Visual Basic for Applications:
Using an interactive shell (REPL)

How to:

Visual Basic for Applications (VBA) itself does not natively support an interactive shell or REPL experience as seen in languages like Python or JavaScript. However, you can simulate this experience to a certain extent using the Immediate Window in the VBA IDE (Integrated Development Environment).

Accessing the Immediate Window:

1. Open the VBA IDE by pressing Alt + F11 in your Office application.
2. If the Immediate Window is not visible, you can open it by pressing Ctrl + G or selecting it from the View menu.

Using the Immediate Window as a REPL:

• To execute a line of code, simply type it in the Immediate Window and press Enter. For example:

Debug.Print 2 + 2

• Sample Output:

 4

• You can also call functions and subroutines defined in your modules:

Public Sub SayHello()
    Debug.Print "Hello, World!"
End Sub

• And then in the Immediate Window:

Call SayHello

• Sample Output:

 Hello, World!

Note: The Immediate Window has limitations. It’s excellent for quick tests and direct function calls, but it doesn’t support defining functions or subroutines directly within it. Complex debugging and programming tasks might require full module development.

Deep Dive

The Immediate Window in VBA serves as the closest counterpart to interactive shells found in other programming ecosystems, despite its limitations. Historically, VBA has been focused on extending the capabilities of Microsoft Office applications through scripts and macros rather than standalone software development, which might explain the absence of a full-fledged REPL.

For tasks requiring extensive interactive testing or complex logic development, other programming environments equipped with native REPL support, such as Python with its IDLE, or JavaScript with Node.js, might offer better alternatives. These environments provide not only interactive shells but also more robust programming, debugging, and testing facilities.

The Immediate Window does provide an invaluable tool for quickly testing expressions, running functions, and directly manipulating Office application objects. As such, it occupies a vital niche within the VBA development process, offering an immediacy and convenience unmatched by more traditional compile-run-debug cycles, albeit with the understood constraints of its operational scope.