latex_math_evaluator 0.1.0

A Dart library for parsing and evaluating mathematical expressions in LaTeX format.

LaTeX Math Evaluator

A Flutter/Dart library for parsing and evaluating mathematical expressions written in LaTeX format.

Features

• Parse LaTeX math expressions into an Abstract Syntax Tree
• Evaluate expressions with variable bindings
• 30+ built-in functions: trigonometry, logarithms, rounding, and more
• Mathematical constants: π, e, φ, γ, τ, and others
• Summation & Product notation: \sum_{i=1}^{n}, \prod_{i=1}^{n}
• Limit notation: \lim_{x \to a}
• Numerical Integration: \int_{a}^{b} f(x) dx (Simpson's Rule)
• Matrix support: \begin{matrix} ... \end{matrix} with operations (+, -, *, ^T, ^-1) and \det
• Extensible: Add custom functions and commands

Installation

Add to your pubspec.yaml:

dependencies:
  latex_math_evaluator: 0.0.2

# or for the latest version

dependencies:
  latex_math_evaluator:
    git:
      url: https://github.com/xirf/latex_math_evaluator.git

Quick Start

import 'package:latex_math_evaluator/latex_math_evaluator.dart';

final evaluator = LatexMathEvaluator();

// Basic arithmetic
evaluator.evaluate(r'2 + 3 \times 4');  // 14.0

// Variables
evaluator.evaluate(r'x^{2} + 1', {'x': 3});  // 10.0

// Functions
evaluator.evaluate(r'\sin{0}');            // 0.0
evaluator.evaluate(r'\sqrt{16}');          // 4.0
evaluator.evaluate(r'\log_{2}{8}');        // 3.0

// Matrices
final matrix = evaluator.evaluate(r'\begin{matrix} 1 & 2 \\ 3 & 4 \end{matrix}');
// Returns a Matrix object

evaluator.evaluate(r'|-5|');               // 5.0 (absolute value)
evaluator.evaluate(r'\frac{1}{2}');        // 0.5 (fraction)

// Constants (used when variable not provided)
evaluator.evaluate('e');                    // 2.71828...
evaluator.evaluate(r'\pi');                 // 3.14159...

// Summation
evaluator.evaluate(r'\sum_{i=1}^{5} i');   // 15.0 (1+2+3+4+5)

// Factorial
evaluator.evaluate(r'\prod_{i=1}^{5} i');  // 120.0 (5!)

Supported Functions

Category	Functions
Trigonometric	\sin, \cos, \tan, \asin, \acos, \atan
Hyperbolic	\sinh, \cosh, \tanh
Logarithmic	\ln, \log, \log_{base}
Rounding	\ceil, \floor, \round
Power/Root	\sqrt, \exp
Other	\abs, `

Also support equation with domain constraints: f(x) = 2x - 3, 3 < x < 5

Built-in Constants

LaTeX constants can be used with backslash notation:

Name	LaTeX	Symbol	Value
e	\e	e	2.71828...
pi	\pi	π	3.14159...
tau	\tau	τ	6.28318...
phi	\phi	φ	1.61803...
gamma	\gamma	γ	0.57721...
Omega	\Omega	Ω	0.56714...
delta	\delta	δ	2.41421...

User-provided variables override built-in constants.

Notation Support

% Fractions
\frac{numerator}{denominator}
\frac{a + b}{c}

% Summation
\sum_{i=1}^{10} i^{2}

% Product
\prod_{i=1}^{5} i

% Limits (numeric approximation)
\lim_{x \to 0} \sin{x}

% Absolute value
|x|
|x^2 - 4|

% Constants
\pi, \tau, \phi, \gamma

Custom Extensions

import 'dart:math' as math;

final registry = ExtensionRegistry();

// Register custom command
registry.registerCommand('cbrt', (cmd, pos) =>
  Token(type: TokenType.function, value: 'cbrt', position: pos));

// Register custom evaluator
registry.registerEvaluator((expr, vars, evaluate) {
  if (expr is FunctionCall && expr.name == 'cbrt') {
    return math.pow(evaluate(expr.argument), 1/3).toDouble();
  }
  return null;
});

final evaluator = LatexMathEvaluator(extensions: registry);
evaluator.evaluate(r'\cbrt{27}');  // 3.0

Documentation

See the doc/ folder for detailed documentation:

• Getting Started
• Functions
• Notation
• Constants
• Extensions

License

MIT License - see LICENSE file.