Class: Lrama::States::Item

Inherits:
Struct
  • Object
show all
Defined in:
lib/lrama/states/item.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#position ⇒ Object

Returns the value of attribute position



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# File 'lib/lrama/states/item.rb', line 5

def position
  @position
end

#rule ⇒ Object

Returns the value of attribute rule



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# File 'lib/lrama/states/item.rb', line 5

def rule
  @rule
end

Instance Method Details

#beginning_of_rule? ⇒ Boolean 



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# File 'lib/lrama/states/item.rb', line 43

def beginning_of_rule?
  position == 0
end

#display_name ⇒ Object 



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# File 'lib/lrama/states/item.rb', line 67

def display_name
  r = rule.rhs.map(&:display_name).insert(position, "•").join(" ")
  "#{r}  (rule #{rule.id})"
end

#display_rest ⇒ Object

Right after position



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# File 'lib/lrama/states/item.rb', line 73

def display_rest
  r = rule.rhs[position..-1].map(&:display_name).join(" ")
  ". #{r}  (rule #{rule.id})"
end

#empty_rule? ⇒ Boolean 



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# File 'lib/lrama/states/item.rb', line 15

def empty_rule?
  rule.empty_rule?
end

#end_of_rule? ⇒ Boolean 



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# File 'lib/lrama/states/item.rb', line 39

def end_of_rule?
  rule.rhs.count == position
end

#hash ⇒ Object

Optimization for States#setup_state



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# File 'lib/lrama/states/item.rb', line 7

def hash
  [rule.id, position].hash
end

#lhs ⇒ Object 



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# File 'lib/lrama/states/item.rb', line 23

def lhs
  rule.lhs
end

#new_by_next_position ⇒ Object 



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# File 'lib/lrama/states/item.rb', line 51

def new_by_next_position
  Item.new(rule: rule, position: position + 1)
end

#next_next_sym ⇒ Object 



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# File 'lib/lrama/states/item.rb', line 31

def next_next_sym
  rule.rhs[position + 1]
end

#next_sym ⇒ Object 



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# File 'lib/lrama/states/item.rb', line 27

def next_sym
  rule.rhs[position]
end

#number_of_rest_symbols ⇒ Object 



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# File 'lib/lrama/states/item.rb', line 19

def number_of_rest_symbols
  rule.rhs.count - position
end

#previous_sym ⇒ Object 



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# File 'lib/lrama/states/item.rb', line 35

def previous_sym
  rule.rhs[position - 1]
end

#rule_id ⇒ Object 



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# File 'lib/lrama/states/item.rb', line 11

def rule_id
  rule.id
end

#start_item? ⇒ Boolean 



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# File 'lib/lrama/states/item.rb', line 47

def start_item?
  rule.id == 0 && position == 0
end

#symbols_after_dot ⇒ Object 



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# File 'lib/lrama/states/item.rb', line 59

def symbols_after_dot
  rule.rhs[position..-1]
end

#symbols_before_dot ⇒ Object 



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# File 'lib/lrama/states/item.rb', line 55

def symbols_before_dot
  rule.rhs[0...position]
end

#to_s ⇒ Object 



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# File 'lib/lrama/states/item.rb', line 63

def to_s
  "#{lhs.id.s_value}: #{display_name}"
end