math_latex_builder 1.0.11

A Dart package to programmatically build and manipulate LaTeX math expressions using a tree-based structure.

Math LaTeX Builder

A powerful and intuitive Dart package to programmatically build, manipulate, and render LaTeX math expressions using a tree-based structure.

Say goodbye to messy string concatenation. This package provides a robust object-oriented approach to handle complex math formulas with ease, making it ideal for educational apps, scientific calculators, or any Flutter/Dart project that requires dynamic LaTeX generation.

Key Features

• 🌳 Intuitive Tree-Based Model: Represents LaTeX expressions as a logical tree of nodes (like fractions, roots) and leaves (like numbers, operators). This makes complex expressions easy to manage.
• ✍️ Cursor-Based Navigation and Editing: Programmatically move a cursor up, down, left, or right through the expression tree to insert or delete elements at any position.
• 🧮 Rich Set of LaTeX Elements: Out-of-the-box support for common elements including fractions, square/cube/nth roots, powers, functions, and inverse functions.
• 🚀 Pure Dart & Flutter Compatible: Written in 100% Dart, ensuring seamless integration with any Dart or Flutter project on any platform.
• ⚡️ Efficient & Reactive: Uses a dirty-checking mechanism to ensure that only modified parts of the expression are recomputed, providing excellent performance.

Visuals

It is highly recommended to add a screenshot or a GIF to demonstrate the package in action, as it is a UI-based package.

Core Concept: The LaTeX Tree

Think of LaTeXTree as a structured text editor for math. Instead of a flat string, your expression lives in a tree.

• LaTeXTree: The main class you interact with. It holds the entire expression.
• The Cursor (Active Node): The tree always has a "cursor" (an active node) that determines where new elements will be placed.
• LaTeXNode: A structural element that can have children. Examples:
  • fractionNode: Has a numerator and a denominator node.
  • squareRootNode: Contains the radicand.
  • nthRootNode: Has an indexOfRoot and a radicand.
• LaTeXLeaf: A content element, like a number (5), an operator (+), or a variable (x). Leaves are the actual content of your expression.

When you add a node, the cursor automatically moves into the logical first part of that node (e.g., into the numerator of a fraction), ready for you to add more elements.

Getting Started

Add this to your pubspec.yaml file:

dependencies:
  math_latex_builder: ^1.0.11 # Use the latest version

Then, run flutter pub get or dart pub get.

Import the package in your Dart file:

import 'package:math_latex_builder/math_latex_builder.dart';

Usage Examples

Simple Example: 5+1

The | character in the output string represents the current cursor position.

import 'package:math_latex_builder/math_latex_builder.dart';

void main() {
  // 1. Create a tree instance.
  final tree = LaTeXTree();
  print(tree.toLaTeXString); // Output: |

  // 2. Add a number leaf. The cursor moves after it.
  tree.addChildLeaf(LEType.numberLeaf, "5");
  print(tree.toLaTeXString); // Output: 5|

  // 3. Add an operator leaf.
  tree.addChildLeaf(LEType.operatorLeaf, "+");
  print(tree.toLaTeXString); // Output: 5+|

  // 4. Add another number leaf.
  tree.addChildLeaf(LEType.numberLeaf, "1");
  print(tree.toLaTeXString); // Output: 5+1|
}

Advanced Example: Building a Fraction

To build a fraction like 2 + 8/5, you need to add a fractionNode and then populate its numerator and denominator.

final tree = LaTeXTree();

// Build "2+"
tree.addChildLeaf(LEType.numberLeaf, "2");
tree.addChildLeaf(LEType.operatorLeaf, "+");
print(tree.toLaTeXString); // Output: 2+|

// Add a fraction node. The cursor automatically moves to the numerator.
tree.addChildNode(LEType.fractionNode);
print(tree.toLaTeXString); // Output: 2+\frac{ |}{\square}

// Add the numerator.
tree.addChildLeaf(LEType.numberLeaf, "8");
print(tree.toLaTeXString); // Output: 2+\frac{8|}{\square}

// Move the cursor down to the denominator.
tree.moveDown();
print(tree.toLaTeXString); // Output: 2+\frac{8}{ |}

// Add the denominator.
tree.addChildLeaf(LEType.numberLeaf, "5");
print(tree.toLaTeXString); // Output: 2+\frac{8}{5|}

Inverse Function Example

final tree = LaTeXTree();

tree.addChildNode(LEType.inverseFunctionNode, content: 'sin');
tree.addChildLeaf(LEType.numberLeaf, '0');
tree.addChildLeaf(LEType.symbolLeaf, '.');
tree.addChildLeaf(LEType.numberLeaf, '5');

print(tree.toLaTeXString); // Output: \sin(0.5|)^{-1}

Complex Example

Here is the code to generate the expression 4+\frac{15-\sqrt{7}}{\sqrt[9]{\frac{3}{8}}}.

final tree = LaTeXTree();

tree.addChildLeaf(LEType.numberLeaf, "4");
tree.addChildLeaf(LEType.operatorLeaf, "+");

// Create the main fraction
tree.addChildNode(LEType.fractionNode); // Cursor moves to numerator

// Build the numerator: 15-\sqrt{7}
tree.addChildLeaf(LEType.numberLeaf, "1");
tree.addChildLeaf(LEType.numberLeaf, "5");
tree.addChildLeaf(LEType.operatorLeaf, "-");
tree.addChildNode(LEType.squareRootNode); // Cursor moves into sqrt
tree.addChildLeaf(LEType.numberLeaf, "7");

// Move from the numerator to the denominator
tree.moveDown(); // Cursor is now in the denominator

// Build the denominator: \sqrt[9]{\frac{3}{8}}
tree.addChildNode(LEType.nthRootNode); // Cursor moves to the root's index
tree.addChildLeaf(LEType.numberLeaf, "9");

tree.moveRight(); // Cursor moves to the radicand (the content of the root)
tree.addChildNode(LEType.fractionNode); // Cursor moves to the inner fraction's numerator
tree.addChildLeaf(LEType.numberLeaf, "3");

tree.moveDown(); // Cursor moves to the inner fraction's denominator
tree.addChildLeaf(LEType.numberLeaf, "8");

// Final result with cursor at the end
print("result : ${tree.toLaTeXString}");
// 4+\frac{15-\sqrt{7}}{\sqrt[9]{\frac{3}{8|}}}

API Reference

• LaTeXTree: The main class.
  • addChildLeaf(LEType type, String content): Adds a content leaf.
  • addChildNode(LEType type, {String content = ""}): Adds a structural node.
  • moveUp(), moveDown(), moveLeft(), moveRight(): Navigates the cursor.
  • delete(): Deletes the element or node to the left of the cursor.
  • clear(): Clears the entire expression.
  • toLaTeXString: Gets the rendered LaTeX string.
• LEType: An enum representing all possible types of leaves and nodes you can add.

Advanced Topics

• Handling User Input: Connect the LaTeXTree methods to a custom keyboard or UI buttons to allow users to build expressions interactively.
• Custom Styling: Since this package generates a LaTeX string, you can use a rendering package (like flutter_math_fork) to control the color, font size, and style of the rendered output.
• Extending with New Elements: You can extend the package by creating your own LaTeXNode or LaTeXLeaf subclasses to support custom LaTeX commands or structures.

Contributing

Contributions are welcome! If you find a bug or have a feature request, please file an issue. If you want to contribute code, please feel free to open a pull request.

License

This package is licensed under the MIT License.