Class: Dendroid::GrmAnalysis::AlternativeItem

Inherits:
DottedItem
  • Object
show all
Defined in:
lib/dendroid/grm_analysis/alternative_item.rb

Overview

A specialization of DottedItem specific for Choice (rule)

Instance Attribute Summary collapse

Attributes inherited from DottedItem

#position, #rule

Instance Method Summary collapse

Methods inherited from DottedItem

#expecting?, #initial_pos?, #intermediate_pos?, #pre_scan?, #state

Constructor Details

#initialize(aChoice, aPosition, index) ⇒ AlternativeItem

Constructor.



16
17
18
19
 
# File 'lib/dendroid/grm_analysis/alternative_item.rb', line 16

def initialize(aChoice, aPosition, index)
  @alt_index = index
  super(aChoice, aPosition)
end

Instance Attribute Details

#alt_index ⇒ Integer (readonly) 



10
11
12
 
# File 'lib/dendroid/grm_analysis/alternative_item.rb', line 10

def alt_index
  @alt_index
end

Instance Method Details

#==(other) ⇒ Boolean

Test for equality with another dotted item. Two dotted items are equal if they refer to the same rule and have both the same rhs and dot positions.



55
56
57
58
59
 
# File 'lib/dendroid/grm_analysis/alternative_item.rb', line 55

def ==(other)
  return true if eql?(other)

  (position == other.position) && rule.eql?(other.rule) && (alt_index == other.alt_index)
end

#empty? ⇒ Boolean

Indicate whether the rhs of the alternative is empty



31
32
33
 
# File 'lib/dendroid/grm_analysis/alternative_item.rb', line 31

def empty?
  rule.alternatives[alt_index].empty?
end

#final_pos? ⇒ Boolean Also known as: completed?

Indicate whether the dot is at the start of rhs



37
38
39
 
# File 'lib/dendroid/grm_analysis/alternative_item.rb', line 37

def final_pos?
  empty? || position == rule.alternatives[alt_index].size
end

#next_symbol ⇒ Dendroid::Syntax::GrmSymbol, NilClass

Return the symbol right after the dot (if any)



45
46
47
48
49
 
# File 'lib/dendroid/grm_analysis/alternative_item.rb', line 45

def next_symbol
  return nil if empty? || completed?

  rule.alternatives[alt_index].members[position]
end

#to_s ⇒ String

Return a String representation of the alternative item.



23
24
25
26
27
 
# File 'lib/dendroid/grm_analysis/alternative_item.rb', line 23

def to_s
  rhs_names = rule.alternatives[alt_index].members.map(&:to_s)
  dotted_rhs = rhs_names.insert(position, '.')
  "#{rule.head} => #{dotted_rhs.join(' ')}"
end