Maximum Length Limit for a Macro

@jamies
I was unaware of the semicolon (;) separator; perhaps you meant the colon (:) separator.

James suggests “put multiple VBA commands on 1 line using the ‘ ; ‘ separator”. I agree this can be done especially in declarations.

However, I’d strongly advise against using this method. One of the aims of your VBA code should be that it’s well laid out and easily readable both for yourself and anyone who may have to maintain it later.

To that end best VBA practice is:
1. one statement per line
2. indent blocks
3. add comments to your code
4. leave blank lines in your code so that complete logical blocks stand out
5. write using subroutines that have well chosen (meaningful) names

Remember your goal should be code that is both reliable and maintainable.

There’s no benefit from either writing the longest possible macro (the stated question). Going to the other extreme and artificially shortening it by putting many statements on the same line is worse. It will confuse the reader (even if it doesn’t confuse VBA’s parser), make the code more difficult to test, debug and maintain.

“A very long macro in Excel—over 1,400 lines”; really? That’s simply TOO long. It’s too long for any programming language or any application.

Skilled programmers write code in a well-structured way that does not ramble over many pages.

I’d be certain that recoding this monster 1,400 into smaller macros and making use of reusable code (instead of just replicating it) will make the code easier to read, easier to maintain and more reliable.

Put multiple VBA commands on 1 line using the " ; " separator
But, ( from experience) there are some combinations that confuse the Syntax decoder.
So have a backup copy of the code and do the multi-line conversion in steps - making it easier to go back to undo a block of changes.

And when using VBA remember you should (usually) be using .VALUE2 rather than accepting the implied default of .VALUE

I have a code, which is generated by a script, which is about 10000 lines. I can generate code for VBA, PHP, JavaScript, etc. It runs fine everywhere except Excel.. VBA no problem in LibreOffice for instance.

Another excellent resource is Excel 2013: Power Programming with VBA, by John Walkenbach, ISBN 978-1-118-49039-6, especially chapters 6-9.

One significant advantage of coding your macros in the modular fashion described in this tip is that they are easier to debug for many reasons. Of these, the most significant is that you can divide and conquer by debugging each private routine separately. The easiest way to do this is by temporarily marking it as Public, then writing code that calls it in the Immediate Window. Another way to accomplish this is by writing a one-statement test routine, which lives in the module, and can be marked as Public as needed for testing, then marked as Private to hide it. Whether you call the test routine from the Immediate Window or put the cursor inside it and hit F5, the macro under test can call Debug.Print to write messages in the Immediate Window. These messages can either display intermediate values or be breadcrumbs that document the actual flow of execution.

Another significant advantage of modular coding is that each macro has fewer variables in scope. Not only is this fewer moving parts for you to monitor and manage, but it decreases the risk of accidentally changing a variable that was intended for the sole use of another part of the overall program.

Another side effect of breaking big code into modules is that you can reuse code. When the overall routine needs to do the same thing at several points in its process, it can call a subroutine, which can remain private. Moreover, by passing arguments (parameters) into the subroutine, it can use different data each time it is called.

Finally, breaking a big procedure into smaller chunks simplifies the code, making it easier to get your head around what the routine is doing.

Whoa 1,400 lines in one Sub. The author of the macro might want to read Robert Martin's book Clean Code (he also has quite a few youtube videos)
I can't find an equivalent book using VBA in the examples but the principles are the same.