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Contents
# frozen_string_literal: true
# Load the builder class
require_relative '../../../lib/rley/syntax/base_grammar_builder'
module GrammarSPPFHelper
# Factory method. Creates a grammar builder for a
# grammar described in paper from Elisabeth Scott
# "SPPF-Style Parsing From Earley Recognizers" in
# Notes in Theoretical Computer Science 203, (2008), pp. 53-67
# contains a hidden left recursion and a cycle
def grammar_sppf_builder
builder = Rley::Syntax::BaseGrammarBuilder.new do
add_terminals('a', 'b')
rule 'Phi' => 'S'
rule 'S' => %w[A T]
rule 'S' => %w[a T]
rule 'A' => 'a'
rule 'A' => %w[B A]
rule 'B' => []
rule 'T' => %w[b b b]
end
return builder
end
end # module
Version data entries
10 entries across 10 versions & 1 rubygems