TexToUnicode

A Ruby gem that converts TeX mathematical and other symbols to their Unicode character equivalents, enabling easier display of mathematical notation in plain text.

Installation

Install the gem locally:

gem build tex_to_unicode.gemspec
gem install tex_to_unicode-0.1.0.gem

Or add it to your Gemfile:

gem 'tex_to_unicode'

Usage

Command Line

The gem provides a tex_to_unicode executable that converts TeX expressions passed as arguments:

# Basic usage
tex_to_unicode '\alpha + \beta = \gamma'
# Output: α + β = γ

# Greek letters
tex_to_unicode '\pi \approx 3.14159'
# Output: π ≈ 3.14159

# Math operators
tex_to_unicode 'x \times y \leq z'
# Output: x × y ≤ z

# Arrows
tex_to_unicode 'A \rightarrow B \Rightarrow C'
# Output: A → B ⇒ C

# Integrals and sums
tex_to_unicode '\int_0^\infty x^2 dx'
# Output: ∫₀∞ x² dx

# Set notation
tex_to_unicode 'x \in \mathbb{R}, y \notin \emptyset'
# Output: x ∈ ℝ, y ∉ ∅

# Complex expressions
tex_to_unicode '\forall x \exists y : x \leq y'
# Output: ∀ x ∃ y : x ≤ y

Ruby API

You can also use the gem in your Ruby code:

require 'tex_to_unicode'

# Convert TeX to Unicode
result = TexToUnicode.convert('\alpha + \beta = \gamma')
puts result  # => α + β = γ

# Use in string interpolation
formula = '\sum_{i=1}^n i'
puts "The formula is: #{TexToUnicode.convert(formula)}"
# Output: The formula is: ∑i=1ⁿ i

Supported Symbols

The gem supports a wide range of TeX symbols including:

Greek Letters

• Lowercase: \alpha, \beta, \gamma, \delta, \epsilon, \theta, \lambda, \mu, \pi, \sigma, \phi, \omega, etc.
• Uppercase: \Gamma, \Delta, \Theta, \Lambda, \Pi, \Sigma, \Phi, \Omega, etc.

Math Operators

• \pm (±), \times (×), \div (÷), \cdot (·)
• \oplus (⊕), \otimes (⊗), \ast (∗)

Relations

• \leq (≤), \geq (≥), \neq (≠), \approx (≈)
• \equiv (≡), \sim (∼), \propto (∝)
• \subset (⊂), \supset (⊃), \in (∈), \notin (∉)

Arrows

• \rightarrow or \to (→), \leftarrow (←), \leftrightarrow (↔)
• \Rightarrow (⇒), \Leftarrow (⇐), \Leftrightarrow (⇔)
• \uparrow (↑), \downarrow (↓)

Calculus & Analysis

• \int (∫), \sum (∑), \prod (∏)
• \partial (∂), \nabla (∇), \infty (∞)

Logic & Set Theory

• \forall (∀), \exists (∃), \neg (¬)
• \land (∧), \lor (∨), \cap (∩), \cup (∪)
• \emptyset (∅), \therefore (∴), \because (∵)

Superscripts & Subscripts

• Superscripts: ^0 through ^9 (⁰¹²³⁴⁵⁶⁷⁸⁹), ^i (ⁱ), ^n (ⁿ)
• Superscript symbols: ^+ (⁺), ^- (⁻), ^= (⁼), ^( (⁽), ^) (⁾)
• Subscripts: _0 through _9 (₀₁₂₃₄₅₆₇₈₉)
• Subscript symbols: _+ (₊), _- (₋), _= (₌), _( (₍), _) (₎)
• Note: Unicode has limited super/subscript characters; unsupported characters will display normally

Brackets

• \langle, \rangle (⟨⟩)
• \lceil, \rceil (⌈⌉)
• \lfloor, \rfloor (⌊⌋)

Miscellaneous

• \checkmark (✓), \degree (°), \copyright (©)
• \dots (…), \cdots (⋯)
• Musical symbols: \sharp (♯), \flat (♭), \natural (♮)

Examples

# Quadratic formula
tex_to_unicode 'x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}'
# Output: x = -b ± √(b² - 4ac)/2a

# Euler's identity
tex_to_unicode 'e^{i\pi} + 1 = 0'
# Output: eⁱπ + 1 = 0

# Set theory
tex_to_unicode 'A \cup B = \{x : x \in A \lor x \in B\}'
# Output: A ∪ B = {x : x ∈ A ∨ x ∈ B}

# Calculus
tex_to_unicode '\int_a^b f(x)dx = F(b) - F(a)'
# Output: ∫ₐᵇ f(x)dx = F(b) - F(a)

Limitations

While Unicode provides many mathematical symbols, some TeX constructs cannot be perfectly represented:

• Complex fractions are approximated
• Matrices and arrays have limited support
• Some accents and diacritics are approximated
• Subscripts and superscripts support limited characters due to Unicode constraints:
  • Supported superscripts: digits (⁰¹²³⁴⁵⁶⁷⁸⁹), letters i and n (ⁱⁿ), and symbols ⁺⁻⁼⁽⁾
  • Supported subscripts: digits (₀₁₂₃₄₅₆₇₈₉) and symbols ₊₋₌₍₎
  • Unsupported characters (like ^\infty, ^\alpha, _\beta) will have the ^ or _ marker removed and display as regular characters
  • Example: \int_0^\infty becomes ∫₀∞ (not ∫₀^∞ with superscript infinity, as Unicode has no superscript ∞)

Development

To build and test locally:

# Build the gem
gem build tex_to_unicode.gemspec

# Install locally
gem install tex_to_unicode-0.1.0.gem

# Test the executable
tex_to_unicode '\alpha + \beta'

Contributing

Bug reports and pull requests are welcome!

License

This gem is available as open source under the terms of the MIT License.