24
 4120 GOTO 8450
 4130  FOR V1=1 TO 24
 4140  Z=(24-V1)*80+H-1
 4150  E=Z-H+78
 4160  S=E-77
 4170  G$=A$(Z,E)
 4180  A$(Z,Z)=J$
 4190  A$(Z+1,E)=G$
 4200  NEXT V1
 4210 GOTO 600
 4220 @\1\T$;
 4230 @"Wraparound right column to left               >  []"
 4240 GOSUB 8310
 4250 IF R<1 OR R>78 THEN@H$;H$ : GOTO 4240
 4260  FOR L=1 TO R
 4270  I$=A$
 4280  A$(1)=I$
 4290   FOR X=0 TO 1840 STEP 80
 4300   Z=X+77
 4310   A$(X,X)=I$(Z,Z)
 4320   NEXT X
 4330  NEXT L
 4340 GOTO 8450
 4350 REM.
 4360 @\1\T$;
 4370 @"Wraparound left column to right                <  []"
 4380 GOSUB 8310
 4390 IF R<1 OR R>78 THEN@H$;H$ : GOTO 4380
 4400  FOR L=1 TO R
 4410  I$=A$
 4420  A$=I$(1)
 4430   FOR X=0 TO 1840 STEP 80
 4440   Z=X+77
 4450   A$(Z,Z)=I$(X,X)
 4460   NEXT X
 4470  NEXT L
 4480 GOTO 8450
 4490 REM.
 4500 @\1\T$;
 4510 @"Wraparound bottom row to top                  V  []"
 4520 GOSUB 8350
 4530 IF R<1 OR R>24 THEN@H$;H$ : GOTO 4520
 4540  FOR L=1 TO R
 4550  I$=A$
 4560  A$(80,1917)=I$(0,1837)
 4570  A$(0,77)=I$(1840,1917)
 4580  NEXT L
 4590 GOTO 600
 4600 REM.
 4610 @\1\T$;
 4620 @"Wraparound top row to bottom                  ^  []"
 4630 GOSUB 8350
 4640 IF R<1 OR R>24 THEN@H$;H$ : GOTO 4630
 4650  FOR L=1 TO R
 4660  I$=A$
 4670  A$(0,1837)=I$(80,1917)
 4680  A$(1840,1917)=I$(0,77)
 4690  NEXT L
 4700 GOTO 600
 4710 REM.
 4720 IF H=79 THEN 600
 4730  FOR V1=1 TO 24
 4740  Z=(24-V1)*80+H-1
 4750  A$(Z,Z)=J$
 4760  NEXT V1
 4770 GOTO 600
 4780 REM.
 4790 A$(S,E)=J$+A$(S,E)
 4800 H=1
 4810 GOTO 600
 4820 REM.
 4830 IF H=78 THEN 630
 4840  FOR V1=1 TO 24
 4850  Z=(24-V1)*80+H-1
 4860  E=Z-H+78
 4870  S=E-77
 4880  G$=A$(Z+1,E)
 4890  A$(E,E)=S$
 4900  A$(Z,E-1)=G$
 4910  NEXT V1
 4920 GOTO 600
 4930 REM.
 4940 @\1\T$;
 4950 @TAB(10);"Press :"
 4960 @TAB(20);"Q  To Quit Screen and exit without updating file ";F$
 4970 @TAB(20);"U  To Update file ";F$;" and exit Screen."
 4980 @TAB(23);"Any other key to return." : @
 4990 GOSUB 8430
 5000 IF A<>85 AND A<>117 THEN 5140
 5010 @"Updated file ";F$;" being written to disc"
 5020 ON ERROR GOTO 5120
 5030 PUT\3,P\A$(-1);K$
 5040 IF F=1 THEN CLOSE\2\ : ERASE F1$ : GOTO 8490
 5050 ON ERROR GOTO 8490
 5060  FOR X=0 TO 9
 5070  IF F(X)=1 THEN 5100
 5080  GET\2,X\A$(-1)
 5090  PUT\3,X\A$(-1);K$
 5100  NEXT X
 5110 GOTO 8490
 5120 @"Output file ";F$;" write error"
 5130 GOTO 8490
 5140 IF A<>81 AND A<>113 THEN 600
 5150 REM.
 5160 @"Discard Screen buffer, restore Input File, and quit SCREEN (Y/N) ? ";
 5170 GOSUB 8430
 5180 IF A<>121 AND A<>89 THEN 600
 5190 CLOSE\3\
 5200 ERASE F$
 5210 RENAME F1$,F$
 5220 GOTO 8490
 5230 REM.
 5240 @\1\T$;
 5250 @"Screen allows you to create or modify upto 10 pages of text numbered 0 - 9 ."
 5260 @ : @"You are currently in page ";P;". Which page next ? ";
 5270 GOSUB 8430
 5280 N=A-48 : IF N<0 OR N>9 THEN 600
 5290 PUT\3,P\A$(-1);K$ : ON ERROR GOTO 5350
 5300 REM.
 5310 @E$;"Read page from sourcefile (else from file created during run) (Y/N) ? ";
 5320 GOSUB 8430
 5330 O=2 : IF A<>121 AND A<>89 THEN O=3
 5340 GET\O,N\A$(-1) : P=N : IF ASC(A$(78,78))=13 THEN 600
 5350 @
 5360 @"Page ";N;" does not exist. Create new page ";N;" ? ";
 5370 GOSUB 8430
 5380 IF A<>89 AND A<>121 THEN 5260
 5390 A$(-1)=S$+A$(-1) : P=N
 5400 GOTO 8450
 5410 REM.
 5420 @\1\T$;
 5430 @"Grid screen with any printable character"
 5440 @"What character is to be used to grid ? ";
 5450 GOSUB 8430
 5460 IF A<32 THEN@H$; : GOTO 5440
 5470 I$=A$
 5480  FOR X=0 TO 1917
 5490  IF I$(X,X)=S$THEN I$(X,X)=C$
 5500  NEXT X
 5510 @\1\T$;
 5520 @I$;D$;K$;M$; : H=1 : V=24 : GOTO 630
 5530 REM.
 5540 @C$; : H=H-1 : GOTO 630
 5550 REM.
 5560 @\1\T$;
 5570 @"Invert parts of the screen."
 5580 @TAB(4);"Press one of the following keys : " : @
 5590 @TAB(11);"A";SPC(4);"Above current cursor position"
 5600 @TAB(11);"B";SPC(4);"Below current cursor position"
 5610 @TAB(11);"C";SPC(4);"Current line"
 5620 @TAB(11);"D";SPC(4);"Top left quadrant"
 5630 @TAB(11);"E";SPC(4);"Top right quadrant"
 5640 @TAB(11);"F";SPC(4);"Bottom left quadrant"
 5650 @TAB(11);"G";SPC(4);"Bottom right quadrant"
 5660 @TAB(11);"H";SPC(4);"Cursor forming top left quadrant"
 5670 @TAB(11);"I";SPC(4);"Cursor forming top right quadrant"
 5680 @TAB(11);"J";SPC(4);"Cursor forming bottom left quadrant"
 5690 @TAB(11);"K";SPC(4);"Cursor forming bottom right quadrant"
 5700 @TAB(11);"L";SPC(4);"Alternate squares (first inverted)"
 5710 @TAB(11);"M";SPC(4);"Alternate squares (first unaltered)"
 5720 @TAB(11);"N";SPC(4);"Cursor to right screen column"
 5730 @TAB(11);"O";SPC(4);"Cursor to left screen column"
 5740 @TAB(11);"P";SPC(4);"Top left traingle"
 5750 @TAB(11);"Q";SPC(4);"Bottom right triangle"
 5760 @TAB(11);"R";SPC(4);"Top right triangle"
 5770 @TAB(11);"S";SPC(4);"Bottom left triangle"
 5780 @TAB(11);"W";SPC(4);"Whole screen"
 5790 @TAB(16);"Any other key to return";D$;
 5800 GOSUB 8390
 5810 @\1\T$;
 5820 Z=(24-V)*80+H-1
 5830 IF A<1 OR A>24 THEN 600
 5840 A1=A
 5850 @
 5860 @"Which character is to be used for inversion ? ";
 5870 GET\1\C$
 5880 @C$;
 5890 A=ASC(C$)
 5900 S=0
 5910 E=1917
 5920 Z=(24-V)*80+H-1
 5930 IF A>127 THEN C$=CHR$(A-128)
 5940 IF A<32 OR A=95 THEN@R$; : GOTO 5860
 5950 ON A1 GOTO 5970,5980,5990,6070,6080,6090,6100,6110,6120,6130
 5960 ON A1-10 GOTO 6140,6250,6310,6370,6380,6480,6630,6780,6940,600,600,600,6010
 5970 E=Z : GOTO 6000
 5980 S=Z : GOTO 6000
 5990 E=Z-H+78 : S=E-77
 6000 @" Computer working ";
 6010  FOR X=S TO E
 6020  IF A$(X,X)=S$THEN A$(X,X)=C$ : GOTO 6040
 6030  A=ASC(A$(X,X)) : IF A<>13 AND A<>10 THEN A$(X,X)=S$
 6040  NEXT X
 6050 GOTO 600
 6060 REM.
 6070 T=24 : B=13 : L=1 : R=39 : GOTO 6160
 6080 T=24 : B=13 : L=40 : R=78 : GOTO 6160
 6090 T=12 : B=1 : L=1 : R=39 : GOTO 6160
 6100 T=12 : B=1 : L=40 : R=78 : GOTO 6160
 6110 T=24 : B=V : L=1 : R=H : GOTO 6160
 6120 T=24 : B=V : L=H : R=78 : GOTO 6160
 6130 T=V : B=1 : L=1 : R=H : GOTO 6160
 6140 T=V : B=1 : L=H : R=78 : GOTO 6160
 6150 REM.
 6160  FOR Y=B TO T
 6170   FOR X=L TO R
 6180   Z=(24-Y)*80+X-1
 6190   IF A$(Z,Z)=S$THEN A$(Z,Z)=C$ : GOTO 6210
 6200   A$(Z,Z)=S$
 6210   NEXT X
 6220  NEXT Y
 6230 GOTO 600
 6240 REM.
 6250  FOR X=0 TO 1916 STEP 2
 6260  IF A$(X,X)=S$THEN A$(X,X)=C$ : GOTO 6280
 6270  A$(X,X)=S$
 6280  NEXT X
 6290 GOTO 8450
 6300 REM.
 6310  FOR X=1 TO 1917 STEP 2
 6320  IF A$(X,X)=S$THEN A$(X,X)=C$ : GOTO 6340
 6330  A$(X,X)=S$
 6340  NEXT X
 6350 GOTO 8450
 6360 REM.
 6370 L=H : R=78 : GOTO 6390
 6380 L=1 : R=H
 6390  FOR Y=1 TO 24
 6400   FOR X=L TO R
 6410   Z=(24-Y)*80+X-1
 6420   IF A$(Z,Z)=S$THEN A$(Z,Z)=C$ : GOTO 6440
 6430   A$(Z,Z)=S$
 6440   NEXT X
 6450  NEXT Y
 6460 GOTO 8450
 6470 REM.
 6480 @\1\T$;
 6490 @"Invert top left triangle"
 6510 IF B<1 OR B>78 THEN@H$;H$ : GOTO 6500
 6520 B1=25-MIN(24,B1)
 6530  FOR Y=24 TO B1 STEP-1
 6540   FOR X=1 TO B
 6550   Z=(24-Y)*80+X-1
 6560   IF A$(Z,Z)=S$THEN A$(Z,Z)=C$ : GOTO 6580
 6570   A$(Z,Z)=S$
 6580   NEXT X
 6590  B=B-1
 6600  NEXT Y
 6610 GOTO 600
 6620 REM.
 6630 @\1\T$;
 6640 @"Invert bottom right triangle"
 6660 IF B<1 OR B>78 THEN@H$;H$ : GOTO 6650
 6670 B1=MIN(24,(79-B1))
 6680  FOR Y=1 TO B1
 6690   FOR X=B TO 78
 6700   Z=(24-Y)*80+X-1
 6710   IF A$(Z,Z)=S$THEN A$(Z,Z)=C$ : GOTO 6730
 6720   A$(Z,Z)=S$
 6730   NEXT X
 6740  B=B+1
 6750  NEXT Y
 6760 GOTO 600
 6770 REM.
 6780 @\1\T$;
 6790 @"Invert top right triangle"
 6810 GOSUB 8270
 6820 IF B<1 OR B>78 THEN@H$;H$ : GOTO 6800
 6830 B1=MIN(24,(79-B))
 6840  FOR Y=24 TO B1 STEP-1
 6850   FOR X=B TO 78
 6860   A=(V/4)*4 : IF V<5 THEN A=A-1
 6870   V=V-1
 6880   GOTO 620
 6890   NEXT X
 6900  B=B+1
 6910  NEXT Y
 6920 GOTO 8450
 6930 REM.
 6940 @\1\T$;
 6950 @"Invert bottom left triangle"
 6960 GOSUB 8230
 6970 IF B<1 OR B>78 THEN@H$;H$ : GOTO 6960
 6980 B1=MIN(B,24)
 6990  FOR Y=1 TO B1
 7000   FOR X=1 TO B
 7010   Z=(24-Y)*80+X-1
 7020   IF A$(Z,Z)=S$THEN A$(Z,Z)=C$ : GOTO 7040
 7030   A$(Z,Z)=S$
 7040   NEXT X
 7050  B=B-1
 7060  NEXT Y
 7070 GOTO 8450
 7080 REM.
 7090 @C$; : V=V-1 : GOTO 630
 7100 @C$; : V=V+1 : GOTO 630
 7110 @C$; : H=H+1 : GOTO 630
 7120 @E$; : H=1 : V=V-1 : GOTO 630
 7130 REM.
 7140 A=V-(V/4)*4 : IF A=0 THEN A=4
 7150 IF V<5 THEN A=A-1
 7160 V=V-A
 7170 GOTO 620
 7180 REM.
 7190 @\1\T$;
 7200 @"Output current page ";P;" of Screen to Printer."
 7210 @"Is page to be Overtyped (Y/N) ? "
 7220 GOSUB 8430
 7230 IF A=89 OR A=121 THEN 7600
 7240 @"If printer is not connected press ^P to return."
 7250 @CHR$(23);A$;K$;CHR$(20); : GOTO 600
 7260 REM.
 7270 H=38
 7280 GOTO 620
 7290 Z=(24-V)*80+H-1
 7300 E=Z-H+78
 7310 S=E-77
 7320 G$=A$(Z,E)
 7330 A$(Z,Z)=J$
 7340 A$(Z+1,E)=G$
 7350 IF V=1 THEN 600
 7360 @E$;M$;A$(S,E);R$;A$(S,Z);
 7370 GOTO 630
 7380 REM.
 7390 @\1\T$;
 7400 @"Specify character to be used in R, U, V and W commands ? ";
 7410 GOSUB 8430
 7420 J$=C$
 7430 IF A<32 OR A=95 THEN@R$; : GOTO 7400
 7440 GOTO 600
 7450 REM.
 7460 F1=0
 7470 GET\1\C$ : @C$;B$;S$;B$;
 7480 A=ASC(C$)-48
 7490 IF A>79 THEN A=A-128
 7500 IF A<0 OR A>9 THEN 7550
 7510 M(A,1)=H
 7520 M(A,2)=V
 7530 IF F1=0 THEN 630
 7540 GOTO 600
 7550 @\1\T$;
 7560 @"Marker must be in range 0-9, renter marker : ";
 7570 F1=1
 7580 GOTO 7470
 7590 REM.
 7600 @\1\T$;
 7610 @"Output page ";P;" to printer, overtyped"
 7620 @CHR$(23);
 7630  FOR X=0 TO 1840 STEP 80
 7640  E=X+77
 7650  @A$(X,E+1);A$(X,E+1);K$;
 7660  NEXT X
 7670 @CHR$(20);
 7680 GOTO 600
 7690 IF V=24 THEN 630
 7700 Z=(24-V)*80+H-1
 7710 A$(Z,Z)=J$
 7720 V=V+1
 7730 @J$;M$;B$;
 7740 GOTO 630
 7750 REM.
 7760 Z=(24-V)*80+H-1 : A$(Z,Z)=J$ : V=V-1 : @J$;K$;B$; : GOTO 630
 7770 Z=(24-V)*80+H-1 : A$(Z,Z)=J$ : @J$;B$;B$; : H=H-1 : IF H=0 THEN H=1
 7780 GOTO 630
 7790 REM.
 7800 V=((V/4)+1)*4
 7810 IF V>24 THEN V=24
 7820 GOTO 620
 7830 REM.
 7840 @\1\T$;
 7850 @"Yank a page from file into the current page" : ON ERROR GOTO 7930
 7860 @"You are in page ";P;". Which page to be read in (0-9) ? ";
 7870 GOSUB 8430
 7880 N=A-48 : IF N<0 OR N>9 THEN 600
 7890 @E$;"Read in page from sourcefile (else from file created during run) (Y/N) ? ";
 7900 GOSUB 8430
 7910 O=2 : IF A<>121 AND A<>89 THEN O=3
 7920 GET\O,N\A$(-1) : GOTO 600
 7930 @"Page";N;" does not exist" : GOTO 7860
 7940 V=12
 7950 GOTO 620
 7960 REM.
 7970 IF H=78 THEN 630
 7980 Z=(24-V)*80+H-1
 7990 E=Z-H+78
 8000 S=E-77
 8010 G$=A$(Z+1,E)
 8020 A$(E,E)=S$
 8030 A$(Z,E-1)=G$
 8040 IF V=1 THEN 600
 8050 @E$;M$;A$(S,E);R$;A$(S,Z); : GOTO 630
 8060 REM.
 8070 H=(((H-2)/8)*8)-1
 8080 IF H<1 THEN H=1
 8090 GOTO 620
 8100 REM.
 8110 H=(((H-1)/8)+1)*8+1
 8120 IF H>78 THEN H=78
 8130 GOTO 620
 8140 @C$; : H=1 : V=24 : GOTO 630
 8150 REM.
 8160  FOR X=77 TO 1917 STEP 80
 8170  A$(X,X)=S$ : NEXT X
 8180 RETURN
 8190 REM.
 8200  FOR X=0 TO 1840 STEP 80
 8210  A$(X,X)=S$ : NEXT X
 8220 RETURN
 8230 @ : @ : INPUT"Enter end column number [24] (1-78) ? ",B1$
 8240 B=VAL(B1$) : IF B=0 THEN B=24
 8250 RETURN
 8260 REM.
 8270 @ : @ : INPUT"Enter starting column number [55] (1-78) ? ",B1$
 8280 B=VAL(B1$) : IF B=0 THEN B=55
 8290 RETURN
 8300 REM.
 8310 @ : @ : INPUT"Enter repeat factor  [1] (1-78) ? ",B1$
 8320 R=VAL(B1$) : IF R=0 THEN R=1
 8330 RETURN
 8340 REM.
 8350 @ : @ : INPUT"Enter repeat factor  [1] (1-24) ? ",B1$
 8360 R=VAL(B1$) : IF R=0 THEN R=1
 8370 RETURN
 8380 REM.
 8390 GOSUB 8430
 8400 IF A>96 THEN A=A-32
 8410 A=A-64
 8420 RETURN
 8430 GET\1\C$ : A=ASC(C$) : IF A>127 THEN A=A-128
 8440 C$=CHR$(A) : RETURN
 8450  FOR L=78 TO 1838 STEP 80
 8460  A$(L,L+1)=E$ : NEXT L
 8470 A$(1918)=R$ : GOTO 600
 8480 REM.
 8490 ON ERROR GOTO 8520
 8500 CLOSE
 8510 @
 8520 END