From f1828933e868bb169f76aa318de7b71f6ddff19d Mon Sep 17 00:00:00 2001
From: Jonathan Berant <joberant@stanford.edu>
Date: Wed, 27 May 2015 16:53:18 -0700
Subject: [PATCH] fix to null pointer bug for type.object.type equivalent
 formula

---
 src/edu/stanford/nlp/sempre/paraphrase/QuestionGenerator.java | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/edu/stanford/nlp/sempre/paraphrase/QuestionGenerator.java b/src/edu/stanford/nlp/sempre/paraphrase/QuestionGenerator.java
index 2d5edf6..9414ec6 100644
--- a/src/edu/stanford/nlp/sempre/paraphrase/QuestionGenerator.java
+++ b/src/edu/stanford/nlp/sempre/paraphrase/QuestionGenerator.java
@@ -107,7 +107,9 @@ public class QuestionGenerator {
     //generate from formula info
     Set<String> res = generateQuestions(fgInfo);
     //generate from equivalent formula if it exists
-    if(fbFormulasInfo.hasOpposite(fgInfo.bInfo.formula)) {
+		//added the check for equivalent formula based on github question (unclear why hasn't happened earlier)
+    if(fbFormulasInfo.hasOpposite(fgInfo.bInfo.formula) && 
+			fbFormulasInfo.getBinaryInfo(fbFormulasInfo.equivalentFormula(fgInfo.bInfo.formula)) != null) {
       FormulaGenerationInfo eqInfo = 
           new FormulaGenerationInfo(fbFormulasInfo.getBinaryInfo(fbFormulasInfo.equivalentFormula(fgInfo.bInfo.formula)),
               fgInfo.injectedInfo, fgInfo.entityInfo1, fgInfo.entityInfo2, fgInfo.uInfo, fgInfo.isCount, fgInfo.isInject, fgInfo.isUnary);