Merge pull request #440 from ydah/improve-report-unused-terms

Improve `--report=terms` command

lib/lrama/states_reporter.rb

@@ -26,39 +26,25 @@ def _report(io, grammar: false, terms: false, states: false, itemsets: false, lo
  end
 
  def report_unused_terms(io)
- io << "Unused Terms\n\n"
-
- results = []
- terms = []
- used_symbols = []
-
- terms = @states.symbols.select(&:term?)
-
- @states.states.select do |state|
- state.shifts.map(&:next_sym)
- end
-
- @states.states.each do |state|
- state.reduces.select do |reduce|
- used_symbols << reduce.look_ahead.flatten if !reduce.look_ahead.nil?
+ look_aheads = @states.states.each do |state|
+ state.reduces.flat_map do |reduce|
+ reduce.look_ahead unless reduce.look_ahead.nil?
  end
  end
 
- @states.states.each do |state|
- used_symbols << state.shifts.map(&:next_sym).select(&:term?).flatten
+ next_terms = @states.states.flat_map do |state|
+ state.shifts.map(&:next_sym).select(&:term?)
  end
 
- used_symbols = used_symbols.flatten
-
- results = terms.select do |term|
- !used_symbols.include?(term)
+ unused_symbols = @states.terms.select do |term|
+ !(look_aheads + next_terms).include?(term)
  end
 
- results.each_with_index do |term, index|
- io << sprintf("%5d %s\n", index, term.id.s_value)
- end
-
- if !results.empty?
+ unless unused_symbols.empty?
+ io << "#{unused_symbols.count} Unused Terms\n\n"
+  unused_symbols.each_with_index do |term, index|
+ io << sprintf("%5d %s\n", index, term.id.s_value)
+  end
  io << "\n\n"
  end
  end

spec/lrama/states_spec.rb

@@ -18,7 +18,7 @@
  states.reporter.report(io, grammar: true, terms: true, states: true, itemsets: true, lookaheads: true)
 
  expect(io.string).to eq(<<~STR)
- Unused Terms
+ 11 Unused Terms
 
  0 YYerror
  1 YYUNDEF