Class: Ibex::Verify::ReferenceCollection

Inherits:
Object
  • Object
show all
Defined in:
lib/ibex/verify/reference_collection.rb

Overview

Independently derives canonical LR(1) and LR(0) item collections.

Defined Under Namespace

Classes: Collection

Instance Method Summary collapse

Constructor Details

#initialize(grammar, max_states: 100_000, max_items: 1_000_000) ⇒ ReferenceCollection

Returns a new instance of ReferenceCollection.

Raises:

  • (ArgumentError) 


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# File 'lib/ibex/verify/reference_collection.rb', line 24

def initialize(grammar, max_states: 100_000, max_items: 1_000_000)
  raise ArgumentError, "max_states must be positive" unless max_states.positive?
  raise ArgumentError, "max_items must be positive" unless max_items.positive?

  @grammar = grammar
  @max_states = max_states
  @max_items = max_items
  @sets = Analysis::Sets.new(grammar)
  @productions = grammar.productions.group_by(&:lhs)
  @item_count = 0
end

Instance Method Details

#build(kind) ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/ibex/verify/reference_collection.rb', line 37

def build(kind)
  raise ArgumentError, "kind must be :lr0 or :lr1" unless %i[lr0 lr1].include?(kind)

  @item_count = 0
  seeds = @grammar.starts.map.with_index do |name, index|
    raise Ibex::Error, "(verify):1:1: missing start symbol #{name}" unless @grammar.symbol(name)

    item = kind == :lr1 ? [-index - 1, 0, eof_id] : [-index - 1, 0]
    
    closure(Set[item], kind)
  end
  collection(seeds, kind)
end