Class: Parser::Lexer::StackState

Inherits:
Object
  • Object
show all
Defined in:
lib/parser/lexer/stack_state.rb

Instance Method Summary collapse

Constructor Details

#initialize(name) ⇒ StackState

Returns a new instance of StackState.



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# File 'lib/parser/lexer/stack_state.rb', line 6

def initialize(name)
  @name  = name.freeze
  clear
end

Instance Method Details

#active? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/parser/lexer/stack_state.rb', line 34

def active?
  @stack[0] == 1
end

#clear ⇒ Object 



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# File 'lib/parser/lexer/stack_state.rb', line 11

def clear
  @stack = 0
end

#empty? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/parser/lexer/stack_state.rb', line 38

def empty?
  @stack == 0
end

#lexpop ⇒ Object 



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# File 'lib/parser/lexer/stack_state.rb', line 29

def lexpop
  @stack = ((@stack >> 1) | (@stack & 1))
  @stack[0] == 1
end

#pop ⇒ Object 



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# File 'lib/parser/lexer/stack_state.rb', line 22

def pop
  bit_value = @stack & 1
  @stack  >>= 1

  bit_value == 1
end

#push(bit) ⇒ Object 



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# File 'lib/parser/lexer/stack_state.rb', line 15

def push(bit)
  bit_value = bit ? 1 : 0
  @stack = (@stack << 1) | bit_value

  bit
end

#to_s ⇒ Object Also known as: inspect 



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# File 'lib/parser/lexer/stack_state.rb', line 42

def to_s
  "[#{@stack.to_s(2)} <= #{@name}]"
end