Why dim? or what does it mean?

[lezawang]

Hi
I did google search to find out why in VBA dim keyword is used. What does that mean? I know it means Dimension, but why that keyboard? Is not easier to define a variable like this:

int x (like Java)

Or

x as int (actually this is used when you define a custom function argument in vba)

I am puzzled why Microsoft people use the word Dim?

https://www.thespreadsheetguru.com/blog/2014/2/19/what-does-dim-mean-when-coding-vba-macros

 

[SpillerBD]

Microsoft people?
It was just the convention began in other programming languages of the time.
JAVA and BASIC (and Visual BASIC) were born in different decades.
...and its declaring variables.

 

[joeu2004]

The BASIC language predates MSFT by nearly 20 years. And even though I was there near the beginning and I was responsible for developing a commercial BASIC interpreter and compiler, I'm afraid those brain cells have weakened with time. But I do find some online references to confirm and refresh my recollections.

In the beginning, there were only numeric and string variables. A string variable name had a "$" suffix; otherwise, it was a "real" numeric variable (floating-point). No declaration was necessary.

The DIM statement was used only to declare the dimensions of arrays.

Much later, data typing was added in a variety of ways. There was no standard. (There is an ANSI standard now. But I cannot find a free reference online.)

Some versions of BASIC used a suffix (e.g. "%") for "integer" numeric variables. Some versions of BASIC had DECLARE and DEFINE.type statements. Some versions had INTEGER, SINGLE and DOUBLE statements.

And yes, MSFT VB extended the use of the DIM statement.

(Although one version of BASIC that I believe predates MSFT VB did allow for declaring non-array "real" variables names in the DIM statement. Again, the type was implied.)

 

[Michael M]

AND if you use Option Explicit in your code, and don't declare a variable, VBA will give you and error that you haven't declared your variable.
If you reread your link....halfway down the page...he tells you why you should declare !

 

[joeu2004]

And yes, MSFT VB extended the use of the DIM statement.

Also note the Deftype statements; for example, DefInt, DefDbl, etc. But these are limited to the module level; that is, outside any procedure.

In another forum, someone speculated that MSFT extended DIM instead of creating one or more new statement types (e.g. DECLARE) in deference to backward-compatibility. I had thought of that, too. But I decided that is probably incorrect, since MSFT introduced other new statement types in VB.

I suspect that MSFT extended the DIM statement because it is was easier to integrate into the parser for the pre-existing versions of MSFT BASIC, and it might have required less additional programming. The issue is not the development effort, but the amount of memory required for the BASIC language processor. The DIM statement already had the components that are necessary to add a new variable.

Bear in mind that these language extensions came at time when computer memory was measured in KBs (multiples of 1024) and MBs, not GBs.