Functions

[dik_coleman]

Scenario ......

function(1) defined yadayadayada (whatever)
function(2) as above

function(3) function(1)/function(2) (or some action using both of the functions)

Which functions are global and which are local????

Looks like 1 and 2 should be global, but they are (used???) (defined????) in function 3.

Xbasic tutorial not really clear on this....

Dick Coleman

[Tom Cone Jr]

RE: Functions

Dick,

If the function is saved to the Code page of the Control Panel it's global. -- tom

[dik_coleman]

RE: Functions

Ok thanx....... BUT

does this mean that all three (of the above example) would be 'local' if not on 'code page' .... OR would only 3 be global (if not on code page) because it calls 1 and 2?????

D

[Lenny Forziati]

RE: Functions

The corollary to Tom's statement "If the function is saved to the Code page of the Control Panel it's global" is

If a function is NOT on the code tab, it is NOT global.

-Lenny

[Scott Emerick]

RE: Functions

Dick,

To expand on Tom and Lenny's reply to help you better understand.

A function like str() or left() are built in A5 GLOBAL Functions.

A user can create their own function known as a UDF just like you would create a script, only a fuction starts with FUNCTION and ends with END FUNCTION. IF these "scripts are saved to the code tab they become GLOBAL.

A local function is a function that was written inside of a script, for example:

'Xbasic script here
Xbasic
Xbasic
Xbasic
my_local_function()
Xbasic

FUNCTION my_local_script(parameter,C)
function code
function code
function code
function code
END FUNCTION

The above sample shows a xbasic script that defines the function with in the script. "my_local_function" is NOT saved on the code tab.

I hope this clears things up better for you.

Scott

[CALocklin]

RE: Functions

I get the feeling there's another question "imbedded" in Richard's original question that's caused by a basic misunderstanding of something. The question is, "What?"

Perhaps this will help...

Any User Defined Functions (UDFs) stored on the Code page can be used globally - i.e., from anywhere. HOWEVER, the results returned by the function must be assigned to a variable (or, less common but also quite acceptable, directly to a field or object) and that variable could be defined as Local, Shared, or Global.

Also, let's separate results from functions.
First, as noted above, whether Function1 calls Function2 has nothing to do with whether or not the results of either one are global. Second, I've never thought of functions as being "Global" but I have thought of them as being "available from anywhere in A5." In other words, the term GLOBAL as used with variables and DIM statements really does not apply to functions. However, Function1 can only call Function2 IF (a) Function2 was defined in the Code tab (which makes it available from anywhere within A5) or (b) Function2 is defined within function1.

I could be wrong on this one last point but (you may have to read this a few times to follow it) I believe that if Function1 is a UDF defined in the Code tab and it is called from a script and that script also has defined within it a Function2, the script can call Function2 but Function1, even though it might be used within the script, cannot call Function2 because the Function1 in the Code tab doesn't know anything about Function2 being stored within the script.

I haven't tested it (yet) so that last paragraph could be wrong but I suspect it would be considered bad form even if it does work.

[Lenny Forziati]

RE: Functions

Actually Cal, referring to UDFs as local or global is in fact correct. They are stored in the same namespaces as the variables. If I open one of my test databases that has two functions in the Code tab, "foo" and "test", I see the following in an interactive window:

dim g as p
g=global_variables()
?g
= C foo() 'Public user defined function.
V test() 'Public user defined function.


We can take this a step further and create a local function in the interactive window as would be done in a script and then see it in the local variables:
function localfunc as c()
#localfunc = "Hello world"
#end function
dim l as p
l = local_variables()
?l
= C localfunc() 'Public user defined function.
+g.
+l.

Because of this behavior, you last statement that you said you thought would not work is incorrect and will work. It is however an accident waiting to happen because function1() can only find function2() if it is run from that particular script. Since function1() is in the code tab, it could be called from anywhere so there is no guarantee of function2() being defined.

-Lenny

[dik_coleman]

RE: Functions

wow!!!
did I cause this????

It's still a little confusing, but I think I have the general idea...

If you want it global, put it under the 'code' tab!!!!

In most cases, all others would be local to a form, session or a layout.....

thanx guys

D