class Racc::Grammar

# File lib/racc/grammar.rb, line 203
def Grammar.define(&block)
  env = DefinitionEnv.new
  env.instance_eval(&block)
  env.grammar
end

# File lib/racc/grammar.rb, line 24
def initialize(debug_flags = DebugFlags.new)
  @symboltable = SymbolTable.new
  @debug_symbol = debug_flags.token
  @rules   = []  # :: [Rule]
  @start   = nil
  @n_expected_srconflicts = nil
  @error_on_expect_mismatch = nil
  @prec_table = []
  @prec_table_closed = false
  @closed = false
  @states = nil
end

# File lib/racc/grammar.rb, line 42
def [](x)
  @rules[x]
end

# File lib/racc/grammar.rb, line 168
def add(rule)
  raise ArgumentError, "rule added after the Grammar closed" if @closed
  @rules.push rule
end

# File lib/racc/grammar.rb, line 173
def added?(sym)
  @rules.detect {|r| r.target == sym }
end

# File lib/racc/grammar.rb, line 182
def declare_precedence(assoc, syms)
  raise CompileError, "precedence table defined twice" if @prec_table_closed
  @prec_table.push [assoc, syms]
end

# File lib/racc/grammar.rb, line 122
def dfa
  (@states ||= States.new(self)).dfa
end

# File lib/racc/grammar.rb, line 52
def each_index(&block)
  @rules.each_index(&block)
end

# File lib/racc/grammar.rb, line 46
def each_rule(&block)
  @rules.each(&block)
end

# File lib/racc/grammar.rb, line 94
def each_useless_nonterminal
  return to_enum __method__ unless block_given?

  @symboltable.each_nonterminal do |sym|
    yield sym if sym.useless?
  end
end

# File lib/racc/grammar.rb, line 110
def each_useless_rule
  return to_enum __method__ unless block_given?

  each do |r|
    yield r if r.useless?
  end
end

# File lib/racc/grammar.rb, line 56
def each_with_index(&block)
  @rules.each_with_index(&block)
end

# File lib/racc/grammar.rb, line 187
def end_precedence_declaration(reverse)
  @prec_table_closed = true
  return if @prec_table.empty?
  table = reverse ? @prec_table.reverse : @prec_table
  table.each_with_index do |(assoc, syms), idx|
    syms.each do |sym|
      sym.assoc = assoc
      sym.precedence = idx
    end
  end
end

# File lib/racc/grammar.rb, line 411
def init
  return if @closed
  @closed = true
  @start ||= @rules.map {|r| r.target }.detect {|sym| not sym.dummy? }
  raise CompileError, 'no rule in input' if @rules.empty?
  add_start_rule
  @rules.freeze
  fix_ident
  compute_hash
  compute_heads
  determine_terminals
  compute_nullable_0
  @symboltable.fix
  compute_locate
  @symboltable.each_nonterminal {|t| compute_expand t }
  compute_nullable
  compute_useless
end

# File lib/racc/grammar.rb, line 74
def intern(value, dummy = false)
  @symboltable.intern(value, dummy)
end

# File lib/racc/grammar.rb, line 90
def n_useless_nonterminals
  @n_useless_nonterminals ||= each_useless_nonterminal.count
end

# File lib/racc/grammar.rb, line 106
def n_useless_rules
  @n_useless_rules ||= each_useless_rule.count
end

# File lib/racc/grammar.rb, line 118
def nfa
  (@states ||= States.new(self)).nfa
end

# File lib/racc/grammar.rb, line 82
def nonterminal_base
  @symboltable.nt_base
end

# File lib/racc/grammar.rb, line 132
def parser_class
  states = states()   # cache
  if $DEBUG
    srcfilename = caller(1).first.slice(/\A(.*?):/, 1)
    begin
      write_log srcfilename + ".output"
    rescue SystemCallError
    end
    report = lambda {|s| $stderr.puts "racc: #{srcfilename}: #{s}" }
    if states.should_report_srconflict?
      report["#{states.n_srconflicts} shift/reduce conflicts"]
    end
    if states.rrconflict_exist?
      report["#{states.n_rrconflicts} reduce/reduce conflicts"]
    end
    g = states.grammar
    if g.useless_nonterminal_exist?
      report["#{g.n_useless_nonterminals} useless nonterminals"]
    end
    if g.useless_rule_exist?
      report["#{g.n_useless_rules} useless rules"]
    end
  end
  states.state_transition_table.parser_class
end

# File lib/racc/grammar.rb, line 60
def size
  @rules.size
end

# File lib/racc/grammar.rb, line 177
def start_symbol=(s)
  raise CompileError, "start symbol set twice'" if @start
  @start = s
end

# File lib/racc/grammar.rb, line 128
def state_transition_table
  states().state_transition_table
end

# File lib/racc/grammar.rb, line 78
def symbols
  @symboltable.symbols
end

# File lib/racc/grammar.rb, line 64
def to_s
  "<Racc::Grammar>"
end

# File lib/racc/grammar.rb, line 86
def useless_nonterminal_exist?
  n_useless_nonterminals() != 0
end

# File lib/racc/grammar.rb, line 102
def useless_rule_exist?
  n_useless_rules() != 0
end

# File lib/racc/grammar.rb, line 158
def write_log(path)
  File.open(path, 'w') {|f|
    LogFileGenerator.new(states()).output f
  }
end