From 474ed85811d93e6086823a2fd8ced2012798729a Mon Sep 17 00:00:00 2001
From: Paul Beckingham <paul@beckingham.net>
Date: Sun, 27 Dec 2015 10:34:59 -0500
Subject: [PATCH] LR0: ::expandNonTerminals now writes expansion state in debug
 mode

---
 src/LR0.cpp | 30 +++++++++++++++++++++++++++++-
 1 file changed, 29 insertions(+), 1 deletion(-)

diff --git a/src/LR0.cpp b/src/LR0.cpp
index 33c90117..53d8dc0c 100644
--- a/src/LR0.cpp
+++ b/src/LR0.cpp
@@ -51,6 +51,8 @@ void LR0::createParseTables (const Grammar& grammar)
         std::cout << " " << term;
       std::cout << "\n";
     }
+
+    std::cout << "\n";
   }
 
   // Add all items from augmented grammar, in initial state:
@@ -59,7 +61,7 @@ void LR0::createParseTables (const Grammar& grammar)
   for (unsigned int i = 0; i < augmented.size (); ++i)
     items.push_back (std::pair <int, int> (i, 0));
 
-  // TODO Add new states.
+  // Iteratively expand non-terminals until there are no more.
   while (expandNonTerminals (augmented, items))
     ;
 }
@@ -69,6 +71,32 @@ bool LR0::expandNonTerminals (
   std::vector <std::vector <std::string>>& augmented,
   std::vector <std::pair <int, int>>& items)
 {
+  if (_debug)
+  {
+    std::cout << "Expand:\n";
+    int count = 0;
+    for (auto& item : items)
+    {
+      std::cout << "  [" << count++ << "] "
+                << augmented[item.first][0]
+                << " "
+                << augmented[item.first][1];
+
+      for (int i = 2; i < (int)augmented[item.first].size (); ++i)
+      {
+        if (i - 2 == item.second)
+          std::cout << " .";
+
+        std::cout << " " << augmented[item.first][i];
+      }
+
+      std::cout << "\n";
+    }
+
+    std::cout << "\n";
+  }
+
+
 
   return false;
 }