Class: Ibex::LALR::IELR::StateSplitter

Inherits:
Object
  • Object
show all
Defined in:
lib/ibex/lalr/ielr/state_splitter.rb

Overview

Splits LR(0) isocores only where an inadequacy would change the resolved action. New states copy their transition arrays; no mutable transition table is shared between isocores.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(grammar, states, transitions, items, goto_follows, resolver: nil) ⇒ StateSplitter

rubocop:disable Metrics/AbcSize -- initialization wires the phase tables once.



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# File 'lib/ibex/lalr/ielr/state_splitter.rb', line 29

def initialize(grammar, states, transitions, items, goto_follows, resolver: nil)
  @grammar = grammar
  @base_states = states
  @base_transitions = transitions
  @base_items = items
  @goto_follows = goto_follows
  @resolver = resolver || ConflictResolver.new(grammar)
  @kernel_cores = states.map { |state| kernel_items(state) }
  annotator = Annotator.new(grammar, states, transitions, items, goto_follows, resolver: @resolver)
  @annotations = annotator.build
  @inadequacies = annotator.inadequacies
  @split_stable_discarded = annotator.split_stable_discarded
  @item_lookaheads = annotator.item_lookaheads
  @states = states.each_with_index.map do |_state, state_id|
    SplitState.new(core: @kernel_cores.fetch(state_id),
                   transitions: transitions.fetch(state_id).sort_by(&:first).map(&:dup),
                   lalr_isocore: state_id)
  end
  @lalr_isocores = states.each_index.to_a
  @isocore_nexts = states.each_index.to_a
  @lookaheads_recomputed = Array.new(states.length, false)
  @lookahead_sets = states.each_with_index.map do |_state, state_id|
    @kernel_cores.fetch(state_id).each_index.map do |index|
      @item_lookaheads.fetch(state_id, index)
    end
  end
  @filters = {}
  @split_states = 0
end

Instance Attribute Details

#annotations ⇒ Object (readonly)

: Array[Array[Annotation]]



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# File 'lib/ibex/lalr/ielr/state_splitter.rb', line 19

def annotations
  @annotations
end

#inadequacies ⇒ Object (readonly)

: Array[Array[Inadequacy]]



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# File 'lib/ibex/lalr/ielr/state_splitter.rb', line 23

def inadequacies
  @inadequacies
end

#lalr_isocores ⇒ Object (readonly)

: Array



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# File 'lib/ibex/lalr/ielr/state_splitter.rb', line 21

def lalr_isocores
  @lalr_isocores
end

#split_stable_discarded ⇒ Object (readonly)

: Integer



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# File 'lib/ibex/lalr/ielr/state_splitter.rb', line 24

def split_stable_discarded
  @split_stable_discarded
end

#split_states ⇒ Object (readonly)

: Integer



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# File 'lib/ibex/lalr/ielr/state_splitter.rb', line 22

def split_states
  @split_states
end

#states ⇒ Object (readonly)

: Array



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# File 'lib/ibex/lalr/ielr/state_splitter.rb', line 20

def states
  @states
end

Instance Method Details

#build ⇒ Object 



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# File 'lib/ibex/lalr/ielr/state_splitter.rb', line 61

def build
  state_id = 0
  while state_id < @states.length
    @states.fetch(state_id).transitions.each_index do |index|
      target = @states.fetch(state_id).transitions.fetch(index).fetch(1)
      compute_state(state_id, target, index)
    end
    state_id += 1
  end
  [pack_items, packed_transitions]
end