From fbd0af0914191f786bdcaeaddd0c01a173a2a347 Mon Sep 17 00:00:00 2001
From: Semyon Proshev <Semyon.Proshev@jetbrains.com>
Date: Thu, 15 Feb 2018 20:50:18 +0300
Subject: [PATCH] Support `and`, `or` and `not` on booleans in PyEvaluator
 (PY-19856)

---
 .../python/psi/impl/PyEvaluator.java          | 25 +++++++++++++++++++
 .../com/jetbrains/python/PyEvaluatorTest.java |  6 +++++
 2 files changed, 31 insertions(+)

diff --git a/python/src/com/jetbrains/python/psi/impl/PyEvaluator.java b/python/src/com/jetbrains/python/psi/impl/PyEvaluator.java
index babc553f24cb..cc71f722a8f5 100644
--- a/python/src/com/jetbrains/python/psi/impl/PyEvaluator.java
+++ b/python/src/com/jetbrains/python/psi/impl/PyEvaluator.java
@@ -98,6 +98,9 @@ public class PyEvaluator {
     else if (expression instanceof PyNumericLiteralExpression) {
       return evaluateNumeric((PyNumericLiteralExpression)expression);
     }
+    else if (expression instanceof PyPrefixExpression) {
+      return evaluatePrefix((PyPrefixExpression)expression);
+    }
     return null;
   }
 
@@ -152,6 +155,16 @@ public class PyEvaluator {
         return first.compareTo(second) != 0;
       }
     }
+    else if (lhs instanceof Boolean && rhs instanceof Boolean) {
+      final Boolean first = (Boolean)lhs;
+      final Boolean second = (Boolean)rhs;
+      if (op == PyTokenTypes.AND_KEYWORD) {
+        return first && second;
+      }
+      else if (op == PyTokenTypes.OR_KEYWORD) {
+        return first || second;
+      }
+    }
 
     return null;
   }
@@ -174,6 +187,18 @@ public class PyEvaluator {
     return null;
   }
 
+  @Nullable
+  private Object evaluatePrefix(@NotNull PyPrefixExpression expression) {
+    if (expression.getOperator() == PyTokenTypes.NOT_KEYWORD) {
+      final Boolean value = PyUtil.as(evaluate(expression.getOperand()), Boolean.class);
+      if (value != null) {
+        return !value;
+      }
+    }
+
+    return null;
+  }
+
   /**
    * Evaluates sequence (tuple, list, set, dict)
    *
diff --git a/python/testSrc/com/jetbrains/python/PyEvaluatorTest.java b/python/testSrc/com/jetbrains/python/PyEvaluatorTest.java
index 5240a3712987..e96607330252 100644
--- a/python/testSrc/com/jetbrains/python/PyEvaluatorTest.java
+++ b/python/testSrc/com/jetbrains/python/PyEvaluatorTest.java
@@ -249,6 +249,12 @@ public class PyEvaluatorTest extends PyTestCase {
     assertTrue(byExpression("2 != 1", Boolean.class));
   }
 
+  public void testBooleanOperators() {
+    assertTrue(byExpression("True and True", Boolean.class));
+    assertTrue(byExpression("True or False", Boolean.class));
+    assertTrue(byExpression("not False", Boolean.class));
+  }
+
   @NotNull
   private <T> T byExpression(@NotNull String expression, @NotNull Class<T> cls) {
     final Object value = new PyEvaluator().evaluate(parseExpression(expression));