90 lines
3.6 KiB
QBasic
90 lines
3.6 KiB
QBasic
10 REM *****************************
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15 REM * *
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20 REM * MORE - TEXT FILE VIEWER *
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30 REM * AUTHOR - BILL CHATFIELD *
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35 REM * *
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40 REM *****************************
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44 :
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45 REM TODO:
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46 REM CD,PREFIX,PWD,CWD,CHDIR,FASTER OUTPUT
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47 REM PREFIX IN PROMPT
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48 REM DETAILED HELP FROM "?" COMMAND, FIX FIRST LINE
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49 :
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50 LET D$ = CHR$ (4)
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55 LET BS$ = CHR$ (7)
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56 LET CR$ = CHR$ (13)
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57 LET PROMPT$ = "[RETURN] NEXT LINE [SPACE] NEXT PAGE [Q] QUIT"
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58 LET LINE = 1
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59 PRINT "ENTER A FILE NAME, * FOR CATALOG, OR JUST HIT RETURN TO ABORT
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."
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60 INPUT "FILE:";F$
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70 IF RIGHT$ (F$,1) = "*" THEN PRINT D$;"CATALOG "; LEFT$ (F$, LEN (F
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$) - 1): GOTO 60
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80 IF F$ = "" THEN END
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85 IF F$ = "?" THEN 59
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110 ONERR GOTO 5050: REM SETUP ERROR HANDLER
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125 PRINT D$;"VERIFY ";F$: REM CHECK IF FILE EXISTS, ERROR CODE 6
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130 PRINT D$;"OPEN ";F$: REM WILL CREATE FILE IF IT DOES NOT EXIST.
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140 PRINT D$;"READ ";F$
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150 GET C$
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160 PRINT C$;
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165 IF C$ = CR$ THEN LINE = LINE + 1
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167 IF LINE = 24 THEN INVERSE : PRINT PROMPT$;: NORMAL : PRINT D$: GOSUB
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4000: GOSUB 3000: GOTO 140
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170 GOTO 150: REM NEXT CHARACTER IN FILE
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180 REM END OF MAIN, BUT UNREACHABLE BECAUSE OF CHARACTER LOOP
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3000 REM ****************
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3005 REM * *
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3010 REM * ERASE PROMPT *
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3015 REM * *
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3020 REM ****************
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3025 LET PL = LEN (PROMPT$)
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3030 POKE 1403,0: REM BACKUP TO BEGINNING OF LINE
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3060 PRINT SPC( PL): REM ERASE PROMPT
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3070 POKE 1403,0: REM BACKUP AGAIN
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3080 RETURN
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4000 REM ***************
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4005 REM * *
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4010 REM * GET COMMAND *
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4015 REM * *
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4020 REM ***************
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4030 GET CMD$
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4040 IF CMD$ = CR$ THEN LINE = 23: GOTO 4060
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4050 IF CMD$ = " " THEN LINE = 1: GOTO 4060
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4055 IF CMD$ = "Q" OR CMD$ = "q" THEN PRINT D$;"CLOSE": PRINT D$: PRINT
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: END
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4060 RETURN
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5000 REM *****************
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5010 REM * *
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5020 REM * ERROR HANDLER *
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5030 REM * *
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5040 REM *****************
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5050 POKE 216,0: REM TURNS OFF 'ONERR GOTO' ERROR HANDLING
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5060 LET ERRCODE = PEEK (222): REM GETS THE CODE FOR THIS ERROR
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5070 PRINT D$;"CLOSE": REM CLOSES ANY OPEN FILES
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5080 PRINT D$: REM TURNS OFF FILE I/O SO PRINTS GO TO SCREEN
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5090 IF ERRCODE = 5 THEN 5290: REM END-OF-FILE IS NOT AN ERROR
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5100 PRINT : PRINT : REM SEPARATES ERR MSG FROM ANY PREVIOUS OUTPUT
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5120 REM CHECK FOR DOS/PRODOS ERRORS NOT IN APPLESOFT TABLE
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5130 IF ERRCODE = 6 THEN PRINT "ERROR:FILE NOT FOUND:";F$
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5140 IF ERRCODE = 11 THEN PRINT "ERROR:INVALID OPTION"
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5150 IF ERRCODE = 255 THEN PRINT : PRINT : PRINT "INTERRUPTED BY CTRL-C"
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5155 GOTO 5290: REM SKIP TO THE END
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5160 REM COPY ERROR MESSAGE FROM APPLESOFT ERROR TABLE
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5170 LET BASE = 53856: REM $D260, START OF APPLESOFT ERR TABLE
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5180 LET PTR = BASE + ERRCODE: REM POINT TO 1ST BYTE OF ERR MSG
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5185 PRINT "ERROR:";: REM PREFIX ALL PRINTED MESSAGES WITH THIS
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5190 :
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5195 REM LOOP TO PRINT CHARS OF ERR MSG FROM APPLESOFT ERROR TABLE
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5200 REM WHILE (THERE ARE MORE CHARS IN MESSAGE) DO
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5210 LET BYTE = PEEK (PTR): REM GETS BYTE POINTED TO BY PTR
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5220 IF BYTE > = 128 THEN 5280: REM DETECTS LAST BYTE
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5230 PRINT CHR$ (BYTE);: REM CNVTS ASCII BYTE TO CHAR, PRINT
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5240 LET PTR = PTR + 1: REM ADVANCES POINTER TO NEXT BYTE
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5250 GOTO 5210: REM LOOPS BACK TO NEXT BYTE
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5260 REM END WHILE
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5270 :
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5280 PRINT CHR$ (BYTE - 128);: REM SETS HIGH BIT TO 0, PRINT
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5290 END : REM THIS IS THE END - JIM MORRISON
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