Class: LatexEval::Latex

Inherits:
Object
  • Object
show all
Defined in:
lib/latex_eval/latex.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(latex) ⇒ Latex

Returns a new instance of Latex.



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# File 'lib/latex_eval/latex.rb', line 5

def initialize(latex)
  @latex = latex
  @greek_letters = [
    'Alpha',
    'alpha',
    'Beta',
    'beta',
    'Gamma',
    'gamma',
    'Delta',
    'delta',
    'Epsilon',
    'epsilon',
    'varepsilon',
    'Zeta',
    'zeta',
    'Eta',
    'eta',
    'Theta',
    'theta',
    'vartheta',
    'Iota',
    'iota',
    'Kappa',
    'kappa',
    'varkappa',
    'Lambda',
    'lambda',
    'Mu',
    'mu',
    'Nu',
    'nu',
    'Xi',
    'xi',
    'Omicron',
    'omicron',
    'Pi',
    'pi',
    'varpi',
    'Rho',
    'rho',
    'varrho',
    'Sigma',
    'sigma',
    'varsigma',
    'Tau',
    'tau',
    'Upsilon',
    'upsilon',
    'Phi',
    'phi',
    'varphi',
    'Chi',
    'chi',
    'Psi',
    'psi',
    'Omega',
    'omega',
  ]
end

Instance Attribute Details

#greek_letters ⇒ Object (readonly)

Returns the value of attribute greek_letters.



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# File 'lib/latex_eval/latex.rb', line 3

def greek_letters
  @greek_letters
end

#latex ⇒ Object (readonly)

Returns the value of attribute latex.



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# File 'lib/latex_eval/latex.rb', line 3

def latex
  @latex
end

Instance Method Details

#equation ⇒ Object 



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# File 'lib/latex_eval/latex.rb', line 66

def equation
  parsed = latex

  parsed.gsub!(/\\left/, "")
  parsed.gsub!(/\\right/, "")

  # fractions
  regex = /\\d?frac{(.*)}{(.*)}/
  while parsed.match(regex)
    parsed.gsub!(regex, '((\1)/(\2))')
  end

  # sqrt
  regex = /\\sqrt{(.*)}/
  while parsed.match(regex)
    parsed.gsub!(regex, '((\1)^(1/2))')
  end

  # nth root
  regex = /\\sqrt(\[?(.*)(?=\])\]?)?{(.*)}/
  while parsed.match(regex)
    parsed.gsub!(regex, '((\3)^(1/(\2)))')
  end

  # \cdot and \times should be *
  parsed.gsub!(/\\cdot/, "*")
  parsed.gsub!(/\\times/, "*")

  # remove remaining curly brackets 
  parsed.gsub!(/{/, "(")
  parsed.gsub!(/}/, ")")

  # cleanup variable names and multiplication
  greek_letters.each do |letter|
    parsed.gsub!(/(\\#{letter})/, ' \1 ')
  end

  # cleans up xyz to x*y*z
  regex = /((?<!\\)\b)([0-9]?[A-Za-z])([A-Za-z])/
  while parsed.match(regex)
    parsed.gsub!(regex, '\2*\3')
  end

  parsed.gsub!(/([0-9])\s+\\([A-Za-z])/, '\1*\2')
  parsed.gsub!(/([0-9])\s*?([A-Za-z])/, '\1*\2')

  parsed.gsub!(/([A-Za-z])\s+\\([A-Za-z])/, '\1*\2')
  parsed.gsub!(/([A-Za-z])\s+([A-Za-z])/, '\1*\2')

  parsed.gsub!(/([A-Za-z])\s+([0-9])/, '\1*\2')
  parsed.gsub!(/([A-Za-z])([0-9])/, '\1*\2')

  parsed.gsub!(/(\))(\()/, '\1*\2')

  parsed.gsub!(/\\/, "")

  # cleanup spaces 
  parsed.gsub!(" ", "")

  return  parsed
end