Math-Interpreter-VBA

Description

A fully functional mathematical expression interpreter built entirely in VBA (Visual Basic for Applications).
It parses and evaluates math expressions with correct precedence, associativity, and unary operator support,
making it ideal for Excel macros, Office automation, or just exploring compiler logic in VBA.

How to use

First you have to download the module, and import it on PowerPoint or Excel.
After that you should be able to use the function Evaluate to calculate an expression in a String.

' It returns the result in a string.
Eval.Evaluate(Expression)   

Features

✅ Built from scratch using the Shunting Yard algorithm
Parses infix expressions into postfix (RPN)
Evaluates expressions with:

Supported	Description
+ - * / ^	Arithmetic operators
()	Parentheses for grouping
-x, +x	Unary operators (e.g., -5)
1.5	Decimal numbers

⚠️ Note: Unlike the built-in VBA.Evaluate, this interpreter correctly handles the ^ operator as right-associative. For example:

• 2^2^2^2 is interpreted as 2^(2^(2^2)) → 65536
• In contrast, VBA.Evaluate("2^2^2^2") incorrectly returns 256, due to left-associative parsing.