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Volume Number: | 1 | |
Issue Number: | 1 | |
Column Tag: | BASIC SCHOOL |
“Alphabet Soup”
By Dave Kelly
“Alphabet Soup”
Welcome to Basic School! This article is dedicated to those of us that enjoy programming in Basic. Programmers of structured languages have put Basic down for several years because it is not considered a structured programming language and many implementations of Basic lack enhancements which give it power to perform advanced functions. Also it has been said many times that it is much harder to follow the program flow in Basic than in other languages like Pascal. Those who complain about the limitations of Basic are sometimes quite justified in their complaints. After all, basic “BASIC” isn’t very powerful and not very flexible at all. Any enhancement at all is an improvement. This has been the caseup until now. Now, the enhancements that we find in Macintosh Basic are approaching the power of the more acceptable high level languages such as Pascal. Exploring Macintosh Basic computing power is what this column is all about.
In the last few months we have seen the evolution of the programming tools needed to program the Mac on the Mac. In the coming issues, we will explore the enhancements included in the new MacBasic and in Microsoft Basic Version 2.0. At the writing of this article Microsoft tells me that they intend to release Microsoft Basic Version 2.0 by the end of October or sometime in November. I’m told that it includes many enhancements which in my opinion should have been included from the very first introduction of Microsoft Basic to the Macintosh world. These enhancements include programmable windows, menus, scrolling, sound and sound effects, compatability with MacWrite, complete mouse control, editing, debugging, access to most if not all of the Mac internal ROM routines, and elimination of the need for line numbers. This is what I call programming made easy. From what I’ve seen so far, there will be quite a competition between MacBasic and Microsoft Basic 2.0 in the coming months.
The Mac Basic listing shows an example of the ease in documenting a program as it is written. I originally wrote the program in Microsoft Basic version 1.0 as an educational tool for my 2 year old to learn his alphabet. The program prints the alphabet and then prompts the user to find each letter one at a time.Then the user points to the letter with the mouse and presses the mouse button. By using variable names that show what is happening and by the use of line labels the program requires little documentation. When I write programs, I rarely have the time to finish up with documentation especially when my 2 year-old can’t wait to start the game. The use of these labels will be familiar to anyone who has used Basic on the Hewlett Packard 9826-36 series computers. The label name is used in each of the gosub statements in place of the line numbers. This makes the use of line numbers unnecessary. The coresponding label name also appears at the beginning of the subroutine followed by a colon. By indenting the text of the program within each subroutine, it is clear where the subroutine starts and ends and the label gives a clue as to what each subroutine does.
Next month we will explore Basic programming on the Mac in more detail.
10 ‘********************************* 20 ‘ Alphabet Soup 30 ‘ By David Kelly 40 ‘ MS Basic Version 1.0 70 ‘********************************* 1000 DIM TOP%(26),BOT%(26),RGT%(26),LFT%(26) 1010 FOR LETTER%=1 TO 26 1020 READ LFT%(LETTER%), TOP%(LETTER%), RGT%(LETTER%), BOT%(LETTER%) 1030 NEXT LETTER% 1040 GOSUB 1090: ‘ Print_alphabet 1050 FOR LETTER%=ASC(“A”) TO ASC(“Z”) 1060 GOSUB 1200: ‘Ask_for_letter 1070 NEXT LETTER% 1080 CALL TEXTMODE(0):CALL TEXTFACE(0):CALL TEXTFONT(1):CALL TEXTSIZE(12):END 1090 ‘ Print_alphabet to screen 1100 CLS : ‘Clearwindow 1110 CALL TEXTFONT(2): ‘ Set to New York Font 1120 CALL TEXTSIZE(24): ‘ Set Font size to 24 1130 CALL TEXTMODE(2): ‘Sets screen to XOR 1140 CALL TEXTFACE(0): ‘Sets face to plain style 1150 FOR LETTER% = 1 TO 26 1160 CALL MOVETO(LFT%(LETTER%),BOT%(LETTER%)):PRINT CHR$(ASC(“A”)-1+LETTER%) 1170 NEXT LETTER% 1180 CALL TEXTSIZE(12): ‘Set font size to 12 1190 RETURN 1200 ‘ Ask_for_letter 1210 CALL MOVETO (125,175):PRINT “Find the letter: “; 1220 CALL TEXTSIZE(24): ‘Set Font size to 24 1230 CALL TEXTMODE(0) 1240 PRINT “ “;CHR$(LETTER%) 1250 CALL TEXTSIZE(12) 1260 CALL PENMODE(10) 1270 IF MOUSE(0)=0 THEN 1270: ‘button wait 1280 X2=MOUSE(1): Y2=MOUSE(2) 1290 CALL MOVETO(238,168):CALL LINETO(X2,Y2) 1300 IF MOUSE(0)<0 THEN 1300 1310 IF (X2<LFT%(LETTER%-64) OR X2>RGT%(LETTER%-64) OR Y2< TOP%(LETTER%-64) OR Y2 >BOT%(LETTER%-64)) THEN FLAG%=1 ELSE FLAG%=0 1320 CALL PENMODE(14):PATTERN%(0)=0:CALL PENPAT(VARPTR(PATTERN%(0))) 1330 CALL MOVETO(238,168): CALL LINETO(X2,Y2):CALL PENNORMAL 1340 CALL TEXTMODE(0):IF FLAG% =1 THEN 1210 1350 BEEP:BEEP 1360 RETURN
1370 DATA 36,20,52,74 :’A data 1380 DATA 72,20,84,74 :’B data 1390 DATA 103,20,115,74 :’C data 1400 DATA 133,20,147,74 :’D data 1410 DATA 165,20,176,74 :’E data 1420 DATA 195,20,207,74 :’F data 1430 DATA 225,20,239,74 :’G data 1440 DATA 257,20,272,74 :’H data 1450 DATA 290,20,315,74 :’I data 1460 DATA 330,20,350,74 :’J data 1470 DATA 369,20,383,74 :’K data 1480 DATA 401,20,414,74 :’L data 1490 DATA 434,20,454,74 :’M data 1500 DATA 35,75,51,120 :’N data 1510 DATA 69,75,83,120 :’O data 1520 DATA 101,75,115,120 :’P data 1530 DATA 133,75,147,120 :’Q data 1540 DATA 165,75,179,120 :’R data 1550 DATA 197,75,208,120 :’S data 1560 DATA 227,75,240,120 :’T data 1570 DATA 259,75,275,120 :’U data 1580 DATA 294,75,310,120 :’V data 1590 DATA 329,75,352,120 :’W data 1600 DATA 371,75,385,120 :’X data 1610 DATA 402,75,417,120 :’Y data 1620 DATA 434,75,445,120 :’Z data
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