From a91bf2f25025e9d1ff6bc0d31f5dd42049f280fb Mon Sep 17 00:00:00 2001
From: Josh Holtrop <jholtrop@gmail.com>
Date: Tue, 14 Jun 2022 22:57:07 -0400
Subject: [PATCH] Clean up parser ItemSet processing

---
 lib/propane/parser.rb | 25 +++++++++++--------------
 1 file changed, 11 insertions(+), 14 deletions(-)

diff --git a/lib/propane/parser.rb b/lib/propane/parser.rb
index 829c39b..9fd4762 100644
--- a/lib/propane/parser.rb
+++ b/lib/propane/parser.rb
@@ -8,22 +8,19 @@ class Propane
       @item_sets = []
       @item_sets_set = {}
       start_item = Item.new(start_rule, 0)
-      eval_item_sets = Set.new
-      eval_item_sets << ItemSet.new([start_item])
+      eval_item_sets = Set[ItemSet.new([start_item])]
 
       while eval_item_sets.size > 0
-        this_eval_item_sets = eval_item_sets
-        eval_item_sets = Set.new
-        this_eval_item_sets.each do |item_set|
-          unless @item_sets_set.include?(item_set)
-            item_set.id = @item_sets.size
-            @item_sets << item_set
-            @item_sets_set[item_set] = item_set
-            item_set.following_symbols.each do |following_symbol|
-              unless following_symbol == @eof_token
-                following_set = item_set.build_following_item_set(following_symbol)
-                eval_item_sets << following_set
-              end
+        item_set = eval_item_sets.first
+        eval_item_sets.delete(item_set)
+        unless @item_sets_set.include?(item_set)
+          item_set.id = @item_sets.size
+          @item_sets << item_set
+          @item_sets_set[item_set] = item_set
+          item_set.following_symbols.each do |following_symbol|
+            unless following_symbol == @eof_token
+              following_set = item_set.build_following_item_set(following_symbol)
+              eval_item_sets << following_set
             end
           end
         end