alexis@dasys1.UUCP (Alexis Rosen) (09/07/88)
Recently, I have gotten a slew of requests for descriptions of how FoxBase can
do menus, windows, and dialogs. Rather than answer each one individually, since
this seems to be a topic of some interest, I am posting this article. Most
people also wanted comparisons with 4D, so I will describe both.
Menus:
In 4D, there is a graphic menu editor. It creates entire menu bars, and you can
set a cmd-key equivalent and style for each menu item. The editor is a little
clunky but it gets the job done. The drawbacks to this system are that any
changes to a menu, except enabling or disabling, require you to draw an
entirely different menu bar which was created previously. It is also impossible
to create menus on the fly. (There are external commands which do this, I
believe, which does help the situation.) The other serious problem with 4D
menus is that in the top level of an application, choosing a menu automatically
activates a procedure. At all other times, you must detect the menu hit and
process it yourself. This is a real pain as it requires you to define every
response to a menu hit twice. Also, certain subtle problems can crop up when
you try to create a global menu hit procedure.
In Foxbase, you create arrays for the menu bar and the menus, fill them up, and
tell it to draw the menus. The Apple, File, and Edit menus are taken care of
automatically, just like 4D. (I wish they weren't. This may change in the
future.)
The following is an annotated extract from some of my code. The "&&" is a
comment delimiter.
Dimension mbar(2), mFiles(2), mGo(4) && create space for menu arrays
mbar(1)="Placement System" && menu title #1
mbar(2)="Go"
mFiles(1)="Clients File" && 1st item in Placement menu
mFiles(2)="Prospects File"
mGo(1)="First"
mGo(2)="Next"
mGo(3)="Previous"
mGo(4)="Last"
Menu Bar mBar && draw the Menu Bar
Menu 1, mFiles && make menu #1 ("Placement System") using mFiles array
Menu 2, mGo && make menu #2
On Menu Do MenuProc With Menu(0),Menu(1) && set up procedure for menu hits
-----
This will set up a menu bar containing:
{Apple} File Edit Placement System Go
vari- New Undo Clients File First
ous Open Cut Prospects File Next
DAs Print Copy Previous
etc. Paste Last
etc.
-----
The drawback to this method is that there is no nice graphic menu editor. You
have to write the code to create menus.
There are advantages, however. The syntax to alter menu items and disable or
enable them on the fly is very clean ("Menu Off 2,1" would turn off the first
item in the second menu- "Last" in the example above). Cmd-keys, styles, marks,
and all the other things you can do in any Mac language are available in
exactly the same way (if mGo(4) were "(Last/L", Last would be disabled and have
the command key 'L').
There will probably be a graphic menu editor for those who don't like to write
code (I would guess around December or January). Until then, you can use the
template-based applications generator to build your menu code for you. If you
do that, you'll only have to write the code once, and then it will work with
whatever menus you want. The template language is very powerful and can do lots
of other good stuff, too.
The other big advantage to Fox's menu system is that I can easily create one
procedure which handles all menu hits. If my menu-handling procedure is called
MenuProc, then the statement "On Menu Do MenuProc With Menu(0), Menu(1)" tells
FoxBase that any menu hit should activate the procedure 'MenuProc', passing it
the parameters 'Menu(0)' and 'Menu(1)' (these are functions which return the
menu title number and menu item number, respectively). The MenuProc procedure
has a bunch of 'Case' of 'If' statements to decide what to do, based on which
menu item was hit.
In fact, writing a menu-handling procedure is pretty much the same for both 4D
and Fox. They both require some programming to use the menus, and the code will
look very similar. I give Fox the edge on the cleanness of the programming
model, though.
Fox 4D
No menu editor (-) Ugly but useable menu editor (1/2 +)
Clean code structure (+) Bad code structure (-)
Easily altered menus (+) Some problems altering menus (-)
All in all, the difference isn't vast. It's mostly a matter of individual
style, but I think that Fox has an edge here.
Windows:
Windowing is one of the weakest points in 4D. It does not have a lot of control
over what type of window to use. Worse, it is not capable of doing multiple
windows under program control. There is a very bogus second window capability,
but when the second window is up the first becomes unavailable. This is
entirely unMacish. This is not likely to change in the near future (i.e., V2.0
in December) because of the way procedures are tied to windows. 4D hangs
uncomfortably between being an object-oriented programming environment and a
procedural one. It is neither entirely, and this will continue to cause
enormous problems for Acius, unless it undergoes a fundamental change-- but
that's another article...
The one good point in 4D's favor is that it can create windows with a document
area larger than the current window size (and larger than the screen).
FoxBase's windowing capabilities are better than any other Mac DBMS's (except
Helix, in some ways). It has a graphic screen generator which is vastly
superior to the current incarnation of 4D (and all the other Mac DBMSs). When
running your program, it can handle ten database browse windows (spreadsheet-
like views of a data file) automatically. In addition, you can create up to
nine separate windows entirely of your own design on the screen at once. The
screen generator will do it all for you, but if you want to do it yourself, you
use the 'Screen' command. You can use the following arguments:
Screen <expN> this is the number of the screen
Heading "<window title>" this text becomes the window title
At <expN>,<expN> location of window from upper left corner
Type <expN> the window type. Just like in Inside Mac!
Size <expN>,<expN> window size. Can be in pixels or characters.
Font <expC>,<expN> Font name, size, and style. This is only a
default and can be changed at any time.
Color <expC>|<expN> default window color. Old QuickDraw or new.
Lock hides the goAwayBox
Off hides the window without erasing it. It can
still be drawn to in this state.
Top bring this window to the front (and show it)
Delete remove and forget this screen
You can have all nine windows up at once, draw to any of them at any time, get
input through any one at any time, move them around, show and hide them, etc.
Note also that the Type clause lets you make windows that look just like DAs
(round-cornered), dialogs (modal and non-modal), and alerts. In fact, you can
use any type supported by the current WDEF. (If that last is gobbledygook to
you, just forget it. In English, it means that Fox can draw any of the windows
that you see in everyday use of your Mac.)
The one limitation in Fox's window scheme is the lack of support for scroll
bars. You can't have a form which is seven feet wide and look at it through a
seven inch window. I don't think that this is a serious restriction, though,
since you can have nine windows. In addition, you can change the particular
data items displayed or entered in any window at any time (unlike 4D, or any
other Mac DBMS), so you could fake scrolling easily enough if it were critical.
I almost forgot- 4D has some really silly limitations on what can go in a
window, whereas there are no such limits in Fox. The upgrade to 4D due in
December relaxes those restrictions, but they were a _major_ pain to deal with.
I'm not going to even try to draw a chart comparing 4D to Fox here- it would be
embarrasing. Let's just say that windows are one area where 4D loses big and
FoxBase really shines.
Dialogs and Alerts:
4D has some rudimentary commands to show an alert or ask for one text string.
They are useful in a limited context, but if you want anything more, you need
to pull up a window which looks like an alert. The problem is that if you want
a Modeless dialog box, you are S.O.L. Even worse, if you already have a second
window up, you _can't_ bring up another window. This is really painful...
FoxBase has a variety of simple alert and dialog commands which all do pretty
much the same thing: Show a modal dialog with one, two, or three buttons, an
icon of your choice and up to six lines of text. The dialogs are resources in
the "FoxUser" file, which can be altered if you really want. You can draw the
dialog centered on the screen or at any location.
Fox's dialogs are even more restricted that 4D's in that you can't read data in
from them. However, this isn't really a problem, since you can fall back on the
wonderful windowing system so easily (not to mention the template language,
which can be set up to generate dialog code to your heart's content).
Therefore, it is very easy to create unusual alerts, modeless dialogs, and very
complex dialogs (like the configuration screens in terminal emulators, for
example). The graphic screen generator can do this very nicely. So in fact,
FoxBase is very good at dialogs of all sorts.
Score: Again, it's FoxBase by a mile...
-----
I hope this has cleared up a lot of questions. Serious debate is always
welcome, flames are not.
I will be running a database mini-conference at the MacUser Business Expo (or
whetever they're calling it now) for three and a half hours on November 1. It
will have no resemblance to the ridiculous kid-gloves-on-and-pat-every-
manufacturer-on-the-back stuff evident at the past two MacWorld Expos. We will
have some really good speakers, such as Wayne Ratliff, Janet Walker from Fox,
Guy Kawasaki from Acius, someone from Oracle, and a few more. We will cover
both current and forthcoming products, and will spend a lot of time going over
techniques to increase the utility of databases on the Mac in current,
real-world environments. There will be a heavy emphasis on DBMSs running on
Local Area Networks. If you go to the Expo, live nearby, or have a deep
interest in these things, come to the conference! It should be a blast.
One last thing- if anyone has lots of experience with the new 4D, why not write
an article and tell us all about the new features?
----
Alexis Rosen {allegra,philabs,cmcl2}!phri\
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