Nglib.Formula 1.1.8-beta

Nglib.Formula

Formula parser and evaluator - Expression engine for dynamic string calculations

Nglib.Formula is a powerful expression parser and evaluator that allows you to parse and execute dynamic formulas with parameters, functions, and operators.

Read Documentation

Features

• Expression Parsing: Parse complex mathematical and logical expressions
• Parameter Support: Dynamic parameter injection with @parameter syntax
• Built-in Functions: Math, string, date, and logical functions
• Custom Functions: Register your own custom functions
• Operators: Arithmetic (+, -, *, /), comparison (==, !=, <, >, ⇐, >=), logical (&&, ||)
• Type Safety: Automatic type conversion and validation
• Performance: Optimized parsing with segment caching
• Extensible: Easy to add new functions and operators

Installation

dotnet add package Nglib.Formula

Note: Requires Nglib package as dependency.

Quick Start

Simple Evaluation

using Nglib.FORMAT.FORMULA;

// Simple calculation
var result = FormulaTools.Evaluate("2 + 3 * 4"); // Returns 14

// With parameters
var context = new FormulaContext();
context.SetParameter("price", 100);
context.SetParameter("tax", 0.20);

var total = FormulaTools.Evaluate("@price * (1 + @tax)", context); // Returns 120

Using Functions

// Built-in functions
var result = FormulaTools.Evaluate("add(10, 20, 30)"); // Returns 60
var result = FormulaTools.Evaluate("mul(5, 3)"); // Returns 15
var result = FormulaTools.Evaluate("max(10, 25, 15)"); // Returns 25

// String functions
var result = FormulaTools.Evaluate("concat('Hello', ' ', 'World')"); // Returns "Hello World"
var result = FormulaTools.Evaluate("upper('hello')"); // Returns "HELLO"

// Conditional
var result = FormulaTools.Evaluate("if(10 > 5, 'yes', 'no')"); // Returns "yes"

Complex Formulas

var context = new FormulaContext();
context.SetParameter("quantity", 5);
context.SetParameter("unitPrice", 25.50);
context.SetParameter("discountRate", 0.10);

var formula = "mul(@quantity, @unitPrice) * (1 - @discountRate)";
var total = FormulaTools.Evaluate(formula, context); // Returns 114.75

Custom Functions

FormulaTools.RegisterFunction("double", args => {
    var value = Convert.ToDouble(args[0]);
    return value * 2;
});

var result = FormulaTools.Evaluate("double(21)"); // Returns 42

Segment Parsing (Advanced)

using Nglib.FORMAT.FORMULA.SEGMENT;

// Parse once, execute multiple times
var segments = FormulaSegmentParseTools.Parse("@price * (1 + @tax)");

// Execute with different contexts
var context1 = new FormulaContext();
context1.SetParameter("price", 100);
context1.SetParameter("tax", 0.20);
var result1 = FormulaTools.EvaluateSegments(segments, context1);

var context2 = new FormulaContext();
context2.SetParameter("price", 200);
context2.SetParameter("tax", 0.15);
var result2 = FormulaTools.EvaluateSegments(segments, context2);

Built-in Functions

Math

• add(x, y, ...) - Addition
• sub(x, y) - Subtraction
• mul(x, y, ...) - Multiplication
• div(x, y) - Division
• mod(x, y) - Modulo
• abs(x) - Absolute value
• max(x, y, ...) - Maximum
• min(x, y, ...) - Minimum
• round(x, decimals) - Round

String

• concat(str1, str2, ...) - Concatenate strings
• upper(str) - Uppercase
• lower(str) - Lowercase
• substring(str, start, length) - Extract substring
• length(str) - String length

Logical

• if(condition, trueValue, falseValue) - Conditional
• isnull(value, default) - Null check
• equals(x, y) - Equality check

Date

• now() - Current date/time
• dateadd(date, days) - Add days to date
• datediff(date1, date2) - Difference in days

📚 Documentation

Full documentation: https://github.com/NueGy/NgLib
Formula documentation https://github.com/NueGy/NgLib/docs/wiki_components_formula.md

🔗 Links

• GitHub Repository
• Report Issues
• NuGet Package
• View License (MIT License)
• Nuegy.net (Agency website)