Expression Parser
Parse and evaluate mathematical and logical expressions at runtime in your Unity projects. Expression Parser compiles custom expressions with support for variables, operators, and built-in functions like MIN, MAX, ROUND, and IF conditionals. Perfect for dynamic gameplay mechanics, balancing systems, and data-driven configurations that require runtime expression evaluation.
com.codewriter.expression-parser 
Install via UPM
Add to Unity Package Manager using this URL
https://www.pkglnk.dev/expression-parser.git README Markdown
Copy this to your project's README.md
## Installation
Add **Expression Parser** to your Unity project via Package Manager:
1. Open **Window > Package Manager**
2. Click **+** > **Add package from git URL**
3. Enter:
```
https://www.pkglnk.dev/expression-parser.git
```
[](https://www.pkglnk.dev/pkg/expression-parser)README
Expression Parser 
Simple expression parser library for unity
Quick Sample
// create context
var context = new ExpresionContext<float>();
// register some variables
context.RegisterVariable("a", () => 1);
context.RegisterVariable("b", () => 2);
context.RegisterVariable("c", () => 3);
var input = "a >= b AND NOT(b) OR (a + b) >= c";
// compile expression
var compiledExpr = FloatExpressionParser.Instance.Compile(input, context, true);
// execute expression
var result = compiledExpr.Invoke();
Create your own ExpressionParser implementation to support other data types
Language Overview
Constants
| Input | Value |
|---|---|
| TRUE | 1 |
| FALSE | 0 |
Numbers
| Input | Value |
|---|---|
| 123 | 123.0 |
| 123.0 | 123.0 |
| 123.4 | 123.4 |
Operators
| Name | Sample | Precedence |
|---|---|---|
| Unary Minus | -2 | 0 |
| Power | 2 ^ 3 | 1 (!!!, -2^2 = (-2) ^ 2 = 4) |
| Multiply | 2 * 3 | 2 |
| Divide | 6 / 3 | 2 |
| Module | 5 % 3 | 2 |
| Addition | 2 + 3 | 3 |
| Subtraction | 3 - 2 | 3 |
| Less Than | 2 < 3 | 4 |
| Less Than Or Equal | 2 <= 3 | 4 |
| Greater Than | 2 > 3 | 4 |
| Greater Than Or Equal | 2 >= 3 | 4 |
| Equality | 2 = 3 | 5 |
| Inequality | 2 != 3 | 5 |
| Logical and | 2 > 1 AND 3 > 2 | 6 |
| Logical or | 2 = 3 OR 2 != 4 | 6 |
Variables
Creation of custom variables is supported. Variable name must starts with english letter or underscore. The rest of the variable name may also contains digits.
Functions
| Name | Sample | Description |
|---|---|---|
| NOT | NOT(TRUE) | Returns FALSE if argument is true, otherwise TRUE |
| IF | IF(n < 5, 5, n < 25, 25, 50) | Returns the second argument if the first argument is true, returns the fourth argument if the third argument is true, and so on. Otherwise, returns the last argument. Odd number of arguments required |
| MIN | MIN(0, 1, ...) | Returns smallest argument |
| MAX | MAX(0, 1, ...) | Returns largest argument |
| ROUND | ROUND(1.1) | Rounds a number |
| CEILING | CEILING(1.1) | Round number up |
| FLOOR | FLOOR(1.1) | Rounds number down |
| LOG | LOG(8, 2) | Returns the logarithm to base B of number A |
How to Install
Minimal Unity Version is 2020.1.
Library distributed as git package (How to install package from git URL)
Git URL: https://github.com/codewriter-packages/Expression-Parser.git
License
Expression-Parser is MIT licensed.
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