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Is there a function that is the inverse of Define, Global, etc. ? (was: small and quick question)
Posted: Sat Aug 03, 2024 3:12 pm
by ZX80
Hi, all.
We have
Define to declare variable etc. and
Defined for check / determine / found it. My question is this:
Is there a function that is the inverse of Define, Global, etc. ?
In other words, I want that the program, at a certain stage, forgot about the existence of a previously declared variable. Then global variables won't seem so scary, right ?
Has anyone thought about it or I just don't know about it ?
Okay. Here's a micro-example:
Code: Select all
EnableExplicit
Global *mem = AllocateMemory(100)
Procedure SomeProc()
; do something
If Defined(*mem, #PB_Variable)
Debug "Okay. I see that a variable named '*mem' already exists."
Debug "Now I want that the program to forgot about this variable, but how ?"
Debug "Of course, the previously requested memory must be freed first."
FreeMemory(*mem)
Debug ""
Debug "Probably also need to clear the pointer itself"
*mem = #Null
EndIf
EndProcedure
SomeProc()
If Defined(*mem, #PB_Variable)
Debug "As you can see, the variable still exists / is recognized by the program :("
EndIf
Thus, a global variable exists only in a separate section of the program.
Please, let's not argue whether this is correct. I'm interested in this possibility itself.
Thank you in advance.
Re: Is there a function that is the inverse of Define, Global, etc. ? (was: small and quick question)
Posted: Sat Aug 03, 2024 4:15 pm
by wilbert
ZX80 wrote: Sat Aug 03, 2024 3:12 pmIs there a function that is the inverse of Define, Global, etc. ?
No there isn't.
I don't know what you need it for but maybe you can use Module.
Re: Is there a function that is the inverse of Define, Global, etc. ? (was: small and quick question)
Posted: Sat Aug 03, 2024 4:38 pm
by ZX80
wilbert,
No doubt, you are right ! Modules are also knowns as namespaces. I was wondering if there was such an opportunity and how much demand it had.
Re: Is there a function that is the inverse of Define, Global, etc. ? (was: small and quick question)
Posted: Sat Aug 03, 2024 5:00 pm
by AZJIO
And we are not afraid of global variables. Surely by adding “g_” to the beginning of such a variable, it will not collide with variables in other functions. In addition, you can search for "g_" to be sure that you do not have a single match. When searching, use match from start.
Today I was just thinking, why do I need to get away with global variables? There is no reason for this, and what's more, you will have to create extra temporary variables inside functions. For example, I store temporary results in a tmp or tmp$ variable and every time I reason, why should I waste memory if I can use one global variable instead of 10 variables inside a function. Although the loss is only 4*10=40 bytes.
I have never used "Shared", perhaps this is the case when the variable is defined as "Define", but will be visible to the function if necessary.
Here we forgot about the variable
Code: Select all
Procedure SomeProc()
Protected *mem
The Defined function is a compiler function and will be defined not while the program is running, but during compilation, and in the program it will already be either 0 or 1
Re: Is there a function that is the inverse of Define, Global, etc. ? (was: small and quick question)
Posted: Sat Aug 03, 2024 7:41 pm
by ZX80
AZJIO,
Does it follow from your words that this is impossible ? What I asked at the beginning of this topic. I'm sure that's the case.
Re: Is there a function that is the inverse of Define, Global, etc. ? (was: small and quick question)
Posted: Sat Aug 03, 2024 7:57 pm
by AZJIO
1. You don't have to delete the variable, you don't have to use it.
2. You can create a structure with a field, and then delete the structure. But it is easier not to use a variable than to make it impossible to use. There's only one byte.
Re: Is there a function that is the inverse of Define, Global, etc. ? (was: small and quick question)
Posted: Sat Aug 03, 2024 9:00 pm
by Bisonte
If you are using "Protected" it doesn't care....
Code: Select all
Global variable1 = 123
Procedure.i Change()
Protected variable1 = 100
Debug variable1
EndProcedure
Debug variable1
Change()
Debug variable1
this is not changing the global variable ....