PureBasic Forums - English

Posted: **Fri Jul 29, 2022 10:53 pm**

I'm new to PureBasic but I've noticed in some examples that define.s can be used to define a string. But also, it seems helpful to suffix a string with ".s"

Which is regarded as the best way in PureBasic? It seems to me that variable.s is more descriptive throughout the rest of the code. What is the best convention to use, that expert coders prefer?

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define.s variable

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define variable.s

Posted: **Fri Jul 29, 2022 11:07 pm**

Technically it doesn't matter, but Define.s is more convenient when declaring a lot of variable with one type:

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Define a.s,b.s,c.s,d.s,e.s;...
;vs
Define.s a,b,c,d,e;...

I'm not an expert, but I declare my variable in a wild horde, so I use the normal Define and append the type to each variable.

Posted: **Fri Jul 29, 2022 11:09 pm**

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Define var.s
Define.s var1, var2, var3...

Posted: **Fri Jul 29, 2022 11:30 pm**

mestnyi wrote: Fri Jul 29, 2022 11:09 pm
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Define var.s
Define.s var1, var2, var3...

Yeah, okay I think my preference would be to define blocks of variables according to their association with each other, rather than all the strings together and then all the numerics together.

This is because when we look at code logic, it can be helpful to group variables according to their relationship. For instance...

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define custcounter.i
define custname.s

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define productcode.s
define productprice.l
define invoicetotal.l

Personally (and this is very much a personal thing) I wouldn't like to see all the strings together and then all the numerics together. Also, software modifications and additions are often best defined in their own right, so they are in a block of code of their own.

Posted: **Fri Jul 29, 2022 11:51 pm**

Well, that's up to you.

Posted: **Sat Jul 30, 2022 12:11 am**

jacdelad wrote: Fri Jul 29, 2022 11:51 pm Well, that's up to you.

This is getting interesting. I just found that it doesn't matter how the variable is referenced, after it's defined. These all appear to be equal...

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Define.s name
name.s=Input()


Define.s name.s
name=Input()


Define.s name.s
name.s=Input()


Define name.s
name=Input()

Posted: **Sat Jul 30, 2022 1:06 am**

Yes, the type is only needed for the declaration. This also means each name can only be used once, for one variable

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Define Var1.a,var1.s

...will result in an error.

Also, string variables can have an appended "$", like

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Define MyString$="Hello"
Debug MyString$

Posted: **Sat Jul 30, 2022 9:00 am**

You should also keep in mind that MyString.S and MyString$ are different variables:

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Define MyString.S = "Test 1"
Define MyString$ = "Test 2"

Debug MyString  ; "Test 1"
Debug MyString$ ; "Test 2"

Posted: **Sat Jul 30, 2022 9:36 am**

And following on from Shardik's post, you can also do this:

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Define MyString.s = "Test 1"
Define MyString$ = "Test 2"
Define *MyString = @"Test 3"

Debug MyString  ; "Test 1"
Debug MyString$ ; "Test 2"
Debug PeekS(*MyString) ; "Test 3"

Posted: **Sat Jul 30, 2022 10:22 am**

In addition to barry's post above:
When using addresses of string literals, keep in mind that identical literals will be reused, so different pointer variables could point to the same string, affecting each other:

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EnableExplicit

Define s1.s = "test"
Define s2.s = "test"
s2 = "test2"
Debug s1             ; test
Debug s2             ; test2

Define *s3 = @"test"
Define *s4 = @"test"
PokeS(*s4, "x")
Debug PeekS(*s3)     ; x
Debug PeekS(*s3)     ; x

But I don't know why you would want to use pointers to string literals, especially poking at them will corrupt memory if the poked string is to long. There is no automatic reallocation like with normal string operations:

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*s = @"0123"
ShowMemoryViewer(*s, 100)
Delay(1000)
PokeS(*s, Space(38))
ShowMemoryViewer(*s, 100)

Posted: **Sat Jul 30, 2022 11:34 am**

To be clear:

once you defined a variable, the trailing .x is no longer needed.

Personally I prefer the $ at the end for strings, this is always at the end of the variable and so I see that it is a string.

And in general: your first command in any code should be:

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EnableExplicit

Posted: **Sat Jul 30, 2022 1:30 pm**

And the last command should always be:

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End

to properly signal the OS that the program has ended.
The OS may want to perform additional cleanup tasks!

Posted: **Sat Jul 30, 2022 2:52 pm**

Mijikai wrote: Sat Jul 30, 2022 1:30 pm And the last command should always be:
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End
to properly signal the OS that the program has ended.
The OS may want to perform additional cleanup tasks!

Just a note... PureBasic automatically inserts "End" internally at the end of your program so unless you are using "End" to terminate your program early, you may be duplicating things.

Using "C" backend...

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SYS_Quit();

void SYS_Quit() {
PB_EndFunctions();
f_heapdestroy_(PB_MemoryBase);
f_exitprocess_(PB_ExitCode);
}

Using "C" backend and including "End" at the end of your program...

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// End
SYS_Quit();
// 
SYS_Quit();

void SYS_Quit() {
PB_EndFunctions();
f_heapdestroy_(PB_MemoryBase);
f_exitprocess_(PB_ExitCode);
}

Using "ASM" backend...

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_PB_EOP:
  CALL   PB_EndFunctions
  MOV    rcx,[PB_MemoryBase]
  CALL   HeapDestroy
  MOV    rcx,[PB_ExitCode]
  CALL   ExitProcess

Using "ASM" backend and including "End" at the end of your program...

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; End
  JMP   _PB_EOP
; 
_PB_EOP:
  CALL   PB_EndFunctions
  MOV    rcx,[PB_MemoryBase]
  CALL   HeapDestroy
  MOV    rcx,[PB_ExitCode]
  CALL   ExitProcess

Posted: **Sat Jul 30, 2022 3:25 pm**

Ok so PB holds your hand, the manual should reflect this behaviour.

Posted: **Sat Jul 30, 2022 5:45 pm**

If you eventually decide to automate your code for documentation or jumping around source code for definitions of variables and other data structures, you should think what is simple?
For me, always enableexplicit, and 1 data type per define.
Define.i x,y,z
Strings are always mystring$
Only 1 array or map or list per define.

Then your parser logic is easy peasy.

Standardize your coding semantics and you minimize your tech burden with debugging and automation.

PureBasic Forums - English

What is best... define.s variable or define variable.s

What is best... define.s variable or define variable.s

Re: What is best... define.s variable or define variable.s

Re: What is best... define.s variable or define variable.s

Re: What is best... define.s variable or define variable.s

Re: What is best... define.s variable or define variable.s

Re: What is best... define.s variable or define variable.s

Re: What is best... define.s variable or define variable.s

Re: What is best... define.s variable or define variable.s

Re: What is best... define.s variable or define variable.s

Re: What is best... define.s variable or define variable.s

Re: What is best... define.s variable or define variable.s

Re: What is best... define.s variable or define variable.s

Re: What is best... define.s variable or define variable.s

Re: What is best... define.s variable or define variable.s

Re: What is best... define.s variable or define variable.s