From d2b1d5c345572dcd3564cb1d08ceb6759664613f Mon Sep 17 00:00:00 2001
From: S-H-GAMELINKS <gamelinks007@gmail.com>
Date: Mon, 3 Jun 2024 22:33:59 +0900
Subject: [PATCH] Add report_unused_terms private method

---
 lib/lrama/option_parser.rb       |  2 +-
 lib/lrama/states_reporter.rb     | 42 ++++++++++++++++++++++++++++++--
 spec/lrama/option_parser_spec.rb |  4 +--
 spec/lrama/states_spec.rb        | 17 ++++++++++++-
 4 files changed, 59 insertions(+), 6 deletions(-)

diff --git a/lib/lrama/option_parser.rb b/lib/lrama/option_parser.rb
index 24ee3792..90535fe5 100644
--- a/lib/lrama/option_parser.rb
+++ b/lib/lrama/option_parser.rb
@@ -91,7 +91,7 @@ def parse_by_option_parser(argv)
       end
     end
 
-    BISON_REPORTS = %w[states itemsets lookaheads solved counterexamples cex all none]
+    BISON_REPORTS = %w[terms states itemsets lookaheads solved counterexamples cex all none]
     OTHER_REPORTS = %w[verbose]
     NOT_SUPPORTED_REPORTS = %w[cex none]
     VALID_REPORTS = BISON_REPORTS + OTHER_REPORTS - NOT_SUPPORTED_REPORTS
diff --git a/lib/lrama/states_reporter.rb b/lib/lrama/states_reporter.rb
index a2dacba2..d05c48c9 100644
--- a/lib/lrama/states_reporter.rb
+++ b/lib/lrama/states_reporter.rb
@@ -16,15 +16,53 @@ def report(io, **options)
 
     private
 
-    def _report(io, grammar: false, states: false, itemsets: false, lookaheads: false, solved: false, counterexamples: false, verbose: false)
-      # TODO: Unused terms
+    def _report(io, grammar: false, terms: false, states: false, itemsets: false, lookaheads: false, solved: false, counterexamples: false, verbose: false)
       # TODO: Unused rules
 
+      report_unused_terms(io) if terms
       report_conflicts(io)
       report_grammar(io) if grammar
       report_states(io, itemsets, lookaheads, solved, counterexamples, verbose)
     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?
+        end
+      end
+
+      @states.states.each do |state|
+        used_symbols << state.shifts.map(&:next_sym).select(&:term?).flatten
+      end
+
+      used_symbols = used_symbols.flatten
+
+      results = terms.select do |term|
+        !used_symbols.include?(term)
+      end
+
+      results.each_with_index do |term, index|
+        io << sprintf("%5d %s\n", index, term.id.s_value)
+      end
+
+      if !results.empty?
+        io << "\n\n"
+      end
+    end
+
     def report_conflicts(io)
       has_conflict = false
 
diff --git a/spec/lrama/option_parser_spec.rb b/spec/lrama/option_parser_spec.rb
index ef629a72..7f2d40de 100644
--- a/spec/lrama/option_parser_spec.rb
+++ b/spec/lrama/option_parser_spec.rb
@@ -68,7 +68,7 @@
               -h, --help                       display this help and exit
 
           Valid Reports:
-              states itemsets lookaheads solved counterexamples all verbose
+              terms states itemsets lookaheads solved counterexamples all verbose
 
           Valid Traces:
               none locations scan parse automaton bitsets closure grammar rules actions resource sets muscles tools m4-early m4 skeleton time ielr cex all
@@ -91,7 +91,7 @@
         it "returns option hash all flags enabled" do
           opts = option_parser.send(:validate_report, ["all"])
           expect(opts).to eq({
-            grammar: true, states: true, itemsets: true,
+            grammar: true, terms: true, states: true, itemsets: true,
             lookaheads: true, solved: true, counterexamples: true,
           })
         end
diff --git a/spec/lrama/states_spec.rb b/spec/lrama/states_spec.rb
index 9dc2db71..6b924e69 100644
--- a/spec/lrama/states_spec.rb
+++ b/spec/lrama/states_spec.rb
@@ -15,9 +15,24 @@
       states.compute
 
       io = StringIO.new
-      states.reporter.report(io, grammar: true, states: true, itemsets: true, lookaheads: true)
+      states.reporter.report(io, grammar: true, terms: true, states: true, itemsets: true, lookaheads: true)
 
       expect(io.string).to eq(<<~STR)
+        Unused Terms
+
+            0 YYerror
+            1 YYUNDEF
+            2 '\\\\'
+            3 '\\13'
+            4 keyword_class2
+            5 tNUMBER
+            6 tPLUS
+            7 tMINUS
+            8 tEQ
+            9 tEQEQ
+           10 '>'
+
+
         State 1 conflicts: 2 shift/reduce, 1 reduce/reduce