Class: Keisan::StringAndGroupParser

Inherits:
Object
  • Object
show all
Defined in:
lib/keisan/string_and_group_parser.rb

Defined Under Namespace

Classes: GroupPortion, OtherPortion, Portion, StringPortion

Constant Summary collapse

STRING_CHARACTER_REGEX = 
/["']/
OPEN_GROUP_REGEX = 
/[\(\{\[]/
CLOSED_GROUP_REGEX = 
/[\)\}\]]/

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(expression, start_index: 0, ending_character: nil) ⇒ StringAndGroupParser

Ending character is used as a second ending condition besides expression size



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# File 'lib/keisan/string_and_group_parser.rb', line 160

def initialize(expression, start_index: 0, ending_character: nil)
  index = start_index
  @portions = []

  while index < expression.size && (ending_character.nil? || expression[index] != ending_character)
    case expression[index]
    when STRING_CHARACTER_REGEX
      portion = StringPortion.new(expression, index)
      index = portion.end_index
      @portions << portion

    when OPEN_GROUP_REGEX
      portion = GroupPortion.new(expression, index)
      index += portion.size
      @portions << portion

    when CLOSED_GROUP_REGEX
      raise Keisan::Exceptions::TokenizingError.new("Tokenizing error, unexpected closing brace #{expression[start_index]}")

    else
      portion = OtherPortion.new(expression, index)
      index += portion.size
      @portions << portion
    end
  end

  @size = index - start_index
end

Instance Attribute Details

#portions ⇒ Object (readonly)

An ordered array of “portions”, which



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# File 'lib/keisan/string_and_group_parser.rb', line 153

def portions
  @portions
end

#size ⇒ Object (readonly)

An ordered array of “portions”, which



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# File 'lib/keisan/string_and_group_parser.rb', line 153

def size
  @size
end

Instance Method Details

#to_s ⇒ Object 



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# File 'lib/keisan/string_and_group_parser.rb', line 189

def to_s
  portions.map(&:to_s).join
end