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BASIC Source File | 1990-10-23 | 25.9 KB | 624 lines

' ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄ ' ██ TUTORIAL.BAS ██ ' ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ 'The assumption is made that this file is being read in the QuickBASIC 'environment--that's what it was designed for. 'This file is a working program, with exactly the same code as PULDOWN.BAS, 'and, if PULDOWN.QLB is loaded, you can run it anytime. Infact, if you don't 'have PULDOWN.QLB loaded, please do so now: exit QB and reload with the 'command line: ' QB /L PULDOWN ' 'This file differs from PULDOWN.BAS only in that it has extensive comments 'that show you how how the program works and how to customize. 'Just be sure that you save at least one original of this file on a diskette, 'and it is highly recommended that you read all the way through the comments 'at least once before editing. ' 'If you have trouble following some of the explanations, don't fret--customizing 'PULDOWN is actually fairly easy. There's a section at the end of this file 'that guides you through a customizining session. Search for: STEP BY STEP. 'Terms used: ' "Barmenu" is used to indicate the horizontal menu at the top of ' of the screen. ' ' "Pulldown" refers to a pulldown window menu such as appears when ' you press ALT+F in QB. ' ' "Trigger letter" indicates a character in a pulldown that can be ' pressed to instantly activate a menu item without actually moving ' to it. They appear in the pulldowns in the opposite color of the ' other characters in the menu item. To see an example of a trigger ' letter (my terminology), press Alt then ENTER: the O in "Open ' Program " is a trigger letter, as are many others in the QB menu. ' ' QB means QuickBASIC in general and the QB Environment in particular. ' AL means Assembly Language. ' ' VM and vm are frequently used in variable names. They stand for ' Vertical Menu, i.e. pulldown. This might help you in reading the code. ' ' If you're not clear on what a QuickLibrary (QLB) or Library (LIB) ' module is, don't despair. A QLB and a LIB that have the same filename ' are essentially the same thing. They are binary files that are CALLed ' by QB much like subroutines. The crucial difference between them is ' that a QLB must be loaded at the same time as QB to work, while a LIB ' must be present in the QB path only when you compile BASIC code to ' an EXE file. ' ' Other technical terms used here are part of the QuickBASIC vocabulary, ' and you should consult your QB manuals and books for them. This text ' is written for programmers and a minimal familiarity with programming ' terms and concepts is assumed, but some accommodations are made for ' the raw beginner. ' 'The presence of an inverse block " ██ " marks crucial information--don't 'miss them. ' 'Some of the crucial information is in the last section: END NOTES. Although 'crucial, it is not needed while familiarizing yourself with the program. 'Notice that there's no DEFINT and each number is declared an integer with ' n% since there's no way of knowing whether a program that incorporates ' PULDOWN won't need other kinds of number declarations. '"PULL" is the actual name of the Assembly Language routine that is CALLed. 'That name cannot be changed, except by aliasing. The names of the variables 'that are used before the actual call can be changed (if you enjoy making 'trouble for yourself). 'Program lines are tabbed (except for labels), like the one 5 lines below: '▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ 'PROGRAM BEGINS: DECLARE FUNCTION PULL% (BYVAL Inverse%, BYVAL Normal%, BYVAL BarMenu%, BYVAL KeyOff%, BYVAL BarNumber%, BYVAL VM1%, BYVAL VM1A%, BYVAL VM10%, BYVAL VM2%, BYVAL VM2A%, BYVAL VM20%, BYVAL VM3%, BYVAL VM3A%, BYVAL VM30%, BYVAL VM4%, BYVAL VM4A% _ , BYVAL VM40%, BYVAL VM5%, BYVAL VM5A%, BYVAL VM50%, BYVAL VM6%, BYVAL VM6A%, BYVAL VM60%, BYVAL VM7%, BYVAL VM7A%, BYVAL VM70%) '█ All the code after this point can be put into a Subprogram in your ultimate ' program, provided you put a 'CALL MySub'in the main program and restructure ' the ensuing code somewhat (like eliminating RETURNs), but that subject is ' beyond the scope of this file. '█ In any case, the above declaration must be in the main program and at or ' near the top. 'This is where the customizing part really starts. 'The next cluster of code initializes the barmenu items, of which there 'can be no more than seven ██ and there must be no fewer than one. ' '█ All the barmenu items must be in the same string, as in BarMenu$ below. '█ Each item MUST be ten spaces long, including blanks. '█ The BarNumber% variable must have the total number of barmenu items, in ' this case 7. '█ BarMenuKeys$ holds the first letter of each of the barmenu items. They ' must be entered in the exact number, form and order in which they appear ' on the menu, with no blank spaces. █ If you change the number or order of ' barmenu items, don't forget to change this string and the BarNumber% variable. '██ You cannot have the same letter appear twice in BarMenuKeys$ (actually, ' you can, but the first instance will be selected every time) '█ A barmenu item can consist of two or more words, so long as they fit in ' ten spaces. BarMenu$ = " English Italian German French Spanish Hellos Quit " BarMenu% = SADD(BarMenu$) BarMenuKeys$ = "EIGFSHQ" KeyOff% = SADD(BarMenuKeys$) 'the 'Off' in KeyOff% stands for offset BarNumber% = 7 'BarMenu section ends '▀▀▀▀▀ '█ Normal% is the foreground color of characters. Inverse% is background 'color. First we must determine if we're in a mono system or color. The 'cluster of code below does that and assigns the colors. Note that only the 'last, CASE ELSE clause applies to color. Mixing the foreground and background 'colors in a one byte value is a tedious business--if you want to experiment, 'round up the usual reference suspects. However, a partial COLOR MIX table is 'provided at the end. The only firm rule is that Inverse% and Normal% must be 'symmetrical--you can't have red on green for one and green on yellow for the 'other. DEF SEG = 0 Attr% = PEEK(&H410) 'this is where BIOS stores video state SELECT CASE Attr% CASE 48 TO 63 Inverse% = 112 'or &H70 'Compare Attr% to all Normal% = 7 'byte numbers that have Attr% = 0 'bits 5 & 4 set. If they CASE 112 TO 127 'are both set, it means Inverse% = 112 'mono, otherwise, color. Normal% = 7 Attr% = 0 CASE 176 TO 191 Inverse% = 112 Normal% = 7 Attr% = 0 CASE 240 TO 255 Inverse% = 112 Normal% = 7 Attr% = 0 CASE ELSE Inverse% = 31 'bright white on blue Normal% = 121 'bright blue on white END SELECT DEF SEG 'The Inverse% and Normal% variables are not used in the BASIC part, they 'are strictly parameters to be passed to the AL routine. And yes, there are 'several other ways of going about this. Use your favorite method, so long 'as the two color values end up properly assigned. '▄▄▄▄▄▄▄ 'Pulldown initializiation sets begin: 'This is where the fun begins. The contents and form of the pulldowns is 'determined in the next section of code. Examine the first set, which 'initializes the first (leftmost) pulldown. The format will be explained 'in the next comment. VM1% = 4 VM1A% = 11 VM1$ = " Hundreds Tho_usands Millions Billions " VM10% = SADD(VM1$) '█ The first value, VM1% determines the number of items in the pulldown, ' that is, the number of lines, or depth (excluding the box). You can, ' theoretically have as many as 21 lines. '█ The second value, VMnA%, determines the number of characters in the ' item field of the pulldown, including blanks, but excluding the box. ' As an example, the item field of the first item in the first pulldown is: ' " Hundreds " ' ' If you've counted the spaces, it comes out to 12, not eleven. ██ The ' field must always be 1 space greater than what is declared in VMn% █ ' --more on that later. ' You can make the pulldowns as wide as you wish, so long as there's room ' on the screen. The width of the box (2 spaces) must be taken into ' account and the fact that each pulldown begins in the same column as its ' corresponding barmenu item. So, on the first pulldown, the item field ' can be as wide as 76 spaces, but only 20 on the seventh pulldown.██ ' VMn$ is the string that actually carries the items in a pulldown. They ' must all be in the same string, and the field length must be consistent ' throughout the string. ' Finally, VMn0% determines where BASIC stores the string so that PULDOWN.QLB ' and PULDOWN.LIB can find it. Leave it alone. '██ The cluster of pulldown initialization sets must be contiguous and in ' ascending order, as they are here, where the VM2 set follows the VM1 set ' etc. ██ 'To get a taste of what customizing is like, use the Insert key to change 'one of the words below in VM2$ (taking care not to change the length of the 'string) then Run (F5) to see the change. VM2% = 9 VM2A% = 7 VM2$ = "Uno Due Tre _QuattroCinque Sei Sette Ot_to Nove " VM20% = SADD(VM2$) 'The VM3 set illustrates the use of Ctrl+Char and Function keys, as displayed 'in the line: ' 'VM3$ = " Ein...Ctrl+E Z_wei Dr_ei Vier Funf..or F10 " 'These two keypresses greatly improve speed and convenience in accessing crucial 'and often-used program features since they can be used anytime the pulldowns 'are active, even if the user is not in the pulldown containing the menu items 'in question. 'ABOUT CTRL+CHAR: '~~~~~~~~~~~~~~~ 'Any letter character can be used but avoid using C--it encourages bad habits. 'Char can duplicate a trigger letter with a different meaning, for 'example Ctrl+e can mean Exit, while trigger key "e" could mean "erase". 'It is irrelevant whether Char is displayed or pressed in upper or lower 'case. PULDOWN will always return the upper case ASCII values. 'Use restraint with Ctrl+Char--it should be limited to a few letters that the 'user can remember easily and are logical, like Ctrl+Q for 'Quit, or Ctrl+F 'for File. 'ABOUT FUNCTION KEYS: '~~~~~~~~~~~~~~~~~~~ 'F11 and F12 are not supported. 'The Function keys are most useful for commands that are in effect throughout 'the program--not just during the menu, like "save what I've entered so far," 'or "let's start over". VM3% = 5 VM3A% = 13 VM3$ = " Ein...Ctrl+E Z_wei Dr_ei Vier Funf..or F10 " VM30% = SADD(VM3$) 'You may have noticed that some of the items are broken up by underscores, 'as in " Vingt et deu_x " below. That's what makes a trigger letter. 'When a pulldown with a trigger letter is activated, pressing a trigger 'letter calls that menu function without need of arrow keys or ENTER. ' ██ An underscore must precede the trigger letter. Items that do not have ' a trigger letter must have an extra blank space to maintain the uniformity ' of field length. (That's why declared field length is one less than actual) ' ██ There is a limit of 5 trigger letters per pulldown. ' ██ You cannot duplicate a trigger letter within the same pulldown, but ' you can have the same trigger letter in different pulldowns. VM4% = 3 VM4A% = 20 ' VM4$ = "Vingt et un Vingt et deu_x Vingt et trois " VM40% = SADD(VM4$) VM5% = 4 VM5A% = 14 VM5$ = "Ciento Ciento y _uno Ciento y _dos Cien_to y tres " VM50% = SADD(VM5$) ' █ You can have as few as 1 pulldown or a as many as 7,██ but make sure ' that the BarNumber% variable reflects the number. ' █ A reminder: as you get to the higher pulldowns, be mindful of how many ' screen columns are left. VM6% = 3 VM6A% = 16 VM6$ = " Hello, there Live long and Prosper. " VM60% = SADD(VM6$) 'Notice that each barmenu item must have a pulldown, even if only one line 'deep. ██ You cannot have a barmenu item without a pulldown: VM7% = 1 'one item VM7A% = 13 VM7$ = " _Quit...Esc " VM70% = SADD(VM7$) 'The cluster of pulldown initialization sets end here. 'All the code that follows is optional, except for the actual CALL PULL CLS '█ If you wish to add any features to the menu screen, like the name of the ' program--as is done here, or a frame around the screen, do so before █ ' calling PULL: LOCATE 2, 34 SELECT CASE Attr% CASE 0 COLOR 0, 7 CASE ELSE COLOR 7, 1 'white on blue END SELECT PRINT " PULDOWN.BAS " COLOR 7, 0 'Here PULDOWN is actually called as a function named PULL. Its return value 'is put into RETVAL%, but you may change that. 'Notice that the list of parameters is exceedingly long. Be careful you don't 'chop it off during the editing process. Also there is no actual CALL in the 'call--the word is used in the text for clarity. RETVAL% = PULL%(Inverse%, Normal%, BarMenu%, KeyOff%, BarNumber%, VM1%, VM1A%, VM10%, VM2%, VM2A%, VM20%, VM3%, VM3A%, VM30%, VM4%, VM4A%, VM40%, VM5%, VM5A%, VM50%, VM6%, VM6A%, VM60%, VM7%, VM7A%, VM70%) 'Before returning control to the main program, PULL erases the active 'pulldown, returns the barmenu to its "rest" state, and restores the screem 'below the barmenu to its pre-CALL condition. 'PULL returns four kinds of values: ' The first type consists exclusively of the number 1. This indicates ' that the user has pressed ESC, and exited the menu without taking ' action. ' The second type indicates that Ctrl+Char has been pressed, and returns ' a value between 64 and 90, which are ASCII codes except that 64 ' indicates that a non-letter key has been pressed. ' (Again: Char may be pressed with or without Shift, but is returned ' as if with) ' █ In the 65-90 range, only the ones that you designate in the menu ' are actually valid. Identifying valid characters is done in the BASIC ' part of the program, as shown below. ' The third type returns values between 159 and 168, and represent ' Function Keys 1 through 10. Each of these numbers is actually the scan ' code of the key plus 100 (i.e.: F1 = 59 + 100 = 159) ' Values that are greater than 168 (and usually they will be >10,000) ' are the fourth type: the offset within the data segment ' of the menu item that was selected. This will by far the most common ' return value. It is the address in memory of the menu item, and is ' rendered useful by means of PEEKs, as shown below. ' 'To see how the Return Value works, use the QB Debug menu to AddWatch: RETVAL%. 'Make the next line of code below a breakpoint, and run the program four times. 'The first time, press Esc in the menu; the second time, Ctrl+Char; the third 'time, an F-Key, and finally select a menu item either with ENTER or with a 'trigger key. Each time, as QB hits the breakpoint, look at RETVAL%. 'Once PULDOWN has returned a value, its job is essentially over. Making something 'useful out that single number is the programmer's job--your job, and 'how you do it depends on your program requirements, and your programming 'style. What follows is a sparse but wide-ranging example of how it can be 'handled. These are only suggestions. LOCATE 5, 1 'First, check for ESC, Ctrl, and F-Keys SELECT CASE RETVAL% CASE 1 GOTO Last 'Yes, it's ESC CASE 2 TO 68 GOTO BadKey 'don't want these CASE 69 GOTO IsCtrl 'we want this one -- CHR$(69) = E CASE 70 TO 167 GOTO BadKey 'don't want these CASE 168 GOTO IsFKey 'F10 END SELECT 'If it's not ESC or Ctrl+Char, then the user must have selected one of the menu 'items. We must find out which one by retrieving the selected string and 'comparing it with all the possibilities. 'The essence of my way of doing that is in the first line of the FOR/NEXT 'loop: we PEEK at RETVAL% and convert it to an ASCII CHR$. Then we add 1 to 'RETVAL%, and repeat the whole process as many times as it takes to get 'enough letters to identify the menu item. I have selected four characters. 'Infact, three should be plenty, but many menu items start with a blank 'because it looks better. If you will consistently have a blank in the first 'position, you can start the loop with RETVAL% + 1, and loop three times. Just 'be careful that each three-letter combination is unique--you wouldn't want 'to confuse "File" with "Fill Screen," for example--a four-loop PEEK would 'be needed to distinguish between these two. 'Rather than concatenating (Final$ = A$ + B$ + C$), I am using a supposedly 'faster method: setting up a blank string of the proper length (RETVAL$), 'then filling it in with MID$: RETVAL$ = " " FOR RT% = 1 TO 4 MID$(RETVAL$, RT%, 1) = CHR$(PEEK(RETVAL%)) RETVAL% = RETVAL% + 1 NEXT 'Here too you might want to set up a breakpoint and a Watch, Run, and see 'what RETVAL$ looks like after you select a menu item. 'Now comes the laborious part. The return string must be compared with 'with each menu item. In this sample program, only a few of the total 'items are compared. A working program will have as many CASEs as there 'are pulldown items. 'There are a few things to watch out for. The comparison string must be 'of the same length as the retrieved string. It must be exactly as it appears 'in its declared form, not its display form, including initial blanks '(unless you retrieve at RETVAL% + n), but █ most important, it means including 'any underscores, as in "_Qu": SELECT CASE RETVAL$ CASE " Hel" 'notice leading blank... GOSUB greeting CASE "Uno " '...but none here GOSUB italian CASE " Z_w" 'Include underscore! GOSUB deutsch CASE "Ving" GOSUB francais CASE " _Qu" '(Quit) GOTO Last CASE ELSE GOTO AnyKey END SELECT GOTO Last '(Please note that many of the items in the sample menu start with the ' same syllable, but that would rarely be the case in a "real" menu) 'And here is the payoff. In a working program of course, a menu selection 'will usually branch to something more than just printing a message, but 'this does illustrate how to get to the actual work: 'This next section handles the first three types of Return Value: AnyKey: PRINT "You have selected "; RETVAL$ GOTO Last IsCtrl: PRINT "You have pressed Ctrl+e and selected 'Ein'" GOTO Last '█ Note that PULDOWN cannnot tell what menu item was selected when Ctrl+Char ' is pressed. That determination is made on the basis that each instance is ' associated with a particular menu item in the BASIC code: if Ctrl+e has ' been pressed, then it MUST be 'Ein'. '...and the same goes for the Function keys: IsFKey: PRINT "You have pressed F10 and selected 'Funf'" GOTO Last BadKey: PRINT "You have pressed an unassigned key" Last: END 'And here are handled the selected "working" menu items: greeting: COLOR 16, 7 PRINT "Hello Hello" WHILE INKEY$ = "": WEND COLOR 7, 0 RETURN Last italian: COLOR 0, 7 PRINT "MA CHE, SCHERZI?" WHILE INKEY$ = "": WEND COLOR 7, 0 RETURN Last deutsch: COLOR 16, 7 PRINT "Ein VolksMenu. Wunderbar!" COLOR 7, 0 RETURN Last francais: COLOR 1, 0 PRINT "Yo, alouette..." COLOR 7, 0 RETURN Last 'PROGRAM ENDS '▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ 'STEP BY STEP: 'Now we will go through a step-by-step exercise in customizing one of the 'pulldowns. We will change the VM6 set "Hellos" to "List" consisting of 'these items: First, Second, Third, Fourth, Fifth, Sixth. 'This is what the original set looks like: ' VM6% = 3 ' VM6A% = 16 ' VM6$ = " Hello, there Live long and Prosper. " ' VM60% = SADD(VM6$) ' 'First, we will change VM6% (depth) to 6, because that's how many items we have. 'Then we change VM7% (width) to 8 because the longest item is six letters long, 'and we want (at least) one blank space at either end just for esthetics. 'Then we edit the VM6 string to the new items, making sure that each field 'has 9 spaces (item length + 1, remember?). '(Be careful with the length of the item fields. The Insert key and the QB 'Cut + Paste feature really come in handy for this kind of editing) 'Then we also want to make "First" a trigger item, so we put an underscore 'before the "F". 'This is what we end up with: ' VM6% = 6 ' VM6A% = 8 ' VM6$ = " _First Second Third Fourth Fifth Sixth " ' VM60% = SADD(VM6$) 'Now we simply delete the original VM6 set and cut and paste the new one in '(remembering to eliminate the comment quotes) 'If we run the program at this point, our new menu will be there, but its 'barmenu item will still read "Hellos". So we change ' BarMenu$ = " English Italian German French Spanish Hellos Quit " ' 'to: ' ' BarMenu$ = " English Italian German French Spanish List Quit " ' 'and we change ' ' BarMenuKeys$ = "EIGFSHQ" ' ' to: ' ' BarMenuKeys$ = "EIGFSLQ" ' 'Voilá! That's all there is to it. But let's take the example a little 'further, and say that "List" will be the last item on the barmenu. So we 'delete the VM7 set ("Quit")... ' '...and we change ' 'BarNumber% = 7 to BarNumber% = 6 ' 'and we go back to BarMenuKeys$ and change it to: EIGFSL ' 'That's all there is to it. Follow these steps and you can customize PULDOWN 'to your CPU's content, so long as you stay within the stated constraints. '▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀ 'END NOTES 'PULDOWN's generated menu will always start at Row 1, Column 1. That cannot 'be changed, except at the source code level. It is, after all, meant to be 'a main menu. But if there is demand for making the starting position a 'variable, I might be talked into it. 'The sum of all the characters and spaces in all the pulldown menus 'cannot exceed 1000. This is the equivalent of seven pulldown menus, each 'ten lines deep and 13 characters wide. That's large enough to go beyond 'practicality. But if you should get to the point where you need to figure out 'precisely how many bytes your menu takes, here's how to do it: ' ' In each pulldown set, add 1 to the VMnA% variable, then multiply ' it by the VMn1% variable. ' ' Repeat this procedure for each set, then add them up. ' ' Example: (VM1A% + 1) * VM1% ' ( 11 + 1) * 4 = 48 ' Repeating this step with each VM set and adding the results ' yields 378 for the current set of pulldowns. 'There may be occasions when, after the user has selected a menu item, you 'want to keep the barmenu at the top of the screen, and the "active" barmenu 'item in reverse color, just as QuickBASIC does when you select something 'from the "File" menu. PULDOWN cannot do this for you, because it's finished. 'You must overwrite the barmenu item with LOCATE, COLOR and PRINT commands. 'PULDOWN disables the Ctrl+C feature while it is in effect, so the user cannot 'blow the menu and the whole program. The only way to get out of the menu is 'to select an item or press ESC. However, when running in QB, Ctrl+Break 'will return you to the environment. 'COLOR MIX TABLE (partial): ' Blue on Yellow 97 ' Yellow on Blue 22 ' Bright blue on yellow 105 ' Bright yellow on blue 22 ' Bright blue on red 73 ' Bright red on blue 28 ' Magenta on green 45 ' Green on magenta 90 ' Red on white 124 ' White on red 79 ' Blue on white 113 ' White on blue 23 ' Bright blue on white 121 'default setting ' Bright white on blue 31 ' etc. 'EOF