1119 lines
22 KiB
Ruby
1119 lines
22 KiB
Ruby
#--
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#
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#
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#
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# Copyright (c) 1999-2006 Minero Aoki
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#
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# This program is free software.
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# You can distribute/modify this program under the same terms of ruby.
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# see the file "COPYING".
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#
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#++
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require 'racc/compat'
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require 'racc/iset'
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require 'racc/sourcetext'
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require 'racc/logfilegenerator'
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require 'racc/exception'
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require 'forwardable'
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module Racc
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class Grammar
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def initialize(debug_flags = DebugFlags.new)
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@symboltable = SymbolTable.new
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@debug_symbol = debug_flags.token
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@rules = [] # :: [Rule]
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@start = nil
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@n_expected_srconflicts = nil
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@prec_table = []
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@prec_table_closed = false
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@closed = false
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@states = nil
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end
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attr_reader :start
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attr_reader :symboltable
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attr_accessor :n_expected_srconflicts
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def [](x)
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@rules[x]
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end
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def each_rule(&block)
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@rules.each(&block)
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end
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alias each each_rule
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def each_index(&block)
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@rules.each_index(&block)
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end
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def each_with_index(&block)
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@rules.each_with_index(&block)
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end
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def size
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@rules.size
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end
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def to_s
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"<Racc::Grammar>"
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end
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extend Forwardable
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def_delegator "@symboltable", :each, :each_symbol
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def_delegator "@symboltable", :each_terminal
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def_delegator "@symboltable", :each_nonterminal
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def intern(value, dummy = false)
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@symboltable.intern(value, dummy)
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end
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def symbols
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@symboltable.symbols
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end
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def nonterminal_base
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@symboltable.nt_base
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end
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def useless_nonterminal_exist?
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n_useless_nonterminals() != 0
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end
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def n_useless_nonterminals
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@n_useless_nonterminals ||= each_useless_nonterminal.count
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end
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def each_useless_nonterminal
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return to_enum __method__ unless block_given?
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@symboltable.each_nonterminal do |sym|
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yield sym if sym.useless?
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end
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end
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def useless_rule_exist?
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n_useless_rules() != 0
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end
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def n_useless_rules
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@n_useless_rules ||= each_useless_rule.count
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end
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def each_useless_rule
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return to_enum __method__ unless block_given?
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each do |r|
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yield r if r.useless?
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end
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end
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def nfa
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(@states ||= States.new(self)).nfa
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end
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def dfa
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(@states ||= States.new(self)).dfa
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end
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alias states dfa
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def state_transition_table
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states().state_transition_table
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end
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def parser_class
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states = states() # cache
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if $DEBUG
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srcfilename = caller(1).first.slice(/\A(.*?):/, 1)
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begin
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write_log srcfilename + ".output"
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rescue SystemCallError
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end
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report = lambda {|s| $stderr.puts "racc: #{srcfilename}: #{s}" }
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if states.should_report_srconflict?
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report["#{states.n_srconflicts} shift/reduce conflicts"]
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end
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if states.rrconflict_exist?
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report["#{states.n_rrconflicts} reduce/reduce conflicts"]
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end
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g = states.grammar
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if g.useless_nonterminal_exist?
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report["#{g.n_useless_nonterminals} useless nonterminals"]
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end
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if g.useless_rule_exist?
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report["#{g.n_useless_rules} useless rules"]
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end
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end
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states.state_transition_table.parser_class
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end
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def write_log(path)
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File.open(path, 'w') {|f|
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LogFileGenerator.new(states()).output f
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}
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end
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#
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# Grammar Definition Interface
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#
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def add(rule)
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raise ArgumentError, "rule added after the Grammar closed" if @closed
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@rules.push rule
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end
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def added?(sym)
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@rules.detect {|r| r.target == sym }
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end
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def start_symbol=(s)
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raise CompileError, "start symbol set twice'" if @start
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@start = s
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end
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def declare_precedence(assoc, syms)
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raise CompileError, "precedence table defined twice" if @prec_table_closed
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@prec_table.push [assoc, syms]
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end
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def end_precedence_declaration(reverse)
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@prec_table_closed = true
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return if @prec_table.empty?
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table = reverse ? @prec_table.reverse : @prec_table
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table.each_with_index do |(assoc, syms), idx|
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syms.each do |sym|
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sym.assoc = assoc
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sym.precedence = idx
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end
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end
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end
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#
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# Dynamic Generation Interface
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#
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def Grammar.define(&block)
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env = DefinitionEnv.new
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env.instance_eval(&block)
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env.grammar
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end
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class DefinitionEnv
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def initialize
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@grammar = Grammar.new
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@seqs = Hash.new(0)
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@delayed = []
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end
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def grammar
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flush_delayed
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@grammar.each do |rule|
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if rule.specified_prec
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rule.specified_prec = @grammar.intern(rule.specified_prec)
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end
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end
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@grammar.init
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@grammar
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end
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def precedence_table(&block)
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env = PrecedenceDefinitionEnv.new(@grammar)
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env.instance_eval(&block)
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@grammar.end_precedence_declaration env.reverse
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end
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def method_missing(mid, *args, &block)
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unless mid.to_s[-1,1] == '='
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super # raises NoMethodError
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end
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target = @grammar.intern(mid.to_s.chop.intern)
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unless args.size == 1
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raise ArgumentError, "too many arguments for #{mid} (#{args.size} for 1)"
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end
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_add target, args.first
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end
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def _add(target, x)
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case x
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when Sym
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@delayed.each do |rule|
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rule.replace x, target if rule.target == x
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end
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@grammar.symboltable.delete x
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else
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x.each_rule do |r|
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r.target = target
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@grammar.add r
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end
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end
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flush_delayed
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end
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def _delayed_add(rule)
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@delayed.push rule
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end
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def _added?(sym)
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@grammar.added?(sym) or @delayed.detect {|r| r.target == sym }
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end
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def flush_delayed
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return if @delayed.empty?
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@delayed.each do |rule|
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@grammar.add rule
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end
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@delayed.clear
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end
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def seq(*list, &block)
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Rule.new(nil, list.map {|x| _intern(x) }, UserAction.proc(block))
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end
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def null(&block)
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seq(&block)
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end
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def action(&block)
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id = "@#{@seqs["action"] += 1}".intern
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_delayed_add Rule.new(@grammar.intern(id), [], UserAction.proc(block))
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id
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end
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alias _ action
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def option(sym, default = nil, &block)
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_defmetasyntax("option", _intern(sym), block) {|target|
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seq() { default } | seq(sym)
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}
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end
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def many(sym, &block)
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_defmetasyntax("many", _intern(sym), block) {|target|
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seq() { [] }\
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| seq(target, sym) {|list, x| list.push x; list }
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}
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end
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def many1(sym, &block)
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_defmetasyntax("many1", _intern(sym), block) {|target|
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seq(sym) {|x| [x] }\
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| seq(target, sym) {|list, x| list.push x; list }
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}
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end
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def separated_by(sep, sym, &block)
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option(separated_by1(sep, sym), [], &block)
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end
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def separated_by1(sep, sym, &block)
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_defmetasyntax("separated_by1", _intern(sym), block) {|target|
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seq(sym) {|x| [x] }\
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| seq(target, sep, sym) {|list, _, x| list.push x; list }
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}
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end
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def _intern(x)
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case x
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when Symbol, String
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@grammar.intern(x)
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when Racc::Sym
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x
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else
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raise TypeError, "wrong type #{x.class} (expected Symbol/String/Racc::Sym)"
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end
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end
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private
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def _defmetasyntax(type, id, action, &block)
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if action
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idbase = "#{type}@#{id}-#{@seqs[type] += 1}"
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target = _wrap(idbase, "#{idbase}-core", action)
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_register("#{idbase}-core", &block)
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else
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target = _register("#{type}@#{id}", &block)
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end
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@grammar.intern(target)
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end
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def _register(target_name)
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target = target_name.intern
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unless _added?(@grammar.intern(target))
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yield(target).each_rule do |rule|
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rule.target = @grammar.intern(target)
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_delayed_add rule
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end
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end
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target
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end
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def _wrap(target_name, sym, block)
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target = target_name.intern
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_delayed_add Rule.new(@grammar.intern(target),
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[@grammar.intern(sym.intern)],
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UserAction.proc(block))
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target
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end
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end
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class PrecedenceDefinitionEnv
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def initialize(g)
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@grammar = g
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@prechigh_seen = false
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@preclow_seen = false
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@reverse = false
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end
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attr_reader :reverse
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def higher
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if @prechigh_seen
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raise CompileError, "prechigh used twice"
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end
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@prechigh_seen = true
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end
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def lower
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if @preclow_seen
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raise CompileError, "preclow used twice"
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end
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if @prechigh_seen
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@reverse = true
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end
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@preclow_seen = true
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end
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def left(*syms)
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@grammar.declare_precedence :Left, syms.map {|s| @grammar.intern(s) }
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end
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def right(*syms)
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@grammar.declare_precedence :Right, syms.map {|s| @grammar.intern(s) }
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end
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def nonassoc(*syms)
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@grammar.declare_precedence :Nonassoc, syms.map {|s| @grammar.intern(s)}
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end
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end
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#
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# Computation
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#
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def init
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return if @closed
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@closed = true
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@start ||= @rules.map {|r| r.target }.detect {|sym| not sym.dummy? }
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raise CompileError, 'no rule in input' if @rules.empty?
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add_start_rule
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@rules.freeze
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fix_ident
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compute_hash
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compute_heads
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determine_terminals
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compute_nullable_0
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@symboltable.fix
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compute_locate
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@symboltable.each_nonterminal {|t| compute_expand t }
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compute_nullable
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compute_useless
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end
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private
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def add_start_rule
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r = Rule.new(@symboltable.dummy,
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[@start, @symboltable.anchor, @symboltable.anchor],
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UserAction.empty)
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r.ident = 0
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r.hash = 0
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r.precedence = nil
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@rules.unshift r
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end
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# Rule#ident
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# LocationPointer#ident
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def fix_ident
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@rules.each_with_index do |rule, idx|
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rule.ident = idx
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end
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end
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# Rule#hash
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def compute_hash
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hash = 4 # size of dummy rule
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@rules.each do |rule|
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rule.hash = hash
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hash += (rule.size + 1)
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end
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end
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# Sym#heads
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def compute_heads
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@rules.each do |rule|
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rule.target.heads.push rule.ptrs[0]
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end
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end
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# Sym#terminal?
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def determine_terminals
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@symboltable.each do |s|
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s.term = s.heads.empty?
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end
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end
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# Sym#self_null?
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def compute_nullable_0
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@symboltable.each do |s|
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if s.terminal?
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s.snull = false
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else
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s.snull = s.heads.any? {|loc| loc.reduce? }
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end
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end
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end
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# Sym#locate
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def compute_locate
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@rules.each do |rule|
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t = nil
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rule.ptrs.each do |ptr|
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unless ptr.reduce?
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tok = ptr.dereference
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tok.locate.push ptr
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t = tok if tok.terminal?
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end
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end
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rule.precedence = t
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end
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end
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# Sym#expand
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def compute_expand(t)
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puts "expand> #{t.to_s}" if @debug_symbol
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t.expand = _compute_expand(t, ISet.new, [])
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puts "expand< #{t.to_s}: #{t.expand.to_s}" if @debug_symbol
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end
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def _compute_expand(t, set, lock)
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if tmp = t.expand
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set.update tmp
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return set
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end
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tok = nil
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set.update_a t.heads
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t.heads.each do |ptr|
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tok = ptr.dereference
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if tok and tok.nonterminal?
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unless lock[tok.ident]
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lock[tok.ident] = true
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_compute_expand tok, set, lock
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end
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end
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end
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set
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end
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# Sym#nullable?, Rule#nullable?
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def compute_nullable
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@rules.each {|r| r.null = false }
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@symboltable.each {|t| t.null = false }
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r = @rules.dup
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s = @symboltable.nonterminals
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begin
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rs = r.size
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ss = s.size
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check_rules_nullable r
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check_symbols_nullable s
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end until rs == r.size and ss == s.size
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end
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def check_rules_nullable(rules)
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rules.delete_if do |rule|
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rule.null = true
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rule.symbols.each do |t|
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unless t.nullable?
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rule.null = false
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break
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end
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end
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rule.nullable?
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end
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end
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def check_symbols_nullable(symbols)
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symbols.delete_if do |sym|
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sym.heads.each do |ptr|
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if ptr.rule.nullable?
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sym.null = true
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break
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end
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end
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sym.nullable?
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end
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end
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# Sym#useless?, Rule#useless?
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# FIXME: what means "useless"?
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def compute_useless
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@symboltable.each_terminal {|sym| sym.useless = false }
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@symboltable.each_nonterminal {|sym| sym.useless = true }
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@rules.each {|rule| rule.useless = true }
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r = @rules.dup
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s = @symboltable.nonterminals
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begin
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rs = r.size
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ss = s.size
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check_rules_useless r
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check_symbols_useless s
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end until r.size == rs and s.size == ss
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end
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def check_rules_useless(rules)
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rules.delete_if do |rule|
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rule.useless = false
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rule.symbols.each do |sym|
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if sym.useless?
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rule.useless = true
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break
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end
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end
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not rule.useless?
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end
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end
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def check_symbols_useless(s)
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s.delete_if do |t|
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t.heads.each do |ptr|
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unless ptr.rule.useless?
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t.useless = false
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break
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end
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end
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not t.useless?
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end
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end
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|
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end # class Grammar
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|
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|
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class Rule
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|
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def initialize(target, syms, act)
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@target = target
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@symbols = syms
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@action = act
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@alternatives = []
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@ident = nil
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@hash = nil
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@ptrs = nil
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|
@precedence = nil
|
|
@specified_prec = nil
|
|
@null = nil
|
|
@useless = nil
|
|
end
|
|
|
|
attr_accessor :target
|
|
attr_reader :symbols
|
|
attr_reader :action
|
|
|
|
def |(x)
|
|
@alternatives.push x.rule
|
|
self
|
|
end
|
|
|
|
def rule
|
|
self
|
|
end
|
|
|
|
def each_rule(&block)
|
|
yield self
|
|
@alternatives.each(&block)
|
|
end
|
|
|
|
attr_accessor :ident
|
|
|
|
attr_reader :hash
|
|
attr_reader :ptrs
|
|
|
|
def hash=(n)
|
|
@hash = n
|
|
ptrs = []
|
|
@symbols.each_with_index do |sym, idx|
|
|
ptrs.push LocationPointer.new(self, idx, sym)
|
|
end
|
|
ptrs.push LocationPointer.new(self, @symbols.size, nil)
|
|
@ptrs = ptrs
|
|
end
|
|
|
|
def precedence
|
|
@specified_prec || @precedence
|
|
end
|
|
|
|
def precedence=(sym)
|
|
@precedence ||= sym
|
|
end
|
|
|
|
def prec(sym, &block)
|
|
@specified_prec = sym
|
|
if block
|
|
unless @action.empty?
|
|
raise CompileError, 'both of rule action block and prec block given'
|
|
end
|
|
@action = UserAction.proc(block)
|
|
end
|
|
self
|
|
end
|
|
|
|
attr_accessor :specified_prec
|
|
|
|
def nullable?() @null end
|
|
def null=(n) @null = n end
|
|
|
|
def useless?() @useless end
|
|
def useless=(u) @useless = u end
|
|
|
|
def inspect
|
|
"#<Racc::Rule id=#{@ident} (#{@target})>"
|
|
end
|
|
|
|
def ==(other)
|
|
other.kind_of?(Rule) and @ident == other.ident
|
|
end
|
|
|
|
def [](idx)
|
|
@symbols[idx]
|
|
end
|
|
|
|
def size
|
|
@symbols.size
|
|
end
|
|
|
|
def empty?
|
|
@symbols.empty?
|
|
end
|
|
|
|
def to_s
|
|
"#<rule#{@ident}>"
|
|
end
|
|
|
|
def accept?
|
|
if tok = @symbols[-1]
|
|
tok.anchor?
|
|
else
|
|
false
|
|
end
|
|
end
|
|
|
|
def each(&block)
|
|
@symbols.each(&block)
|
|
end
|
|
|
|
def replace(src, dest)
|
|
@target = dest
|
|
@symbols = @symbols.map {|s| s == src ? dest : s }
|
|
end
|
|
|
|
end # class Rule
|
|
|
|
|
|
class UserAction
|
|
|
|
def UserAction.source_text(src)
|
|
new(src, nil)
|
|
end
|
|
|
|
def UserAction.proc(pr = nil, &block)
|
|
if pr and block
|
|
raise ArgumentError, "both of argument and block given"
|
|
end
|
|
new(nil, pr || block)
|
|
end
|
|
|
|
def UserAction.empty
|
|
new(nil, nil)
|
|
end
|
|
|
|
private_class_method :new
|
|
|
|
def initialize(src, proc)
|
|
@source = src
|
|
@proc = proc
|
|
end
|
|
|
|
attr_reader :source
|
|
attr_reader :proc
|
|
|
|
def source?
|
|
not @proc
|
|
end
|
|
|
|
def proc?
|
|
not @source
|
|
end
|
|
|
|
def empty?
|
|
not @proc and not @source
|
|
end
|
|
|
|
def name
|
|
"{action type=#{@source || @proc || 'nil'}}"
|
|
end
|
|
|
|
alias inspect name
|
|
|
|
end
|
|
|
|
|
|
class OrMark
|
|
def initialize(lineno)
|
|
@lineno = lineno
|
|
end
|
|
|
|
def name
|
|
'|'
|
|
end
|
|
|
|
alias inspect name
|
|
|
|
attr_reader :lineno
|
|
end
|
|
|
|
|
|
class Prec
|
|
def initialize(symbol, lineno)
|
|
@symbol = symbol
|
|
@lineno = lineno
|
|
end
|
|
|
|
def name
|
|
"=#{@symbol}"
|
|
end
|
|
|
|
alias inspect name
|
|
|
|
attr_reader :symbol
|
|
attr_reader :lineno
|
|
end
|
|
|
|
|
|
#
|
|
# A set of rule and position in it's RHS.
|
|
# Note that the number of pointers is more than rule's RHS array,
|
|
# because pointer points right edge of the final symbol when reducing.
|
|
#
|
|
class LocationPointer
|
|
|
|
def initialize(rule, i, sym)
|
|
@rule = rule
|
|
@index = i
|
|
@symbol = sym
|
|
@ident = @rule.hash + i
|
|
@reduce = sym.nil?
|
|
end
|
|
|
|
attr_reader :rule
|
|
attr_reader :index
|
|
attr_reader :symbol
|
|
|
|
alias dereference symbol
|
|
|
|
attr_reader :ident
|
|
alias hash ident
|
|
attr_reader :reduce
|
|
alias reduce? reduce
|
|
|
|
def to_s
|
|
sprintf('(%d,%d %s)',
|
|
@rule.ident, @index, (reduce?() ? '#' : @symbol.to_s))
|
|
end
|
|
|
|
alias inspect to_s
|
|
|
|
def eql?(ot)
|
|
@hash == ot.hash
|
|
end
|
|
|
|
alias == eql?
|
|
|
|
def head?
|
|
@index == 0
|
|
end
|
|
|
|
def next
|
|
@rule.ptrs[@index + 1] or ptr_bug!
|
|
end
|
|
|
|
alias increment next
|
|
|
|
def before(len)
|
|
@rule.ptrs[@index - len] or ptr_bug!
|
|
end
|
|
|
|
private
|
|
|
|
def ptr_bug!
|
|
raise "racc: fatal: pointer not exist: self: #{to_s}"
|
|
end
|
|
|
|
end # class LocationPointer
|
|
|
|
|
|
class SymbolTable
|
|
|
|
include Enumerable
|
|
|
|
def initialize
|
|
@symbols = [] # :: [Racc::Sym]
|
|
@cache = {} # :: {(String|Symbol) => Racc::Sym}
|
|
@dummy = intern(:$start, true)
|
|
@anchor = intern(false, true) # Symbol ID = 0
|
|
@error = intern(:error, false) # Symbol ID = 1
|
|
end
|
|
|
|
attr_reader :dummy
|
|
attr_reader :anchor
|
|
attr_reader :error
|
|
|
|
def [](id)
|
|
@symbols[id]
|
|
end
|
|
|
|
def intern(val, dummy = false)
|
|
@cache[val] ||=
|
|
begin
|
|
sym = Sym.new(val, dummy)
|
|
@symbols.push sym
|
|
sym
|
|
end
|
|
end
|
|
|
|
attr_reader :symbols
|
|
alias to_a symbols
|
|
|
|
def delete(sym)
|
|
@symbols.delete sym
|
|
@cache.delete sym.value
|
|
end
|
|
|
|
attr_reader :nt_base
|
|
|
|
def nt_max
|
|
@symbols.size
|
|
end
|
|
|
|
def each(&block)
|
|
@symbols.each(&block)
|
|
end
|
|
|
|
def terminals(&block)
|
|
@symbols[0, @nt_base]
|
|
end
|
|
|
|
def each_terminal(&block)
|
|
@terms.each(&block)
|
|
end
|
|
|
|
def nonterminals
|
|
@symbols[@nt_base, @symbols.size - @nt_base]
|
|
end
|
|
|
|
def each_nonterminal(&block)
|
|
@nterms.each(&block)
|
|
end
|
|
|
|
def fix
|
|
terms, nterms = @symbols.partition {|s| s.terminal? }
|
|
@symbols = terms + nterms
|
|
@terms = terms
|
|
@nterms = nterms
|
|
@nt_base = terms.size
|
|
fix_ident
|
|
check_terminals
|
|
end
|
|
|
|
private
|
|
|
|
def fix_ident
|
|
@symbols.each_with_index do |t, i|
|
|
t.ident = i
|
|
end
|
|
end
|
|
|
|
def check_terminals
|
|
return unless @symbols.any? {|s| s.should_terminal? }
|
|
@anchor.should_terminal
|
|
@error.should_terminal
|
|
each_terminal do |t|
|
|
t.should_terminal if t.string_symbol?
|
|
end
|
|
each do |s|
|
|
s.should_terminal if s.assoc
|
|
end
|
|
terminals().reject {|t| t.should_terminal? }.each do |t|
|
|
raise CompileError, "terminal #{t} not declared as terminal"
|
|
end
|
|
nonterminals().select {|n| n.should_terminal? }.each do |n|
|
|
raise CompileError, "symbol #{n} declared as terminal but is not terminal"
|
|
end
|
|
end
|
|
|
|
end # class SymbolTable
|
|
|
|
|
|
# Stands terminal and nonterminal symbols.
|
|
class Sym
|
|
|
|
def initialize(value, dummyp)
|
|
@ident = nil
|
|
@value = value
|
|
@dummyp = dummyp
|
|
|
|
@term = nil
|
|
@nterm = nil
|
|
@should_terminal = false
|
|
@precedence = nil
|
|
case value
|
|
when Symbol
|
|
@to_s = value.to_s
|
|
@serialized = value.inspect
|
|
@string = false
|
|
when String
|
|
@to_s = value.inspect
|
|
@serialized = value.dump
|
|
@string = true
|
|
when false
|
|
@to_s = '$end'
|
|
@serialized = 'false'
|
|
@string = false
|
|
when ErrorSymbolValue
|
|
@to_s = 'error'
|
|
@serialized = 'Object.new'
|
|
@string = false
|
|
else
|
|
raise ArgumentError, "unknown symbol value: #{value.class}"
|
|
end
|
|
|
|
@heads = []
|
|
@locate = []
|
|
@snull = nil
|
|
@null = nil
|
|
@expand = nil
|
|
@useless = nil
|
|
end
|
|
|
|
class << self
|
|
def once_writer(nm)
|
|
nm = nm.id2name
|
|
module_eval(<<-EOS)
|
|
def #{nm}=(v)
|
|
raise 'racc: fatal: @#{nm} != nil' unless @#{nm}.nil?
|
|
@#{nm} = v
|
|
end
|
|
EOS
|
|
end
|
|
end
|
|
|
|
once_writer :ident
|
|
attr_reader :ident
|
|
|
|
alias hash ident
|
|
|
|
attr_reader :value
|
|
|
|
def dummy?
|
|
@dummyp
|
|
end
|
|
|
|
def terminal?
|
|
@term
|
|
end
|
|
|
|
def nonterminal?
|
|
@nterm
|
|
end
|
|
|
|
def term=(t)
|
|
raise 'racc: fatal: term= called twice' unless @term.nil?
|
|
@term = t
|
|
@nterm = !t
|
|
end
|
|
|
|
def should_terminal
|
|
@should_terminal = true
|
|
end
|
|
|
|
def should_terminal?
|
|
@should_terminal
|
|
end
|
|
|
|
def string_symbol?
|
|
@string
|
|
end
|
|
|
|
def serialize
|
|
@serialized
|
|
end
|
|
|
|
attr_writer :serialized
|
|
|
|
attr_accessor :precedence
|
|
attr_accessor :assoc
|
|
|
|
def to_s
|
|
@to_s.dup
|
|
end
|
|
|
|
alias inspect to_s
|
|
|
|
def |(x)
|
|
rule() | x.rule
|
|
end
|
|
|
|
def rule
|
|
Rule.new(nil, [self], UserAction.empty)
|
|
end
|
|
|
|
#
|
|
# cache
|
|
#
|
|
|
|
attr_reader :heads
|
|
attr_reader :locate
|
|
|
|
def self_null?
|
|
@snull
|
|
end
|
|
|
|
once_writer :snull
|
|
|
|
def nullable?
|
|
@null
|
|
end
|
|
|
|
def null=(n)
|
|
@null = n
|
|
end
|
|
|
|
attr_reader :expand
|
|
once_writer :expand
|
|
|
|
def useless?
|
|
@useless
|
|
end
|
|
|
|
def useless=(f)
|
|
@useless = f
|
|
end
|
|
|
|
end # class Sym
|
|
|
|
end # module Racc
|