Class: Romanesco::Tokeniser

Inherits:
Object
  • Object
show all
Defined in:
lib/romanesco/tokeniser.rb

Constant Summary collapse

TOKEN_TYPES = 
[
    {name: 'addition', regex: /^\+/, token_class: AdditionToken},
    {name: 'multiplication', regex: /^\*/, token_class: MultiplicationToken},
    {name: 'subtraction', regex: /^\-/, token_class: SubtractionToken},
    {name: 'division', regex: /^\//, token_class: DivisionToken},
    {name: 'open parenthesis', regex: /^\(/, token_class: OpenParenthesisToken},
    {name: 'close parenthesis', regex: /^\)/, token_class: CloseParenthesisToken},
    {name: 'constant', regex: /^[0-9]*\.?[0-9]+/, token_class: ConstantToken},
    {name: 'string', regex: /^[a-zA-Z_]+/, token_class: VariableToken}
]

Instance Method Summary collapse

Instance Method Details

#tokenise(raw_expression) ⇒ Object 



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# File 'lib/romanesco/tokeniser.rb', line 17

def tokenise(raw_expression)
  expression = remove_commas_and_whitespace(raw_expression)

  tokens = []

  while expression.length > 0
    token_count = tokens.count
    TOKEN_TYPES.each do |type|
      if expression =~ type[:regex]
        token_string = expression.slice!(type[:regex])
        tokens << type[:token_class].send(:new, token_string)
      end
    end

    raise InvalidExpressionError.new("Expression error starting at #{expression}") if tokens.size == token_count
  end

  tokens
end